/* GNU/Linux native-dependent code for debugging multiple forks.
- Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
+ Free Software Foundation, Inc.
This file is part of GDB.
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
+#include "arch-utils.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 "gdbthread.h"
#include <sys/ptrace.h>
#include "gdb_wait.h"
/* 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;
+ ptid_t parent_ptid;
int num; /* Convenient handle (GDB fork id) */
- struct regcache *savedregs; /* Convenient for info fork, saves
+ 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
+int
forks_exist_p (void)
{
return (fork_list != NULL);
}
-/* Add a fork to internal fork list.
- Called from linux child_follow_fork. */
+/* Add a fork to the internal fork list. */
-extern struct fork_info *
+struct fork_info *
add_fork (pid_t pid)
{
struct fork_info *fp;
free_fork (fp);
- /* Special case: if there is now only one process in the list,
+ /* 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. */
/* Fork list <-> gdb interface. */
-/* Utility function for fork_load/fork_save.
+/* Utility function for fork_load/fork_save.
Calls lseek in the (current) inferior process. */
static off_t
extern void nullify_last_target_wait_ptid ();
int i;
- inferior_ptid = fp->ptid;
-
- linux_nat_switch_fork (inferior_ptid);
+ linux_nat_switch_fork (fp->ptid);
if (fp->savedregs && fp->clobber_regs)
regcache_cpy (get_current_regcache (), fp->savedregs);
registers_changed ();
reinit_frame_cache ();
- stop_pc = read_pc ();
+ stop_pc = regcache_read_pc (get_current_regcache ());
nullify_last_target_wait_ptid ();
/* Now restore the file positions of open file descriptors. */
/* Save infrun state for the fork PTID.
Exported for use by linux child_follow_fork. */
-extern void
+static void
fork_save_infrun_state (struct fork_info *fp, int clobber_regs)
{
char path[MAXPATHLEN];
fp->savedregs = regcache_dup (get_current_regcache ());
fp->clobber_regs = clobber_regs;
- fp->pc = read_pc ();
if (clobber_regs)
{
fp->maxfd = tmp;
}
/* Allocate array of file positions. */
- fp->filepos = xrealloc (fp->filepos,
+ fp->filepos = xrealloc (fp->filepos,
(fp->maxfd + 1) * sizeof (*fp->filepos));
/* Initialize to -1 (invalid). */
/* Kill 'em all, let God sort 'em out... */
-extern void
+void
linux_fork_killall (void)
{
/* Walk list and kill every pid. No need to treat the
{
pid = PIDGET (fp->ptid);
do {
- ptrace (PT_KILL, pid, 0, 0);
+ /* 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
forks to debug. Delete the exiting one and context-switch to the
first available. */
-extern void
+void
linux_fork_mourn_inferior (void)
{
/* Wait just one more time to collect the inferior's exit status.
delete_fork (inferior_ptid);
}
+/* The current inferior_ptid is being detached, but there are other
+ viable forks to debug. Detach and delete it and context-switch to
+ the first available. */
+
+void
+linux_fork_detach (char *args, int from_tty)
+{
+ /* OK, inferior_ptid is the one we are detaching from. We need to
+ delete it from the fork_list, and switch to the next available
+ fork. */
+
+ if (ptrace (PTRACE_DETACH, PIDGET (inferior_ptid), 0, 0))
+ error (_("Unable to detach %s"), target_pid_to_str (inferior_ptid));
+
+ delete_fork (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);
+
+ if (from_tty)
+ 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);
+}
+
+static void
+inferior_call_waitpid_cleanup (void *fp)
+{
+ struct fork_info *oldfp = fp;
+
+ if (oldfp)
+ {
+ /* Switch back to inferior_ptid. */
+ remove_breakpoints ();
+ fork_load_infrun_state (oldfp);
+ insert_breakpoints ();
+ }
+}
+
+static int
+inferior_call_waitpid (ptid_t pptid, int pid)
+{
+ struct objfile *waitpid_objf;
+ struct value *waitpid_fn = NULL;
+ struct value *argv[4], *retv;
+ struct gdbarch *gdbarch = get_current_arch ();
+ struct fork_info *oldfp = NULL, *newfp = NULL;
+ struct cleanup *old_cleanup;
+ int ret = -1;
+
+ if (!ptid_equal (pptid, inferior_ptid))
+ {
+ /* Switch to pptid. */
+ oldfp = find_fork_ptid (inferior_ptid);
+ gdb_assert (oldfp != NULL);
+ newfp = find_fork_ptid (pptid);
+ gdb_assert (oldfp != NULL);
+ fork_save_infrun_state (oldfp, 1);
+ remove_breakpoints ();
+ fork_load_infrun_state (newfp);
+ insert_breakpoints ();
+ }
+
+ old_cleanup = make_cleanup (inferior_call_waitpid_cleanup, oldfp);
+
+ /* Get the waitpid_fn. */
+ if (lookup_minimal_symbol ("waitpid", NULL, NULL) != NULL)
+ waitpid_fn = find_function_in_inferior ("waitpid", &waitpid_objf);
+ if (!waitpid_fn && lookup_minimal_symbol ("_waitpid", NULL, NULL) != NULL)
+ waitpid_fn = find_function_in_inferior ("_waitpid", &waitpid_objf);
+ if (!waitpid_fn)
+ goto out;
+
+ /* Get the argv. */
+ argv[0] = value_from_longest (builtin_type (gdbarch)->builtin_int, pid);
+ argv[1] = value_from_pointer (builtin_type (gdbarch)->builtin_data_ptr, 0);
+ argv[2] = value_from_longest (builtin_type (gdbarch)->builtin_int, 0);
+ argv[3] = 0;
+
+ retv = call_function_by_hand (waitpid_fn, 3, argv);
+ if (value_as_long (retv) < 0)
+ goto out;
+
+ ret = 0;
+
+out:
+ do_cleanups (old_cleanup);
+ return ret;
+}
+
/* Fork list <-> user interface. */
static void
-delete_fork_command (char *args, int from_tty)
+delete_checkpoint_command (char *args, int from_tty)
{
- ptid_t ptid;
+ ptid_t ptid, pptid;
+ struct fork_info *fi;
if (!args || !*args)
- error (_("Requires argument (fork/checkpoint id to delete)"));
+ error (_("Requires argument (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);
+ error (_("No such checkpoint id, %s"), args);
if (ptid_equal (ptid, inferior_ptid))
- error (_("Please switch to another fork/checkpoint before deleting the current one"));
+ error (_("\
+Please switch to another 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));
+ error (_("Unable to kill pid %s"), target_pid_to_str (ptid));
+
+ fi = find_fork_ptid (ptid);
+ gdb_assert (fi);
+ pptid = fi->parent_ptid;
if (from_tty)
printf_filtered (_("Killed %s\n"), target_pid_to_str (ptid));
delete_fork (ptid);
+
+ /* If fi->parent_ptid is not a part of lwp but it's a part of checkpoint
+ list, waitpid the ptid.
+ If fi->parent_ptid is a part of lwp and it is stoped, waitpid the
+ ptid. */
+ if ((!find_thread_ptid (pptid) && find_fork_ptid (pptid))
+ || (find_thread_ptid (pptid) && is_stopped (pptid)))
+ {
+ if (inferior_call_waitpid (pptid, PIDGET (ptid)))
+ warning (_("Unable to wait pid %s"), target_pid_to_str (ptid));
+ }
}
static void
-detach_fork_command (char *args, int from_tty)
+detach_checkpoint_command (char *args, int from_tty)
{
ptid_t ptid;
if (!args || !*args)
- error (_("Requires argument (fork id to detach)"));
+ error (_("Requires argument (checkpoint 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);
+ error (_("No such checkpoint id, %s"), args);
if (ptid_equal (ptid, inferior_ptid))
- error (_("Please switch to another fork before detaching the current one"));
+ error (_("\
+Please switch to another checkpoint before detaching the current one"));
if (ptrace (PTRACE_DETACH, PIDGET (ptid), 0, 0))
error (_("Unable to detach %s"), target_pid_to_str (ptid));
delete_fork (ptid);
}
-/* Print information about currently known forks. */
+/* Print information about currently known checkpoints. */
static void
-info_forks_command (char *arg, int from_tty)
+info_checkpoints_command (char *arg, int from_tty)
{
- struct frame_info *cur_frame;
+ struct gdbarch *gdbarch = get_current_arch ();
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 (ptid_equal (fp->ptid, inferior_ptid))
{
printf_filtered ("* ");
- pc = read_pc ();
+ pc = regcache_read_pc (get_current_regcache ());
}
else
{
printf_filtered (" ");
- pc = fp->pc;
+ pc = regcache_read_pc (fp->savedregs);
}
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);
+ fputs_filtered (paddress (gdbarch, pc), gdb_stdout);
sal = find_pc_line (pc, 0);
if (sal.symtab)
if (printed == NULL)
{
if (requested > 0)
- printf_filtered (_("No fork number %d.\n"), requested);
+ printf_filtered (_("No checkpoint number %d.\n"), requested);
else
- printf_filtered (_("No forks.\n"));
+ printf_filtered (_("No checkpoints.\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). */
+/* The PID of the process we're checkpointing. */
+static int checkpointing_pid = 0;
-static void
-restore_detach_fork (void *arg)
+int
+linux_fork_checkpointing_p (int pid)
{
- 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);
+ return (checkpointing_pid == pid);
}
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_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_fn = find_function_in_inferior ("fork", &fork_objf);
if (!fork_fn)
error (_("checkpoint: can't find fork function in inferior."));
- ret = value_from_longest (builtin_type_int, 0);
- old_chain = save_detach_fork (&temp_detach_fork);
- detach_fork = 0;
+ gdbarch = get_objfile_arch (fork_objf);
+ ret = value_from_longest (builtin_type (gdbarch)->builtin_int, 0);
+
+ /* Tell linux-nat.c that we're checkpointing this inferior. */
+ old_chain = make_cleanup_restore_integer (&checkpointing_pid);
+ checkpointing_pid = PIDGET (inferior_ptid);
+
ret = call_function_by_hand (fork_fn, 0, &ret);
do_cleanups (old_chain);
if (!ret) /* Probably can't happen. */
{
int parent_pid;
- printf_filtered (_("checkpoint: fork returned pid %ld.\n"),
+ 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"),
+ printf_filtered (_(" gdb says parent = %ld.\n"),
(long) parent_pid);
}
}
if (!fp)
error (_("Failed to find new fork"));
fork_save_infrun_state (fp, 1);
- insert_breakpoints ();
+ fp->parent_ptid = last_target_ptid;
}
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;
+ struct fork_info *oldfp;
- if (!newfp)
- error (_("No such fork/process"));
+ gdb_assert (newfp != NULL);
- if (!oldfp)
- oldfp = add_fork (ptid_get_pid (inferior_ptid));
+ oldfp = find_fork_ptid (inferior_ptid);
+ gdb_assert (oldfp != NULL);
fork_save_infrun_state (oldfp, 1);
remove_breakpoints ();
fork_load_infrun_state (newfp);
insert_breakpoints ();
- printf_filtered (_("Switching to %s\n"),
+ 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. */
+/* Switch inferior process (checkpoint) context, by checkpoint id. */
static void
restart_command (char *args, int from_tty)
{
{
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). */
+ /* Restart command: restore the context of a specified checkpoint
+ process. */
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. */
+ the fork list. */
- add_cmd ("checkpoint", class_obscure, delete_fork_command, _("\
-Delete a fork/checkpoint (experimental)."),
+ add_cmd ("checkpoint", class_obscure, delete_checkpoint_command, _("\
+Delete a checkpoint (experimental)."),
&deletelist);
- /* Detach checkpoint command: release the process to run independently,
+ /* 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)."),
+ add_cmd ("checkpoint", class_obscure, detach_checkpoint_command, _("\
+Detach from a checkpoint (experimental)."),
&detachlist);
- /* Info checkpoints command: list all forks/checkpoints
+ /* 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'."));
+ add_info ("checkpoints", info_checkpoints_command,
+ _("IDs of currently known checkpoints."));
}