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gnu / binutils-gdb / e6009837c579d273715da2a10e47ca2ff1073d8f / . / gdb / gdbserver / linux-low.c
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/* Low level interface to ptrace, for the remote server for GDB.
Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
2006, 2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "server.h"
#include "linux-low.h"
#include "ansidecl.h" /* For ATTRIBUTE_PACKED, must be bug in external.h. */
#include "elf/common.h"
#include "elf/external.h"
#include <sys/wait.h>
#include <stdio.h>
#include <sys/param.h>
#include <sys/ptrace.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sched.h>
#include <ctype.h>
#include <pwd.h>
#include <sys/types.h>
#include <dirent.h>
#ifndef PTRACE_GETSIGINFO
# define PTRACE_GETSIGINFO 0x4202
# define PTRACE_SETSIGINFO 0x4203
#endif
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
/* If the system headers did not provide the constants, hard-code the normal
values. */
#ifndef PTRACE_EVENT_FORK
#define PTRACE_SETOPTIONS 0x4200
#define PTRACE_GETEVENTMSG 0x4201
/* options set using PTRACE_SETOPTIONS */
#define PTRACE_O_TRACESYSGOOD 0x00000001
#define PTRACE_O_TRACEFORK 0x00000002
#define PTRACE_O_TRACEVFORK 0x00000004
#define PTRACE_O_TRACECLONE 0x00000008
#define PTRACE_O_TRACEEXEC 0x00000010
#define PTRACE_O_TRACEVFORKDONE 0x00000020
#define PTRACE_O_TRACEEXIT 0x00000040
/* Wait extended result codes for the above trace options. */
#define PTRACE_EVENT_FORK 1
#define PTRACE_EVENT_VFORK 2
#define PTRACE_EVENT_CLONE 3
#define PTRACE_EVENT_EXEC 4
#define PTRACE_EVENT_VFORK_DONE 5
#define PTRACE_EVENT_EXIT 6
#endif /* PTRACE_EVENT_FORK */
/* We can't always assume that this flag is available, but all systems
with the ptrace event handlers also have __WALL, so it's safe to use
in some contexts. */
#ifndef __WALL
#define __WALL 0x40000000 /* Wait for any child. */
#endif
#ifdef __UCLIBC__
#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
#define HAS_NOMMU
#endif
#endif
/* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol
representation of the thread ID.
``all_lwps'' is keyed by the process ID - which on Linux is (presently)
the same as the LWP ID.
``all_processes'' is keyed by the "overall process ID", which
GNU/Linux calls tgid, "thread group ID". */
struct inferior_list all_lwps;
/* A list of all unknown processes which receive stop signals. Some other
process will presumably claim each of these as forked children
momentarily. */
struct inferior_list stopped_pids;
/* FIXME this is a bit of a hack, and could be removed. */
int stopping_threads;
/* FIXME make into a target method? */
int using_threads = 1;
/* This flag is true iff we've just created or attached to our first
inferior but it has not stopped yet. As soon as it does, we need
to call the low target's arch_setup callback. Doing this only on
the first inferior avoids reinializing the architecture on every
inferior, and avoids messing with the register caches of the
already running inferiors. NOTE: this assumes all inferiors under
control of gdbserver have the same architecture. */
static int new_inferior;
static void linux_resume_one_lwp (struct lwp_info *lwp,
int step, int signal, siginfo_t *info);
static void linux_resume (struct thread_resume *resume_info, size_t n);
static void stop_all_lwps (void);
static int linux_wait_for_event (ptid_t ptid, int *wstat, int options);
static int check_removed_breakpoint (struct lwp_info *event_child);
static void *add_lwp (ptid_t ptid);
static int my_waitpid (int pid, int *status, int flags);
static int linux_stopped_by_watchpoint (void);
static void mark_lwp_dead (struct lwp_info *lwp, int wstat);
struct pending_signals
{
int signal;
siginfo_t info;
struct pending_signals *prev;
};
#define PTRACE_ARG3_TYPE long
#define PTRACE_XFER_TYPE long
#ifdef HAVE_LINUX_REGSETS
static char *disabled_regsets;
static int num_regsets;
#endif
/* The read/write ends of the pipe registered as waitable file in the
event loop. */
static int linux_event_pipe[2] = { -1, -1 };
/* True if we're currently in async mode. */
#define target_is_async_p() (linux_event_pipe[0] != -1)
static void send_sigstop (struct inferior_list_entry *entry);
static void wait_for_sigstop (struct inferior_list_entry *entry);
/* Accepts an integer PID; Returns a string representing a file that
can be opened to get info for the child process.
Space for the result is malloc'd, caller must free. */
char *
linux_child_pid_to_exec_file (int pid)
{
char *name1, *name2;
name1 = xmalloc (MAXPATHLEN);
name2 = xmalloc (MAXPATHLEN);
memset (name2, 0, MAXPATHLEN);
sprintf (name1, "/proc/%d/exe", pid);
if (readlink (name1, name2, MAXPATHLEN) > 0)
{
free (name1);
return name2;
}
else
{
free (name2);
return name1;
}
}
/* Return non-zero if HEADER is a 64-bit ELF file. */
static int
elf_64_header_p (const Elf64_External_Ehdr *header)
{
return (header->e_ident[EI_MAG0] == ELFMAG0
&& header->e_ident[EI_MAG1] == ELFMAG1
&& header->e_ident[EI_MAG2] == ELFMAG2
&& header->e_ident[EI_MAG3] == ELFMAG3
&& header->e_ident[EI_CLASS] == ELFCLASS64);
}
/* Return non-zero if FILE is a 64-bit ELF file,
zero if the file is not a 64-bit ELF file,
and -1 if the file is not accessible or doesn't exist. */
int
elf_64_file_p (const char *file)
{
Elf64_External_Ehdr header;
int fd;
fd = open (file, O_RDONLY);
if (fd < 0)
return -1;
if (read (fd, &header, sizeof (header)) != sizeof (header))
{
close (fd);
return 0;
}
close (fd);
return elf_64_header_p (&header);
}
static void
delete_lwp (struct lwp_info *lwp)
{
remove_thread (get_lwp_thread (lwp));
remove_inferior (&all_lwps, &lwp->head);
free (lwp->arch_private);
free (lwp);
}
/* Add a process to the common process list, and set its private
data. */
static struct process_info *
linux_add_process (int pid, int attached)
{
struct process_info *proc;
/* Is this the first process? If so, then set the arch. */
if (all_processes.head == NULL)
new_inferior = 1;
proc = add_process (pid, attached);
proc->private = xcalloc (1, sizeof (*proc->private));
if (the_low_target.new_process != NULL)
proc->private->arch_private = the_low_target.new_process ();
return proc;
}
/* Remove a process from the common process list,
also freeing all private data. */
static void
linux_remove_process (struct process_info *process)
{
free (process->private->arch_private);
free (process->private);
remove_process (process);
}
/* Handle a GNU/Linux extended wait response. If we see a clone
event, we need to add the new LWP to our list (and not report the
trap to higher layers). */
static void
handle_extended_wait (struct lwp_info *event_child, int wstat)
{
int event = wstat >> 16;
struct lwp_info *new_lwp;
if (event == PTRACE_EVENT_CLONE)
{
ptid_t ptid;
unsigned long new_pid;
int ret, status = W_STOPCODE (SIGSTOP);
ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_child), 0, &new_pid);
/* If we haven't already seen the new PID stop, wait for it now. */
if (! pull_pid_from_list (&stopped_pids, new_pid))
{
/* The new child has a pending SIGSTOP. We can't affect it until it
hits the SIGSTOP, but we're already attached. */
ret = my_waitpid (new_pid, &status, __WALL);
if (ret == -1)
perror_with_name ("waiting for new child");
else if (ret != new_pid)
warning ("wait returned unexpected PID %d", ret);
else if (!WIFSTOPPED (status))
warning ("wait returned unexpected status 0x%x", status);
}
ptrace (PTRACE_SETOPTIONS, new_pid, 0, PTRACE_O_TRACECLONE);
ptid = ptid_build (pid_of (event_child), new_pid, 0);
new_lwp = (struct lwp_info *) add_lwp (ptid);
add_thread (ptid, new_lwp);
/* Either we're going to immediately resume the new thread
or leave it stopped. linux_resume_one_lwp is a nop if it
thinks the thread is currently running, so set this first
before calling linux_resume_one_lwp. */
new_lwp->stopped = 1;
/* Normally we will get the pending SIGSTOP. But in some cases
we might get another signal delivered to the group first.
If we do get another signal, be sure not to lose it. */
if (WSTOPSIG (status) == SIGSTOP)
{
if (! stopping_threads)
linux_resume_one_lwp (new_lwp, 0, 0, NULL);
}
else
{
new_lwp->stop_expected = 1;
if (stopping_threads)
{
new_lwp->status_pending_p = 1;
new_lwp->status_pending = status;
}
else
/* Pass the signal on. This is what GDB does - except
shouldn't we really report it instead? */
linux_resume_one_lwp (new_lwp, 0, WSTOPSIG (status), NULL);
}
/* Always resume the current thread. If we are stopping
threads, it will have a pending SIGSTOP; we may as well
collect it now. */
linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL);
}
}
/* This function should only be called if the process got a SIGTRAP.
The SIGTRAP could mean several things.
On i386, where decr_pc_after_break is non-zero:
If we were single-stepping this process using PTRACE_SINGLESTEP,
we will get only the one SIGTRAP (even if the instruction we
stepped over was a breakpoint). The value of $eip will be the
next instruction.
If we continue the process using PTRACE_CONT, we will get a
SIGTRAP when we hit a breakpoint. The value of $eip will be
the instruction after the breakpoint (i.e. needs to be
decremented). If we report the SIGTRAP to GDB, we must also
report the undecremented PC. If we cancel the SIGTRAP, we
must resume at the decremented PC.
(Presumably, not yet tested) On a non-decr_pc_after_break machine
with hardware or kernel single-step:
If we single-step over a breakpoint instruction, our PC will
point at the following instruction. If we continue and hit a
breakpoint instruction, our PC will point at the breakpoint
instruction. */
static CORE_ADDR
get_stop_pc (void)
{
CORE_ADDR stop_pc = (*the_low_target.get_pc) ();
if (! get_thread_lwp (current_inferior)->stepping)
stop_pc -= the_low_target.decr_pc_after_break;
if (debug_threads)
fprintf (stderr, "stop pc is 0x%lx\n", (long) stop_pc);
return stop_pc;
}
static void *
add_lwp (ptid_t ptid)
{
struct lwp_info *lwp;
lwp = (struct lwp_info *) xmalloc (sizeof (*lwp));
memset (lwp, 0, sizeof (*lwp));
lwp->head.id = ptid;
if (the_low_target.new_thread != NULL)
lwp->arch_private = the_low_target.new_thread ();
add_inferior_to_list (&all_lwps, &lwp->head);
return lwp;
}
/* Start an inferior process and returns its pid.
ALLARGS is a vector of program-name and args. */
static int
linux_create_inferior (char *program, char **allargs)
{
struct lwp_info *new_lwp;
int pid;
ptid_t ptid;
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
pid = vfork ();
#else
pid = fork ();
#endif
if (pid < 0)
perror_with_name ("fork");
if (pid == 0)
{
ptrace (PTRACE_TRACEME, 0, 0, 0);
signal (__SIGRTMIN + 1, SIG_DFL);
setpgid (0, 0);
execv (program, allargs);
if (errno == ENOENT)
execvp (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program,
strerror (errno));
fflush (stderr);
_exit (0177);
}
linux_add_process (pid, 0);
ptid = ptid_build (pid, pid, 0);
new_lwp = add_lwp (ptid);
add_thread (ptid, new_lwp);
new_lwp->must_set_ptrace_flags = 1;
return pid;
}
/* Attach to an inferior process. */
static void
linux_attach_lwp_1 (unsigned long lwpid, int initial)
{
ptid_t ptid;
struct lwp_info *new_lwp;
if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) != 0)
{
if (!initial)
{
/* If we fail to attach to an LWP, just warn. */
fprintf (stderr, "Cannot attach to lwp %ld: %s (%d)\n", lwpid,
strerror (errno), errno);
fflush (stderr);
return;
}
else
/* If we fail to attach to a process, report an error. */
error ("Cannot attach to lwp %ld: %s (%d)\n", lwpid,
strerror (errno), errno);
}
if (initial)
/* NOTE/FIXME: This lwp might have not been the tgid. */
ptid = ptid_build (lwpid, lwpid, 0);
else
{
/* Note that extracting the pid from the current inferior is
safe, since we're always called in the context of the same
process as this new thread. */
int pid = pid_of (get_thread_lwp (current_inferior));
ptid = ptid_build (pid, lwpid, 0);
}
new_lwp = (struct lwp_info *) add_lwp (ptid);
add_thread (ptid, new_lwp);
/* We need to wait for SIGSTOP before being able to make the next
ptrace call on this LWP. */
new_lwp->must_set_ptrace_flags = 1;
/* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
brings it to a halt.
There are several cases to consider here:
1) gdbserver has already attached to the process and is being notified
of a new thread that is being created.
In this case we should ignore that SIGSTOP and resume the process.
This is handled below by setting stop_expected = 1.
2) This is the first thread (the process thread), and we're attaching
to it via attach_inferior.
In this case we want the process thread to stop.
This is handled by having linux_attach clear stop_expected after
we return.
??? If the process already has several threads we leave the other
threads running.
3) GDB is connecting to gdbserver and is requesting an enumeration of all
existing threads.
In this case we want the thread to stop.
FIXME: This case is currently not properly handled.
We should wait for the SIGSTOP but don't. Things work apparently
because enough time passes between when we ptrace (ATTACH) and when
gdb makes the next ptrace call on the thread.
On the other hand, if we are currently trying to stop all threads, we
should treat the new thread as if we had sent it a SIGSTOP. This works
because we are guaranteed that the add_lwp call above added us to the
end of the list, and so the new thread has not yet reached
wait_for_sigstop (but will). */
if (! stopping_threads)
new_lwp->stop_expected = 1;
}
void
linux_attach_lwp (unsigned long lwpid)
{
linux_attach_lwp_1 (lwpid, 0);
}
int
linux_attach (unsigned long pid)
{
struct lwp_info *lwp;
linux_attach_lwp_1 (pid, 1);
linux_add_process (pid, 1);
if (!non_stop)
{
/* Don't ignore the initial SIGSTOP if we just attached to this
process. It will be collected by wait shortly. */
lwp = (struct lwp_info *) find_inferior_id (&all_lwps,
ptid_build (pid, pid, 0));
lwp->stop_expected = 0;
}
return 0;
}
struct counter
{
int pid;
int count;
};
static int
second_thread_of_pid_p (struct inferior_list_entry *entry, void *args)
{
struct counter *counter = args;
if (ptid_get_pid (entry->id) == counter->pid)
{
if (++counter->count > 1)
return 1;
}
return 0;
}
static int
last_thread_of_process_p (struct thread_info *thread)
{
ptid_t ptid = ((struct inferior_list_entry *)thread)->id;
int pid = ptid_get_pid (ptid);
struct counter counter = { pid , 0 };
return (find_inferior (&all_threads,
second_thread_of_pid_p, &counter) == NULL);
}
/* Kill the inferior lwp. */
static int
linux_kill_one_lwp (struct inferior_list_entry *entry, void *args)
{
struct thread_info *thread = (struct thread_info *) entry;
struct lwp_info *lwp = get_thread_lwp (thread);
int wstat;
int pid = * (int *) args;
if (ptid_get_pid (entry->id) != pid)
return 0;
/* We avoid killing the first thread here, because of a Linux kernel (at
least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
the children get a chance to be reaped, it will remain a zombie
forever. */
if (last_thread_of_process_p (thread))
{
if (debug_threads)
fprintf (stderr, "lkop: is last of process %s\n",
target_pid_to_str (entry->id));
return 0;
}
/* If we're killing a running inferior, make sure it is stopped
first, as PTRACE_KILL will not work otherwise. */
if (!lwp->stopped)
send_sigstop (&lwp->head);
do
{
ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0);
/* Make sure it died. The loop is most likely unnecessary. */
pid = linux_wait_for_event (lwp->head.id, &wstat, __WALL);
} while (pid > 0 && WIFSTOPPED (wstat));
return 0;
}
static int
linux_kill (int pid)
{
struct process_info *process;
struct lwp_info *lwp;
struct thread_info *thread;
int wstat;
int lwpid;
process = find_process_pid (pid);
if (process == NULL)
return -1;
find_inferior (&all_threads, linux_kill_one_lwp, &pid);
/* See the comment in linux_kill_one_lwp. We did not kill the first
thread in the list, so do so now. */
lwp = find_lwp_pid (pid_to_ptid (pid));
thread = get_lwp_thread (lwp);
if (debug_threads)
fprintf (stderr, "lk_1: killing lwp %ld, for pid: %d\n",
lwpid_of (lwp), pid);
/* If we're killing a running inferior, make sure it is stopped
first, as PTRACE_KILL will not work otherwise. */
if (!lwp->stopped)
send_sigstop (&lwp->head);
do
{
ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0);
/* Make sure it died. The loop is most likely unnecessary. */
lwpid = linux_wait_for_event (lwp->head.id, &wstat, __WALL);
} while (lwpid > 0 && WIFSTOPPED (wstat));
delete_lwp (lwp);
linux_remove_process (process);
return 0;
}
static int
linux_detach_one_lwp (struct inferior_list_entry *entry, void *args)
{
struct thread_info *thread = (struct thread_info *) entry;
struct lwp_info *lwp = get_thread_lwp (thread);
int pid = * (int *) args;
if (ptid_get_pid (entry->id) != pid)
return 0;
/* If we're detaching from a running inferior, make sure it is
stopped first, as PTRACE_DETACH will not work otherwise. */
if (!lwp->stopped)
{
int lwpid = lwpid_of (lwp);
stopping_threads = 1;
send_sigstop (&lwp->head);
/* If this detects a new thread through a clone event, the new
thread is appended to the end of the lwp list, so we'll
eventually detach from it. */
wait_for_sigstop (&lwp->head);
stopping_threads = 0;
/* If LWP exits while we're trying to stop it, there's nothing
left to do. */
lwp = find_lwp_pid (pid_to_ptid (lwpid));
if (lwp == NULL)
return 0;
}
/* Make sure the process isn't stopped at a breakpoint that's
no longer there. */
check_removed_breakpoint (lwp);
/* If this process is stopped but is expecting a SIGSTOP, then make
sure we take care of that now. This isn't absolutely guaranteed
to collect the SIGSTOP, but is fairly likely to. */
if (lwp->stop_expected)
{
int wstat;
/* Clear stop_expected, so that the SIGSTOP will be reported. */
lwp->stop_expected = 0;
if (lwp->stopped)
linux_resume_one_lwp (lwp, 0, 0, NULL);
linux_wait_for_event (lwp->head.id, &wstat, __WALL);
}
/* Flush any pending changes to the process's registers. */
regcache_invalidate_one ((struct inferior_list_entry *)
get_lwp_thread (lwp));
/* Finally, let it resume. */
ptrace (PTRACE_DETACH, lwpid_of (lwp), 0, 0);
delete_lwp (lwp);
return 0;
}
static int
any_thread_of (struct inferior_list_entry *entry, void *args)
{
int *pid_p = args;
if (ptid_get_pid (entry->id) == *pid_p)
return 1;
return 0;
}
static int
linux_detach (int pid)
{
struct process_info *process;
process = find_process_pid (pid);
if (process == NULL)
return -1;
current_inferior =
(struct thread_info *) find_inferior (&all_threads, any_thread_of, &pid);
delete_all_breakpoints ();
find_inferior (&all_threads, linux_detach_one_lwp, &pid);
linux_remove_process (process);
return 0;
}
static void
linux_join (int pid)
{
int status, ret;
struct process_info *process;
process = find_process_pid (pid);
if (process == NULL)
return;
do {
ret = my_waitpid (pid, &status, 0);
if (WIFEXITED (status) || WIFSIGNALED (status))
break;
} while (ret != -1 || errno != ECHILD);
}
/* Return nonzero if the given thread is still alive. */
static int
linux_thread_alive (ptid_t ptid)
{
struct lwp_info *lwp = find_lwp_pid (ptid);
/* We assume we always know if a thread exits. If a whole process
exited but we still haven't been able to report it to GDB, we'll
hold on to the last lwp of the dead process. */
if (lwp != NULL)
return !lwp->dead;
else
return 0;
}
/* Return nonzero if this process stopped at a breakpoint which
no longer appears to be inserted. Also adjust the PC
appropriately to resume where the breakpoint used to be. */
static int
check_removed_breakpoint (struct lwp_info *event_child)
{
CORE_ADDR stop_pc;
struct thread_info *saved_inferior;
if (event_child->pending_is_breakpoint == 0)
return 0;
if (debug_threads)
fprintf (stderr, "Checking for breakpoint in lwp %ld.\n",
lwpid_of (event_child));
saved_inferior = current_inferior;
current_inferior = get_lwp_thread (event_child);
stop_pc = get_stop_pc ();
/* If the PC has changed since we stopped, then we shouldn't do
anything. This happens if, for instance, GDB handled the
decr_pc_after_break subtraction itself. */
if (stop_pc != event_child->pending_stop_pc)
{
if (debug_threads)
fprintf (stderr, "Ignoring, PC was changed. Old PC was 0x%08llx\n",
event_child->pending_stop_pc);
event_child->pending_is_breakpoint = 0;
current_inferior = saved_inferior;
return 0;
}
/* If the breakpoint is still there, we will report hitting it. */
if ((*the_low_target.breakpoint_at) (stop_pc))
{
if (debug_threads)
fprintf (stderr, "Ignoring, breakpoint is still present.\n");
current_inferior = saved_inferior;
return 0;
}
if (debug_threads)
fprintf (stderr, "Removed breakpoint.\n");
/* For decr_pc_after_break targets, here is where we perform the
decrement. We go immediately from this function to resuming,
and can not safely call get_stop_pc () again. */
if (the_low_target.set_pc != NULL)
{
if (debug_threads)
fprintf (stderr, "Set pc to 0x%lx\n", (long) stop_pc);
(*the_low_target.set_pc) (stop_pc);
}
/* We consumed the pending SIGTRAP. */
event_child->pending_is_breakpoint = 0;
event_child->status_pending_p = 0;
event_child->status_pending = 0;
current_inferior = saved_inferior;
return 1;
}
/* Return 1 if this lwp has an interesting status pending. This
function may silently resume an inferior lwp. */
static int
status_pending_p (struct inferior_list_entry *entry, void *arg)
{
struct lwp_info *lwp = (struct lwp_info *) entry;
ptid_t ptid = * (ptid_t *) arg;
/* Check if we're only interested in events from a specific process
or its lwps. */
if (!ptid_equal (minus_one_ptid, ptid)
&& ptid_get_pid (ptid) != ptid_get_pid (lwp->head.id))
return 0;
if (lwp->status_pending_p && !lwp->suspended)
if (check_removed_breakpoint (lwp))
{
/* This thread was stopped at a breakpoint, and the breakpoint
is now gone. We were told to continue (or step...) all threads,
so GDB isn't trying to single-step past this breakpoint.
So instead of reporting the old SIGTRAP, pretend we got to
the breakpoint just after it was removed instead of just
before; resume the process. */
linux_resume_one_lwp (lwp, 0, 0, NULL);
return 0;
}
return (lwp->status_pending_p && !lwp->suspended);
}
static int
same_lwp (struct inferior_list_entry *entry, void *data)
{
ptid_t ptid = *(ptid_t *) data;
int lwp;
if (ptid_get_lwp (ptid) != 0)
lwp = ptid_get_lwp (ptid);
else
lwp = ptid_get_pid (ptid);
if (ptid_get_lwp (entry->id) == lwp)
return 1;
return 0;
}
struct lwp_info *
find_lwp_pid (ptid_t ptid)
{
return (struct lwp_info*) find_inferior (&all_lwps, same_lwp, &ptid);
}
static struct lwp_info *
linux_wait_for_lwp (ptid_t ptid, int *wstatp, int options)
{
int ret;
int to_wait_for = -1;
struct lwp_info *child = NULL;
if (debug_threads)
fprintf (stderr, "linux_wait_for_lwp: %s\n", target_pid_to_str (ptid));
if (ptid_equal (ptid, minus_one_ptid))
to_wait_for = -1; /* any child */
else
to_wait_for = ptid_get_lwp (ptid); /* this lwp only */
options |= __WALL;
retry:
ret = my_waitpid (to_wait_for, wstatp, options);
if (ret == 0 || (ret == -1 && errno == ECHILD && (options & WNOHANG)))
return NULL;
else if (ret == -1)
perror_with_name ("waitpid");
if (debug_threads
&& (!WIFSTOPPED (*wstatp)
|| (WSTOPSIG (*wstatp) != 32
&& WSTOPSIG (*wstatp) != 33)))
fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);
child = find_lwp_pid (pid_to_ptid (ret));
/* If we didn't find a process, one of two things presumably happened:
- A process we started and then detached from has exited. Ignore it.
- A process we are controlling has forked and the new child's stop
was reported to us by the kernel. Save its PID. */
if (child == NULL && WIFSTOPPED (*wstatp))
{
add_pid_to_list (&stopped_pids, ret);
goto retry;
}
else if (child == NULL)
goto retry;
child->stopped = 1;
child->pending_is_breakpoint = 0;
child->last_status = *wstatp;
/* Architecture-specific setup after inferior is running.
This needs to happen after we have attached to the inferior
and it is stopped for the first time, but before we access
any inferior registers. */
if (new_inferior)
{
the_low_target.arch_setup ();
#ifdef HAVE_LINUX_REGSETS
memset (disabled_regsets, 0, num_regsets);
#endif
new_inferior = 0;
}
if (debug_threads
&& WIFSTOPPED (*wstatp)
&& the_low_target.get_pc != NULL)
{
struct thread_info *saved_inferior = current_inferior;
CORE_ADDR pc;
current_inferior = (struct thread_info *)
find_inferior_id (&all_threads, child->head.id);
pc = (*the_low_target.get_pc) ();
fprintf (stderr, "linux_wait_for_lwp: pc is 0x%lx\n", (long) pc);
current_inferior = saved_inferior;
}
return child;
}
/* Wait for an event from child PID. If PID is -1, wait for any
child. Store the stop status through the status pointer WSTAT.
OPTIONS is passed to the waitpid call. Return 0 if no child stop
event was found and OPTIONS contains WNOHANG. Return the PID of
the stopped child otherwise. */
static int
linux_wait_for_event_1 (ptid_t ptid, int *wstat, int options)
{
CORE_ADDR stop_pc;
struct lwp_info *event_child = NULL;
int bp_status;
struct lwp_info *requested_child = NULL;
/* Check for a lwp with a pending status. */
/* It is possible that the user changed the pending task's registers since
it stopped. We correctly handle the change of PC if we hit a breakpoint
(in check_removed_breakpoint); signals should be reported anyway. */
if (ptid_equal (ptid, minus_one_ptid)
|| ptid_equal (pid_to_ptid (ptid_get_pid (ptid)), ptid))
{
event_child = (struct lwp_info *)
find_inferior (&all_lwps, status_pending_p, &ptid);
if (debug_threads && event_child)
fprintf (stderr, "Got a pending child %ld\n", lwpid_of (event_child));
}
else
{
requested_child = find_lwp_pid (ptid);
if (requested_child->status_pending_p
&& !check_removed_breakpoint (requested_child))
event_child = requested_child;
}
if (event_child != NULL)
{
if (debug_threads)
fprintf (stderr, "Got an event from pending child %ld (%04x)\n",
lwpid_of (event_child), event_child->status_pending);
*wstat = event_child->status_pending;
event_child->status_pending_p = 0;
event_child->status_pending = 0;
current_inferior = get_lwp_thread (event_child);
return lwpid_of (event_child);
}
/* We only enter this loop if no process has a pending wait status. Thus
any action taken in response to a wait status inside this loop is
responding as soon as we detect the status, not after any pending
events. */
while (1)
{
event_child = linux_wait_for_lwp (ptid, wstat, options);
if ((options & WNOHANG) && event_child == NULL)
return 0;
if (event_child == NULL)
error ("event from unknown child");
current_inferior = get_lwp_thread (event_child);
/* Check for thread exit. */
if (! WIFSTOPPED (*wstat))
{
if (debug_threads)
fprintf (stderr, "LWP %ld exiting\n", lwpid_of (event_child));
/* If the last thread is exiting, just return. */
if (last_thread_of_process_p (current_inferior))
{
if (debug_threads)
fprintf (stderr, "LWP %ld is last lwp of process\n",
lwpid_of (event_child));
return lwpid_of (event_child);
}
delete_lwp (event_child);
if (!non_stop)
{
current_inferior = (struct thread_info *) all_threads.head;
if (debug_threads)
fprintf (stderr, "Current inferior is now %ld\n",
lwpid_of (get_thread_lwp (current_inferior)));
}
else
{
current_inferior = NULL;
if (debug_threads)
fprintf (stderr, "Current inferior is now <NULL>\n");
}
/* If we were waiting for this particular child to do something...
well, it did something. */
if (requested_child != NULL)
return lwpid_of (event_child);
/* Wait for a more interesting event. */
continue;
}
if (event_child->must_set_ptrace_flags)
{
ptrace (PTRACE_SETOPTIONS, lwpid_of (event_child),
0, PTRACE_O_TRACECLONE);
event_child->must_set_ptrace_flags = 0;
}
if (WIFSTOPPED (*wstat)
&& WSTOPSIG (*wstat) == SIGSTOP
&& event_child->stop_expected)
{
if (debug_threads)
fprintf (stderr, "Expected stop.\n");
event_child->stop_expected = 0;
linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL);
continue;
}
if (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) == SIGTRAP
&& *wstat >> 16 != 0)
{
handle_extended_wait (event_child, *wstat);
continue;
}
/* If GDB is not interested in this signal, don't stop other
threads, and don't report it to GDB. Just resume the
inferior right away. We do this for threading-related
signals as well as any that GDB specifically requested we
ignore. But never ignore SIGSTOP if we sent it ourselves,
and do not ignore signals when stepping - they may require
special handling to skip the signal handler. */
/* FIXME drow/2002-06-09: Get signal numbers from the inferior's
thread library? */
if (WIFSTOPPED (*wstat)
&& !event_child->stepping
&& (
#ifdef USE_THREAD_DB
(current_process ()->private->thread_db_active
&& (WSTOPSIG (*wstat) == __SIGRTMIN
|| WSTOPSIG (*wstat) == __SIGRTMIN + 1))
||
#endif
(pass_signals[target_signal_from_host (WSTOPSIG (*wstat))]
&& (WSTOPSIG (*wstat) != SIGSTOP || !stopping_threads))))
{
siginfo_t info, *info_p;
if (debug_threads)
fprintf (stderr, "Ignored signal %d for LWP %ld.\n",
WSTOPSIG (*wstat), lwpid_of (event_child));
if (ptrace (PTRACE_GETSIGINFO, lwpid_of (event_child), 0, &info) == 0)
info_p = &info;
else
info_p = NULL;
linux_resume_one_lwp (event_child,
event_child->stepping,
WSTOPSIG (*wstat), info_p);
continue;
}
/* If this event was not handled above, and is not a SIGTRAP, report
it. */
if (!WIFSTOPPED (*wstat) || WSTOPSIG (*wstat) != SIGTRAP)
return lwpid_of (event_child);
/* If this target does not support breakpoints, we simply report the
SIGTRAP; it's of no concern to us. */
if (the_low_target.get_pc == NULL)
return lwpid_of (event_child);
stop_pc = get_stop_pc ();
/* bp_reinsert will only be set if we were single-stepping.
Notice that we will resume the process after hitting
a gdbserver breakpoint; single-stepping to/over one
is not supported (yet). */
if (event_child->bp_reinsert != 0)
{
if (debug_threads)
fprintf (stderr, "Reinserted breakpoint.\n");
reinsert_breakpoint (event_child->bp_reinsert);
event_child->bp_reinsert = 0;
/* Clear the single-stepping flag and SIGTRAP as we resume. */
linux_resume_one_lwp (event_child, 0, 0, NULL);
continue;
}
bp_status = check_breakpoints (stop_pc);
if (bp_status != 0)
{
if (debug_threads)
fprintf (stderr, "Hit a gdbserver breakpoint.\n");
/* We hit one of our own breakpoints. We mark it as a pending
breakpoint, so that check_removed_breakpoint () will do the PC
adjustment for us at the appropriate time. */
event_child->pending_is_breakpoint = 1;
event_child->pending_stop_pc = stop_pc;
/* We may need to put the breakpoint back. We continue in the event
loop instead of simply replacing the breakpoint right away,
in order to not lose signals sent to the thread that hit the
breakpoint. Unfortunately this increases the window where another
thread could sneak past the removed breakpoint. For the current
use of server-side breakpoints (thread creation) this is
acceptable; but it needs to be considered before this breakpoint
mechanism can be used in more general ways. For some breakpoints
it may be necessary to stop all other threads, but that should
be avoided where possible.
If breakpoint_reinsert_addr is NULL, that means that we can
use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint,
mark it for reinsertion, and single-step.
Otherwise, call the target function to figure out where we need
our temporary breakpoint, create it, and continue executing this
process. */
/* NOTE: we're lifting breakpoints in non-stop mode. This
is currently only used for thread event breakpoints, so
it isn't that bad as long as we have PTRACE_EVENT_CLONE
events. */
if (bp_status == 2)
/* No need to reinsert. */
linux_resume_one_lwp (event_child, 0, 0, NULL);
else if (the_low_target.breakpoint_reinsert_addr == NULL)
{
event_child->bp_reinsert = stop_pc;
uninsert_breakpoint (stop_pc);
linux_resume_one_lwp (event_child, 1, 0, NULL);
}
else
{
reinsert_breakpoint_by_bp
(stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
linux_resume_one_lwp (event_child, 0, 0, NULL);
}
continue;
}
if (debug_threads)
fprintf (stderr, "Hit a non-gdbserver breakpoint.\n");
/* If we were single-stepping, we definitely want to report the
SIGTRAP. Although the single-step operation has completed,
do not clear clear the stepping flag yet; we need to check it
in wait_for_sigstop. */
if (event_child->stepping)
return lwpid_of (event_child);
/* A SIGTRAP that we can't explain. It may have been a breakpoint.
Check if it is a breakpoint, and if so mark the process information
accordingly. This will handle both the necessary fiddling with the
PC on decr_pc_after_break targets and suppressing extra threads
hitting a breakpoint if two hit it at once and then GDB removes it
after the first is reported. Arguably it would be better to report
multiple threads hitting breakpoints simultaneously, but the current
remote protocol does not allow this. */
if ((*the_low_target.breakpoint_at) (stop_pc))
{
event_child->pending_is_breakpoint = 1;
event_child->pending_stop_pc = stop_pc;
}
return lwpid_of (event_child);
}
/* NOTREACHED */
return 0;
}
static int
linux_wait_for_event (ptid_t ptid, int *wstat, int options)
{
ptid_t wait_ptid;
if (ptid_is_pid (ptid))
{
/* A request to wait for a specific tgid. This is not possible
with waitpid, so instead, we wait for any child, and leave
children we're not interested in right now with a pending
status to report later. */
wait_ptid = minus_one_ptid;
}
else
wait_ptid = ptid;
while (1)
{
int event_pid;
event_pid = linux_wait_for_event_1 (wait_ptid, wstat, options);
if (event_pid > 0
&& ptid_is_pid (ptid) && ptid_get_pid (ptid) != event_pid)
{
struct lwp_info *event_child = find_lwp_pid (pid_to_ptid (event_pid));
if (! WIFSTOPPED (*wstat))
mark_lwp_dead (event_child, *wstat);
else
{
event_child->status_pending_p = 1;
event_child->status_pending = *wstat;
}
}
else
return event_pid;
}
}
/* Wait for process, returns status. */
static ptid_t
linux_wait_1 (ptid_t ptid,
struct target_waitstatus *ourstatus, int target_options)
{
int w;
struct thread_info *thread = NULL;
struct lwp_info *lwp = NULL;
int options;
int pid;
/* Translate generic target options into linux options. */
options = __WALL;
if (target_options & TARGET_WNOHANG)
options |= WNOHANG;
retry:
ourstatus->kind = TARGET_WAITKIND_IGNORE;
/* If we were only supposed to resume one thread, only wait for
that thread - if it's still alive. If it died, however - which
can happen if we're coming from the thread death case below -
then we need to make sure we restart the other threads. We could
pick a thread at random or restart all; restarting all is less
arbitrary. */
if (!non_stop
&& !ptid_equal (cont_thread, null_ptid)
&& !ptid_equal (cont_thread, minus_one_ptid))
{
thread = (struct thread_info *) find_inferior_id (&all_threads,
cont_thread);
/* No stepping, no signal - unless one is pending already, of course. */
if (thread == NULL)
{
struct thread_resume resume_info;
resume_info.thread = minus_one_ptid;
resume_info.kind = resume_continue;
resume_info.sig = 0;
linux_resume (&resume_info, 1);
}
else
ptid = cont_thread;
}
pid = linux_wait_for_event (ptid, &w, options);
if (pid == 0) /* only if TARGET_WNOHANG */
return null_ptid;
lwp = get_thread_lwp (current_inferior);
/* If we are waiting for a particular child, and it exited,
linux_wait_for_event will return its exit status. Similarly if
the last child exited. If this is not the last child, however,
do not report it as exited until there is a 'thread exited' response
available in the remote protocol. Instead, just wait for another event.
This should be safe, because if the thread crashed we will already
have reported the termination signal to GDB; that should stop any
in-progress stepping operations, etc.
Report the exit status of the last thread to exit. This matches
LinuxThreads' behavior. */
if (last_thread_of_process_p (current_inferior))
{
if (WIFEXITED (w) || WIFSIGNALED (w))
{
int pid = pid_of (lwp);
struct process_info *process = find_process_pid (pid);
delete_lwp (lwp);
linux_remove_process (process);
current_inferior = NULL;
if (WIFEXITED (w))
{
ourstatus->kind = TARGET_WAITKIND_EXITED;
ourstatus->value.integer = WEXITSTATUS (w);
if (debug_threads)
fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
}
else
{
ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
ourstatus->value.sig = target_signal_from_host (WTERMSIG (w));
if (debug_threads)
fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
}
return pid_to_ptid (pid);
}
}
else
{
if (!WIFSTOPPED (w))
goto retry;
}
/* In all-stop, stop all threads. Be careful to only do this if
we're about to report an event to GDB. */
if (!non_stop)
stop_all_lwps ();
ourstatus->kind = TARGET_WAITKIND_STOPPED;
if (lwp->suspended && WSTOPSIG (w) == SIGSTOP)
{
/* A thread that has been requested to stop by GDB with vCont;t,
and it stopped cleanly, so report as SIG0. The use of
SIGSTOP is an implementation detail. */
ourstatus->value.sig = TARGET_SIGNAL_0;
}
else if (lwp->suspended && WSTOPSIG (w) != SIGSTOP)
{
/* A thread that has been requested to stop by GDB with vCont;t,
but, it stopped for other reasons. Set stop_expected so the
pending SIGSTOP is ignored and the LWP is resumed. */
lwp->stop_expected = 1;
ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
}
else
{
ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
}
if (debug_threads)
fprintf (stderr, "linux_wait ret = %s, %d, %d\n",
target_pid_to_str (lwp->head.id),
ourstatus->kind,
ourstatus->value.sig);
return lwp->head.id;
}
/* Get rid of any pending event in the pipe. */
static void
async_file_flush (void)
{
int ret;
char buf;
do
ret = read (linux_event_pipe[0], &buf, 1);
while (ret >= 0 || (ret == -1 && errno == EINTR));
}
/* Put something in the pipe, so the event loop wakes up. */
static void
async_file_mark (void)
{
int ret;
async_file_flush ();
do
ret = write (linux_event_pipe[1], "+", 1);
while (ret == 0 || (ret == -1 && errno == EINTR));
/* Ignore EAGAIN. If the pipe is full, the event loop will already
be awakened anyway. */
}
static ptid_t
linux_wait (ptid_t ptid,
struct target_waitstatus *ourstatus, int target_options)
{
ptid_t event_ptid;
if (debug_threads)
fprintf (stderr, "linux_wait: [%s]\n", target_pid_to_str (ptid));
/* Flush the async file first. */
if (target_is_async_p ())
async_file_flush ();
event_ptid = linux_wait_1 (ptid, ourstatus, target_options);
/* If at least one stop was reported, there may be more. A single
SIGCHLD can signal more than one child stop. */
if (target_is_async_p ()
&& (target_options & TARGET_WNOHANG) != 0
&& !ptid_equal (event_ptid, null_ptid))
async_file_mark ();
return event_ptid;
}
/* Send a signal to an LWP. For LinuxThreads, kill is enough; however, if
thread groups are in use, we need to use tkill. */
static int
kill_lwp (unsigned long lwpid, int signo)
{
static int tkill_failed;
errno = 0;
#ifdef SYS_tkill
if (!tkill_failed)
{
int ret = syscall (SYS_tkill, lwpid, signo);
if (errno != ENOSYS)
return ret;
errno = 0;
tkill_failed = 1;
}
#endif
return kill (lwpid, signo);
}
static void
send_sigstop (struct inferior_list_entry *entry)
{
struct lwp_info *lwp = (struct lwp_info *) entry;
int pid;
if (lwp->stopped)
return;
pid = lwpid_of (lwp);
/* If we already have a pending stop signal for this process, don't
send another. */
if (lwp->stop_expected)
{
if (debug_threads)
fprintf (stderr, "Have pending sigstop for lwp %d\n", pid);
/* We clear the stop_expected flag so that wait_for_sigstop
will receive the SIGSTOP event (instead of silently resuming and
waiting again). It'll be reset below. */
lwp->stop_expected = 0;
return;
}
if (debug_threads)
fprintf (stderr, "Sending sigstop to lwp %d\n", pid);
kill_lwp (pid, SIGSTOP);
}
static void
mark_lwp_dead (struct lwp_info *lwp, int wstat)
{
/* It's dead, really. */
lwp->dead = 1;
/* Store the exit status for later. */
lwp->status_pending_p = 1;
lwp->status_pending = wstat;
/* So that check_removed_breakpoint doesn't try to figure out if
this is stopped at a breakpoint. */
lwp->pending_is_breakpoint = 0;
/* Prevent trying to stop it. */
lwp->stopped = 1;
/* No further stops are expected from a dead lwp. */
lwp->stop_expected = 0;
}
static void
wait_for_sigstop (struct inferior_list_entry *entry)
{
struct lwp_info *lwp = (struct lwp_info *) entry;
struct thread_info *saved_inferior;
int wstat;
ptid_t saved_tid;
ptid_t ptid;
if (lwp->stopped)
return;
saved_inferior = current_inferior;
if (saved_inferior != NULL)
saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
else
saved_tid = null_ptid; /* avoid bogus unused warning */
ptid = lwp->head.id;
linux_wait_for_event (ptid, &wstat, __WALL);
/* If we stopped with a non-SIGSTOP signal, save it for later
and record the pending SIGSTOP. If the process exited, just
return. */
if (WIFSTOPPED (wstat)
&& WSTOPSIG (wstat) != SIGSTOP)
{
if (debug_threads)
fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
lwpid_of (lwp), wstat);
/* Do not leave a pending single-step finish to be reported to
the client. The client will give us a new action for this
thread, possibly a continue request --- otherwise, the client
would consider this pending SIGTRAP reported later a spurious
signal. */
if (WSTOPSIG (wstat) == SIGTRAP
&& lwp->stepping
&& !linux_stopped_by_watchpoint ())
{
if (debug_threads)
fprintf (stderr, " single-step SIGTRAP ignored\n");
}
else
{
lwp->status_pending_p = 1;
lwp->status_pending = wstat;
}
lwp->stop_expected = 1;
}
else if (!WIFSTOPPED (wstat))
{
if (debug_threads)
fprintf (stderr, "Process %ld exited while stopping LWPs\n",
lwpid_of (lwp));
/* Leave this status pending for the next time we're able to
report it. In the mean time, we'll report this lwp as dead
to GDB, so GDB doesn't try to read registers and memory from
it. */
mark_lwp_dead (lwp, wstat);
}
if (saved_inferior == NULL || linux_thread_alive (saved_tid))
current_inferior = saved_inferior;
else
{
if (debug_threads)
fprintf (stderr, "Previously current thread died.\n");
if (non_stop)
{
/* We can't change the current inferior behind GDB's back,
otherwise, a subsequent command may apply to the wrong
process. */
current_inferior = NULL;
}
else
{
/* Set a valid thread as current. */
set_desired_inferior (0);
}
}
}
static void
stop_all_lwps (void)
{
stopping_threads = 1;
for_each_inferior (&all_lwps, send_sigstop);
for_each_inferior (&all_lwps, wait_for_sigstop);
stopping_threads = 0;
}
/* Resume execution of the inferior process.
If STEP is nonzero, single-step it.
If SIGNAL is nonzero, give it that signal. */
static void
linux_resume_one_lwp (struct lwp_info *lwp,
int step, int signal, siginfo_t *info)
{
struct thread_info *saved_inferior;
if (lwp->stopped == 0)
return;
/* If we have pending signals or status, and a new signal, enqueue the
signal. Also enqueue the signal if we are waiting to reinsert a
breakpoint; it will be picked up again below. */
if (signal != 0
&& (lwp->status_pending_p || lwp->pending_signals != NULL
|| lwp->bp_reinsert != 0))
{
struct pending_signals *p_sig;
p_sig = xmalloc (sizeof (*p_sig));
p_sig->prev = lwp->pending_signals;
p_sig->signal = signal;
if (info == NULL)
memset (&p_sig->info, 0, sizeof (siginfo_t));
else
memcpy (&p_sig->info, info, sizeof (siginfo_t));
lwp->pending_signals = p_sig;
}
if (lwp->status_pending_p && !check_removed_breakpoint (lwp))
return;
saved_inferior = current_inferior;
current_inferior = get_lwp_thread (lwp);
if (debug_threads)
fprintf (stderr, "Resuming lwp %ld (%s, signal %d, stop %s)\n",
lwpid_of (lwp), step ? "step" : "continue", signal,
lwp->stop_expected ? "expected" : "not expected");
/* This bit needs some thinking about. If we get a signal that
we must report while a single-step reinsert is still pending,
we often end up resuming the thread. It might be better to
(ew) allow a stack of pending events; then we could be sure that
the reinsert happened right away and not lose any signals.
Making this stack would also shrink the window in which breakpoints are
uninserted (see comment in linux_wait_for_lwp) but not enough for
complete correctness, so it won't solve that problem. It may be
worthwhile just to solve this one, however. */
if (lwp->bp_reinsert != 0)
{
if (debug_threads)
fprintf (stderr, " pending reinsert at %08lx", (long)lwp->bp_reinsert);
if (step == 0)
fprintf (stderr, "BAD - reinserting but not stepping.\n");
step = 1;
/* Postpone any pending signal. It was enqueued above. */
signal = 0;
}
check_removed_breakpoint (lwp);
if (debug_threads && the_low_target.get_pc != NULL)
{
CORE_ADDR pc = (*the_low_target.get_pc) ();
fprintf (stderr, " resuming from pc 0x%lx\n", (long) pc);
}
/* If we have pending signals, consume one unless we are trying to reinsert
a breakpoint. */
if (lwp->pending_signals != NULL && lwp->bp_reinsert == 0)
{
struct pending_signals **p_sig;
p_sig = &lwp->pending_signals;
while ((*p_sig)->prev != NULL)
p_sig = &(*p_sig)->prev;
signal = (*p_sig)->signal;
if ((*p_sig)->info.si_signo != 0)
ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &(*p_sig)->info);
free (*p_sig);
*p_sig = NULL;
}
if (the_low_target.prepare_to_resume != NULL)
the_low_target.prepare_to_resume (lwp);
regcache_invalidate_one ((struct inferior_list_entry *)
get_lwp_thread (lwp));
errno = 0;
lwp->stopped = 0;
lwp->stepping = step;
ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, lwpid_of (lwp), 0, signal);
current_inferior = saved_inferior;
if (errno)
{
/* ESRCH from ptrace either means that the thread was already
running (an error) or that it is gone (a race condition). If
it's gone, we will get a notification the next time we wait,
so we can ignore the error. We could differentiate these
two, but it's tricky without waiting; the thread still exists
as a zombie, so sending it signal 0 would succeed. So just
ignore ESRCH. */
if (errno == ESRCH)
return;
perror_with_name ("ptrace");
}
}
struct thread_resume_array
{
struct thread_resume *resume;
size_t n;
};
/* This function is called once per thread. We look up the thread
in RESUME_PTR, and mark the thread with a pointer to the appropriate
resume request.
This algorithm is O(threads * resume elements), but resume elements
is small (and will remain small at least until GDB supports thread
suspension). */
static int
linux_set_resume_request (struct inferior_list_entry *entry, void *arg)
{
struct lwp_info *lwp;
struct thread_info *thread;
int ndx;
struct thread_resume_array *r;
thread = (struct thread_info *) entry;
lwp = get_thread_lwp (thread);
r = arg;
for (ndx = 0; ndx < r->n; ndx++)
{
ptid_t ptid = r->resume[ndx].thread;
if (ptid_equal (ptid, minus_one_ptid)
|| ptid_equal (ptid, entry->id)
|| (ptid_is_pid (ptid)
&& (ptid_get_pid (ptid) == pid_of (lwp)))
|| (ptid_get_lwp (ptid) == -1
&& (ptid_get_pid (ptid) == pid_of (lwp))))
{
lwp->resume = &r->resume[ndx];
return 0;
}
}
/* No resume action for this thread. */
lwp->resume = NULL;
return 0;
}
/* Set *FLAG_P if this lwp has an interesting status pending. */
static int
resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p)
{
struct lwp_info *lwp = (struct lwp_info *) entry;
/* LWPs which will not be resumed are not interesting, because
we might not wait for them next time through linux_wait. */
if (lwp->resume == NULL)
return 0;
/* If this thread has a removed breakpoint, we won't have any
events to report later, so check now. check_removed_breakpoint
may clear status_pending_p. We avoid calling check_removed_breakpoint
for any thread that we are not otherwise going to resume - this
lets us preserve stopped status when two threads hit a breakpoint.
GDB removes the breakpoint to single-step a particular thread
past it, then re-inserts it and resumes all threads. We want
to report the second thread without resuming it in the interim. */
if (lwp->status_pending_p)
check_removed_breakpoint (lwp);
if (lwp->status_pending_p)
* (int *) flag_p = 1;
return 0;
}
/* This function is called once per thread. We check the thread's resume
request, which will tell us whether to resume, step, or leave the thread
stopped; and what signal, if any, it should be sent.
For threads which we aren't explicitly told otherwise, we preserve
the stepping flag; this is used for stepping over gdbserver-placed
breakpoints.
If pending_flags was set in any thread, we queue any needed
signals, since we won't actually resume. We already have a pending
event to report, so we don't need to preserve any step requests;
they should be re-issued if necessary. */
static int
linux_resume_one_thread (struct inferior_list_entry *entry, void *arg)
{
struct lwp_info *lwp;
struct thread_info *thread;
int step;
int pending_flag = * (int *) arg;
thread = (struct thread_info *) entry;
lwp = get_thread_lwp (thread);
if (lwp->resume == NULL)
return 0;
if (lwp->resume->kind == resume_stop)
{
if (debug_threads)
fprintf (stderr, "suspending LWP %ld\n", lwpid_of (lwp));
if (!lwp->stopped)
{
if (debug_threads)
fprintf (stderr, "running -> suspending LWP %ld\n", lwpid_of (lwp));
lwp->suspended = 1;
send_sigstop (&lwp->head);
}
else
{
if (debug_threads)
{
if (lwp->suspended)
fprintf (stderr, "already stopped/suspended LWP %ld\n",
lwpid_of (lwp));
else
fprintf (stderr, "already stopped/not suspended LWP %ld\n",
lwpid_of (lwp));
}
/* Make sure we leave the LWP suspended, so we don't try to
resume it without GDB telling us to. FIXME: The LWP may
have been stopped in an internal event that was not meant
to be notified back to GDB (e.g., gdbserver breakpoint),
so we should be reporting a stop event in that case
too. */
lwp->suspended = 1;
}
/* For stop requests, we're done. */
lwp->resume = NULL;
return 0;
}
else
lwp->suspended = 0;
/* If this thread which is about to be resumed has a pending status,
then don't resume any threads - we can just report the pending
status. Make sure to queue any signals that would otherwise be
sent. In all-stop mode, we do this decision based on if *any*
thread has a pending status. */
if (non_stop)
resume_status_pending_p (&lwp->head, &pending_flag);
if (!pending_flag)
{
if (debug_threads)
fprintf (stderr, "resuming LWP %ld\n", lwpid_of (lwp));
if (ptid_equal (lwp->resume->thread, minus_one_ptid)
&& lwp->stepping
&& lwp->pending_is_breakpoint)
step = 1;
else
step = (lwp->resume->kind == resume_step);
linux_resume_one_lwp (lwp, step, lwp->resume->sig, NULL);
}
else
{
if (debug_threads)
fprintf (stderr, "leaving LWP %ld stopped\n", lwpid_of (lwp));
/* If we have a new signal, enqueue the signal. */
if (lwp->resume->sig != 0)
{
struct pending_signals *p_sig;
p_sig = xmalloc (sizeof (*p_sig));
p_sig->prev = lwp->pending_signals;
p_sig->signal = lwp->resume->sig;
memset (&p_sig->info, 0, sizeof (siginfo_t));
/* If this is the same signal we were previously stopped by,
make sure to queue its siginfo. We can ignore the return
value of ptrace; if it fails, we'll skip
PTRACE_SETSIGINFO. */
if (WIFSTOPPED (lwp->last_status)
&& WSTOPSIG (lwp->last_status) == lwp->resume->sig)
ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &p_sig->info);
lwp->pending_signals = p_sig;
}
}
lwp->resume = NULL;
return 0;
}
static void
linux_resume (struct thread_resume *resume_info, size_t n)
{
int pending_flag;
struct thread_resume_array array = { resume_info, n };
find_inferior (&all_threads, linux_set_resume_request, &array);
/* If there is a thread which would otherwise be resumed, which
has a pending status, then don't resume any threads - we can just
report the pending status. Make sure to queue any signals
that would otherwise be sent. In non-stop mode, we'll apply this
logic to each thread individually. */
pending_flag = 0;
if (!non_stop)
find_inferior (&all_lwps, resume_status_pending_p, &pending_flag);
if (debug_threads)
{
if (pending_flag)
fprintf (stderr, "Not resuming, pending status\n");
else
fprintf (stderr, "Resuming, no pending status\n");
}
find_inferior (&all_threads, linux_resume_one_thread, &pending_flag);
}
#ifdef HAVE_LINUX_USRREGS
int
register_addr (int regnum)
{
int addr;
if (regnum < 0 || regnum >= the_low_target.num_regs)
error ("Invalid register number %d.", regnum);
addr = the_low_target.regmap[regnum];
return addr;
}
/* Fetch one register. */
static void
fetch_register (int regno)
{
CORE_ADDR regaddr;
int i, size;
char *buf;
int pid;
if (regno >= the_low_target.num_regs)
return;
if ((*the_low_target.cannot_fetch_register) (regno))
return;
regaddr = register_addr (regno);
if (regaddr == -1)
return;
pid = lwpid_of (get_thread_lwp (current_inferior));
size = ((register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
& - sizeof (PTRACE_XFER_TYPE));
buf = alloca (size);
for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
*(PTRACE_XFER_TYPE *) (buf + i) =
ptrace (PTRACE_PEEKUSER, pid, (PTRACE_ARG3_TYPE) regaddr, 0);
regaddr += sizeof (PTRACE_XFER_TYPE);
if (errno != 0)
{
/* Warning, not error, in case we are attached; sometimes the
kernel doesn't let us at the registers. */
char *err = strerror (errno);
char *msg = alloca (strlen (err) + 128);
sprintf (msg, "reading register %d: %s", regno, err);
error (msg);
goto error_exit;
}
}
if (the_low_target.supply_ptrace_register)
the_low_target.supply_ptrace_register (regno, buf);
else
supply_register (regno, buf);
error_exit:;
}
/* Fetch all registers, or just one, from the child process. */
static void
usr_fetch_inferior_registers (int regno)
{
if (regno == -1)
for (regno = 0; regno < the_low_target.num_regs; regno++)
fetch_register (regno);
else
fetch_register (regno);
}
/* Store our register values back into the inferior.
If REGNO is -1, do this for all registers.
Otherwise, REGNO specifies which register (so we can save time). */
static void
usr_store_inferior_registers (int regno)
{
CORE_ADDR regaddr;
int i, size;
char *buf;
int pid;
if (regno >= 0)
{
if (regno >= the_low_target.num_regs)
return;
if ((*the_low_target.cannot_store_register) (regno) == 1)
return;
regaddr = register_addr (regno);
if (regaddr == -1)
return;
errno = 0;
size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
& - sizeof (PTRACE_XFER_TYPE);
buf = alloca (size);
memset (buf, 0, size);
if (the_low_target.collect_ptrace_register)
the_low_target.collect_ptrace_register (regno, buf);
else
collect_register (regno, buf);
pid = lwpid_of (get_thread_lwp (current_inferior));
for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
ptrace (PTRACE_POKEUSER, pid, (PTRACE_ARG3_TYPE) regaddr,
*(PTRACE_XFER_TYPE *) (buf + i));
if (errno != 0)
{
/* At this point, ESRCH should mean the process is
already gone, in which case we simply ignore attempts
to change its registers. See also the related
comment in linux_resume_one_lwp. */
if (errno == ESRCH)
return;
if ((*the_low_target.cannot_store_register) (regno) == 0)
{
char *err = strerror (errno);
char *msg = alloca (strlen (err) + 128);
sprintf (msg, "writing register %d: %s",
regno, err);
error (msg);
return;
}
}
regaddr += sizeof (PTRACE_XFER_TYPE);
}
}
else
for (regno = 0; regno < the_low_target.num_regs; regno++)
usr_store_inferior_registers (regno);
}
#endif /* HAVE_LINUX_USRREGS */
#ifdef HAVE_LINUX_REGSETS
static int
regsets_fetch_inferior_registers ()
{
struct regset_info *regset;
int saw_general_regs = 0;
int pid;
regset = target_regsets;
pid = lwpid_of (get_thread_lwp (current_inferior));
while (regset->size >= 0)
{
void *buf;
int res;
if (regset->size == 0 || disabled_regsets[regset - target_regsets])
{
regset ++;
continue;
}
buf = xmalloc (regset->size);
#ifndef __sparc__
res = ptrace (regset->get_request, pid, 0, buf);
#else
res = ptrace (regset->get_request, pid, buf, 0);
#endif
if (res < 0)
{
if (errno == EIO)
{
/* If we get EIO on a regset, do not try it again for
this process. */
disabled_regsets[regset - target_regsets] = 1;
free (buf);
continue;
}
else
{
char s[256];
sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d",
pid);
perror (s);
}
}
else if (regset->type == GENERAL_REGS)
saw_general_regs = 1;
regset->store_function (buf);
regset ++;
free (buf);
}
if (saw_general_regs)
return 0;
else
return 1;
}
static int
regsets_store_inferior_registers ()
{
struct regset_info *regset;
int saw_general_regs = 0;
int pid;
regset = target_regsets;
pid = lwpid_of (get_thread_lwp (current_inferior));
while (regset->size >= 0)
{
void *buf;
int res;
if (regset->size == 0 || disabled_regsets[regset - target_regsets])
{
regset ++;
continue;
}
buf = xmalloc (regset->size);
/* First fill the buffer with the current register set contents,
in case there are any items in the kernel's regset that are
not in gdbserver's regcache. */
#ifndef __sparc__
res = ptrace (regset->get_request, pid, 0, buf);
#else
res = ptrace (regset->get_request, pid, buf, 0);
#endif
if (res == 0)
{
/* Then overlay our cached registers on that. */
regset->fill_function (buf);
/* Only now do we write the register set. */
#ifndef __sparc__
res = ptrace (regset->set_request, pid, 0, buf);
#else
res = ptrace (regset->set_request, pid, buf, 0);
#endif
}
if (res < 0)
{
if (errno == EIO)
{
/* If we get EIO on a regset, do not try it again for
this process. */
disabled_regsets[regset - target_regsets] = 1;
free (buf);
continue;
}
else if (errno == ESRCH)
{
/* At this point, ESRCH should mean the process is
already gone, in which case we simply ignore attempts
to change its registers. See also the related
comment in linux_resume_one_lwp. */
free (buf);
return 0;
}
else
{
perror ("Warning: ptrace(regsets_store_inferior_registers)");
}
}
else if (regset->type == GENERAL_REGS)
saw_general_regs = 1;
regset ++;
free (buf);
}
if (saw_general_regs)
return 0;
else
return 1;
return 0;
}
#endif /* HAVE_LINUX_REGSETS */
void
linux_fetch_registers (int regno)
{
#ifdef HAVE_LINUX_REGSETS
if (regsets_fetch_inferior_registers () == 0)
return;
#endif
#ifdef HAVE_LINUX_USRREGS
usr_fetch_inferior_registers (regno);
#endif
}
void
linux_store_registers (int regno)
{
#ifdef HAVE_LINUX_REGSETS
if (regsets_store_inferior_registers () == 0)
return;
#endif
#ifdef HAVE_LINUX_USRREGS
usr_store_inferior_registers (regno);
#endif
}
/* Copy LEN bytes from inferior's memory starting at MEMADDR
to debugger memory starting at MYADDR. */
static int
linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
{
register int i;
/* Round starting address down to longword boundary. */
register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
/* Round ending address up; get number of longwords that makes. */
register int count
= (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
/ sizeof (PTRACE_XFER_TYPE);
/* Allocate buffer of that many longwords. */
register PTRACE_XFER_TYPE *buffer
= (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
int fd;
char filename[64];
int pid = lwpid_of (get_thread_lwp (current_inferior));
/* Try using /proc. Don't bother for one word. */
if (len >= 3 * sizeof (long))
{
/* We could keep this file open and cache it - possibly one per
thread. That requires some juggling, but is even faster. */
sprintf (filename, "/proc/%d/mem", pid);
fd = open (filename, O_RDONLY | O_LARGEFILE);
if (fd == -1)
goto no_proc;
/* If pread64 is available, use it. It's faster if the kernel
supports it (only one syscall), and it's 64-bit safe even on
32-bit platforms (for instance, SPARC debugging a SPARC64
application). */
#ifdef HAVE_PREAD64
if (pread64 (fd, myaddr, len, memaddr) != len)
#else
if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, memaddr, len) != len)
#endif
{
close (fd);
goto no_proc;
}
close (fd);
return 0;
}
no_proc:
/* Read all the longwords */
for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
buffer[i] = ptrace (PTRACE_PEEKTEXT, pid, (PTRACE_ARG3_TYPE) addr, 0);
if (errno)
return errno;
}
/* Copy appropriate bytes out of the buffer. */
memcpy (myaddr,
(char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
len);
return 0;
}
/* Copy LEN bytes of data from debugger memory at MYADDR
to inferior's memory at MEMADDR.
On failure (cannot write the inferior)
returns the value of errno. */
static int
linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
{
register int i;
/* Round starting address down to longword boundary. */
register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
/* Round ending address up; get number of longwords that makes. */
register int count
= (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
/* Allocate buffer of that many longwords. */
register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
int pid = lwpid_of (get_thread_lwp (current_inferior));
if (debug_threads)
{
fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr);
}
/* Fill start and end extra bytes of buffer with existing memory data. */
buffer[0] = ptrace (PTRACE_PEEKTEXT, pid, (PTRACE_ARG3_TYPE) addr, 0);
if (count > 1)
{
buffer[count - 1]
= ptrace (PTRACE_PEEKTEXT, pid,
(PTRACE_ARG3_TYPE) (addr + (count - 1)
* sizeof (PTRACE_XFER_TYPE)),
0);
}
/* Copy data to be written over corresponding part of buffer */
memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len);
/* Write the entire buffer. */
for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
ptrace (PTRACE_POKETEXT, pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
if (errno)
return errno;
}
return 0;
}
static int linux_supports_tracefork_flag;
/* Helper functions for linux_test_for_tracefork, called via clone (). */
static int
linux_tracefork_grandchild (void *arg)
{
_exit (0);
}
#define STACK_SIZE 4096
static int
linux_tracefork_child (void *arg)
{
ptrace (PTRACE_TRACEME, 0, 0, 0);
kill (getpid (), SIGSTOP);
#ifdef __ia64__
__clone2 (linux_tracefork_grandchild, arg, STACK_SIZE,
CLONE_VM | SIGCHLD, NULL);
#else
clone (linux_tracefork_grandchild, arg + STACK_SIZE,
CLONE_VM | SIGCHLD, NULL);
#endif
_exit (0);
}
/* Wrapper function for waitpid which handles EINTR, and emulates
__WALL for systems where that is not available. */
static int
my_waitpid (int pid, int *status, int flags)
{
int ret, out_errno;
if (debug_threads)
fprintf (stderr, "my_waitpid (%d, 0x%x)\n", pid, flags);
if (flags & __WALL)
{
sigset_t block_mask, org_mask, wake_mask;
int wnohang;
wnohang = (flags & WNOHANG) != 0;
flags &= ~(__WALL | __WCLONE);
flags |= WNOHANG;
/* Block all signals while here. This avoids knowing about
LinuxThread's signals. */
sigfillset (&block_mask);
sigprocmask (SIG_BLOCK, &block_mask, &org_mask);
/* ... except during the sigsuspend below. */
sigemptyset (&wake_mask);
while (1)
{
/* Since all signals are blocked, there's no need to check
for EINTR here. */
ret = waitpid (pid, status, flags);
out_errno = errno;
if (ret == -1 && out_errno != ECHILD)
break;
else if (ret > 0)
break;
if (flags & __WCLONE)
{
/* We've tried both flavors now. If WNOHANG is set,
there's nothing else to do, just bail out. */
if (wnohang)
break;
if (debug_threads)
fprintf (stderr, "blocking\n");
/* Block waiting for signals. */
sigsuspend (&wake_mask);
}
flags ^= __WCLONE;
}
sigprocmask (SIG_SETMASK, &org_mask, NULL);
}
else
{
do
ret = waitpid (pid, status, flags);
while (ret == -1 && errno == EINTR);
out_errno = errno;
}
if (debug_threads)
fprintf (stderr, "my_waitpid (%d, 0x%x): status(%x), %d\n",
pid, flags, status ? *status : -1, ret);
errno = out_errno;
return ret;
}
/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. Make
sure that we can enable the option, and that it had the desired
effect. */
static void
linux_test_for_tracefork (void)
{
int child_pid, ret, status;
long second_pid;
char *stack = xmalloc (STACK_SIZE * 4);
linux_supports_tracefork_flag = 0;
/* Use CLONE_VM instead of fork, to support uClinux (no MMU). */
#ifdef __ia64__
child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE,
CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
#else
child_pid = clone (linux_tracefork_child, stack + STACK_SIZE,
CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
#endif
if (child_pid == -1)
perror_with_name ("clone");
ret = my_waitpid (child_pid, &status, 0);
if (ret == -1)
perror_with_name ("waitpid");
else if (ret != child_pid)
error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret);
if (! WIFSTOPPED (status))
error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status);
ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
if (ret != 0)
{
ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
if (ret != 0)
{
warning ("linux_test_for_tracefork: failed to kill child");
return;
}
ret = my_waitpid (child_pid, &status, 0);
if (ret != child_pid)
warning ("linux_test_for_tracefork: failed to wait for killed child");
else if (!WIFSIGNALED (status))
warning ("linux_test_for_tracefork: unexpected wait status 0x%x from "
"killed child", status);
return;
}
ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
if (ret != 0)
warning ("linux_test_for_tracefork: failed to resume child");
ret = my_waitpid (child_pid, &status, 0);
if (ret == child_pid && WIFSTOPPED (status)
&& status >> 16 == PTRACE_EVENT_FORK)
{
second_pid = 0;
ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
if (ret == 0 && second_pid != 0)
{
int second_status;
linux_supports_tracefork_flag = 1;
my_waitpid (second_pid, &second_status, 0);
ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
if (ret != 0)
warning ("linux_test_for_tracefork: failed to kill second child");
my_waitpid (second_pid, &status, 0);
}
}
else
warning ("linux_test_for_tracefork: unexpected result from waitpid "
"(%d, status 0x%x)", ret, status);
do
{
ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
if (ret != 0)
warning ("linux_test_for_tracefork: failed to kill child");
my_waitpid (child_pid, &status, 0);
}
while (WIFSTOPPED (status));
free (stack);
}
static void
linux_look_up_symbols (void)
{
#ifdef USE_THREAD_DB
struct process_info *proc = current_process ();
if (proc->private->thread_db_active)
return;
proc->private->thread_db_active
= thread_db_init (!linux_supports_tracefork_flag);
#endif
}
static void
linux_request_interrupt (void)
{
extern unsigned long signal_pid;
if (!ptid_equal (cont_thread, null_ptid)
&& !ptid_equal (cont_thread, minus_one_ptid))
{
struct lwp_info *lwp;
int lwpid;
lwp = get_thread_lwp (current_inferior);
lwpid = lwpid_of (lwp);
kill_lwp (lwpid, SIGINT);
}
else
kill_lwp (signal_pid, SIGINT);
}
/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
to debugger memory starting at MYADDR. */
static int
linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len)
{
char filename[PATH_MAX];
int fd, n;
int pid = lwpid_of (get_thread_lwp (current_inferior));
snprintf (filename, sizeof filename, "/proc/%d/auxv", pid);
fd = open (filename, O_RDONLY);
if (fd < 0)
return -1;
if (offset != (CORE_ADDR) 0
&& lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
n = -1;
else
n = read (fd, myaddr, len);
close (fd);
return n;
}
/* These breakpoint and watchpoint related wrapper functions simply
pass on the function call if the target has registered a
corresponding function. */
static int
linux_insert_point (char type, CORE_ADDR addr, int len)
{
if (the_low_target.insert_point != NULL)
return the_low_target.insert_point (type, addr, len);
else
/* Unsupported (see target.h). */
return 1;
}
static int
linux_remove_point (char type, CORE_ADDR addr, int len)
{
if (the_low_target.remove_point != NULL)
return the_low_target.remove_point (type, addr, len);
else
/* Unsupported (see target.h). */
return 1;
}
static int
linux_stopped_by_watchpoint (void)
{
if (the_low_target.stopped_by_watchpoint != NULL)
return the_low_target.stopped_by_watchpoint ();
else
return 0;
}
static CORE_ADDR
linux_stopped_data_address (void)
{
if (the_low_target.stopped_data_address != NULL)
return the_low_target.stopped_data_address ();
else
return 0;
}
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
#if defined(__mcoldfire__)
/* These should really be defined in the kernel's ptrace.h header. */
#define PT_TEXT_ADDR 49*4
#define PT_DATA_ADDR 50*4
#define PT_TEXT_END_ADDR 51*4
#endif
/* Under uClinux, programs are loaded at non-zero offsets, which we need
to tell gdb about. */
static int
linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
{
#if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
unsigned long text, text_end, data;
int pid = lwpid_of (get_thread_lwp (current_inferior));
errno = 0;
text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0);
text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0);
data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0);
if (errno == 0)
{
/* Both text and data offsets produced at compile-time (and so
used by gdb) are relative to the beginning of the program,
with the data segment immediately following the text segment.
However, the actual runtime layout in memory may put the data
somewhere else, so when we send gdb a data base-address, we
use the real data base address and subtract the compile-time
data base-address from it (which is just the length of the
text segment). BSS immediately follows data in both
cases. */
*text_p = text;
*data_p = data - (text_end - text);
return 1;
}
#endif
return 0;
}
#endif
static int
linux_qxfer_osdata (const char *annex,
unsigned char *readbuf, unsigned const char *writebuf,
CORE_ADDR offset, int len)
{
/* We make the process list snapshot when the object starts to be
read. */
static const char *buf;
static long len_avail = -1;
static struct buffer buffer;
DIR *dirp;
if (strcmp (annex, "processes") != 0)
return 0;
if (!readbuf || writebuf)
return 0;
if (offset == 0)
{
if (len_avail != -1 && len_avail != 0)
buffer_free (&buffer);
len_avail = 0;
buf = NULL;
buffer_init (&buffer);
buffer_grow_str (&buffer, "<osdata type=\"processes\">");
dirp = opendir ("/proc");
if (dirp)
{
struct dirent *dp;
while ((dp = readdir (dirp)) != NULL)
{
struct stat statbuf;
char procentry[sizeof ("/proc/4294967295")];
if (!isdigit (dp->d_name[0])
|| strlen (dp->d_name) > sizeof ("4294967295") - 1)
continue;
sprintf (procentry, "/proc/%s", dp->d_name);
if (stat (procentry, &statbuf) == 0
&& S_ISDIR (statbuf.st_mode))
{
char pathname[128];
FILE *f;
char cmd[MAXPATHLEN + 1];
struct passwd *entry;
sprintf (pathname, "/proc/%s/cmdline", dp->d_name);
entry = getpwuid (statbuf.st_uid);
if ((f = fopen (pathname, "r")) != NULL)
{
size_t len = fread (cmd, 1, sizeof (cmd) - 1, f);
if (len > 0)
{
int i;
for (i = 0; i < len; i++)
if (cmd[i] == '\0')
cmd[i] = ' ';
cmd[len] = '\0';
buffer_xml_printf (
&buffer,
"<item>"
"<column name=\"pid\">%s</column>"
"<column name=\"user\">%s</column>"
"<column name=\"command\">%s</column>"
"</item>",
dp->d_name,
entry ? entry->pw_name : "?",
cmd);
}
fclose (f);
}
}
}
closedir (dirp);
}
buffer_grow_str0 (&buffer, "</osdata>\n");
buf = buffer_finish (&buffer);
len_avail = strlen (buf);
}
if (offset >= len_avail)
{
/* Done. Get rid of the data. */
buffer_free (&buffer);
buf = NULL;
len_avail = 0;
return 0;
}
if (len > len_avail - offset)
len = len_avail - offset;
memcpy (readbuf, buf + offset, len);
return len;
}
/* Convert a native/host siginfo object, into/from the siginfo in the
layout of the inferiors' architecture. */
static void
siginfo_fixup (struct siginfo *siginfo, void *inf_siginfo, int direction)
{
int done = 0;
if (the_low_target.siginfo_fixup != NULL)
done = the_low_target.siginfo_fixup (siginfo, inf_siginfo, direction);
/* If there was no callback, or the callback didn't do anything,
then just do a straight memcpy. */
if (!done)
{
if (direction == 1)
memcpy (siginfo, inf_siginfo, sizeof (struct siginfo));
else
memcpy (inf_siginfo, siginfo, sizeof (struct siginfo));
}
}
static int
linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
unsigned const char *writebuf, CORE_ADDR offset, int len)
{
int pid;
struct siginfo siginfo;
char inf_siginfo[sizeof (struct siginfo)];
if (current_inferior == NULL)
return -1;
pid = lwpid_of (get_thread_lwp (current_inferior));
if (debug_threads)
fprintf (stderr, "%s siginfo for lwp %d.\n",
readbuf != NULL ? "Reading" : "Writing",
pid);
if (offset > sizeof (siginfo))
return -1;
if (ptrace (PTRACE_GETSIGINFO, pid, 0, &siginfo) != 0)
return -1;
/* When GDBSERVER is built as a 64-bit application, ptrace writes into
SIGINFO an object with 64-bit layout. Since debugging a 32-bit
inferior with a 64-bit GDBSERVER should look the same as debugging it
with a 32-bit GDBSERVER, we need to convert it. */
siginfo_fixup (&siginfo, inf_siginfo, 0);
if (offset + len > sizeof (siginfo))
len = sizeof (siginfo) - offset;
if (readbuf != NULL)
memcpy (readbuf, inf_siginfo + offset, len);
else
{
memcpy (inf_siginfo + offset, writebuf, len);
/* Convert back to ptrace layout before flushing it out. */
siginfo_fixup (&siginfo, inf_siginfo, 1);
if (ptrace (PTRACE_SETSIGINFO, pid, 0, &siginfo) != 0)
return -1;
}
return len;
}
/* SIGCHLD handler that serves two purposes: In non-stop/async mode,
so we notice when children change state; as the handler for the
sigsuspend in my_waitpid. */
static void
sigchld_handler (int signo)
{
int old_errno = errno;
if (debug_threads)
/* fprintf is not async-signal-safe, so call write directly. */
write (2, "sigchld_handler\n", sizeof ("sigchld_handler\n") - 1);
if (target_is_async_p ())
async_file_mark (); /* trigger a linux_wait */
errno = old_errno;
}
static int
linux_supports_non_stop (void)
{
return 1;
}
static int
linux_async (int enable)
{
int previous = (linux_event_pipe[0] != -1);
if (previous != enable)
{
sigset_t mask;
sigemptyset (&mask);
sigaddset (&mask, SIGCHLD);
sigprocmask (SIG_BLOCK, &mask, NULL);
if (enable)
{
if (pipe (linux_event_pipe) == -1)
fatal ("creating event pipe failed.");
fcntl (linux_event_pipe[0], F_SETFL, O_NONBLOCK);
fcntl (linux_event_pipe[1], F_SETFL, O_NONBLOCK);
/* Register the event loop handler. */
add_file_handler (linux_event_pipe[0],
handle_target_event, NULL);
/* Always trigger a linux_wait. */
async_file_mark ();
}
else
{
delete_file_handler (linux_event_pipe[0]);
close (linux_event_pipe[0]);
close (linux_event_pipe[1]);
linux_event_pipe[0] = -1;
linux_event_pipe[1] = -1;
}
sigprocmask (SIG_UNBLOCK, &mask, NULL);
}
return previous;
}
static int
linux_start_non_stop (int nonstop)
{
/* Register or unregister from event-loop accordingly. */
linux_async (nonstop);
return 0;
}
static int
linux_supports_multi_process (void)
{
return 1;
}
static struct target_ops linux_target_ops = {
linux_create_inferior,
linux_attach,
linux_kill,
linux_detach,
linux_join,
linux_thread_alive,
linux_resume,
linux_wait,
linux_fetch_registers,
linux_store_registers,
linux_read_memory,
linux_write_memory,
linux_look_up_symbols,
linux_request_interrupt,
linux_read_auxv,
linux_insert_point,
linux_remove_point,
linux_stopped_by_watchpoint,
linux_stopped_data_address,
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
linux_read_offsets,
#else
NULL,
#endif
#ifdef USE_THREAD_DB
thread_db_get_tls_address,
#else
NULL,
#endif
NULL,
hostio_last_error_from_errno,
linux_qxfer_osdata,
linux_xfer_siginfo,
linux_supports_non_stop,
linux_async,
linux_start_non_stop,
linux_supports_multi_process
};
static void
linux_init_signals ()
{
/* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
to find what the cancel signal actually is. */
signal (__SIGRTMIN+1, SIG_IGN);
}
void
initialize_low (void)
{
struct sigaction sigchld_action;
memset (&sigchld_action, 0, sizeof (sigchld_action));
set_target_ops (&linux_target_ops);
set_breakpoint_data (the_low_target.breakpoint,
the_low_target.breakpoint_len);
linux_init_signals ();
linux_test_for_tracefork ();
#ifdef HAVE_LINUX_REGSETS
for (num_regsets = 0; target_regsets[num_regsets].size >= 0; num_regsets++)
;
disabled_regsets = xmalloc (num_regsets);
#endif
sigchld_action.sa_handler = sigchld_handler;
sigemptyset (&sigchld_action.sa_mask);
sigchld_action.sa_flags = SA_RESTART;
sigaction (SIGCHLD, &sigchld_action, NULL);
}