| /* GNU/Linux native-dependent code for debugging multiple forks. |
| |
| Copyright (C) 2005, 2006, 2007, 2008 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 "inferior.h" |
| #include "regcache.h" |
| #include "gdbcmd.h" |
| #include "infcall.h" |
| #include "objfiles.h" |
| #include "gdb_assert.h" |
| #include "gdb_string.h" |
| #include "linux-fork.h" |
| #include "linux-nat.h" |
| |
| #include <sys/ptrace.h> |
| #include "gdb_wait.h" |
| #include <sys/param.h> |
| #include "gdb_dirent.h" |
| #include <ctype.h> |
| |
| struct fork_info *fork_list; |
| static int highest_fork_num; |
| |
| /* Prevent warning from -Wmissing-prototypes. */ |
| extern void _initialize_linux_fork (void); |
| |
| int detach_fork = 1; /* Default behavior is to detach |
| newly forked processes (legacy). */ |
| |
| /* Fork list data structure: */ |
| struct fork_info |
| { |
| struct fork_info *next; |
| ptid_t ptid; |
| int num; /* Convenient handle (GDB fork id) */ |
| struct regcache *savedregs; /* Convenient for info fork, saves |
| having to actually switch contexts. */ |
| int clobber_regs; /* True if we should restore saved regs. */ |
| ULONGEST pc; /* PC for info fork. */ |
| off_t *filepos; /* Set of open file descriptors' offsets. */ |
| int maxfd; |
| }; |
| |
| /* Fork list methods: */ |
| |
| extern int |
| forks_exist_p (void) |
| { |
| return (fork_list != NULL); |
| } |
| |
| /* Add a fork to internal fork list. |
| Called from linux child_follow_fork. */ |
| |
| extern struct fork_info * |
| add_fork (pid_t pid) |
| { |
| struct fork_info *fp; |
| |
| if (fork_list == NULL && pid != PIDGET (inferior_ptid)) |
| { |
| /* Special case -- if this is the first fork in the list |
| (the list is hitherto empty), and if this new fork is |
| NOT the current inferior_ptid, then add inferior_ptid |
| first, as a special zeroeth fork id. */ |
| highest_fork_num = -1; |
| add_fork (PIDGET (inferior_ptid)); /* safe recursion */ |
| } |
| |
| fp = XZALLOC (struct fork_info); |
| fp->ptid = ptid_build (pid, pid, 0); |
| fp->num = ++highest_fork_num; |
| fp->next = fork_list; |
| fork_list = fp; |
| return fp; |
| } |
| |
| static void |
| free_fork (struct fork_info *fp) |
| { |
| /* Notes on step-resume breakpoints: since this is a concern for |
| threads, let's convince ourselves that it's not a concern for |
| forks. There are two ways for a fork_info to be created. First, |
| by the checkpoint command, in which case we're at a gdb prompt |
| and there can't be any step-resume breakpoint. Second, by a fork |
| in the user program, in which case we *may* have stepped into the |
| fork call, but regardless of whether we follow the parent or the |
| child, we will return to the same place and the step-resume |
| breakpoint, if any, will take care of itself as usual. And |
| unlike threads, we do not save a private copy of the step-resume |
| breakpoint -- so we're OK. */ |
| |
| if (fp) |
| { |
| if (fp->savedregs) |
| regcache_xfree (fp->savedregs); |
| if (fp->filepos) |
| xfree (fp->filepos); |
| xfree (fp); |
| } |
| } |
| |
| static void |
| delete_fork (ptid_t ptid) |
| { |
| struct fork_info *fp, *fpprev; |
| |
| fpprev = NULL; |
| |
| for (fp = fork_list; fp; fpprev = fp, fp = fp->next) |
| if (ptid_equal (fp->ptid, ptid)) |
| break; |
| |
| if (!fp) |
| return; |
| |
| if (fpprev) |
| fpprev->next = fp->next; |
| else |
| fork_list = fp->next; |
| |
| free_fork (fp); |
| |
| /* Special case: if there is now only one process in the list, |
| and if it is (hopefully!) the current inferior_ptid, then |
| remove it, leaving the list empty -- we're now down to the |
| default case of debugging a single process. */ |
| if (fork_list != NULL && fork_list->next == NULL && |
| ptid_equal (fork_list->ptid, inferior_ptid)) |
| { |
| /* Last fork -- delete from list and handle as solo process |
| (should be a safe recursion). */ |
| delete_fork (inferior_ptid); |
| } |
| } |
| |
| /* Find a fork_info by matching PTID. */ |
| static struct fork_info * |
| find_fork_ptid (ptid_t ptid) |
| { |
| struct fork_info *fp; |
| |
| for (fp = fork_list; fp; fp = fp->next) |
| if (ptid_equal (fp->ptid, ptid)) |
| return fp; |
| |
| return NULL; |
| } |
| |
| /* Find a fork_info by matching ID. */ |
| static struct fork_info * |
| find_fork_id (int num) |
| { |
| struct fork_info *fp; |
| |
| for (fp = fork_list; fp; fp = fp->next) |
| if (fp->num == num) |
| return fp; |
| |
| return NULL; |
| } |
| |
| /* Find a fork_info by matching pid. */ |
| extern struct fork_info * |
| find_fork_pid (pid_t pid) |
| { |
| struct fork_info *fp; |
| |
| for (fp = fork_list; fp; fp = fp->next) |
| if (pid == ptid_get_pid (fp->ptid)) |
| return fp; |
| |
| return NULL; |
| } |
| |
| static ptid_t |
| fork_id_to_ptid (int num) |
| { |
| struct fork_info *fork = find_fork_id (num); |
| if (fork) |
| return fork->ptid; |
| else |
| return pid_to_ptid (-1); |
| } |
| |
| static void |
| init_fork_list (void) |
| { |
| struct fork_info *fp, *fpnext; |
| |
| if (!fork_list) |
| return; |
| |
| for (fp = fork_list; fp; fp = fpnext) |
| { |
| fpnext = fp->next; |
| delete_inferior (ptid_get_pid (fp->ptid)); |
| free_fork (fp); |
| } |
| |
| fork_list = NULL; |
| } |
| |
| /* Fork list <-> gdb interface. */ |
| |
| /* Utility function for fork_load/fork_save. |
| Calls lseek in the (current) inferior process. */ |
| |
| static off_t |
| call_lseek (int fd, off_t offset, int whence) |
| { |
| char exp[80]; |
| |
| snprintf (&exp[0], sizeof (exp), "lseek (%d, %ld, %d)", |
| fd, (long) offset, whence); |
| return (off_t) parse_and_eval_long (&exp[0]); |
| } |
| |
| /* Load infrun state for the fork PTID. */ |
| |
| static void |
| fork_load_infrun_state (struct fork_info *fp) |
| { |
| extern void nullify_last_target_wait_ptid (); |
| int i; |
| |
| inferior_ptid = fp->ptid; |
| |
| linux_nat_switch_fork (inferior_ptid); |
| |
| if (fp->savedregs && fp->clobber_regs) |
| regcache_cpy (get_current_regcache (), fp->savedregs); |
| |
| registers_changed (); |
| reinit_frame_cache (); |
| |
| stop_pc = read_pc (); |
| nullify_last_target_wait_ptid (); |
| |
| /* Now restore the file positions of open file descriptors. */ |
| if (fp->filepos) |
| { |
| for (i = 0; i <= fp->maxfd; i++) |
| if (fp->filepos[i] != (off_t) -1) |
| call_lseek (i, fp->filepos[i], SEEK_SET); |
| /* NOTE: I can get away with using SEEK_SET and SEEK_CUR because |
| this is native-only. If it ever has to be cross, we'll have |
| to rethink this. */ |
| } |
| } |
| |
| /* Save infrun state for the fork PTID. |
| Exported for use by linux child_follow_fork. */ |
| |
| extern void |
| fork_save_infrun_state (struct fork_info *fp, int clobber_regs) |
| { |
| char path[MAXPATHLEN]; |
| struct dirent *de; |
| DIR *d; |
| |
| if (fp->savedregs) |
| regcache_xfree (fp->savedregs); |
| |
| fp->savedregs = regcache_dup (get_current_regcache ()); |
| fp->clobber_regs = clobber_regs; |
| fp->pc = read_pc (); |
| |
| if (clobber_regs) |
| { |
| /* Now save the 'state' (file position) of all open file descriptors. |
| Unfortunately fork does not take care of that for us... */ |
| snprintf (path, MAXPATHLEN, "/proc/%ld/fd", (long) PIDGET (fp->ptid)); |
| if ((d = opendir (path)) != NULL) |
| { |
| long tmp; |
| |
| fp->maxfd = 0; |
| while ((de = readdir (d)) != NULL) |
| { |
| /* Count open file descriptors (actually find highest |
| numbered). */ |
| tmp = strtol (&de->d_name[0], NULL, 10); |
| if (fp->maxfd < tmp) |
| fp->maxfd = tmp; |
| } |
| /* Allocate array of file positions. */ |
| fp->filepos = xrealloc (fp->filepos, |
| (fp->maxfd + 1) * sizeof (*fp->filepos)); |
| |
| /* Initialize to -1 (invalid). */ |
| for (tmp = 0; tmp <= fp->maxfd; tmp++) |
| fp->filepos[tmp] = -1; |
| |
| /* Now find actual file positions. */ |
| rewinddir (d); |
| while ((de = readdir (d)) != NULL) |
| if (isdigit (de->d_name[0])) |
| { |
| tmp = strtol (&de->d_name[0], NULL, 10); |
| fp->filepos[tmp] = call_lseek (tmp, 0, SEEK_CUR); |
| } |
| closedir (d); |
| } |
| } |
| } |
| |
| /* Kill 'em all, let God sort 'em out... */ |
| |
| extern void |
| linux_fork_killall (void) |
| { |
| /* Walk list and kill every pid. No need to treat the |
| current inferior_ptid as special (we do not return a |
| status for it) -- however any process may be a child |
| or a parent, so may get a SIGCHLD from a previously |
| killed child. Wait them all out. */ |
| struct fork_info *fp; |
| pid_t pid, ret; |
| int status; |
| |
| for (fp = fork_list; fp; fp = fp->next) |
| { |
| pid = PIDGET (fp->ptid); |
| do { |
| /* Use SIGKILL instead of PTRACE_KILL because the former works even |
| if the thread is running, while the later doesn't. */ |
| kill (pid, SIGKILL); |
| ret = waitpid (pid, &status, 0); |
| /* We might get a SIGCHLD instead of an exit status. This is |
| aggravated by the first kill above - a child has just |
| died. MVS comment cut-and-pasted from linux-nat. */ |
| } while (ret == pid && WIFSTOPPED (status)); |
| } |
| init_fork_list (); /* Clear list, prepare to start fresh. */ |
| } |
| |
| /* The current inferior_ptid has exited, but there are other viable |
| forks to debug. Delete the exiting one and context-switch to the |
| first available. */ |
| |
| extern void |
| linux_fork_mourn_inferior (void) |
| { |
| /* Wait just one more time to collect the inferior's exit status. |
| Do not check whether this succeeds though, since we may be |
| dealing with a process that we attached to. Such a process will |
| only report its exit status to its original parent. */ |
| int status; |
| |
| waitpid (ptid_get_pid (inferior_ptid), &status, 0); |
| |
| /* OK, presumably inferior_ptid is the one who has exited. |
| We need to delete that one from the fork_list, and switch |
| to the next available fork. */ |
| delete_fork (inferior_ptid); |
| /* Delete process from GDB's inferior list. */ |
| delete_inferior (ptid_get_pid (inferior_ptid)); |
| |
| /* There should still be a fork - if there's only one left, |
| delete_fork won't remove it, because we haven't updated |
| inferior_ptid yet. */ |
| gdb_assert (fork_list); |
| |
| fork_load_infrun_state (fork_list); |
| printf_filtered (_("[Switching to %s]\n"), |
| target_pid_to_str (inferior_ptid)); |
| |
| /* If there's only one fork, switch back to non-fork mode. */ |
| if (fork_list->next == NULL) |
| delete_fork (inferior_ptid); |
| } |
| |
| /* Fork list <-> user interface. */ |
| |
| static void |
| delete_fork_command (char *args, int from_tty) |
| { |
| ptid_t ptid; |
| |
| if (!args || !*args) |
| error (_("Requires argument (fork/checkpoint id to delete)")); |
| |
| ptid = fork_id_to_ptid (parse_and_eval_long (args)); |
| if (ptid_equal (ptid, minus_one_ptid)) |
| error (_("No such fork/checkpoint id, %s"), args); |
| |
| if (ptid_equal (ptid, inferior_ptid)) |
| error (_("Please switch to another fork/checkpoint before deleting the current one")); |
| |
| if (ptrace (PTRACE_KILL, PIDGET (ptid), 0, 0)) |
| error (_("Unable to kill pid %s"), target_tid_to_str (ptid)); |
| |
| if (from_tty) |
| printf_filtered (_("Killed %s\n"), target_pid_to_str (ptid)); |
| |
| delete_fork (ptid); |
| /* Delete process from GDB's inferior list. */ |
| delete_inferior (ptid_get_pid (ptid)); |
| } |
| |
| static void |
| detach_fork_command (char *args, int from_tty) |
| { |
| ptid_t ptid; |
| |
| if (!args || !*args) |
| error (_("Requires argument (fork id to detach)")); |
| |
| ptid = fork_id_to_ptid (parse_and_eval_long (args)); |
| if (ptid_equal (ptid, minus_one_ptid)) |
| error (_("No such fork id, %s"), args); |
| |
| if (ptid_equal (ptid, inferior_ptid)) |
| error (_("Please switch to another fork before detaching the current one")); |
| |
| if (ptrace (PTRACE_DETACH, PIDGET (ptid), 0, 0)) |
| error (_("Unable to detach %s"), target_pid_to_str (ptid)); |
| |
| if (from_tty) |
| printf_filtered (_("Detached %s\n"), target_pid_to_str (ptid)); |
| |
| delete_fork (ptid); |
| /* Delete process from GDB's process table. */ |
| detach_inferior (ptid_get_pid (ptid)); |
| } |
| |
| /* Print information about currently known forks. */ |
| |
| static void |
| info_forks_command (char *arg, int from_tty) |
| { |
| struct frame_info *cur_frame; |
| struct symtab_and_line sal; |
| struct symtab *cur_symtab; |
| struct fork_info *fp; |
| int cur_line; |
| ULONGEST pc; |
| int requested = -1; |
| struct fork_info *printed = NULL; |
| |
| if (arg && *arg) |
| requested = (int) parse_and_eval_long (arg); |
| |
| for (fp = fork_list; fp; fp = fp->next) |
| { |
| if (requested > 0 && fp->num != requested) |
| continue; |
| |
| printed = fp; |
| if (ptid_equal (fp->ptid, inferior_ptid)) |
| { |
| printf_filtered ("* "); |
| pc = read_pc (); |
| } |
| else |
| { |
| printf_filtered (" "); |
| pc = fp->pc; |
| } |
| printf_filtered ("%d %s", fp->num, target_pid_to_str (fp->ptid)); |
| if (fp->num == 0) |
| printf_filtered (_(" (main process)")); |
| printf_filtered (_(" at ")); |
| fputs_filtered (paddress (pc), gdb_stdout); |
| |
| sal = find_pc_line (pc, 0); |
| if (sal.symtab) |
| { |
| char *tmp = strrchr (sal.symtab->filename, '/'); |
| |
| if (tmp) |
| printf_filtered (_(", file %s"), tmp + 1); |
| else |
| printf_filtered (_(", file %s"), sal.symtab->filename); |
| } |
| if (sal.line) |
| printf_filtered (_(", line %d"), sal.line); |
| if (!sal.symtab && !sal.line) |
| { |
| struct minimal_symbol *msym; |
| |
| msym = lookup_minimal_symbol_by_pc (pc); |
| if (msym) |
| printf_filtered (", <%s>", SYMBOL_LINKAGE_NAME (msym)); |
| } |
| |
| putchar_filtered ('\n'); |
| } |
| if (printed == NULL) |
| { |
| if (requested > 0) |
| printf_filtered (_("No fork number %d.\n"), requested); |
| else |
| printf_filtered (_("No forks.\n")); |
| } |
| } |
| |
| /* Save/restore mode variable 'detach_fork': |
| We need to temporarily take over this mode variable, while |
| preserving the user-specified state, and make sure that it |
| gets restored in case of error. |
| |
| The int pointer that we use comes from the caller, so we can |
| be called more than once (even though currently we don't need to). */ |
| |
| static void |
| restore_detach_fork (void *arg) |
| { |
| detach_fork = *(int *) arg; |
| } |
| |
| static struct cleanup * |
| save_detach_fork (int *saved_val) |
| { |
| *saved_val = detach_fork; |
| return make_cleanup (restore_detach_fork, (void *) saved_val); |
| } |
| |
| static void |
| checkpoint_command (char *args, int from_tty) |
| { |
| struct objfile *fork_objf; |
| struct gdbarch *gdbarch; |
| struct target_waitstatus last_target_waitstatus; |
| ptid_t last_target_ptid; |
| struct value *fork_fn = NULL, *ret; |
| struct fork_info *fp; |
| pid_t retpid; |
| struct cleanup *old_chain; |
| long i; |
| /* Make this temp var static, 'cause it's used in the error context. */ |
| static int temp_detach_fork; |
| |
| /* Remove breakpoints, so that they are not inserted |
| in the forked process. */ |
| remove_breakpoints (); |
| |
| /* Make the inferior fork, record its (and gdb's) state. */ |
| |
| if (lookup_minimal_symbol ("fork", NULL, NULL) != NULL) |
| fork_fn = find_function_in_inferior ("fork", &fork_objf); |
| if (!fork_fn) |
| if (lookup_minimal_symbol ("_fork", NULL, NULL) != NULL) |
| fork_fn = find_function_in_inferior ("fork", &fork_objf); |
| if (!fork_fn) |
| error (_("checkpoint: can't find fork function in inferior.")); |
| |
| gdbarch = get_objfile_arch (fork_objf); |
| ret = value_from_longest (builtin_type (gdbarch)->builtin_int, 0); |
| old_chain = save_detach_fork (&temp_detach_fork); |
| detach_fork = 0; |
| ret = call_function_by_hand (fork_fn, 0, &ret); |
| do_cleanups (old_chain); |
| if (!ret) /* Probably can't happen. */ |
| error (_("checkpoint: call_function_by_hand returned null.")); |
| |
| retpid = value_as_long (ret); |
| get_last_target_status (&last_target_ptid, &last_target_waitstatus); |
| if (from_tty) |
| { |
| int parent_pid; |
| |
| printf_filtered (_("checkpoint: fork returned pid %ld.\n"), |
| (long) retpid); |
| if (info_verbose) |
| { |
| parent_pid = ptid_get_lwp (last_target_ptid); |
| if (parent_pid == 0) |
| parent_pid = ptid_get_pid (last_target_ptid); |
| printf_filtered (_(" gdb says parent = %ld.\n"), |
| (long) parent_pid); |
| } |
| } |
| |
| fp = find_fork_pid (retpid); |
| if (!fp) |
| error (_("Failed to find new fork")); |
| fork_save_infrun_state (fp, 1); |
| insert_breakpoints (); |
| } |
| |
| static void |
| linux_fork_context (struct fork_info *newfp, int from_tty) |
| { |
| /* Now we attempt to switch processes. */ |
| struct fork_info *oldfp = find_fork_ptid (inferior_ptid); |
| ptid_t ptid; |
| int id, i; |
| |
| if (!newfp) |
| error (_("No such fork/process")); |
| |
| if (!oldfp) |
| oldfp = add_fork (ptid_get_pid (inferior_ptid)); |
| |
| fork_save_infrun_state (oldfp, 1); |
| remove_breakpoints (); |
| fork_load_infrun_state (newfp); |
| insert_breakpoints (); |
| |
| printf_filtered (_("Switching to %s\n"), |
| target_pid_to_str (inferior_ptid)); |
| |
| print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC); |
| } |
| |
| /* Switch inferior process (fork) context, by process id. */ |
| static void |
| process_command (char *args, int from_tty) |
| { |
| struct fork_info *fp; |
| |
| if (!args || !*args) |
| error (_("Requires argument (process id to switch to)")); |
| |
| if ((fp = find_fork_pid (parse_and_eval_long (args))) == NULL) |
| error (_("Not found: process id %s"), args); |
| |
| linux_fork_context (fp, from_tty); |
| } |
| |
| /* Switch inferior process (fork) context, by fork id. */ |
| static void |
| fork_command (char *args, int from_tty) |
| { |
| struct fork_info *fp; |
| |
| if (!args || !*args) |
| error (_("Requires argument (fork id to switch to)")); |
| |
| if ((fp = find_fork_id (parse_and_eval_long (args))) == NULL) |
| error (_("Not found: fork id %s"), args); |
| |
| linux_fork_context (fp, from_tty); |
| } |
| |
| /* Switch inferior process (fork) context, by checkpoint id. */ |
| static void |
| restart_command (char *args, int from_tty) |
| { |
| struct fork_info *fp; |
| |
| if (!args || !*args) |
| error (_("Requires argument (checkpoint id to restart)")); |
| |
| if ((fp = find_fork_id (parse_and_eval_long (args))) == NULL) |
| error (_("Not found: checkpoint id %s"), args); |
| |
| linux_fork_context (fp, from_tty); |
| } |
| |
| void |
| _initialize_linux_fork (void) |
| { |
| init_fork_list (); |
| |
| /* Set/show detach-on-fork: user-settable mode. */ |
| |
| add_setshow_boolean_cmd ("detach-on-fork", class_obscure, &detach_fork, _("\ |
| Set whether gdb will detach the child of a fork."), _("\ |
| Show whether gdb will detach the child of a fork."), _("\ |
| Tells gdb whether to detach the child of a fork."), |
| NULL, NULL, &setlist, &showlist); |
| |
| /* Set/show restart-auto-finish: user-settable count. Causes the |
| first "restart" of a fork to do some number of "finish" commands |
| before returning to user. |
| |
| Useful because otherwise the virgin fork process will be stopped |
| somewhere in the un-interesting fork system call. */ |
| |
| /* Checkpoint command: create a fork of the inferior process |
| and set it aside for later debugging. */ |
| |
| add_com ("checkpoint", class_obscure, checkpoint_command, _("\ |
| Fork a duplicate process (experimental).")); |
| |
| /* Restart command: restore the context of a specified fork |
| process. May be used for "program forks" as well as for |
| "debugger forks" (checkpoints). */ |
| |
| add_com ("restart", class_obscure, restart_command, _("\ |
| restart <n>: restore program context from a checkpoint.\n\ |
| Argument 'n' is checkpoint ID, as displayed by 'info checkpoints'.")); |
| |
| /* Delete checkpoint command: kill the process and remove it from |
| fork list. */ |
| |
| add_cmd ("checkpoint", class_obscure, delete_fork_command, _("\ |
| Delete a fork/checkpoint (experimental)."), |
| &deletelist); |
| |
| /* Detach checkpoint command: release the process to run independently, |
| and remove it from the fork list. */ |
| |
| add_cmd ("checkpoint", class_obscure, detach_fork_command, _("\ |
| Detach from a fork/checkpoint (experimental)."), |
| &detachlist); |
| |
| /* Info checkpoints command: list all forks/checkpoints |
| currently under gdb's control. */ |
| |
| add_info ("checkpoints", info_forks_command, |
| _("IDs of currently known forks/checkpoints.")); |
| |
| /* Command aliases (let "fork" and "checkpoint" be used |
| interchangeably). */ |
| |
| add_alias_cmd ("fork", "checkpoint", class_obscure, 1, &deletelist); |
| add_alias_cmd ("fork", "checkpoint", class_obscure, 1, &detachlist); |
| add_info_alias ("forks", "checkpoints", 0); |
| |
| /* "fork <n>" (by analogy to "thread <n>"). */ |
| add_com ("fork", class_obscure, fork_command, _("\ |
| fork <n>: Switch between forked processes.\n\ |
| Argument 'n' is fork ID, as displayed by 'info forks'.")); |
| |
| /* "process <proc id>" as opposed to "fork <fork id>". */ |
| add_com ("process", class_obscure, process_command, _("\ |
| process <pid>: Switch between forked processes.\n\ |
| Argument 'pid' is process ID, as displayed by 'info forks' or 'shell ps'.")); |
| } |