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2006-01-04 Michael Snyder <msnyder@redhat.com>

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Checkpoint/Restart for Linux.
	* linux-nat.c: Add support for debugging multiple forks.
	Add #include for linux-fork.h (interface spec).
	(super_mourn_inferior): New function pointer.
	(child_mourn_inferior): New function / target method.
	(linux_target): Claim to_mourn_inferior method pointer.
	(child_follow_fork): Call interface to linux-fork, conditionally
	add new fork processes to list of debugged processes.
	(kill_inferior): Use interface to linux-fork to kill
	multiple processes.

	* linux-fork.h: New file.
	* linux-fork.c: New file.  Support for debugging multiple forks
	of the same program.  Support for checkpoint and restart commands.

	* infrun.c (nullify_last_target_wait_ptid): New function.

	* Makefile.in: Add linux-fork.
	* config/*/linux.mh: Add linux-fork.
	* NEWS: Mention new functionality.
This commit is contained in:
Michael Snyder 2006-01-04 19:34:58 +00:00
parent 5c95884b4c
commit ac264b3b9c
20 changed files with 903 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
gdb/ChangeLog
View File

@ -1,3 +1,26 @@
2006-01-04 Michael Snyder <msnyder@redhat.com>
Checkpoint/Restart for Linux.
* linux-nat.c: Add support for debugging multiple forks.
Add #include for linux-fork.h (interface spec).
(super_mourn_inferior): New function pointer.
(child_mourn_inferior): New function / target method.
(linux_target): Claim to_mourn_inferior method pointer.
(child_follow_fork): Call interface to linux-fork, conditionally
add new fork processes to list of debugged processes.
(kill_inferior): Use interface to linux-fork to kill
multiple processes.
* linux-fork.h: New file.
* linux-fork.c: New file. Support for debugging multiple forks
of the same program. Support for checkpoint and restart commands.
* infrun.c (nullify_last_target_wait_ptid): New function.
* Makefile.in: Add linux-fork.
* config/*/linux.mh: Add linux-fork.
* NEWS: Mention new functionality.
2006-01-02 Paul Hilfinger <hilfingr@nile.gnat.com>
* ada-exp.y (syntax definitions,write_var_or_type,write_name_assoc):

6
gdb/Makefile.in
View File

@ -1377,7 +1377,7 @@ MAKEOVERRIDES=
ALLDEPFILES = \
aix-thread.c \
alpha-nat.c alphabsd-nat.c alpha-linux-nat.c \
alpha-nat.c alphabsd-nat.c alpha-linux-nat.c linux-fork.c \
alpha-tdep.c alpha-linux-tdep.c alphabsd-tdep.c alphanbsd-tdep.c \
alpha-osf1-tdep.c alphafbsd-tdep.c alpha-mdebug-tdep.c \
amd64-nat.c amd64-tdep.c \
@ -2180,10 +2180,12 @@ linespec.o: linespec.c $(defs_h) $(symtab_h) $(frame_h) $(command_h) \
$(symfile_h) $(objfiles_h) $(source_h) $(demangle_h) $(value_h) \
$(completer_h) $(cp_abi_h) $(parser_defs_h) $(block_h) \
$(objc_lang_h) $(linespec_h) $(exceptions_h)
linux-fork.o: linux-fork.c linux-fork.h $(defs_h) $(inferior_h) \
$(regcache_h) $(gdbcmd_h) $(infcall_h)
linux-nat.o: linux-nat.c $(defs_h) $(inferior_h) $(target_h) $(gdb_string_h) \
$(gdb_wait_h) $(gdb_assert_h) $(linux_nat_h) $(gdbthread_h) \
$(gdbcmd_h) $(regcache_h) $(inf_ptrace.h) $(auxv.h) $(elf_bfd_h) \
$(gregset_h) $(gdbcore_h) $(gdbthread_h) $(gdb_stat_h)
$(gregset_h) $(gdbcore_h) $(gdbthread_h) $(gdb_stat_h) linux-fork.h
linux-thread-db.o: linux-thread-db.c $(defs_h) $(gdb_assert_h) \
$(gdb_proc_service_h) $(gdb_thread_db_h) $(bfd_h) $(exceptions_h) \
$(gdbthread_h) $(inferior_h) $(symfile_h) $(objfiles_h) $(target_h) \

29
gdb/NEWS
View File

@ -8,6 +8,35 @@
init-if-undefined Initialize a convenience variable, but
only if it doesn't already have a value.
The following commands are presently only implemented for native GNU/Linux:
checkpoint Save a snapshot of the program state.
restart <n> Return the program state to a
previously saved state.
info checkpoints List currently saved checkpoints.
delete-checkpoint <n> Delete a previously saved checkpoint.
set|show detach-on-fork Tell gdb whether to detach from a newly
forked process, or to keep debugging it.
info forks List forks of the user program that
are available to be debugged.
fork <n> Switch to debugging one of several
forks of the user program that are
available to be debugged.
delete-fork <n> Delete a fork from the list of forks
that are available to be debugged (and
kill the forked process).
detach-fork <n> Delete a fork from the list of forks
that are available to be debugged (and
allow the process to continue).
* New architecture
Morpho Technologies ms2 ms1-elf

2
gdb/config/alpha/alpha-linux.mh
View File

@ -2,7 +2,7 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o corelow.o alpha-nat.o alpha-linux-nat.o \
fork-child.o proc-service.o linux-thread-db.o gcore.o \
linux-nat.o
linux-nat.o linux-fork.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.

2
gdb/config/arm/linux.mh
View File

@ -3,7 +3,7 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o corelow.o \
core-regset.o arm-linux-nat.o gcore.o \
proc-service.o linux-thread-db.o linux-nat.o
proc-service.o linux-thread-db.o linux-nat.o linux-fork.o
LOADLIBES= -ldl -rdynamic

2
gdb/config/i386/linux.mh
View File

@ -4,7 +4,7 @@ NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o corelow.o \
core-aout.o i386-nat.o i386-linux-nat.o \
proc-service.o linux-thread-db.o gcore.o \
linux-nat.o
linux-nat.o linux-fork.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.

2
gdb/config/i386/linux64.mh
View File

@ -1,7 +1,7 @@
# Host: GNU/Linux x86-64
NATDEPFILES= inf-ptrace.o fork-child.o \
i386-nat.o amd64-nat.o amd64-linux-nat.o linux-nat.o \
proc-service.o linux-thread-db.o gcore.o
proc-service.o linux-thread-db.o gcore.o linux-fork.o
NAT_FILE= nm-linux64.h
# The dynamically loaded libthread_db needs access to symbols in the

2
gdb/config/ia64/linux.mh
View File

@ -3,6 +3,6 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o corelow.o gcore.o \
core-aout.o core-regset.o ia64-linux-nat.o \
proc-service.o linux-thread-db.o linux-nat.o
proc-service.o linux-thread-db.o linux-nat.o linux-fork.o
LOADLIBES = -ldl -rdynamic

2
gdb/config/m32r/linux.mh
View File

@ -3,6 +3,6 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o corelow.o \
m32r-linux-nat.o gcore.o proc-service.o linux-thread-db.o \
linux-nat.o
linux-nat.o linux-fork.o
LOADLIBES= -ldl -rdynamic

2
gdb/config/m68k/linux.mh
View File

@ -3,7 +3,7 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o \
corelow.o core-aout.o m68klinux-nat.o gcore.o \
proc-service.o linux-thread-db.o linux-nat.o
proc-service.o linux-thread-db.o linux-nat.o linux-fork.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.

2
gdb/config/mips/linux.mh
View File

@ -2,6 +2,6 @@
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o mips-linux-nat.o \
linux-thread-db.o proc-service.o gcore.o \
linux-nat.o
linux-nat.o linux-fork.o
LOADLIBES = -ldl -rdynamic

2
gdb/config/pa/linux.mh
View File

@ -3,6 +3,6 @@ XDEPFILES=
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o corelow.o gcore.o \
core-regset.o hppa-linux-nat.o \
proc-service.o linux-thread-db.o linux-nat.o
proc-service.o linux-thread-db.o linux-nat.o linux-fork.o
LOADLIBES = -ldl -rdynamic

2
gdb/config/powerpc/linux.mh
View File

@ -5,6 +5,6 @@ XM_CLIBS=
NAT_FILE= nm-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o \
ppc-linux-nat.o proc-service.o linux-thread-db.o \
gcore.o linux-nat.o
gcore.o linux-nat.o linux-fork.o
LOADLIBES = -ldl -rdynamic

2
gdb/config/powerpc/ppc64-linux.mh
View File

@ -5,7 +5,7 @@ XM_CLIBS=
NAT_FILE= nm-ppc64-linux.h
NATDEPFILES= inf-ptrace.o fork-child.o \
ppc-linux-nat.o proc-service.o linux-thread-db.o \
gcore.o linux-nat.o
gcore.o linux-nat.o linux-fork.o
# The PowerPC has severe limitations on TOC size, and uses them even
# for non-PIC code. GDB overflows those tables when compiling with

2
gdb/config/sparc/linux.mh
View File

@ -3,7 +3,7 @@ NAT_FILE= nm-linux.h
NATDEPFILES= sparc-nat.o sparc-sol2-nat.o sparc-linux-nat.o \
corelow.o core-regset.o fork-child.o inf-ptrace.o \
proc-service.o linux-thread-db.o \
gcore.o linux-nat.o
gcore.o linux-nat.o linux-fork.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.

2
gdb/config/sparc/linux64.mh
View File

@ -4,7 +4,7 @@ NATDEPFILES= sparc-nat.o sparc64-nat.o sparc-sol2-nat.o sparc64-linux-nat.o \
corelow.o core-regset.o \
fork-child.o inf-ptrace.o \
proc-service.o linux-thread-db.o \
gcore.o linux-nat.o
gcore.o linux-nat.o linux-fork.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.

6
gdb/infrun.c
View File

@ -1102,6 +1102,12 @@ get_last_target_status (ptid_t *ptidp, struct target_waitstatus *status)
*status = target_last_waitstatus;
}
void
nullify_last_target_wait_ptid (void)
{
target_last_wait_ptid = minus_one_ptid;
}
/* Switch thread contexts, maintaining "infrun state". */
static void

689
gdb/linux-fork.c Normal file
View File

@ -0,0 +1,689 @@
/* GNU/Linux native-dependent code for debugging multiple forks.
Copyright (C) 2005 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 2 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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "defs.h"
#include "inferior.h"
#include "regcache.h"
#include "gdbcmd.h"
#include "infcall.h"
#include "gdb_string.h"
#include "linux-fork.h"
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/param.h>
#include <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 = pid_to_ptid (pid);
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;
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;
if (fp->savedregs && fp->clobber_regs)
regcache_cpy (current_regcache, fp->savedregs);
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 (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. */
pid_t pid, ret;
int status;
do {
pid = PIDGET (fork_list->ptid);
do {
ptrace (PT_KILL, pid, 0, 0);
ret = waitpid (pid, &status, 0);
} while (ret == pid && WIFSTOPPED (status));
delete_fork (fork_list->ptid);
} while (fork_list != NULL);
}
/* 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);
if (fork_list) /* Paranoia, shouldn't happen. */
{
inferior_ptid = fork_list[0].ptid;
printf_filtered (_("[Switching to %s]\n"),
target_pid_to_str (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, 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);
}
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, 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);
}
/* 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;
for (fp = fork_list; fp; fp = fp->next)
{
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 "));
deprecated_print_address_numeric (pc, 1, 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');
}
}
/* 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 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;
/* 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");
if (!fork_fn)
if (lookup_minimal_symbol ("_fork", NULL, NULL) != NULL)
fork_fn = find_function_in_inferior ("fork");
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;
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);
}
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);
inferior_ptid = newfp->ptid;
fork_load_infrun_state (newfp);
registers_changed ();
reinit_frame_cache ();
stop_pc = read_pc ();
select_frame (get_current_frame ());
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_com ("delete-checkpoint", class_obscure, delete_fork_command, _("\
Delete a fork/checkpoint (experimental)."));
/* Detach-checkpoint command: release the process to run independantly,
and remove it from the fork list. */
add_com ("detach-checkpoint", class_obscure, detach_fork_command, _("\
Detach from a fork/checkpoint (experimental)."));
/* 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_com_alias ("delete-fork", "delete-checkpoint", class_obscure, 1);
add_com_alias ("detach-fork", "detach-checkpoint", class_obscure, 1);
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'."));
}

33
gdb/linux-fork.h Normal file
View File

@ -0,0 +1,33 @@
/* GNU/Linux native-dependent code for debugging multiple forks.
Copyright 2005 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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
struct fork_info;
extern struct fork_info *add_fork (pid_t);
extern struct fork_info *find_fork_pid (pid_t);
extern void fork_save_infrun_state (struct fork_info *, int);
extern void linux_fork_killall (void);
extern void linux_fork_mourn_inferior (void);
extern int forks_exist_p (void);
struct fork_info *fork_list;
extern int detach_fork;

143
gdb/linux-nat.c
View File

@ -31,6 +31,7 @@
#endif
#include <sys/ptrace.h>
#include "linux-nat.h"
#include "linux-fork.h"
#include "gdbthread.h"
#include "gdbcmd.h"
#include "regcache.h"
@ -87,12 +88,18 @@
the use of the multi-threaded target. */
static struct target_ops *linux_ops;
/* The saved to_xfer_partial method, inherited from inf-ptrace.c. Called
by our to_xfer_partial. */
static LONGEST (*super_xfer_partial) (struct target_ops *, enum target_object,
const char *, gdb_byte *, const gdb_byte *,
/* The saved to_xfer_partial method, inherited from inf-ptrace.c.
Called by our to_xfer_partial. */
static LONGEST (*super_xfer_partial) (struct target_ops *,
enum target_object,
const char *, gdb_byte *,
const gdb_byte *,
ULONGEST, LONGEST);
/* The saved to_mourn_inferior method, inherited from inf-ptrace.c.
Called by our to_mourn_inferior. */
static void (*super_mourn_inferior) (void);
static int debug_linux_nat;
static void
show_debug_linux_nat (struct ui_file *file, int from_tty,
@ -363,15 +370,28 @@ child_follow_fork (struct target_ops *ops, int follow_child)
also, but they'll be reinserted below. */
detach_breakpoints (child_pid);
if (debug_linux_nat)
/* Detach new forked process? */
if (detach_fork)
{
target_terminal_ours ();
fprintf_unfiltered (gdb_stdlog,
"Detaching after fork from child process %d.\n",
child_pid);
}
if (debug_linux_nat)
{
target_terminal_ours ();
fprintf_filtered (gdb_stdlog,
"Detaching after fork from child process %d.\n",
child_pid);
}
ptrace (PTRACE_DETACH, child_pid, 0, 0);
ptrace (PTRACE_DETACH, child_pid, 0, 0);
}
else
{
struct fork_info *fp;
/* Retain child fork in ptrace (stopped) state. */
fp = find_fork_pid (child_pid);
if (!fp)
fp = add_fork (child_pid);
fork_save_infrun_state (fp, 0);
}
if (has_vforked)
{
@ -441,9 +461,9 @@ child_follow_fork (struct target_ops *ops, int follow_child)
if (debug_linux_nat)
{
target_terminal_ours ();
fprintf_unfiltered (gdb_stdlog,
"Attaching after fork to child process %d.\n",
child_pid);
fprintf_filtered (gdb_stdlog,
"Attaching after fork to child process %d.\n",
child_pid);
}
/* If we're vforking, we may want to hold on to the parent until
@ -466,13 +486,25 @@ child_follow_fork (struct target_ops *ops, int follow_child)
if (has_vforked)
linux_parent_pid = parent_pid;
else if (!detach_fork)
{
struct fork_info *fp;
/* Retain parent fork in ptrace (stopped) state. */
fp = find_fork_pid (parent_pid);
if (!fp)
fp = add_fork (parent_pid);
fork_save_infrun_state (fp, 0);
}
else
target_detach (NULL, 0);
{
target_detach (NULL, 0);
}
inferior_ptid = pid_to_ptid (child_pid);
/* Reinstall ourselves, since we might have been removed in
target_detach (which does other necessary cleanup). */
push_target (ops);
/* Reset breakpoints in the child as appropriate. */
@ -579,33 +611,42 @@ kill_inferior (void)
if (pid == 0)
return;
/* If we're stopped while forking and we haven't followed yet, kill the
other task. We need to do this first because the parent will be
sleeping if this is a vfork. */
get_last_target_status (&last_ptid, &last);
if (last.kind == TARGET_WAITKIND_FORKED
|| last.kind == TARGET_WAITKIND_VFORKED)
/* First cut -- let's crudely do everything inline. */
if (forks_exist_p ())
{
ptrace (PT_KILL, last.value.related_pid, 0, 0);
wait (&status);
linux_fork_killall ();
pop_target ();
generic_mourn_inferior ();
}
/* Kill the current process. */
ptrace (PT_KILL, pid, 0, 0);
ret = wait (&status);
/* We might get a SIGCHLD instead of an exit status. This is
aggravated by the first kill above - a child has just died. */
while (ret == pid && WIFSTOPPED (status))
else
{
/* If we're stopped while forking and we haven't followed yet,
kill the other task. We need to do this first because the
parent will be sleeping if this is a vfork. */
get_last_target_status (&last_ptid, &last);
if (last.kind == TARGET_WAITKIND_FORKED
|| last.kind == TARGET_WAITKIND_VFORKED)
{
ptrace (PT_KILL, last.value.related_pid, 0, 0);
wait (&status);
}
/* Kill the current process. */
ptrace (PT_KILL, pid, 0, 0);
ret = wait (&status);
}
target_mourn_inferior ();
/* We might get a SIGCHLD instead of an exit status. This is
aggravated by the first kill above - a child has just died. */
while (ret == pid && WIFSTOPPED (status))
{
ptrace (PT_KILL, pid, 0, 0);
ret = wait (&status);
}
target_mourn_inferior ();
}
}
/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
@ -1677,7 +1718,7 @@ select_event_lwp (struct lwp_info **orig_lp, int *status)
int random_selector;
struct lwp_info *event_lp;
/* Record the wait status for the origional LWP. */
/* Record the wait status for the original LWP. */
(*orig_lp)->status = *status;
/* Give preference to any LWP that is being single-stepped. */
@ -1729,6 +1770,30 @@ resumed_callback (struct lwp_info *lp, void *data)
return lp->resumed;
}
/* Local mourn_inferior -- we need to override mourn_inferior
so that we can do something clever if one of several forks
has exited. */
static void
child_mourn_inferior (void)
{
int status;
if (! forks_exist_p ())
{
/* Normal case, no other forks available. */
super_mourn_inferior ();
return;
}
else
{
/* Multi-fork case. 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. */
linux_fork_mourn_inferior ();
}
}
/* We need to override child_wait to support attaching to cloned
processes, since a normal wait (as done by the default version)
ignores those processes. */
@ -3201,6 +3266,9 @@ linux_target (void)
super_xfer_partial = t->to_xfer_partial;
t->to_xfer_partial = linux_xfer_partial;
super_mourn_inferior = t->to_mourn_inferior;
t->to_mourn_inferior = child_mourn_inferior;
linux_ops = t;
return t;
}
@ -3312,3 +3380,4 @@ lin_thread_get_thread_signals (sigset_t *set)
/* ... except during a sigsuspend. */
sigdelset (&suspend_mask, cancel);
}