]>
git.ipfire.org Git - thirdparty/systemd.git/blob - src/basic/process-util.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2010 Lennart Poettering
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 #include <linux/oom.h>
29 #include <stdio_ext.h>
33 #include <sys/personality.h>
34 #include <sys/prctl.h>
35 #include <sys/types.h>
39 #if HAVE_VALGRIND_VALGRIND_H
40 #include <valgrind/valgrind.h>
43 #include "alloc-util.h"
44 #include "architecture.h"
53 #include "process-util.h"
54 #include "raw-clone.h"
55 #include "signal-util.h"
56 #include "stat-util.h"
57 #include "string-table.h"
58 #include "string-util.h"
59 #include "terminal-util.h"
60 #include "user-util.h"
63 int get_process_state(pid_t pid
) {
67 _cleanup_free_
char *line
= NULL
;
71 p
= procfs_file_alloca(pid
, "stat");
73 r
= read_one_line_file(p
, &line
);
79 p
= strrchr(line
, ')');
85 if (sscanf(p
, " %c", &state
) != 1)
88 return (unsigned char) state
;
91 int get_process_comm(pid_t pid
, char **name
) {
98 p
= procfs_file_alloca(pid
, "comm");
100 r
= read_one_line_file(p
, name
);
107 int get_process_cmdline(pid_t pid
, size_t max_length
, bool comm_fallback
, char **line
) {
108 _cleanup_fclose_
FILE *f
= NULL
;
110 char *k
, *ans
= NULL
;
117 /* Retrieves a process' command line. Replaces unprintable characters while doing so by whitespace (coalescing
118 * multiple sequential ones into one). If max_length is != 0 will return a string of the specified size at most
119 * (the trailing NUL byte does count towards the length here!), abbreviated with a "..." ellipsis. If
120 * comm_fallback is true and the process has no command line set (the case for kernel threads), or has a
121 * command line that resolves to the empty string will return the "comm" name of the process instead.
123 * Returns -ESRCH if the process doesn't exist, and -ENOENT if the process has no command line (and
124 * comm_fallback is false). Returns 0 and sets *line otherwise. */
126 p
= procfs_file_alloca(pid
, "cmdline");
135 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
137 if (max_length
== 1) {
139 /* If there's only room for one byte, return the empty string */
147 } else if (max_length
== 0) {
148 size_t len
= 0, allocated
= 0;
150 while ((c
= getc(f
)) != EOF
) {
152 if (!GREEDY_REALLOC(ans
, allocated
, len
+3)) {
174 bool dotdotdot
= false;
177 ans
= new(char, max_length
);
183 while ((c
= getc(f
)) != EOF
) {
210 if (max_length
<= 4) {
214 k
= ans
+ max_length
- 4;
217 /* Eat up final spaces */
218 while (k
> ans
&& isspace(k
[-1])) {
224 strncpy(k
, "...", left
-1);
230 /* Kernel threads have no argv[] */
232 _cleanup_free_
char *t
= NULL
;
240 h
= get_process_comm(pid
, &t
);
245 ans
= strjoin("[", t
, "]");
251 if (l
+ 3 <= max_length
)
252 ans
= strjoin("[", t
, "]");
253 else if (max_length
<= 6) {
255 ans
= new(char, max_length
);
259 memcpy(ans
, "[...]", max_length
-1);
260 ans
[max_length
-1] = 0;
264 t
[max_length
- 6] = 0;
266 /* Chop off final spaces */
268 while (e
> t
&& isspace(e
[-1]))
272 ans
= strjoin("[", t
, "...]");
283 int rename_process(const char name
[]) {
284 static size_t mm_size
= 0;
285 static char *mm
= NULL
;
286 bool truncated
= false;
289 /* This is a like a poor man's setproctitle(). It changes the comm field, argv[0], and also the glibc's
290 * internally used name of the process. For the first one a limit of 16 chars applies; to the second one in
291 * many cases one of 10 (i.e. length of "/sbin/init") — however if we have CAP_SYS_RESOURCES it is unbounded;
292 * to the third one 7 (i.e. the length of "systemd". If you pass a longer string it will likely be
295 * Returns 0 if a name was set but truncated, > 0 if it was set but not truncated. */
298 return -EINVAL
; /* let's not confuse users unnecessarily with an empty name */
300 if (!is_main_thread())
301 return -EPERM
; /* Let's not allow setting the process name from other threads than the main one, as we
302 * cache things without locking, and we make assumptions that PR_SET_NAME sets the
303 * process name that isn't correct on any other threads */
307 /* First step, change the comm field. The main thread's comm is identical to the process comm. This means we
308 * can use PR_SET_NAME, which sets the thread name for the calling thread. */
309 if (prctl(PR_SET_NAME
, name
) < 0)
310 log_debug_errno(errno
, "PR_SET_NAME failed: %m");
311 if (l
> 15) /* Linux process names can be 15 chars at max */
314 /* Second step, change glibc's ID of the process name. */
315 if (program_invocation_name
) {
318 k
= strlen(program_invocation_name
);
319 strncpy(program_invocation_name
, name
, k
);
324 /* Third step, completely replace the argv[] array the kernel maintains for us. This requires privileges, but
325 * has the advantage that the argv[] array is exactly what we want it to be, and not filled up with zeros at
326 * the end. This is the best option for changing /proc/self/cmdline. */
328 /* Let's not bother with this if we don't have euid == 0. Strictly speaking we should check for the
329 * CAP_SYS_RESOURCE capability which is independent of the euid. In our own code the capability generally is
330 * present only for euid == 0, hence let's use this as quick bypass check, to avoid calling mmap() if
331 * PR_SET_MM_ARG_{START,END} fails with EPERM later on anyway. After all geteuid() is dead cheap to call, but
334 log_debug("Skipping PR_SET_MM, as we don't have privileges.");
335 else if (mm_size
< l
+1) {
339 nn_size
= PAGE_ALIGN(l
+1);
340 nn
= mmap(NULL
, nn_size
, PROT_READ
|PROT_WRITE
, MAP_PRIVATE
|MAP_ANONYMOUS
, -1, 0);
341 if (nn
== MAP_FAILED
) {
342 log_debug_errno(errno
, "mmap() failed: %m");
346 strncpy(nn
, name
, nn_size
);
348 /* Now, let's tell the kernel about this new memory */
349 if (prctl(PR_SET_MM
, PR_SET_MM_ARG_START
, (unsigned long) nn
, 0, 0) < 0) {
350 log_debug_errno(errno
, "PR_SET_MM_ARG_START failed, proceeding without: %m");
351 (void) munmap(nn
, nn_size
);
355 /* And update the end pointer to the new end, too. If this fails, we don't really know what to do, it's
356 * pretty unlikely that we can rollback, hence we'll just accept the failure, and continue. */
357 if (prctl(PR_SET_MM
, PR_SET_MM_ARG_END
, (unsigned long) nn
+ l
+ 1, 0, 0) < 0)
358 log_debug_errno(errno
, "PR_SET_MM_ARG_END failed, proceeding without: %m");
361 (void) munmap(mm
, mm_size
);
366 strncpy(mm
, name
, mm_size
);
368 /* Update the end pointer, continuing regardless of any failure. */
369 if (prctl(PR_SET_MM
, PR_SET_MM_ARG_END
, (unsigned long) mm
+ l
+ 1, 0, 0) < 0)
370 log_debug_errno(errno
, "PR_SET_MM_ARG_END failed, proceeding without: %m");
374 /* Fourth step: in all cases we'll also update the original argv[], so that our own code gets it right too if
375 * it still looks here */
377 if (saved_argc
> 0) {
383 k
= strlen(saved_argv
[0]);
384 strncpy(saved_argv
[0], name
, k
);
389 for (i
= 1; i
< saved_argc
; i
++) {
393 memzero(saved_argv
[i
], strlen(saved_argv
[i
]));
400 int is_kernel_thread(pid_t pid
) {
407 if (IN_SET(pid
, 0, 1) || pid
== getpid_cached()) /* pid 1, and we ourselves certainly aren't a kernel thread */
412 p
= procfs_file_alloca(pid
, "cmdline");
420 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
422 count
= fread(&c
, 1, 1, f
);
426 /* Kernel threads have an empty cmdline */
429 return eof
? 1 : -errno
;
434 int get_process_capeff(pid_t pid
, char **capeff
) {
441 p
= procfs_file_alloca(pid
, "status");
443 r
= get_proc_field(p
, "CapEff", WHITESPACE
, capeff
);
450 static int get_process_link_contents(const char *proc_file
, char **name
) {
456 r
= readlink_malloc(proc_file
, name
);
465 int get_process_exe(pid_t pid
, char **name
) {
472 p
= procfs_file_alloca(pid
, "exe");
473 r
= get_process_link_contents(p
, name
);
477 d
= endswith(*name
, " (deleted)");
484 static int get_process_id(pid_t pid
, const char *field
, uid_t
*uid
) {
485 _cleanup_fclose_
FILE *f
= NULL
;
495 p
= procfs_file_alloca(pid
, "status");
503 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
505 FOREACH_LINE(line
, f
, return -errno
) {
510 if (startswith(l
, field
)) {
512 l
+= strspn(l
, WHITESPACE
);
514 l
[strcspn(l
, WHITESPACE
)] = 0;
516 return parse_uid(l
, uid
);
523 int get_process_uid(pid_t pid
, uid_t
*uid
) {
525 if (pid
== 0 || pid
== getpid_cached()) {
530 return get_process_id(pid
, "Uid:", uid
);
533 int get_process_gid(pid_t pid
, gid_t
*gid
) {
535 if (pid
== 0 || pid
== getpid_cached()) {
540 assert_cc(sizeof(uid_t
) == sizeof(gid_t
));
541 return get_process_id(pid
, "Gid:", gid
);
544 int get_process_cwd(pid_t pid
, char **cwd
) {
549 p
= procfs_file_alloca(pid
, "cwd");
551 return get_process_link_contents(p
, cwd
);
554 int get_process_root(pid_t pid
, char **root
) {
559 p
= procfs_file_alloca(pid
, "root");
561 return get_process_link_contents(p
, root
);
564 int get_process_environ(pid_t pid
, char **env
) {
565 _cleanup_fclose_
FILE *f
= NULL
;
566 _cleanup_free_
char *outcome
= NULL
;
569 size_t allocated
= 0, sz
= 0;
574 p
= procfs_file_alloca(pid
, "environ");
583 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
585 while ((c
= fgetc(f
)) != EOF
) {
586 if (!GREEDY_REALLOC(outcome
, allocated
, sz
+ 5))
590 outcome
[sz
++] = '\n';
592 sz
+= cescape_char(c
, outcome
+ sz
);
596 outcome
= strdup("");
608 int get_process_ppid(pid_t pid
, pid_t
*_ppid
) {
610 _cleanup_free_
char *line
= NULL
;
617 if (pid
== 0 || pid
== getpid_cached()) {
622 p
= procfs_file_alloca(pid
, "stat");
623 r
= read_one_line_file(p
, &line
);
629 /* Let's skip the pid and comm fields. The latter is enclosed
630 * in () but does not escape any () in its value, so let's
631 * skip over it manually */
633 p
= strrchr(line
, ')');
645 if ((long unsigned) (pid_t
) ppid
!= ppid
)
648 *_ppid
= (pid_t
) ppid
;
653 int wait_for_terminate(pid_t pid
, siginfo_t
*status
) {
664 if (waitid(P_PID
, pid
, status
, WEXITED
) < 0) {
669 return negative_errno();
678 * < 0 : wait_for_terminate() failed to get the state of the
679 * process, the process was terminated by a signal, or
680 * failed for an unknown reason.
681 * >=0 : The process terminated normally, and its exit code is
684 * That is, success is indicated by a return value of zero, and an
685 * error is indicated by a non-zero value.
687 * A warning is emitted if the process terminates abnormally,
688 * and also if it returns non-zero unless check_exit_code is true.
690 int wait_for_terminate_and_warn(const char *name
, pid_t pid
, bool check_exit_code
) {
697 r
= wait_for_terminate(pid
, &status
);
699 return log_warning_errno(r
, "Failed to wait for %s: %m", name
);
701 if (status
.si_code
== CLD_EXITED
) {
702 if (status
.si_status
!= 0)
703 log_full(check_exit_code
? LOG_WARNING
: LOG_DEBUG
,
704 "%s failed with error code %i.", name
, status
.si_status
);
706 log_debug("%s succeeded.", name
);
708 return status
.si_status
;
709 } else if (IN_SET(status
.si_code
, CLD_KILLED
, CLD_DUMPED
)) {
711 log_warning("%s terminated by signal %s.", name
, signal_to_string(status
.si_status
));
715 log_warning("%s failed due to unknown reason.", name
);
721 * < 0 : wait_for_terminate_with_timeout() failed to get the state of the
722 * process, the process timed out, the process was terminated by a
723 * signal, or failed for an unknown reason.
724 * >=0 : The process terminated normally with no failures.
726 * Success is indicated by a return value of zero, a timeout is indicated
727 * by ETIMEDOUT, and all other child failure states are indicated by error
728 * is indicated by a non-zero value.
730 int wait_for_terminate_with_timeout(pid_t pid
, usec_t timeout
) {
735 assert_se(sigemptyset(&mask
) == 0);
736 assert_se(sigaddset(&mask
, SIGCHLD
) == 0);
738 /* Drop into a sigtimewait-based timeout. Waiting for the
740 until
= now(CLOCK_MONOTONIC
) + timeout
;
743 siginfo_t status
= {};
746 n
= now(CLOCK_MONOTONIC
);
750 r
= sigtimedwait(&mask
, NULL
, timespec_store(&ts
, until
- n
)) < 0 ? -errno
: 0;
751 /* Assuming we woke due to the child exiting. */
752 if (waitid(P_PID
, pid
, &status
, WEXITED
|WNOHANG
) == 0) {
753 if (status
.si_pid
== pid
) {
754 /* This is the correct child.*/
755 if (status
.si_code
== CLD_EXITED
)
756 return (status
.si_status
== 0) ? 0 : -EPROTO
;
761 /* Not the child, check for errors and proceed appropriately */
765 /* Timed out, child is likely hung. */
768 /* Received a different signal and should retry */
771 /* Return any unexpected errors */
780 void sigkill_wait(pid_t pid
) {
783 if (kill(pid
, SIGKILL
) > 0)
784 (void) wait_for_terminate(pid
, NULL
);
787 void sigkill_waitp(pid_t
*pid
) {
796 int kill_and_sigcont(pid_t pid
, int sig
) {
799 r
= kill(pid
, sig
) < 0 ? -errno
: 0;
801 /* If this worked, also send SIGCONT, unless we already just sent a SIGCONT, or SIGKILL was sent which isn't
802 * affected by a process being suspended anyway. */
803 if (r
>= 0 && !IN_SET(sig
, SIGCONT
, SIGKILL
))
804 (void) kill(pid
, SIGCONT
);
809 int getenv_for_pid(pid_t pid
, const char *field
, char **_value
) {
810 _cleanup_fclose_
FILE *f
= NULL
;
821 path
= procfs_file_alloca(pid
, "environ");
823 f
= fopen(path
, "re");
830 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
839 for (i
= 0; i
< sizeof(line
)-1; i
++) {
843 if (_unlikely_(c
== EOF
)) {
853 if (strneq(line
, field
, l
) && line
[l
] == '=') {
854 value
= strdup(line
+ l
+ 1);
868 bool pid_is_unwaited(pid_t pid
) {
869 /* Checks whether a PID is still valid at all, including a zombie */
874 if (pid
<= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
877 if (pid
== getpid_cached())
880 if (kill(pid
, 0) >= 0)
883 return errno
!= ESRCH
;
886 bool pid_is_alive(pid_t pid
) {
889 /* Checks whether a PID is still valid and not a zombie */
894 if (pid
<= 1) /* If we or PID 1 would be a zombie, this code would not be running */
897 if (pid
== getpid_cached())
900 r
= get_process_state(pid
);
901 if (IN_SET(r
, -ESRCH
, 'Z'))
907 int pid_from_same_root_fs(pid_t pid
) {
913 if (pid
== 0 || pid
== getpid_cached())
916 root
= procfs_file_alloca(pid
, "root");
918 return files_same(root
, "/proc/1/root", 0);
921 bool is_main_thread(void) {
922 static thread_local
int cached
= 0;
924 if (_unlikely_(cached
== 0))
925 cached
= getpid_cached() == gettid() ? 1 : -1;
930 noreturn
void freeze(void) {
934 /* Make sure nobody waits for us on a socket anymore */
935 close_all_fds(NULL
, 0);
943 bool oom_score_adjust_is_valid(int oa
) {
944 return oa
>= OOM_SCORE_ADJ_MIN
&& oa
<= OOM_SCORE_ADJ_MAX
;
947 unsigned long personality_from_string(const char *p
) {
951 return PERSONALITY_INVALID
;
953 /* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
954 * hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
955 * the same register size. */
957 architecture
= architecture_from_string(p
);
958 if (architecture
< 0)
959 return PERSONALITY_INVALID
;
961 if (architecture
== native_architecture())
963 #ifdef SECONDARY_ARCHITECTURE
964 if (architecture
== SECONDARY_ARCHITECTURE
)
968 return PERSONALITY_INVALID
;
971 const char* personality_to_string(unsigned long p
) {
972 int architecture
= _ARCHITECTURE_INVALID
;
975 architecture
= native_architecture();
976 #ifdef SECONDARY_ARCHITECTURE
977 else if (p
== PER_LINUX32
)
978 architecture
= SECONDARY_ARCHITECTURE
;
981 if (architecture
< 0)
984 return architecture_to_string(architecture
);
987 int safe_personality(unsigned long p
) {
990 /* So here's the deal, personality() is weirdly defined by glibc. In some cases it returns a failure via errno,
991 * and in others as negative return value containing an errno-like value. Let's work around this: this is a
992 * wrapper that uses errno if it is set, and uses the return value otherwise. And then it sets both errno and
993 * the return value indicating the same issue, so that we are definitely on the safe side.
995 * See https://github.com/systemd/systemd/issues/6737 */
998 ret
= personality(p
);
1009 int opinionated_personality(unsigned long *ret
) {
1012 /* Returns the current personality, or PERSONALITY_INVALID if we can't determine it. This function is a bit
1013 * opinionated though, and ignores all the finer-grained bits and exotic personalities, only distinguishing the
1014 * two most relevant personalities: PER_LINUX and PER_LINUX32. */
1016 current
= safe_personality(PERSONALITY_INVALID
);
1020 if (((unsigned long) current
& 0xffff) == PER_LINUX32
)
1028 void valgrind_summary_hack(void) {
1029 #if HAVE_VALGRIND_VALGRIND_H
1030 if (getpid_cached() == 1 && RUNNING_ON_VALGRIND
) {
1032 pid
= raw_clone(SIGCHLD
);
1034 log_emergency_errno(errno
, "Failed to fork off valgrind helper: %m");
1038 log_info("Spawned valgrind helper as PID "PID_FMT
".", pid
);
1039 (void) wait_for_terminate(pid
, NULL
);
1045 int pid_compare_func(const void *a
, const void *b
) {
1046 const pid_t
*p
= a
, *q
= b
;
1048 /* Suitable for usage in qsort() */
1057 int ioprio_parse_priority(const char *s
, int *ret
) {
1063 r
= safe_atoi(s
, &i
);
1067 if (!ioprio_priority_is_valid(i
))
1074 /* The cached PID, possible values:
1076 * == UNSET [0] → cache not initialized yet
1077 * == BUSY [-1] → some thread is initializing it at the moment
1078 * any other → the cached PID
1081 #define CACHED_PID_UNSET ((pid_t) 0)
1082 #define CACHED_PID_BUSY ((pid_t) -1)
1084 static pid_t cached_pid
= CACHED_PID_UNSET
;
1086 static void reset_cached_pid(void) {
1087 /* Invoked in the child after a fork(), i.e. at the first moment the PID changed */
1088 cached_pid
= CACHED_PID_UNSET
;
1091 /* We use glibc __register_atfork() + __dso_handle directly here, as they are not included in the glibc
1092 * headers. __register_atfork() is mostly equivalent to pthread_atfork(), but doesn't require us to link against
1093 * libpthread, as it is part of glibc anyway. */
1094 extern int __register_atfork(void (*prepare
) (void), void (*parent
) (void), void (*child
) (void), void * __dso_handle
);
1095 extern void* __dso_handle
__attribute__ ((__weak__
));
1097 pid_t
getpid_cached(void) {
1098 pid_t current_value
;
1100 /* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
1101 * system call each time. This restores glibc behaviour from before 2.24, when getpid() was unconditionally
1102 * cached. Starting with 2.24 getpid() started to become prohibitively expensive when used for detecting when
1103 * objects were used across fork()s. With this caching the old behaviour is somewhat restored.
1105 * https://bugzilla.redhat.com/show_bug.cgi?id=1443976
1106 * https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c579f48edba88380635ab98cb612030e3ed8691e
1109 current_value
= __sync_val_compare_and_swap(&cached_pid
, CACHED_PID_UNSET
, CACHED_PID_BUSY
);
1111 switch (current_value
) {
1113 case CACHED_PID_UNSET
: { /* Not initialized yet, then do so now */
1118 if (__register_atfork(NULL
, NULL
, reset_cached_pid
, __dso_handle
) != 0) {
1119 /* OOM? Let's try again later */
1120 cached_pid
= CACHED_PID_UNSET
;
1124 cached_pid
= new_pid
;
1128 case CACHED_PID_BUSY
: /* Somebody else is currently initializing */
1131 default: /* Properly initialized */
1132 return current_value
;
1136 int must_be_root(void) {
1141 log_error("Need to be root.");
1147 const int except_fds
[],
1148 size_t n_except_fds
,
1152 pid_t original_pid
, pid
;
1157 /* A wrapper around fork(), that does a couple of important initializations in addition to mere forking. Always
1158 * returns the child's PID in *ret_pid. Returns == 0 in the child, and > 0 in the parent. */
1160 original_pid
= getpid_cached();
1162 block_signals
= flags
& (FORK_RESET_SIGNALS
|FORK_DEATHSIG
);
1164 if (block_signals
) {
1167 /* We temporarily block all signals, so that the new child has them blocked initially. This way, we can be sure
1168 * that SIGTERMs are not lost we might send to the child. */
1169 if (sigfillset(&ss
) < 0)
1170 return log_debug_errno(errno
, "Failed to reset signal set: %m");
1172 if (sigprocmask(SIG_SETMASK
, &ss
, &saved_ss
) < 0)
1173 return log_debug_errno(errno
, "Failed to reset signal mask: %m");
1180 if (block_signals
) /* undo what we did above */
1181 (void) sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
);
1183 return log_debug_errno(r
, "Failed to fork: %m");
1186 /* We are in the parent process */
1188 if (block_signals
) /* undo what we did above */
1189 (void) sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
);
1191 log_debug("Sucessfully forked off '%s' as PID " PID_FMT
".", strna(name
), pid
);
1199 /* We are in the child process */
1201 if (flags
& FORK_REOPEN_LOG
) {
1202 /* Close the logs if requested, before we log anything. And make sure we reopen it if needed. */
1204 log_set_open_when_needed(true);
1208 r
= rename_process(name
);
1210 log_debug_errno(r
, "Failed to rename process, ignoring: %m");
1213 if (flags
& FORK_DEATHSIG
)
1214 if (prctl(PR_SET_PDEATHSIG
, SIGTERM
) < 0) {
1215 log_debug_errno(errno
, "Failed to set death signal: %m");
1216 _exit(EXIT_FAILURE
);
1219 if (flags
& FORK_RESET_SIGNALS
) {
1220 r
= reset_all_signal_handlers();
1222 log_debug_errno(r
, "Failed to reset signal handlers: %m");
1223 _exit(EXIT_FAILURE
);
1226 /* This implicitly undoes the signal mask stuff we did before the fork()ing above */
1227 r
= reset_signal_mask();
1229 log_debug_errno(r
, "Failed to reset signal mask: %m");
1230 _exit(EXIT_FAILURE
);
1232 } else if (block_signals
) { /* undo what we did above */
1233 if (sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
) < 0) {
1234 log_debug_errno(errno
, "Failed to restore signal mask: %m");
1235 _exit(EXIT_FAILURE
);
1239 if (flags
& FORK_DEATHSIG
) {
1240 /* Let's see if the parent PID is still the one we started from? If not, then the parent
1241 * already died by the time we set PR_SET_PDEATHSIG, hence let's emulate the effect */
1243 if (getppid() != original_pid
) {
1244 log_debug("Parent died early, raising SIGTERM.");
1245 (void) raise(SIGTERM
);
1246 _exit(EXIT_FAILURE
);
1250 if (flags
& FORK_CLOSE_ALL_FDS
) {
1251 /* Close the logs here in case it got reopened above, as close_all_fds() would close them for us */
1254 r
= close_all_fds(except_fds
, n_except_fds
);
1256 log_debug_errno(r
, "Failed to close all file descriptors: %m");
1257 _exit(EXIT_FAILURE
);
1261 /* When we were asked to reopen the logs, do so again now */
1262 if (flags
& FORK_REOPEN_LOG
) {
1264 log_set_open_when_needed(false);
1267 if (flags
& FORK_NULL_STDIO
) {
1268 r
= make_null_stdio();
1270 log_debug_errno(r
, "Failed to connect stdin/stdout to /dev/null: %m");
1271 _exit(EXIT_FAILURE
);
1276 *ret_pid
= getpid_cached();
1281 int fork_agent(const char *name
, const int except
[], unsigned n_except
, pid_t
*ret_pid
, const char *path
, ...) {
1282 bool stdout_is_tty
, stderr_is_tty
;
1290 /* Spawns a temporary TTY agent, making sure it goes away when we go away */
1292 r
= safe_fork_full(name
, except
, n_except
, FORK_RESET_SIGNALS
|FORK_DEATHSIG
|FORK_CLOSE_ALL_FDS
, ret_pid
);
1300 stdout_is_tty
= isatty(STDOUT_FILENO
);
1301 stderr_is_tty
= isatty(STDERR_FILENO
);
1303 if (!stdout_is_tty
|| !stderr_is_tty
) {
1306 /* Detach from stdout/stderr. and reopen
1307 * /dev/tty for them. This is important to
1308 * ensure that when systemctl is started via
1309 * popen() or a similar call that expects to
1310 * read EOF we actually do generate EOF and
1311 * not delay this indefinitely by because we
1312 * keep an unused copy of stdin around. */
1313 fd
= open("/dev/tty", O_WRONLY
);
1315 log_error_errno(errno
, "Failed to open /dev/tty: %m");
1316 _exit(EXIT_FAILURE
);
1319 if (!stdout_is_tty
&& dup2(fd
, STDOUT_FILENO
) < 0) {
1320 log_error_errno(errno
, "Failed to dup2 /dev/tty: %m");
1321 _exit(EXIT_FAILURE
);
1324 if (!stderr_is_tty
&& dup2(fd
, STDERR_FILENO
) < 0) {
1325 log_error_errno(errno
, "Failed to dup2 /dev/tty: %m");
1326 _exit(EXIT_FAILURE
);
1329 if (fd
> STDERR_FILENO
)
1333 /* Count arguments */
1335 for (n
= 0; va_arg(ap
, char*); n
++)
1340 l
= alloca(sizeof(char *) * (n
+ 1));
1342 /* Fill in arguments */
1344 for (i
= 0; i
<= n
; i
++)
1345 l
[i
] = va_arg(ap
, char*);
1349 _exit(EXIT_FAILURE
);
1352 static const char *const ioprio_class_table
[] = {
1353 [IOPRIO_CLASS_NONE
] = "none",
1354 [IOPRIO_CLASS_RT
] = "realtime",
1355 [IOPRIO_CLASS_BE
] = "best-effort",
1356 [IOPRIO_CLASS_IDLE
] = "idle"
1359 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ioprio_class
, int, INT_MAX
);
1361 static const char *const sigchld_code_table
[] = {
1362 [CLD_EXITED
] = "exited",
1363 [CLD_KILLED
] = "killed",
1364 [CLD_DUMPED
] = "dumped",
1365 [CLD_TRAPPED
] = "trapped",
1366 [CLD_STOPPED
] = "stopped",
1367 [CLD_CONTINUED
] = "continued",
1370 DEFINE_STRING_TABLE_LOOKUP(sigchld_code
, int);
1372 static const char* const sched_policy_table
[] = {
1373 [SCHED_OTHER
] = "other",
1374 [SCHED_BATCH
] = "batch",
1375 [SCHED_IDLE
] = "idle",
1376 [SCHED_FIFO
] = "fifo",
1380 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy
, int, INT_MAX
);