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binutils-gdb/gdb/fbsd-nat.c
John Baldwin 92fce24de2 Support 'info proc' for native FreeBSD processes. 
- Command line arguments are fetched via the kern.proc.args.<pid>
  sysctl.
- The 'cwd' and 'exe' values are obtained from the per-process
  file descriptor table returned by kinfo_getfile() from libutil.
- 'mappings' is implemented by walking the array of VM map entries
  returned by kinfo_getvmmap() from libutil.
- 'status' output is generated by outputting fields from the structure
  returned by the kern.proc.pid.<pid> sysctl.
- 'stat' is aliased to 'status'.

gdb/ChangeLog:

	* configure.ac: Check for kinfo_getfile in libutil.
	* configure: Regenerate.
	* config.in: Regenerate.
	* fbsd-nat.c: Include "fbsd-tdep.h".
	(fbsd_fetch_cmdline): New.
	(fbsd_fetch_kinfo_proc): Move earlier and change to return a bool
	rather than calling error.
	(fbsd_info_proc): New.
	(fbsd_thread_name): Report error if fbsd_fetch_kinfo_proc fails.
	(fbsd_wait): Report warning if fbsd_fetch_kinfo_proc fails.
	(fbsd_nat_add_target): Set "to_info_proc" to "fbsd_info_proc".
2018-01-09 13:35:17 -08:00

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/* Native-dependent code for FreeBSD.
Copyright (C) 2002-2018 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 "byte-vector.h"
#include "gdbcore.h"
#include "inferior.h"
#include "regcache.h"
#include "regset.h"
#include "gdbcmd.h"
#include "gdbthread.h"
#include "gdb_wait.h"
#include <sys/types.h>
#include <sys/procfs.h>
#include <sys/ptrace.h>
#include <sys/signal.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#if defined(HAVE_KINFO_GETFILE) || defined(HAVE_KINFO_GETVMMAP)
#include <libutil.h>
#endif
#if !defined(HAVE_KINFO_GETVMMAP)
#include "filestuff.h"
#endif
#include "elf-bfd.h"
#include "fbsd-nat.h"
#include "fbsd-tdep.h"
#include <list>
/* Return the name of a file that can be opened to get the symbols for
the child process identified by PID. */
static char *
fbsd_pid_to_exec_file (struct target_ops *self, int pid)
{
ssize_t len;
static char buf[PATH_MAX];
char name[PATH_MAX];
#ifdef KERN_PROC_PATHNAME
size_t buflen;
int mib[4];
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PATHNAME;
mib[3] = pid;
buflen = sizeof buf;
if (sysctl (mib, 4, buf, &buflen, NULL, 0) == 0)
/* The kern.proc.pathname.<pid> sysctl returns a length of zero
for processes without an associated executable such as kernel
processes. */
return buflen == 0 ? NULL : buf;
#endif
xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
len = readlink (name, buf, PATH_MAX - 1);
if (len != -1)
{
buf[len] = '\0';
return buf;
}
return NULL;
}
#ifdef HAVE_KINFO_GETVMMAP
/* Iterate over all the memory regions in the current inferior,
calling FUNC for each memory region. OBFD is passed as the last
argument to FUNC. */
static int
fbsd_find_memory_regions (struct target_ops *self,
find_memory_region_ftype func, void *obfd)
{
pid_t pid = ptid_get_pid (inferior_ptid);
struct kinfo_vmentry *kve;
uint64_t size;
int i, nitems;
gdb::unique_xmalloc_ptr<struct kinfo_vmentry>
vmentl (kinfo_getvmmap (pid, &nitems));
if (vmentl == NULL)
perror_with_name (_("Couldn't fetch VM map entries."));
for (i = 0, kve = vmentl.get (); i < nitems; i++, kve++)
{
/* Skip unreadable segments and those where MAP_NOCORE has been set. */
if (!(kve->kve_protection & KVME_PROT_READ)
|| kve->kve_flags & KVME_FLAG_NOCOREDUMP)
continue;
/* Skip segments with an invalid type. */
if (kve->kve_type != KVME_TYPE_DEFAULT
&& kve->kve_type != KVME_TYPE_VNODE
&& kve->kve_type != KVME_TYPE_SWAP
&& kve->kve_type != KVME_TYPE_PHYS)
continue;
size = kve->kve_end - kve->kve_start;
if (info_verbose)
{
fprintf_filtered (gdb_stdout,
"Save segment, %ld bytes at %s (%c%c%c)\n",
(long) size,
paddress (target_gdbarch (), kve->kve_start),
kve->kve_protection & KVME_PROT_READ ? 'r' : '-',
kve->kve_protection & KVME_PROT_WRITE ? 'w' : '-',
kve->kve_protection & KVME_PROT_EXEC ? 'x' : '-');
}
/* Invoke the callback function to create the corefile segment.
Pass MODIFIED as true, we do not know the real modification state. */
func (kve->kve_start, size, kve->kve_protection & KVME_PROT_READ,
kve->kve_protection & KVME_PROT_WRITE,
kve->kve_protection & KVME_PROT_EXEC, 1, obfd);
}
return 0;
}
#else
static int
fbsd_read_mapping (FILE *mapfile, unsigned long *start, unsigned long *end,
char *protection)
{
/* FreeBSD 5.1-RELEASE uses a 256-byte buffer. */
char buf[256];
int resident, privateresident;
unsigned long obj;
int ret = EOF;
/* As of FreeBSD 5.0-RELEASE, the layout is described in
/usr/src/sys/fs/procfs/procfs_map.c. Somewhere in 5.1-CURRENT a
new column was added to the procfs map. Therefore we can't use
fscanf since we need to support older releases too. */
if (fgets (buf, sizeof buf, mapfile) != NULL)
ret = sscanf (buf, "%lx %lx %d %d %lx %s", start, end,
&resident, &privateresident, &obj, protection);
return (ret != 0 && ret != EOF);
}
/* Iterate over all the memory regions in the current inferior,
calling FUNC for each memory region. OBFD is passed as the last
argument to FUNC. */
static int
fbsd_find_memory_regions (struct target_ops *self,
find_memory_region_ftype func, void *obfd)
{
pid_t pid = ptid_get_pid (inferior_ptid);
unsigned long start, end, size;
char protection[4];
int read, write, exec;
std::string mapfilename = string_printf ("/proc/%ld/map", (long) pid);
gdb_file_up mapfile (fopen (mapfilename.c_str (), "r"));
if (mapfile == NULL)
error (_("Couldn't open %s."), mapfilename.c_str ());
if (info_verbose)
fprintf_filtered (gdb_stdout,
"Reading memory regions from %s\n", mapfilename.c_str ());
/* Now iterate until end-of-file. */
while (fbsd_read_mapping (mapfile.get (), &start, &end, &protection[0]))
{
size = end - start;
read = (strchr (protection, 'r') != 0);
write = (strchr (protection, 'w') != 0);
exec = (strchr (protection, 'x') != 0);
if (info_verbose)
{
fprintf_filtered (gdb_stdout,
"Save segment, %ld bytes at %s (%c%c%c)\n",
size, paddress (target_gdbarch (), start),
read ? 'r' : '-',
write ? 'w' : '-',
exec ? 'x' : '-');
}
/* Invoke the callback function to create the corefile segment.
Pass MODIFIED as true, we do not know the real modification state. */
func (start, size, read, write, exec, 1, obfd);
}
return 0;
}
#endif
/* Fetch the command line for a running process. */
static gdb::unique_xmalloc_ptr<char>
fbsd_fetch_cmdline (pid_t pid)
{
size_t len;
int mib[4];
len = 0;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_ARGS;
mib[3] = pid;
if (sysctl (mib, 4, NULL, &len, NULL, 0) == -1)
return nullptr;
if (len == 0)
return nullptr;
gdb::unique_xmalloc_ptr<char> cmdline ((char *) xmalloc (len));
if (sysctl (mib, 4, cmdline.get (), &len, NULL, 0) == -1)
return nullptr;
return cmdline;
}
/* Fetch the external variant of the kernel's internal process
structure for the process PID into KP. */
static bool
fbsd_fetch_kinfo_proc (pid_t pid, struct kinfo_proc *kp)
{
size_t len;
int mib[4];
len = sizeof *kp;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PID;
mib[3] = pid;
return (sysctl (mib, 4, kp, &len, NULL, 0) == 0);
}
/* Implement the "to_info_proc target_ops" method. */
static void
fbsd_info_proc (struct target_ops *ops, const char *args,
enum info_proc_what what)
{
#ifdef HAVE_KINFO_GETFILE
gdb::unique_xmalloc_ptr<struct kinfo_file> fdtbl;
int nfd = 0;
#endif
struct kinfo_proc kp;
char *tmp;
pid_t pid;
bool do_cmdline = false;
bool do_cwd = false;
bool do_exe = false;
#ifdef HAVE_KINFO_GETVMMAP
bool do_mappings = false;
#endif
bool do_status = false;
switch (what)
{
case IP_MINIMAL:
do_cmdline = true;
do_cwd = true;
do_exe = true;
break;
#ifdef HAVE_KINFO_GETVMMAP
case IP_MAPPINGS:
do_mappings = true;
break;
#endif
case IP_STATUS:
case IP_STAT:
do_status = true;
break;
case IP_CMDLINE:
do_cmdline = true;
break;
case IP_EXE:
do_exe = true;
break;
case IP_CWD:
do_cwd = true;
break;
case IP_ALL:
do_cmdline = true;
do_cwd = true;
do_exe = true;
#ifdef HAVE_KINFO_GETVMMAP
do_mappings = true;
#endif
do_status = true;
break;
default:
error (_("Not supported on this target."));
}
gdb_argv built_argv (args);
if (built_argv.count () == 0)
{
pid = ptid_get_pid (inferior_ptid);
if (pid == 0)
error (_("No current process: you must name one."));
}
else if (built_argv.count () == 1 && isdigit (built_argv[0][0]))
pid = strtol (built_argv[0], NULL, 10);
else
error (_("Invalid arguments."));
printf_filtered (_("process %d\n"), pid);
#ifdef HAVE_KINFO_GETFILE
if (do_cwd || do_exe)
fdtbl.reset (kinfo_getfile (pid, &nfd));
#endif
if (do_cmdline)
{
gdb::unique_xmalloc_ptr<char> cmdline = fbsd_fetch_cmdline (pid);
if (cmdline != nullptr)
printf_filtered ("cmdline = '%s'\n", cmdline.get ());
else
warning (_("unable to fetch command line"));
}
if (do_cwd)
{
const char *cwd = NULL;
#ifdef HAVE_KINFO_GETFILE
struct kinfo_file *kf = fdtbl.get ();
for (int i = 0; i < nfd; i++, kf++)
{
if (kf->kf_type == KF_TYPE_VNODE && kf->kf_fd == KF_FD_TYPE_CWD)
{
cwd = kf->kf_path;
break;
}
}
#endif
if (cwd != NULL)
printf_filtered ("cwd = '%s'\n", cwd);
else
warning (_("unable to fetch current working directory"));
}
if (do_exe)
{
const char *exe = NULL;
#ifdef HAVE_KINFO_GETFILE
struct kinfo_file *kf = fdtbl.get ();
for (int i = 0; i < nfd; i++, kf++)
{
if (kf->kf_type == KF_TYPE_VNODE && kf->kf_fd == KF_FD_TYPE_TEXT)
{
exe = kf->kf_path;
break;
}
}
#endif
if (exe == NULL)
exe = fbsd_pid_to_exec_file (ops, pid);
if (exe != NULL)
printf_filtered ("exe = '%s'\n", exe);
else
warning (_("unable to fetch executable path name"));
}
#ifdef HAVE_KINFO_GETVMMAP
if (do_mappings)
{
int nvment;
gdb::unique_xmalloc_ptr<struct kinfo_vmentry>
vmentl (kinfo_getvmmap (pid, &nvment));
if (vmentl != nullptr)
{
printf_filtered (_("Mapped address spaces:\n\n"));
#ifdef __LP64__
printf_filtered (" %18s %18s %10s %10s %9s %s\n",
"Start Addr",
" End Addr",
" Size", " Offset", "Flags ", "File");
#else
printf_filtered ("\t%10s %10s %10s %10s %9s %s\n",
"Start Addr",
" End Addr",
" Size", " Offset", "Flags ", "File");
#endif
struct kinfo_vmentry *kve = vmentl.get ();
for (int i = 0; i < nvment; i++, kve++)
{
ULONGEST start, end;
start = kve->kve_start;
end = kve->kve_end;
#ifdef __LP64__
printf_filtered (" %18s %18s %10s %10s %9s %s\n",
hex_string (start),
hex_string (end),
hex_string (end - start),
hex_string (kve->kve_offset),
fbsd_vm_map_entry_flags (kve->kve_flags,
kve->kve_protection),
kve->kve_path);
#else
printf_filtered ("\t%10s %10s %10s %10s %9s %s\n",
hex_string (start),
hex_string (end),
hex_string (end - start),
hex_string (kve->kve_offset),
fbsd_vm_map_entry_flags (kve->kve_flags,
kve->kve_protection),
kve->kve_path);
#endif
}
}
else
warning (_("unable to fetch virtual memory map"));
}
#endif
if (do_status)
{
if (!fbsd_fetch_kinfo_proc (pid, &kp))
warning (_("Failed to fetch process information"));
else
{
const char *state;
int pgtok;
printf_filtered ("Name: %s\n", kp.ki_comm);
switch (kp.ki_stat)
{
case SIDL:
state = "I (idle)";
break;
case SRUN:
state = "R (running)";
break;
case SSTOP:
state = "T (stopped)";
break;
case SZOMB:
state = "Z (zombie)";
break;
case SSLEEP:
state = "S (sleeping)";
break;
case SWAIT:
state = "W (interrupt wait)";
break;
case SLOCK:
state = "L (blocked on lock)";
break;
default:
state = "? (unknown)";
break;
}
printf_filtered ("State: %s\n", state);
printf_filtered ("Parent process: %d\n", kp.ki_ppid);
printf_filtered ("Process group: %d\n", kp.ki_pgid);
printf_filtered ("Session id: %d\n", kp.ki_sid);
printf_filtered ("TTY: %ju\n", (uintmax_t) kp.ki_tdev);
printf_filtered ("TTY owner process group: %d\n", kp.ki_tpgid);
printf_filtered ("User IDs (real, effective, saved): %d %d %d\n",
kp.ki_ruid, kp.ki_uid, kp.ki_svuid);
printf_filtered ("Group IDs (real, effective, saved): %d %d %d\n",
kp.ki_rgid, kp.ki_groups[0], kp.ki_svgid);
printf_filtered ("Groups: ");
for (int i = 0; i < kp.ki_ngroups; i++)
printf_filtered ("%d ", kp.ki_groups[i]);
printf_filtered ("\n");
printf_filtered ("Minor faults (no memory page): %ld\n",
kp.ki_rusage.ru_minflt);
printf_filtered ("Minor faults, children: %ld\n",
kp.ki_rusage_ch.ru_minflt);
printf_filtered ("Major faults (memory page faults): %ld\n",
kp.ki_rusage.ru_majflt);
printf_filtered ("Major faults, children: %ld\n",
kp.ki_rusage_ch.ru_majflt);
printf_filtered ("utime: %jd.%06ld\n",
(intmax_t) kp.ki_rusage.ru_utime.tv_sec,
kp.ki_rusage.ru_utime.tv_usec);
printf_filtered ("stime: %jd.%06ld\n",
(intmax_t) kp.ki_rusage.ru_stime.tv_sec,
kp.ki_rusage.ru_stime.tv_usec);
printf_filtered ("utime, children: %jd.%06ld\n",
(intmax_t) kp.ki_rusage_ch.ru_utime.tv_sec,
kp.ki_rusage_ch.ru_utime.tv_usec);
printf_filtered ("stime, children: %jd.%06ld\n",
(intmax_t) kp.ki_rusage_ch.ru_stime.tv_sec,
kp.ki_rusage_ch.ru_stime.tv_usec);
printf_filtered ("'nice' value: %d\n", kp.ki_nice);
printf_filtered ("Start time: %jd.%06ld\n", kp.ki_start.tv_sec,
kp.ki_start.tv_usec);
pgtok = getpagesize () / 1024;
printf_filtered ("Virtual memory size: %ju kB\n",
(uintmax_t) kp.ki_size / 1024);
printf_filtered ("Data size: %ju kB\n",
(uintmax_t) kp.ki_dsize * pgtok);
printf_filtered ("Stack size: %ju kB\n",
(uintmax_t) kp.ki_ssize * pgtok);
printf_filtered ("Text size: %ju kB\n",
(uintmax_t) kp.ki_tsize * pgtok);
printf_filtered ("Resident set size: %ju kB\n",
(uintmax_t) kp.ki_rssize * pgtok);
printf_filtered ("Maximum RSS: %ju kB\n",
(uintmax_t) kp.ki_rusage.ru_maxrss);
printf_filtered ("Pending Signals: ");
for (int i = 0; i < _SIG_WORDS; i++)
printf_filtered ("%08x ", kp.ki_siglist.__bits[i]);
printf_filtered ("\n");
printf_filtered ("Ignored Signals: ");
for (int i = 0; i < _SIG_WORDS; i++)
printf_filtered ("%08x ", kp.ki_sigignore.__bits[i]);
printf_filtered ("\n");
printf_filtered ("Caught Signals: ");
for (int i = 0; i < _SIG_WORDS; i++)
printf_filtered ("%08x ", kp.ki_sigcatch.__bits[i]);
printf_filtered ("\n");
}
}
}
#ifdef KERN_PROC_AUXV
static enum target_xfer_status (*super_xfer_partial) (struct target_ops *ops,
enum target_object object,
const char *annex,
gdb_byte *readbuf,
const gdb_byte *writebuf,
ULONGEST offset,
ULONGEST len,
ULONGEST *xfered_len);
#ifdef PT_LWPINFO
/* Return the size of siginfo for the current inferior. */
#ifdef __LP64__
union sigval32 {
int sival_int;
uint32_t sival_ptr;
};
/* This structure matches the naming and layout of `siginfo_t' in
<sys/signal.h>. In particular, the `si_foo' macros defined in that
header can be used with both types to copy fields in the `_reason'
union. */
struct siginfo32
{
int si_signo;
int si_errno;
int si_code;
__pid_t si_pid;
__uid_t si_uid;
int si_status;
uint32_t si_addr;
union sigval32 si_value;
union
{
struct
{
int _trapno;
} _fault;
struct
{
int _timerid;
int _overrun;
} _timer;
struct
{
int _mqd;
} _mesgq;
struct
{
int32_t _band;
} _poll;
struct
{
int32_t __spare1__;
int __spare2__[7];
} __spare__;
} _reason;
};
#endif
static size_t
fbsd_siginfo_size ()
{
#ifdef __LP64__
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If so, use the 32-bit siginfo size. */
if (gdbarch_long_bit (gdbarch) == 32)
return sizeof (struct siginfo32);
#endif
return sizeof (siginfo_t);
}
/* Convert a native 64-bit siginfo object to a 32-bit object. Note
that FreeBSD doesn't support writing to $_siginfo, so this only
needs to convert one way. */
static void
fbsd_convert_siginfo (siginfo_t *si)
{
#ifdef __LP64__
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If not, nothing to do. */
if (gdbarch_long_bit (gdbarch) != 32)
return;
struct siginfo32 si32;
si32.si_signo = si->si_signo;
si32.si_errno = si->si_errno;
si32.si_code = si->si_code;
si32.si_pid = si->si_pid;
si32.si_uid = si->si_uid;
si32.si_status = si->si_status;
si32.si_addr = (uintptr_t) si->si_addr;
/* If sival_ptr is being used instead of sival_int on a big-endian
platform, then sival_int will be zero since it holds the upper
32-bits of the pointer value. */
#if _BYTE_ORDER == _BIG_ENDIAN
if (si->si_value.sival_int == 0)
si32.si_value.sival_ptr = (uintptr_t) si->si_value.sival_ptr;
else
si32.si_value.sival_int = si->si_value.sival_int;
#else
si32.si_value.sival_int = si->si_value.sival_int;
#endif
/* Always copy the spare fields and then possibly overwrite them for
signal-specific or code-specific fields. */
si32._reason.__spare__.__spare1__ = si->_reason.__spare__.__spare1__;
for (int i = 0; i < 7; i++)
si32._reason.__spare__.__spare2__[i] = si->_reason.__spare__.__spare2__[i];
switch (si->si_signo) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
si32.si_trapno = si->si_trapno;
break;
}
switch (si->si_code) {
case SI_TIMER:
si32.si_timerid = si->si_timerid;
si32.si_overrun = si->si_overrun;
break;
case SI_MESGQ:
si32.si_mqd = si->si_mqd;
break;
}
memcpy(si, &si32, sizeof (si32));
#endif
}
#endif
/* Implement the "to_xfer_partial target_ops" method. */
static enum target_xfer_status
fbsd_xfer_partial (struct target_ops *ops, enum target_object object,
const char *annex, gdb_byte *readbuf,
const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
{
pid_t pid = ptid_get_pid (inferior_ptid);
switch (object)
{
#ifdef PT_LWPINFO
case TARGET_OBJECT_SIGNAL_INFO:
{
struct ptrace_lwpinfo pl;
size_t siginfo_size;
/* FreeBSD doesn't support writing to $_siginfo. */
if (writebuf != NULL)
return TARGET_XFER_E_IO;
if (inferior_ptid.lwp_p ())
pid = inferior_ptid.lwp ();
siginfo_size = fbsd_siginfo_size ();
if (offset > siginfo_size)
return TARGET_XFER_E_IO;
if (ptrace (PT_LWPINFO, pid, (PTRACE_TYPE_ARG3) &pl, sizeof (pl)) == -1)
return TARGET_XFER_E_IO;
if (!(pl.pl_flags & PL_FLAG_SI))
return TARGET_XFER_E_IO;
fbsd_convert_siginfo (&pl.pl_siginfo);
if (offset + len > siginfo_size)
len = siginfo_size - offset;
memcpy (readbuf, ((gdb_byte *) &pl.pl_siginfo) + offset, len);
*xfered_len = len;
return TARGET_XFER_OK;
}
#endif
case TARGET_OBJECT_AUXV:
{
gdb::byte_vector buf_storage;
gdb_byte *buf;
size_t buflen;
int mib[4];
if (writebuf != NULL)
return TARGET_XFER_E_IO;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_AUXV;
mib[3] = pid;
if (offset == 0)
{
buf = readbuf;
buflen = len;
}
else
{
buflen = offset + len;
buf_storage.resize (buflen);
buf = buf_storage.data ();
}
if (sysctl (mib, 4, buf, &buflen, NULL, 0) == 0)
{
if (offset != 0)
{
if (buflen > offset)
{
buflen -= offset;
memcpy (readbuf, buf + offset, buflen);
}
else
buflen = 0;
}
*xfered_len = buflen;
return (buflen == 0) ? TARGET_XFER_EOF : TARGET_XFER_OK;
}
return TARGET_XFER_E_IO;
}
default:
return super_xfer_partial (ops, object, annex, readbuf, writebuf, offset,
len, xfered_len);
}
}
#endif
#ifdef PT_LWPINFO
static int debug_fbsd_lwp;
static void (*super_resume) (struct target_ops *,
ptid_t,
int,
enum gdb_signal);
static ptid_t (*super_wait) (struct target_ops *,
ptid_t,
struct target_waitstatus *,
int);
static void
show_fbsd_lwp_debug (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Debugging of FreeBSD lwp module is %s.\n"), value);
}
/*
FreeBSD's first thread support was via a "reentrant" version of libc
(libc_r) that first shipped in 2.2.7. This library multiplexed all
of the threads in a process onto a single kernel thread. This
library was supported via the bsd-uthread target.
FreeBSD 5.1 introduced two new threading libraries that made use of
multiple kernel threads. The first (libkse) scheduled M user
threads onto N (<= M) kernel threads (LWPs). The second (libthr)
bound each user thread to a dedicated kernel thread. libkse shipped
as the default threading library (libpthread).
FreeBSD 5.3 added a libthread_db to abstract the interface across
the various thread libraries (libc_r, libkse, and libthr).
FreeBSD 7.0 switched the default threading library from from libkse
to libpthread and removed libc_r.
FreeBSD 8.0 removed libkse and the in-kernel support for it. The
only threading library supported by 8.0 and later is libthr which
ties each user thread directly to an LWP. To simplify the
implementation, this target only supports LWP-backed threads using
ptrace directly rather than libthread_db.
FreeBSD 11.0 introduced LWP event reporting via PT_LWP_EVENTS.
*/
/* Return true if PTID is still active in the inferior. */
static int
fbsd_thread_alive (struct target_ops *ops, ptid_t ptid)
{
if (ptid_lwp_p (ptid))
{
struct ptrace_lwpinfo pl;
if (ptrace (PT_LWPINFO, ptid_get_lwp (ptid), (caddr_t) &pl, sizeof pl)
== -1)
return 0;
#ifdef PL_FLAG_EXITED
if (pl.pl_flags & PL_FLAG_EXITED)
return 0;
#endif
}
return 1;
}
/* Convert PTID to a string. Returns the string in a static
buffer. */
static const char *
fbsd_pid_to_str (struct target_ops *ops, ptid_t ptid)
{
lwpid_t lwp;
lwp = ptid_get_lwp (ptid);
if (lwp != 0)
{
static char buf[64];
int pid = ptid_get_pid (ptid);
xsnprintf (buf, sizeof buf, "LWP %d of process %d", lwp, pid);
return buf;
}
return normal_pid_to_str (ptid);
}
#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
/* Return the name assigned to a thread by an application. Returns
the string in a static buffer. */
static const char *
fbsd_thread_name (struct target_ops *self, struct thread_info *thr)
{
struct ptrace_lwpinfo pl;
struct kinfo_proc kp;
int pid = ptid_get_pid (thr->ptid);
long lwp = ptid_get_lwp (thr->ptid);
static char buf[sizeof pl.pl_tdname + 1];
/* Note that ptrace_lwpinfo returns the process command in pl_tdname
if a name has not been set explicitly. Return a NULL name in
that case. */
if (!fbsd_fetch_kinfo_proc (pid, &kp))
perror_with_name (_("Failed to fetch process information"));
if (ptrace (PT_LWPINFO, lwp, (caddr_t) &pl, sizeof pl) == -1)
perror_with_name (("ptrace"));
if (strcmp (kp.ki_comm, pl.pl_tdname) == 0)
return NULL;
xsnprintf (buf, sizeof buf, "%s", pl.pl_tdname);
return buf;
}
#endif
/* Enable additional event reporting on new processes.
To catch fork events, PTRACE_FORK is set on every traced process
to enable stops on returns from fork or vfork. Note that both the
parent and child will always stop, even if system call stops are
not enabled.
To catch LWP events, PTRACE_EVENTS is set on every traced process.
This enables stops on the birth for new LWPs (excluding the "main" LWP)
and the death of LWPs (excluding the last LWP in a process). Note
that unlike fork events, the LWP that creates a new LWP does not
report an event. */
static void
fbsd_enable_proc_events (pid_t pid)
{
#ifdef PT_GET_EVENT_MASK
int events;
if (ptrace (PT_GET_EVENT_MASK, pid, (PTRACE_TYPE_ARG3)&events,
sizeof (events)) == -1)
perror_with_name (("ptrace"));
events |= PTRACE_FORK | PTRACE_LWP;
#ifdef PTRACE_VFORK
events |= PTRACE_VFORK;
#endif
if (ptrace (PT_SET_EVENT_MASK, pid, (PTRACE_TYPE_ARG3)&events,
sizeof (events)) == -1)
perror_with_name (("ptrace"));
#else
#ifdef TDP_RFPPWAIT
if (ptrace (PT_FOLLOW_FORK, pid, (PTRACE_TYPE_ARG3)0, 1) == -1)
perror_with_name (("ptrace"));
#endif
#ifdef PT_LWP_EVENTS
if (ptrace (PT_LWP_EVENTS, pid, (PTRACE_TYPE_ARG3)0, 1) == -1)
perror_with_name (("ptrace"));
#endif
#endif
}
/* Add threads for any new LWPs in a process.
When LWP events are used, this function is only used to detect existing
threads when attaching to a process. On older systems, this function is
called to discover new threads each time the thread list is updated. */
static void
fbsd_add_threads (pid_t pid)
{
int i, nlwps;
gdb_assert (!in_thread_list (pid_to_ptid (pid)));
nlwps = ptrace (PT_GETNUMLWPS, pid, NULL, 0);
if (nlwps == -1)
perror_with_name (("ptrace"));
gdb::unique_xmalloc_ptr<lwpid_t[]> lwps (XCNEWVEC (lwpid_t, nlwps));
nlwps = ptrace (PT_GETLWPLIST, pid, (caddr_t) lwps.get (), nlwps);
if (nlwps == -1)
perror_with_name (("ptrace"));
for (i = 0; i < nlwps; i++)
{
ptid_t ptid = ptid_build (pid, lwps[i], 0);
if (!in_thread_list (ptid))
{
#ifdef PT_LWP_EVENTS
struct ptrace_lwpinfo pl;
/* Don't add exited threads. Note that this is only called
when attaching to a multi-threaded process. */
if (ptrace (PT_LWPINFO, lwps[i], (caddr_t) &pl, sizeof pl) == -1)
perror_with_name (("ptrace"));
if (pl.pl_flags & PL_FLAG_EXITED)
continue;
#endif
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
"FLWP: adding thread for LWP %u\n",
lwps[i]);
add_thread (ptid);
}
}
}
/* Implement the "to_update_thread_list" target_ops method. */
static void
fbsd_update_thread_list (struct target_ops *ops)
{
#ifdef PT_LWP_EVENTS
/* With support for thread events, threads are added/deleted from the
list as events are reported, so just try deleting exited threads. */
delete_exited_threads ();
#else
prune_threads ();
fbsd_add_threads (ptid_get_pid (inferior_ptid));
#endif
}
#ifdef TDP_RFPPWAIT
/*
To catch fork events, PT_FOLLOW_FORK is set on every traced process
to enable stops on returns from fork or vfork. Note that both the
parent and child will always stop, even if system call stops are not
enabled.
After a fork, both the child and parent process will stop and report
an event. However, there is no guarantee of order. If the parent
reports its stop first, then fbsd_wait explicitly waits for the new
child before returning. If the child reports its stop first, then
the event is saved on a list and ignored until the parent's stop is
reported. fbsd_wait could have been changed to fetch the parent PID
of the new child and used that to wait for the parent explicitly.
However, if two threads in the parent fork at the same time, then
the wait on the parent might return the "wrong" fork event.
The initial version of PT_FOLLOW_FORK did not set PL_FLAG_CHILD for
the new child process. This flag could be inferred by treating any
events for an unknown pid as a new child.
In addition, the initial version of PT_FOLLOW_FORK did not report a
stop event for the parent process of a vfork until after the child
process executed a new program or exited. The kernel was changed to
defer the wait for exit or exec of the child until after posting the
stop event shortly after the change to introduce PL_FLAG_CHILD.
This could be worked around by reporting a vfork event when the
child event posted and ignoring the subsequent event from the
parent.
This implementation requires both of these fixes for simplicity's
sake. FreeBSD versions newer than 9.1 contain both fixes.
*/
static std::list<ptid_t> fbsd_pending_children;
/* Record a new child process event that is reported before the
corresponding fork event in the parent. */
static void
fbsd_remember_child (ptid_t pid)
{
fbsd_pending_children.push_front (pid);
}
/* Check for a previously-recorded new child process event for PID.
If one is found, remove it from the list and return the PTID. */
static ptid_t
fbsd_is_child_pending (pid_t pid)
{
for (auto it = fbsd_pending_children.begin ();
it != fbsd_pending_children.end (); it++)
if (it->pid () == pid)
{
ptid_t ptid = *it;
fbsd_pending_children.erase (it);
return ptid;
}
return null_ptid;
}
#ifndef PTRACE_VFORK
static std::forward_list<ptid_t> fbsd_pending_vfork_done;
/* Record a pending vfork done event. */
static void
fbsd_add_vfork_done (ptid_t pid)
{
fbsd_pending_vfork_done.push_front (pid);
}
/* Check for a pending vfork done event for a specific PID. */
static int
fbsd_is_vfork_done_pending (pid_t pid)
{
for (auto it = fbsd_pending_vfork_done.begin ();
it != fbsd_pending_vfork_done.end (); it++)
if (it->pid () == pid)
return 1;
return 0;
}
/* Check for a pending vfork done event. If one is found, remove it
from the list and return the PTID. */
static ptid_t
fbsd_next_vfork_done (void)
{
if (!fbsd_pending_vfork_done.empty ())
{
ptid_t ptid = fbsd_pending_vfork_done.front ();
fbsd_pending_vfork_done.pop_front ();
return ptid;
}
return null_ptid;
}
#endif
#endif
/* Implement the "to_resume" target_ops method. */
static void
fbsd_resume (struct target_ops *ops,
ptid_t ptid, int step, enum gdb_signal signo)
{
#if defined(TDP_RFPPWAIT) && !defined(PTRACE_VFORK)
pid_t pid;
/* Don't PT_CONTINUE a process which has a pending vfork done event. */
if (ptid_equal (minus_one_ptid, ptid))
pid = ptid_get_pid (inferior_ptid);
else
pid = ptid_get_pid (ptid);
if (fbsd_is_vfork_done_pending (pid))
return;
#endif
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
"FLWP: fbsd_resume for ptid (%d, %ld, %ld)\n",
ptid_get_pid (ptid), ptid_get_lwp (ptid),
ptid_get_tid (ptid));
if (ptid_lwp_p (ptid))
{
/* If ptid is a specific LWP, suspend all other LWPs in the process. */
struct thread_info *tp;
int request;
ALL_NON_EXITED_THREADS (tp)
{
if (ptid_get_pid (tp->ptid) != ptid_get_pid (ptid))
continue;
if (ptid_get_lwp (tp->ptid) == ptid_get_lwp (ptid))
request = PT_RESUME;
else
request = PT_SUSPEND;
if (ptrace (request, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
perror_with_name (("ptrace"));
}
}
else
{
/* If ptid is a wildcard, resume all matching threads (they won't run
until the process is continued however). */
struct thread_info *tp;
ALL_NON_EXITED_THREADS (tp)
{
if (!ptid_match (tp->ptid, ptid))
continue;
if (ptrace (PT_RESUME, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
perror_with_name (("ptrace"));
}
ptid = inferior_ptid;
}
super_resume (ops, ptid, step, signo);
}
/* Wait for the child specified by PTID to do something. Return the
process ID of the child, or MINUS_ONE_PTID in case of error; store
the status in *OURSTATUS. */
static ptid_t
fbsd_wait (struct target_ops *ops,
ptid_t ptid, struct target_waitstatus *ourstatus,
int target_options)
{
ptid_t wptid;
while (1)
{
#ifndef PTRACE_VFORK
wptid = fbsd_next_vfork_done ();
if (!ptid_equal (wptid, null_ptid))
{
ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
return wptid;
}
#endif
wptid = super_wait (ops, ptid, ourstatus, target_options);
if (ourstatus->kind == TARGET_WAITKIND_STOPPED)
{
struct ptrace_lwpinfo pl;
pid_t pid;
int status;
pid = ptid_get_pid (wptid);
if (ptrace (PT_LWPINFO, pid, (caddr_t) &pl, sizeof pl) == -1)
perror_with_name (("ptrace"));
wptid = ptid_build (pid, pl.pl_lwpid, 0);
#ifdef PT_LWP_EVENTS
if (pl.pl_flags & PL_FLAG_EXITED)
{
/* If GDB attaches to a multi-threaded process, exiting
threads might be skipped during fbsd_post_attach that
have not yet reported their PL_FLAG_EXITED event.
Ignore EXITED events for an unknown LWP. */
if (in_thread_list (wptid))
{
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
"FLWP: deleting thread for LWP %u\n",
pl.pl_lwpid);
if (print_thread_events)
printf_unfiltered (_("[%s exited]\n"), target_pid_to_str
(wptid));
delete_thread (wptid);
}
if (ptrace (PT_CONTINUE, pid, (caddr_t) 1, 0) == -1)
perror_with_name (("ptrace"));
continue;
}
#endif
/* Switch to an LWP PTID on the first stop in a new process.
This is done after handling PL_FLAG_EXITED to avoid
switching to an exited LWP. It is done before checking
PL_FLAG_BORN in case the first stop reported after
attaching to an existing process is a PL_FLAG_BORN
event. */
if (in_thread_list (pid_to_ptid (pid)))
{
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
"FLWP: using LWP %u for first thread\n",
pl.pl_lwpid);
thread_change_ptid (pid_to_ptid (pid), wptid);
}
#ifdef PT_LWP_EVENTS
if (pl.pl_flags & PL_FLAG_BORN)
{
/* If GDB attaches to a multi-threaded process, newborn
threads might be added by fbsd_add_threads that have
not yet reported their PL_FLAG_BORN event. Ignore
BORN events for an already-known LWP. */
if (!in_thread_list (wptid))
{
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
"FLWP: adding thread for LWP %u\n",
pl.pl_lwpid);
add_thread (wptid);
}
ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
return wptid;
}
#endif
#ifdef TDP_RFPPWAIT
if (pl.pl_flags & PL_FLAG_FORKED)
{
#ifndef PTRACE_VFORK
struct kinfo_proc kp;
#endif
ptid_t child_ptid;
pid_t child;
child = pl.pl_child_pid;
ourstatus->kind = TARGET_WAITKIND_FORKED;
#ifdef PTRACE_VFORK
if (pl.pl_flags & PL_FLAG_VFORKED)
ourstatus->kind = TARGET_WAITKIND_VFORKED;
#endif
/* Make sure the other end of the fork is stopped too. */
child_ptid = fbsd_is_child_pending (child);
if (ptid_equal (child_ptid, null_ptid))
{
pid = waitpid (child, &status, 0);
if (pid == -1)
perror_with_name (("waitpid"));
gdb_assert (pid == child);
if (ptrace (PT_LWPINFO, child, (caddr_t)&pl, sizeof pl) == -1)
perror_with_name (("ptrace"));
gdb_assert (pl.pl_flags & PL_FLAG_CHILD);
child_ptid = ptid_build (child, pl.pl_lwpid, 0);
}
/* Enable additional events on the child process. */
fbsd_enable_proc_events (ptid_get_pid (child_ptid));
#ifndef PTRACE_VFORK
/* For vfork, the child process will have the P_PPWAIT
flag set. */
if (fbsd_fetch_kinfo_proc (child, &kp))
{
if (kp.ki_flag & P_PPWAIT)
ourstatus->kind = TARGET_WAITKIND_VFORKED;
}
else
warning (_("Failed to fetch process information"));
#endif
ourstatus->value.related_pid = child_ptid;
return wptid;
}
if (pl.pl_flags & PL_FLAG_CHILD)
{
/* Remember that this child forked, but do not report it
until the parent reports its corresponding fork
event. */
fbsd_remember_child (wptid);
continue;
}
#ifdef PTRACE_VFORK
if (pl.pl_flags & PL_FLAG_VFORK_DONE)
{
ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
return wptid;
}
#endif
#endif
#ifdef PL_FLAG_EXEC
if (pl.pl_flags & PL_FLAG_EXEC)
{
ourstatus->kind = TARGET_WAITKIND_EXECD;
ourstatus->value.execd_pathname
= xstrdup (fbsd_pid_to_exec_file (NULL, pid));
return wptid;
}
#endif
/* Note that PL_FLAG_SCE is set for any event reported while
a thread is executing a system call in the kernel. In
particular, signals that interrupt a sleep in a system
call will report this flag as part of their event. Stops
explicitly for system call entry and exit always use
SIGTRAP, so only treat SIGTRAP events as system call
entry/exit events. */
if (pl.pl_flags & (PL_FLAG_SCE | PL_FLAG_SCX)
&& ourstatus->value.sig == SIGTRAP)
{
#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE
if (catch_syscall_enabled ())
{
if (catching_syscall_number (pl.pl_syscall_code))
{
if (pl.pl_flags & PL_FLAG_SCE)
ourstatus->kind = TARGET_WAITKIND_SYSCALL_ENTRY;
else
ourstatus->kind = TARGET_WAITKIND_SYSCALL_RETURN;
ourstatus->value.syscall_number = pl.pl_syscall_code;
return wptid;
}
}
#endif
/* If the core isn't interested in this event, just
continue the process explicitly and wait for another
event. Note that PT_SYSCALL is "sticky" on FreeBSD
and once system call stops are enabled on a process
it stops for all system call entries and exits. */
if (ptrace (PT_CONTINUE, pid, (caddr_t) 1, 0) == -1)
perror_with_name (("ptrace"));
continue;
}
}
return wptid;
}
}
#ifdef TDP_RFPPWAIT
/* Target hook for follow_fork. On entry and at return inferior_ptid is
the ptid of the followed inferior. */
static int
fbsd_follow_fork (struct target_ops *ops, int follow_child,
int detach_fork)
{
if (!follow_child && detach_fork)
{
struct thread_info *tp = inferior_thread ();
pid_t child_pid = ptid_get_pid (tp->pending_follow.value.related_pid);
/* Breakpoints have already been detached from the child by
infrun.c. */
if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
perror_with_name (("ptrace"));
#ifndef PTRACE_VFORK
if (tp->pending_follow.kind == TARGET_WAITKIND_VFORKED)
{
/* We can't insert breakpoints until the child process has
finished with the shared memory region. The parent
process doesn't wait for the child process to exit or
exec until after it has been resumed from the ptrace stop
to report the fork. Once it has been resumed it doesn't
stop again before returning to userland, so there is no
reliable way to wait on the parent.
We can't stay attached to the child to wait for an exec
or exit because it may invoke ptrace(PT_TRACE_ME)
(e.g. if the parent process is a debugger forking a new
child process).
In the end, the best we can do is to make sure it runs
for a little while. Hopefully it will be out of range of
any breakpoints we reinsert. Usually this is only the
single-step breakpoint at vfork's return point. */
usleep (10000);
/* Schedule a fake VFORK_DONE event to report on the next
wait. */
fbsd_add_vfork_done (inferior_ptid);
}
#endif
}
return 0;
}
static int
fbsd_insert_fork_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
static int
fbsd_remove_fork_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
static int
fbsd_insert_vfork_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
static int
fbsd_remove_vfork_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
#endif
/* Implement the "to_post_startup_inferior" target_ops method. */
static void
fbsd_post_startup_inferior (struct target_ops *self, ptid_t pid)
{
fbsd_enable_proc_events (ptid_get_pid (pid));
}
/* Implement the "to_post_attach" target_ops method. */
static void
fbsd_post_attach (struct target_ops *self, int pid)
{
fbsd_enable_proc_events (pid);
fbsd_add_threads (pid);
}
#ifdef PL_FLAG_EXEC
/* If the FreeBSD kernel supports PL_FLAG_EXEC, then traced processes
will always stop after exec. */
static int
fbsd_insert_exec_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
static int
fbsd_remove_exec_catchpoint (struct target_ops *self, int pid)
{
return 0;
}
#endif
#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE
static int
fbsd_set_syscall_catchpoint (struct target_ops *self, int pid, bool needed,
int any_count,
gdb::array_view<const int> syscall_counts)
{
/* Ignore the arguments. inf-ptrace.c will use PT_SYSCALL which
will catch all system call entries and exits. The system calls
are filtered by GDB rather than the kernel. */
return 0;
}
#endif
#endif
void
fbsd_nat_add_target (struct target_ops *t)
{
t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
t->to_find_memory_regions = fbsd_find_memory_regions;
t->to_info_proc = fbsd_info_proc;
#ifdef KERN_PROC_AUXV
super_xfer_partial = t->to_xfer_partial;
t->to_xfer_partial = fbsd_xfer_partial;
#endif
#ifdef PT_LWPINFO
t->to_thread_alive = fbsd_thread_alive;
t->to_pid_to_str = fbsd_pid_to_str;
#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
t->to_thread_name = fbsd_thread_name;
#endif
t->to_update_thread_list = fbsd_update_thread_list;
t->to_has_thread_control = tc_schedlock;
super_resume = t->to_resume;
t->to_resume = fbsd_resume;
super_wait = t->to_wait;
t->to_wait = fbsd_wait;
t->to_post_startup_inferior = fbsd_post_startup_inferior;
t->to_post_attach = fbsd_post_attach;
#ifdef TDP_RFPPWAIT
t->to_follow_fork = fbsd_follow_fork;
t->to_insert_fork_catchpoint = fbsd_insert_fork_catchpoint;
t->to_remove_fork_catchpoint = fbsd_remove_fork_catchpoint;
t->to_insert_vfork_catchpoint = fbsd_insert_vfork_catchpoint;
t->to_remove_vfork_catchpoint = fbsd_remove_vfork_catchpoint;
#endif
#ifdef PL_FLAG_EXEC
t->to_insert_exec_catchpoint = fbsd_insert_exec_catchpoint;
t->to_remove_exec_catchpoint = fbsd_remove_exec_catchpoint;
#endif
#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE
t->to_set_syscall_catchpoint = fbsd_set_syscall_catchpoint;
#endif
#endif
add_target (t);
}
void
_initialize_fbsd_nat (void)
{
#ifdef PT_LWPINFO
add_setshow_boolean_cmd ("fbsd-lwp", class_maintenance,
&debug_fbsd_lwp, _("\
Set debugging of FreeBSD lwp module."), _("\
Show debugging of FreeBSD lwp module."), _("\
Enables printf debugging output."),
NULL,
&show_fbsd_lwp_debug,
&setdebuglist, &showdebuglist);
#endif
}
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