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_check(const char *name
, pid_t pid
, WaitFlags flags
) {
691 _cleanup_free_
char *buffer
= NULL
;
698 r
= get_process_comm(pid
, &buffer
);
700 log_debug_errno(r
, "Failed to acquire process name of " PID_FMT
", ignoring: %m", pid
);
705 prio
= flags
& WAIT_LOG_ABNORMAL
? LOG_ERR
: LOG_DEBUG
;
707 r
= wait_for_terminate(pid
, &status
);
709 return log_full_errno(prio
, r
, "Failed to wait for %s: %m", strna(name
));
711 if (status
.si_code
== CLD_EXITED
) {
712 if (status
.si_status
!= EXIT_SUCCESS
)
713 log_full(flags
& WAIT_LOG_NON_ZERO_EXIT_STATUS
? LOG_ERR
: LOG_DEBUG
,
714 "%s failed with exit status %i.", strna(name
), status
.si_status
);
716 log_debug("%s succeeded.", name
);
718 return status
.si_status
;
720 } else if (IN_SET(status
.si_code
, CLD_KILLED
, CLD_DUMPED
)) {
722 log_full(prio
, "%s terminated by signal %s.", strna(name
), signal_to_string(status
.si_status
));
726 log_full(prio
, "%s failed due to unknown reason.", strna(name
));
732 * < 0 : wait_for_terminate_with_timeout() failed to get the state of the
733 * process, the process timed out, the process was terminated by a
734 * signal, or failed for an unknown reason.
735 * >=0 : The process terminated normally with no failures.
737 * Success is indicated by a return value of zero, a timeout is indicated
738 * by ETIMEDOUT, and all other child failure states are indicated by error
739 * is indicated by a non-zero value.
741 int wait_for_terminate_with_timeout(pid_t pid
, usec_t timeout
) {
746 assert_se(sigemptyset(&mask
) == 0);
747 assert_se(sigaddset(&mask
, SIGCHLD
) == 0);
749 /* Drop into a sigtimewait-based timeout. Waiting for the
751 until
= now(CLOCK_MONOTONIC
) + timeout
;
754 siginfo_t status
= {};
757 n
= now(CLOCK_MONOTONIC
);
761 r
= sigtimedwait(&mask
, NULL
, timespec_store(&ts
, until
- n
)) < 0 ? -errno
: 0;
762 /* Assuming we woke due to the child exiting. */
763 if (waitid(P_PID
, pid
, &status
, WEXITED
|WNOHANG
) == 0) {
764 if (status
.si_pid
== pid
) {
765 /* This is the correct child.*/
766 if (status
.si_code
== CLD_EXITED
)
767 return (status
.si_status
== 0) ? 0 : -EPROTO
;
772 /* Not the child, check for errors and proceed appropriately */
776 /* Timed out, child is likely hung. */
779 /* Received a different signal and should retry */
782 /* Return any unexpected errors */
791 void sigkill_wait(pid_t pid
) {
794 if (kill(pid
, SIGKILL
) > 0)
795 (void) wait_for_terminate(pid
, NULL
);
798 void sigkill_waitp(pid_t
*pid
) {
807 int kill_and_sigcont(pid_t pid
, int sig
) {
810 r
= kill(pid
, sig
) < 0 ? -errno
: 0;
812 /* If this worked, also send SIGCONT, unless we already just sent a SIGCONT, or SIGKILL was sent which isn't
813 * affected by a process being suspended anyway. */
814 if (r
>= 0 && !IN_SET(sig
, SIGCONT
, SIGKILL
))
815 (void) kill(pid
, SIGCONT
);
820 int getenv_for_pid(pid_t pid
, const char *field
, char **_value
) {
821 _cleanup_fclose_
FILE *f
= NULL
;
832 path
= procfs_file_alloca(pid
, "environ");
834 f
= fopen(path
, "re");
841 (void) __fsetlocking(f
, FSETLOCKING_BYCALLER
);
850 for (i
= 0; i
< sizeof(line
)-1; i
++) {
854 if (_unlikely_(c
== EOF
)) {
864 if (strneq(line
, field
, l
) && line
[l
] == '=') {
865 value
= strdup(line
+ l
+ 1);
879 bool pid_is_unwaited(pid_t pid
) {
880 /* Checks whether a PID is still valid at all, including a zombie */
885 if (pid
<= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
888 if (pid
== getpid_cached())
891 if (kill(pid
, 0) >= 0)
894 return errno
!= ESRCH
;
897 bool pid_is_alive(pid_t pid
) {
900 /* Checks whether a PID is still valid and not a zombie */
905 if (pid
<= 1) /* If we or PID 1 would be a zombie, this code would not be running */
908 if (pid
== getpid_cached())
911 r
= get_process_state(pid
);
912 if (IN_SET(r
, -ESRCH
, 'Z'))
918 int pid_from_same_root_fs(pid_t pid
) {
924 if (pid
== 0 || pid
== getpid_cached())
927 root
= procfs_file_alloca(pid
, "root");
929 return files_same(root
, "/proc/1/root", 0);
932 bool is_main_thread(void) {
933 static thread_local
int cached
= 0;
935 if (_unlikely_(cached
== 0))
936 cached
= getpid_cached() == gettid() ? 1 : -1;
941 noreturn
void freeze(void) {
945 /* Make sure nobody waits for us on a socket anymore */
946 close_all_fds(NULL
, 0);
954 bool oom_score_adjust_is_valid(int oa
) {
955 return oa
>= OOM_SCORE_ADJ_MIN
&& oa
<= OOM_SCORE_ADJ_MAX
;
958 unsigned long personality_from_string(const char *p
) {
962 return PERSONALITY_INVALID
;
964 /* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
965 * hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
966 * the same register size. */
968 architecture
= architecture_from_string(p
);
969 if (architecture
< 0)
970 return PERSONALITY_INVALID
;
972 if (architecture
== native_architecture())
974 #ifdef SECONDARY_ARCHITECTURE
975 if (architecture
== SECONDARY_ARCHITECTURE
)
979 return PERSONALITY_INVALID
;
982 const char* personality_to_string(unsigned long p
) {
983 int architecture
= _ARCHITECTURE_INVALID
;
986 architecture
= native_architecture();
987 #ifdef SECONDARY_ARCHITECTURE
988 else if (p
== PER_LINUX32
)
989 architecture
= SECONDARY_ARCHITECTURE
;
992 if (architecture
< 0)
995 return architecture_to_string(architecture
);
998 int safe_personality(unsigned long p
) {
1001 /* So here's the deal, personality() is weirdly defined by glibc. In some cases it returns a failure via errno,
1002 * and in others as negative return value containing an errno-like value. Let's work around this: this is a
1003 * wrapper that uses errno if it is set, and uses the return value otherwise. And then it sets both errno and
1004 * the return value indicating the same issue, so that we are definitely on the safe side.
1006 * See https://github.com/systemd/systemd/issues/6737 */
1009 ret
= personality(p
);
1020 int opinionated_personality(unsigned long *ret
) {
1023 /* Returns the current personality, or PERSONALITY_INVALID if we can't determine it. This function is a bit
1024 * opinionated though, and ignores all the finer-grained bits and exotic personalities, only distinguishing the
1025 * two most relevant personalities: PER_LINUX and PER_LINUX32. */
1027 current
= safe_personality(PERSONALITY_INVALID
);
1031 if (((unsigned long) current
& 0xffff) == PER_LINUX32
)
1039 void valgrind_summary_hack(void) {
1040 #if HAVE_VALGRIND_VALGRIND_H
1041 if (getpid_cached() == 1 && RUNNING_ON_VALGRIND
) {
1043 pid
= raw_clone(SIGCHLD
);
1045 log_emergency_errno(errno
, "Failed to fork off valgrind helper: %m");
1049 log_info("Spawned valgrind helper as PID "PID_FMT
".", pid
);
1050 (void) wait_for_terminate(pid
, NULL
);
1056 int pid_compare_func(const void *a
, const void *b
) {
1057 const pid_t
*p
= a
, *q
= b
;
1059 /* Suitable for usage in qsort() */
1068 int ioprio_parse_priority(const char *s
, int *ret
) {
1074 r
= safe_atoi(s
, &i
);
1078 if (!ioprio_priority_is_valid(i
))
1085 /* The cached PID, possible values:
1087 * == UNSET [0] → cache not initialized yet
1088 * == BUSY [-1] → some thread is initializing it at the moment
1089 * any other → the cached PID
1092 #define CACHED_PID_UNSET ((pid_t) 0)
1093 #define CACHED_PID_BUSY ((pid_t) -1)
1095 static pid_t cached_pid
= CACHED_PID_UNSET
;
1097 void reset_cached_pid(void) {
1098 /* Invoked in the child after a fork(), i.e. at the first moment the PID changed */
1099 cached_pid
= CACHED_PID_UNSET
;
1102 /* We use glibc __register_atfork() + __dso_handle directly here, as they are not included in the glibc
1103 * headers. __register_atfork() is mostly equivalent to pthread_atfork(), but doesn't require us to link against
1104 * libpthread, as it is part of glibc anyway. */
1105 extern int __register_atfork(void (*prepare
) (void), void (*parent
) (void), void (*child
) (void), void * __dso_handle
);
1106 extern void* __dso_handle
__attribute__ ((__weak__
));
1108 pid_t
getpid_cached(void) {
1109 pid_t current_value
;
1111 /* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
1112 * system call each time. This restores glibc behaviour from before 2.24, when getpid() was unconditionally
1113 * cached. Starting with 2.24 getpid() started to become prohibitively expensive when used for detecting when
1114 * objects were used across fork()s. With this caching the old behaviour is somewhat restored.
1116 * https://bugzilla.redhat.com/show_bug.cgi?id=1443976
1117 * https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c579f48edba88380635ab98cb612030e3ed8691e
1120 current_value
= __sync_val_compare_and_swap(&cached_pid
, CACHED_PID_UNSET
, CACHED_PID_BUSY
);
1122 switch (current_value
) {
1124 case CACHED_PID_UNSET
: { /* Not initialized yet, then do so now */
1129 if (__register_atfork(NULL
, NULL
, reset_cached_pid
, __dso_handle
) != 0) {
1130 /* OOM? Let's try again later */
1131 cached_pid
= CACHED_PID_UNSET
;
1135 cached_pid
= new_pid
;
1139 case CACHED_PID_BUSY
: /* Somebody else is currently initializing */
1142 default: /* Properly initialized */
1143 return current_value
;
1147 int must_be_root(void) {
1152 log_error("Need to be root.");
1158 const int except_fds
[],
1159 size_t n_except_fds
,
1163 pid_t original_pid
, pid
;
1168 /* A wrapper around fork(), that does a couple of important initializations in addition to mere forking. Always
1169 * returns the child's PID in *ret_pid. Returns == 0 in the child, and > 0 in the parent. */
1171 prio
= flags
& FORK_LOG
? LOG_ERR
: LOG_DEBUG
;
1173 original_pid
= getpid_cached();
1175 block_signals
= flags
& (FORK_RESET_SIGNALS
|FORK_DEATHSIG
);
1177 if (block_signals
) {
1180 /* We temporarily block all signals, so that the new child has them blocked initially. This way, we can be sure
1181 * that SIGTERMs are not lost we might send to the child. */
1182 if (sigfillset(&ss
) < 0)
1183 return log_full_errno(prio
, errno
, "Failed to reset signal set: %m");
1185 if (sigprocmask(SIG_SETMASK
, &ss
, &saved_ss
) < 0)
1186 return log_full_errno(prio
, errno
, "Failed to reset signal mask: %m");
1193 if (block_signals
) /* undo what we did above */
1194 (void) sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
);
1196 return log_full_errno(prio
, r
, "Failed to fork: %m");
1199 /* We are in the parent process */
1201 if (block_signals
) /* undo what we did above */
1202 (void) sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
);
1204 log_debug("Sucessfully forked off '%s' as PID " PID_FMT
".", strna(name
), pid
);
1212 /* We are in the child process */
1214 if (flags
& FORK_REOPEN_LOG
) {
1215 /* Close the logs if requested, before we log anything. And make sure we reopen it if needed. */
1217 log_set_open_when_needed(true);
1221 r
= rename_process(name
);
1223 log_full_errno(flags
& FORK_LOG
? LOG_WARNING
: LOG_DEBUG
,
1224 r
, "Failed to rename process, ignoring: %m");
1227 if (flags
& FORK_DEATHSIG
)
1228 if (prctl(PR_SET_PDEATHSIG
, SIGTERM
) < 0) {
1229 log_full_errno(prio
, errno
, "Failed to set death signal: %m");
1230 _exit(EXIT_FAILURE
);
1233 if (flags
& FORK_RESET_SIGNALS
) {
1234 r
= reset_all_signal_handlers();
1236 log_full_errno(prio
, r
, "Failed to reset signal handlers: %m");
1237 _exit(EXIT_FAILURE
);
1240 /* This implicitly undoes the signal mask stuff we did before the fork()ing above */
1241 r
= reset_signal_mask();
1243 log_full_errno(prio
, r
, "Failed to reset signal mask: %m");
1244 _exit(EXIT_FAILURE
);
1246 } else if (block_signals
) { /* undo what we did above */
1247 if (sigprocmask(SIG_SETMASK
, &saved_ss
, NULL
) < 0) {
1248 log_full_errno(prio
, errno
, "Failed to restore signal mask: %m");
1249 _exit(EXIT_FAILURE
);
1253 if (flags
& FORK_DEATHSIG
) {
1255 /* Let's see if the parent PID is still the one we started from? If not, then the parent
1256 * already died by the time we set PR_SET_PDEATHSIG, hence let's emulate the effect */
1260 /* Parent is in a differn't PID namespace. */;
1261 else if (ppid
!= original_pid
) {
1262 log_debug("Parent died early, raising SIGTERM.");
1263 (void) raise(SIGTERM
);
1264 _exit(EXIT_FAILURE
);
1268 if (flags
& FORK_CLOSE_ALL_FDS
) {
1269 /* Close the logs here in case it got reopened above, as close_all_fds() would close them for us */
1272 r
= close_all_fds(except_fds
, n_except_fds
);
1274 log_full_errno(prio
, r
, "Failed to close all file descriptors: %m");
1275 _exit(EXIT_FAILURE
);
1279 /* When we were asked to reopen the logs, do so again now */
1280 if (flags
& FORK_REOPEN_LOG
) {
1282 log_set_open_when_needed(false);
1285 if (flags
& FORK_NULL_STDIO
) {
1286 r
= make_null_stdio();
1288 log_full_errno(prio
, r
, "Failed to connect stdin/stdout to /dev/null: %m");
1289 _exit(EXIT_FAILURE
);
1294 *ret_pid
= getpid_cached();
1299 int fork_agent(const char *name
, const int except
[], unsigned n_except
, pid_t
*ret_pid
, const char *path
, ...) {
1300 bool stdout_is_tty
, stderr_is_tty
;
1308 /* Spawns a temporary TTY agent, making sure it goes away when we go away */
1310 r
= safe_fork_full(name
, except
, n_except
, FORK_RESET_SIGNALS
|FORK_DEATHSIG
|FORK_CLOSE_ALL_FDS
, ret_pid
);
1318 stdout_is_tty
= isatty(STDOUT_FILENO
);
1319 stderr_is_tty
= isatty(STDERR_FILENO
);
1321 if (!stdout_is_tty
|| !stderr_is_tty
) {
1324 /* Detach from stdout/stderr. and reopen
1325 * /dev/tty for them. This is important to
1326 * ensure that when systemctl is started via
1327 * popen() or a similar call that expects to
1328 * read EOF we actually do generate EOF and
1329 * not delay this indefinitely by because we
1330 * keep an unused copy of stdin around. */
1331 fd
= open("/dev/tty", O_WRONLY
);
1333 log_error_errno(errno
, "Failed to open /dev/tty: %m");
1334 _exit(EXIT_FAILURE
);
1337 if (!stdout_is_tty
&& dup2(fd
, STDOUT_FILENO
) < 0) {
1338 log_error_errno(errno
, "Failed to dup2 /dev/tty: %m");
1339 _exit(EXIT_FAILURE
);
1342 if (!stderr_is_tty
&& dup2(fd
, STDERR_FILENO
) < 0) {
1343 log_error_errno(errno
, "Failed to dup2 /dev/tty: %m");
1344 _exit(EXIT_FAILURE
);
1347 if (fd
> STDERR_FILENO
)
1351 /* Count arguments */
1353 for (n
= 0; va_arg(ap
, char*); n
++)
1358 l
= alloca(sizeof(char *) * (n
+ 1));
1360 /* Fill in arguments */
1362 for (i
= 0; i
<= n
; i
++)
1363 l
[i
] = va_arg(ap
, char*);
1367 _exit(EXIT_FAILURE
);
1370 static const char *const ioprio_class_table
[] = {
1371 [IOPRIO_CLASS_NONE
] = "none",
1372 [IOPRIO_CLASS_RT
] = "realtime",
1373 [IOPRIO_CLASS_BE
] = "best-effort",
1374 [IOPRIO_CLASS_IDLE
] = "idle"
1377 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ioprio_class
, int, INT_MAX
);
1379 static const char *const sigchld_code_table
[] = {
1380 [CLD_EXITED
] = "exited",
1381 [CLD_KILLED
] = "killed",
1382 [CLD_DUMPED
] = "dumped",
1383 [CLD_TRAPPED
] = "trapped",
1384 [CLD_STOPPED
] = "stopped",
1385 [CLD_CONTINUED
] = "continued",
1388 DEFINE_STRING_TABLE_LOOKUP(sigchld_code
, int);
1390 static const char* const sched_policy_table
[] = {
1391 [SCHED_OTHER
] = "other",
1392 [SCHED_BATCH
] = "batch",
1393 [SCHED_IDLE
] = "idle",
1394 [SCHED_FIFO
] = "fifo",
1398 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy
, int, INT_MAX
);