gdb/sol2-tdep.c

/* Target-dependent code for Solaris.

   Copyright (C) 2006-2021 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 "defs.h"
#include "frame.h"
#include "symtab.h"
#include "inferior.h"
#include "objfiles.h"

#include "sol2-tdep.h"

/* The Solaris signal trampolines reside in libc.  For normal signals,
   the function `sigacthandler' is used.  This signal trampoline will
   call the signal handler using the System V calling convention,
   where the third argument is a pointer to an instance of
   `ucontext_t', which has a member `uc_mcontext' that contains the
   saved registers.  Incidentally, the kernel passes the `ucontext_t'
   pointer as the third argument of the signal trampoline too, and
   `sigacthandler' simply passes it on.  However, if you link your
   program with "-L/usr/ucblib -R/usr/ucblib -lucb", the function
   `ucbsigvechandler' will be used, which invokes the using the BSD
   convention, where the third argument is a pointer to an instance of
   `struct sigcontext'.  It is the `ucbsigvechandler' function that
   converts the `ucontext_t' to a `sigcontext', and back.  Unless the
   signal handler modifies the `struct sigcontext' we can safely
   ignore this.  */

static int
sol2_pc_in_sigtramp (CORE_ADDR pc, const char *name)
{
  return (name && (strcmp (name, "sigacthandler") == 0
		   || strcmp (name, "ucbsigvechandler") == 0
		   || strcmp (name, "__sighndlr") == 0));
}

/* Return whether THIS_FRAME corresponds to a Solaris sigtramp routine.  */

int
sol2_sigtramp_p (struct frame_info *this_frame)
{
  CORE_ADDR pc = get_frame_pc (this_frame);
  const char *name;

  find_pc_partial_function (pc, &name, NULL, NULL);
  return sol2_pc_in_sigtramp (pc, name);
}

static CORE_ADDR
sol2_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  struct bound_minimal_symbol msym;

  msym = lookup_minimal_symbol("elf_bndr", NULL, NULL);
  if (msym.minsym && BMSYMBOL_VALUE_ADDRESS (msym) == pc)
    return frame_unwind_caller_pc (get_current_frame ());

  return 0;
}

/* This is how we want PTIDs from Solaris core files to be printed.  */

static std::string
sol2_core_pid_to_str (struct gdbarch *gdbarch, ptid_t ptid)
{
  struct inferior *inf;
  int pid;

  /* Check whether we're printing an LWP (gdb thread) or a process.  */
  pid = ptid.lwp ();
  if (pid != 0)
    {
      /* A thread.  */
      return string_printf ("LWP %ld", ptid.lwp ());
    }

  /* GDB didn't use to put a NT_PSTATUS note in Solaris cores.  If
     that's missing, then we're dealing with a fake PID corelow.c made up.  */
  inf = find_inferior_ptid (current_inferior ()->process_target (), ptid);
  if (inf == NULL || inf->fake_pid_p)
    return "<core>";

  /* Not fake; print as usual.  */
  return normal_pid_to_str (ptid);
}

/* To be called from GDB_OSABI_SOLARIS handlers.  */

void
sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  /* The Sun compilers (Sun ONE Studio, Forte Developer, Sun WorkShop, SunPRO)
     compiler puts out 0 instead of the address in N_SO stabs.  Starting with
     SunPRO 3.0, the compiler does this for N_FUN stabs too.  */
  set_gdbarch_sofun_address_maybe_missing (gdbarch, 1);

  /* Solaris uses SVR4-style shared libraries.  */
  set_gdbarch_skip_solib_resolver (gdbarch, sol2_skip_solib_resolver);

  /* How to print LWP PTIDs from core files.  */
  set_gdbarch_core_pid_to_str (gdbarch, sol2_core_pid_to_str);
}