1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361
|
/* Waiting for a subprocess to finish.
Copyright (C) 2001-2003, 2005-2014 Free Software Foundation, Inc.
Written by Bruno Haible <haible@clisp.cons.org>, 2001.
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 <config.h>
/* Specification. */
#include "wait-process.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "error.h"
#include "fatal-signal.h"
#include "xalloc.h"
#include "gettext.h"
#define _(str) gettext (str)
#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
#if defined _MSC_VER || defined __MINGW32__
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
/* The return value of spawnvp() is really a process handle as returned
by CreateProcess(). Therefore we can kill it using TerminateProcess. */
#define kill(pid,sig) TerminateProcess ((HANDLE) (pid), sig)
#endif
/* Type of an entry in the slaves array.
The 'used' bit determines whether this entry is currently in use.
(If pid_t was an atomic type like sig_atomic_t, we could just set the
'child' field to 0 when unregistering a slave process, and wouldn't need
the 'used' field.)
The 'used' and 'child' fields are accessed from within the cleanup_slaves()
action, therefore we mark them as 'volatile'. */
typedef struct
{
volatile sig_atomic_t used;
volatile pid_t child;
}
slaves_entry_t;
/* The registered slave subprocesses. */
static slaves_entry_t static_slaves[32];
static slaves_entry_t * volatile slaves = static_slaves;
static sig_atomic_t volatile slaves_count = 0;
static size_t slaves_allocated = SIZEOF (static_slaves);
/* The termination signal for slave subprocesses.
2003-10-07: Terminator becomes Governator. */
#ifdef SIGHUP
# define TERMINATOR SIGHUP
#else
# define TERMINATOR SIGTERM
#endif
/* The cleanup action. It gets called asynchronously. */
static void
cleanup_slaves (void)
{
for (;;)
{
/* Get the last registered slave. */
size_t n = slaves_count;
if (n == 0)
break;
n--;
slaves_count = n;
/* Skip unused entries in the slaves array. */
if (slaves[n].used)
{
pid_t slave = slaves[n].child;
/* Kill the slave. */
kill (slave, TERMINATOR);
}
}
}
/* Register a subprocess as being a slave process. This means that the
subprocess will be terminated when its creator receives a catchable fatal
signal or exits normally. Registration ends when wait_subprocess()
notices that the subprocess has exited. */
void
register_slave_subprocess (pid_t child)
{
static bool cleanup_slaves_registered = false;
if (!cleanup_slaves_registered)
{
atexit (cleanup_slaves);
at_fatal_signal (cleanup_slaves);
cleanup_slaves_registered = true;
}
/* Try to store the new slave in an unused entry of the slaves array. */
{
slaves_entry_t *s = slaves;
slaves_entry_t *s_end = s + slaves_count;
for (; s < s_end; s++)
if (!s->used)
{
/* The two uses of 'volatile' in the slaves_entry_t type above
(and ISO C 99 section 5.1.2.3.(5)) ensure that we mark the
entry as used only after the child pid has been written to the
memory location s->child. */
s->child = child;
s->used = 1;
return;
}
}
if (slaves_count == slaves_allocated)
{
/* Extend the slaves array. Note that we cannot use xrealloc(),
because then the cleanup_slaves() function could access an already
deallocated array. */
slaves_entry_t *old_slaves = slaves;
size_t new_slaves_allocated = 2 * slaves_allocated;
slaves_entry_t *new_slaves =
(slaves_entry_t *)
malloc (new_slaves_allocated * sizeof (slaves_entry_t));
if (new_slaves == NULL)
{
/* xalloc_die() will call exit() which will invoke cleanup_slaves().
Additionally we need to kill child, because it's not yet among
the slaves list. */
kill (child, TERMINATOR);
xalloc_die ();
}
memcpy (new_slaves, old_slaves,
slaves_allocated * sizeof (slaves_entry_t));
slaves = new_slaves;
slaves_allocated = new_slaves_allocated;
/* Now we can free the old slaves array. */
if (old_slaves != static_slaves)
free (old_slaves);
}
/* The three uses of 'volatile' in the types above (and ISO C 99 section
5.1.2.3.(5)) ensure that we increment the slaves_count only after the
new slave and its 'used' bit have been written to the memory locations
that make up slaves[slaves_count]. */
slaves[slaves_count].child = child;
slaves[slaves_count].used = 1;
slaves_count++;
}
/* Unregister a child from the list of slave subprocesses. */
static void
unregister_slave_subprocess (pid_t child)
{
/* The easiest way to remove an entry from a list that can be used by
an asynchronous signal handler is just to mark it as unused. For this,
we rely on sig_atomic_t. */
slaves_entry_t *s = slaves;
slaves_entry_t *s_end = s + slaves_count;
for (; s < s_end; s++)
if (s->used && s->child == child)
s->used = 0;
}
/* Wait for a subprocess to finish. Return its exit code.
If it didn't terminate correctly, exit if exit_on_error is true, otherwise
return 127. */
int
wait_subprocess (pid_t child, const char *progname,
bool ignore_sigpipe, bool null_stderr,
bool slave_process, bool exit_on_error,
int *termsigp)
{
#if HAVE_WAITID && defined WNOWAIT && 0
/* Commented out because waitid() without WEXITED and with WNOWAIT doesn't
work: On Solaris 7 and OSF/1 4.0, it returns -1 and sets errno = ECHILD,
and on HP-UX 10.20 it just hangs. */
/* Use of waitid() with WNOWAIT avoids a race condition: If slave_process is
true, and this process sleeps a very long time between the return from
waitpid() and the execution of unregister_slave_subprocess(), and
meanwhile another process acquires the same PID as child, and then - still
before unregister_slave_subprocess() - this process gets a fatal signal,
it would kill the other totally unrelated process. */
siginfo_t info;
if (termsigp != NULL)
*termsigp = 0;
for (;;)
{
if (waitid (P_PID, child, &info, WEXITED | (slave_process ? WNOWAIT : 0))
< 0)
{
# ifdef EINTR
if (errno == EINTR)
continue;
# endif
if (exit_on_error || !null_stderr)
error (exit_on_error ? EXIT_FAILURE : 0, errno,
_("%s subprocess"), progname);
return 127;
}
/* info.si_code is set to one of CLD_EXITED, CLD_KILLED, CLD_DUMPED,
CLD_TRAPPED, CLD_STOPPED, CLD_CONTINUED. Loop until the program
terminates. */
if (info.si_code == CLD_EXITED
|| info.si_code == CLD_KILLED || info.si_code == CLD_DUMPED)
break;
}
/* The child process has exited or was signalled. */
if (slave_process)
{
/* Unregister the child from the list of slave subprocesses, so that
later, when we exit, we don't kill a totally unrelated process which
may have acquired the same pid. */
unregister_slave_subprocess (child);
/* Now remove the zombie from the process list. */
for (;;)
{
if (waitid (P_PID, child, &info, WEXITED) < 0)
{
# ifdef EINTR
if (errno == EINTR)
continue;
# endif
if (exit_on_error || !null_stderr)
error (exit_on_error ? EXIT_FAILURE : 0, errno,
_("%s subprocess"), progname);
return 127;
}
break;
}
}
switch (info.si_code)
{
case CLD_KILLED:
case CLD_DUMPED:
if (termsigp != NULL)
*termsigp = info.si_status; /* TODO: or info.si_signo? */
# ifdef SIGPIPE
if (info.si_status == SIGPIPE && ignore_sigpipe)
return 0;
# endif
if (exit_on_error || (!null_stderr && termsigp == NULL))
error (exit_on_error ? EXIT_FAILURE : 0, 0,
_("%s subprocess got fatal signal %d"),
progname, info.si_status);
return 127;
case CLD_EXITED:
if (info.si_status == 127)
{
if (exit_on_error || !null_stderr)
error (exit_on_error ? EXIT_FAILURE : 0, 0,
_("%s subprocess failed"), progname);
return 127;
}
return info.si_status;
default:
abort ();
}
#else
/* waitpid() is just as portable as wait() nowadays. */
int status;
if (termsigp != NULL)
*termsigp = 0;
status = 0;
for (;;)
{
int result = waitpid (child, &status, 0);
if (result != child)
{
# ifdef EINTR
if (errno == EINTR)
continue;
# endif
# if 0 /* defined ECHILD */
if (errno == ECHILD)
{
/* Child process nonexistent?! Assume it terminated
successfully. */
status = 0;
break;
}
# endif
if (exit_on_error || !null_stderr)
error (exit_on_error ? EXIT_FAILURE : 0, errno,
_("%s subprocess"), progname);
return 127;
}
/* One of WIFSIGNALED (status), WIFEXITED (status), WIFSTOPPED (status)
must always be true, since we did not specify WCONTINUED in the
waitpid() call. Loop until the program terminates. */
if (!WIFSTOPPED (status))
break;
}
/* The child process has exited or was signalled. */
if (slave_process)
/* Unregister the child from the list of slave subprocesses, so that
later, when we exit, we don't kill a totally unrelated process which
may have acquired the same pid. */
unregister_slave_subprocess (child);
if (WIFSIGNALED (status))
{
if (termsigp != NULL)
*termsigp = WTERMSIG (status);
# ifdef SIGPIPE
if (WTERMSIG (status) == SIGPIPE && ignore_sigpipe)
return 0;
# endif
if (exit_on_error || (!null_stderr && termsigp == NULL))
error (exit_on_error ? EXIT_FAILURE : 0, 0,
_("%s subprocess got fatal signal %d"),
progname, (int) WTERMSIG (status));
return 127;
}
if (!WIFEXITED (status))
abort ();
if (WEXITSTATUS (status) == 127)
{
if (exit_on_error || !null_stderr)
error (exit_on_error ? EXIT_FAILURE : 0, 0,
_("%s subprocess failed"), progname);
return 127;
}
return WEXITSTATUS (status);
#endif
}
|