3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008-2018 Teddy Hogeborn
6
* Copyright © 2008-2018 Björn Påhlsson
8
* This file is part of Mandos.
10
* Mandos is free software: you can redistribute it and/or modify it
11
* under the terms of the GNU General Public License as published by
12
* the Free Software Foundation, either version 3 of the License, or
13
* (at your option) any later version.
15
* Mandos is distributed in the hope that it will be useful, but
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 Björn Påhlsson
8
* This program is free software: you can redistribute it and/or
9
* modify it under the terms of the GNU General Public License as
10
* published by the Free Software Foundation, either version 3 of the
11
* License, or (at your option) any later version.
13
* This program is distributed in the hope that it will be useful, but
16
14
* WITHOUT ANY WARRANTY; without even the implied warranty of
17
15
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18
16
* General Public License for more details.
20
18
* You should have received a copy of the GNU General Public License
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
23
* Contact the authors at <mandos@recompile.se>.
22
* Contact the authors at <mandos@fukt.bsnet.se>.
26
25
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
28
27
#include <stddef.h> /* size_t, NULL */
29
#include <stdlib.h> /* malloc(), reallocarray(), realloc(),
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EXIT_SUCCESS, exit() */
28
#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
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EXIT_SUCCESS, realloc() */
31
30
#include <stdbool.h> /* bool, true, false */
32
#include <stdio.h> /* fileno(), fprintf(),
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stderr, STDOUT_FILENO, fclose() */
34
#include <sys/types.h> /* fstat(), struct stat, waitpid(),
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WIFEXITED(), WEXITSTATUS(), wait(),
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pid_t, uid_t, gid_t, getuid(),
31
#include <stdio.h> /* perror, fileno(), fprintf(),
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stderr, STDOUT_FILENO */
33
#include <sys/types.h> /* DIR, opendir(), stat(), struct
34
stat, waitpid(), WIFEXITED(),
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WEXITSTATUS(), wait(), pid_t,
36
uid_t, gid_t, getuid(), getgid(),
38
38
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
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FD_SET(), FD_ISSET(), FD_CLR */
40
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#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
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WEXITSTATUS(), WTERMSIG() */
42
#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
41
WEXITSTATUS(), WTERMSIG(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
43
44
#include <iso646.h> /* and, or, not */
44
#include <dirent.h> /* struct dirent, scandirat() */
45
#include <unistd.h> /* fcntl(), F_GETFD, F_SETFD,
46
FD_CLOEXEC, write(), STDOUT_FILENO,
47
struct stat, fstat(), close(),
48
setgid(), setuid(), S_ISREG(),
49
faccessat() pipe2(), fork(),
50
_exit(), dup2(), fexecve(), read()
45
#include <dirent.h> /* DIR, struct dirent, opendir(),
46
readdir(), closedir(), dirfd() */
47
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
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fcntl(), setuid(), setgid(),
49
F_GETFD, F_SETFD, FD_CLOEXEC,
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access(), pipe(), fork(), close()
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dup2(), STDOUT_FILENO, _exit(),
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execv(), write(), read(),
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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FD_CLOEXEC, openat(), scandirat(),
55
#include <string.h> /* strsep, strlen(), strsignal(),
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strcmp(), strncmp() */
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#include <string.h> /* strsep, strlen(), asprintf(),
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strsignal(), strcmp(), strncmp() */
57
58
#include <errno.h> /* errno */
58
59
#include <argp.h> /* struct argp_option, struct
59
60
argp_state, struct argp,
428
393
.doc = "Group ID the plugins will run as", .group = 3 },
429
394
{ .name = "debug", .key = 132,
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.doc = "Debug mode", .group = 4 },
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{ .name = "plugin-helper-dir", .key = 133,
433
.doc = "Specify a different plugin helper directory",
436
* These reproduce what we would get without ARGP_NO_HELP
438
{ .name = "help", .key = '?',
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.doc = "Give this help list", .group = -1 },
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{ .name = "usage", .key = -3,
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.doc = "Give a short usage message", .group = -1 },
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{ .name = "version", .key = 'V',
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.doc = "Print program version", .group = -1 },
447
__attribute__((nonnull(3)))
448
error_t parse_opt(int key, char *arg, struct argp_state *state){
399
error_t parse_opt(int key, char *arg, __attribute__((unused))
400
struct argp_state *state){
453
404
case 'g': /* --global-options */
455
406
char *plugin_option;
456
407
while((plugin_option = strsep(&arg, ",")) != NULL){
408
if(plugin_option[0] == '\0'){
457
411
if(not add_argument(getplugin(NULL), plugin_option)){
412
perror("add_argument");
413
return ARGP_ERR_UNKNOWN;
464
418
case 'G': /* --global-env */
465
if(add_environment(getplugin(NULL), arg, true)){
422
if(not add_environment(getplugin(NULL), arg, true)){
423
perror("add_environment");
469
426
case 'o': /* --options-for */
471
char *option_list = strchr(arg, ':');
472
if(option_list == NULL){
473
argp_error(state, "No colon in \"%s\"", arg);
480
argp_error(state, "Empty plugin name");
485
while((option = strsep(&option_list, ",")) != NULL){
486
if(not add_argument(getplugin(arg), option)){
428
char *plugin_name = strsep(&arg, ":");
429
if(plugin_name[0] == '\0'){
433
while((plugin_option = strsep(&arg, ",")) != NULL){
434
if(not add_argument(getplugin(plugin_name), plugin_option)){
435
perror("add_argument");
436
return ARGP_ERR_UNKNOWN;
493
441
case 'E': /* --env-for */
495
446
char *envdef = strchr(arg, ':');
496
447
if(envdef == NULL){
497
argp_error(state, "No colon in \"%s\"", arg);
504
argp_error(state, "Empty plugin name");
508
if(add_environment(getplugin(arg), envdef, true)){
451
if(not add_environment(getplugin(arg), envdef+1, true)){
452
perror("add_environment");
513
456
case 'd': /* --disable */
515
458
plugin *p = getplugin(arg);
460
return ARGP_ERR_UNKNOWN;
522
465
case 'e': /* --enable */
524
467
plugin *p = getplugin(arg);
469
return ARGP_ERR_UNKNOWN;
531
474
case 128: /* --plugin-dir */
533
476
plugindir = strdup(arg);
534
if(plugindir != NULL){
477
if(plugindir == NULL){
538
481
case 129: /* --config-file */
539
482
/* This is already done by parse_opt_config_file() */
541
484
case 130: /* --userid */
542
tmp_id = strtoimax(arg, &tmp, 10);
486
tmpmax = strtoimax(arg, &tmp, 10);
543
487
if(errno != 0 or tmp == arg or *tmp != '\0'
544
or tmp_id != (uid_t)tmp_id){
545
argp_error(state, "Bad user ID number: \"%s\", using %"
546
PRIdMAX, arg, (intmax_t)uid);
488
or tmpmax != (uid_t)tmpmax){
489
fprintf(stderr, "Bad user ID number: \"%s\", using %"
490
PRIdMAX "\n", arg, (intmax_t)uid);
552
495
case 131: /* --groupid */
553
tmp_id = strtoimax(arg, &tmp, 10);
497
tmpmax = strtoimax(arg, &tmp, 10);
554
498
if(errno != 0 or tmp == arg or *tmp != '\0'
555
or tmp_id != (gid_t)tmp_id){
556
argp_error(state, "Bad group ID number: \"%s\", using %"
557
PRIdMAX, arg, (intmax_t)gid);
499
or tmpmax != (gid_t)tmpmax){
500
fprintf(stderr, "Bad group ID number: \"%s\", using %"
501
PRIdMAX "\n", arg, (intmax_t)gid);
563
506
case 132: /* --debug */
566
case 133: /* --plugin-helper-dir */
567
free(pluginhelperdir);
568
pluginhelperdir = strdup(arg);
569
if(pluginhelperdir != NULL){
574
* These reproduce what we would get without ARGP_NO_HELP
576
case '?': /* --help */
577
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
578
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
579
__builtin_unreachable();
580
case -3: /* --usage */
581
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
582
argp_state_help(state, state->out_stream,
583
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
584
__builtin_unreachable();
585
case 'V': /* --version */
586
fprintf(state->out_stream, "%s\n", argp_program_version);
590
510
* When adding more options before this line, remember to also add a
591
511
* "case" to the "parse_opt_config_file" function below.
759
647
/* Check for harmful errors and go to fallback. Other errors might
760
648
not affect opening plugins */
761
649
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
762
error(0, errno, "fopen");
763
exitstatus = EX_OSERR;
651
exitstatus = EXIT_FAILURE;
767
/* If there were any arguments from the configuration file, pass
768
them to parser as command line arguments */
655
/* If there was any arguments from configuration file,
656
pass them to parser as command arguments */
769
657
if(custom_argv != NULL){
770
ret = argp_parse(&argp, custom_argc, custom_argv,
771
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
779
error(0, errno, "argp_parse");
780
exitstatus = EX_OSERR;
783
exitstatus = EX_CONFIG;
658
ret = argp_parse(&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
660
if(ret == ARGP_ERR_UNKNOWN){
661
fprintf(stderr, "Unknown error while parsing arguments\n");
662
exitstatus = EXIT_FAILURE;
788
667
/* Parse actual command line arguments, to let them override the
790
ret = argp_parse(&argp, argc, argv,
791
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
799
error(0, errno, "argp_parse");
800
exitstatus = EX_OSERR;
803
exitstatus = EX_USAGE;
808
char *pluginhelperenv;
810
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
811
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
813
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
815
if(ret == -1 or not bret){
816
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
817
" environment variable to \"%s\" for all plugins\n",
818
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
821
free(pluginhelperenv);
669
ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
670
if(ret == ARGP_ERR_UNKNOWN){
671
fprintf(stderr, "Unknown error while parsing arguments\n");
672
exitstatus = EXIT_FAILURE;
826
for(plugin *p = plugin_list; p != NULL; p = p->next){
677
for(plugin *p = plugin_list; p != NULL; p=p->next){
827
678
fprintf(stderr, "Plugin: %s has %d arguments\n",
828
679
p->name ? p->name : "Global", p->argc - 1);
829
680
for(char **a = p->argv; *a != NULL; a++){
840
/* Work around Debian bug #633582:
841
<https://bugs.debian.org/633582> */
842
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
843
if(plugindir_fd == -1){
845
error(0, errno, "open(\"" PDIR "\")");
848
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
850
error(0, errno, "fstat");
852
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
853
ret = fchown(plugindir_fd, uid, gid);
855
error(0, errno, "fchown");
863
/* Lower permissions */
690
/* Strip permissions down to nobody */
866
error(0, errno, "setgid");
868
695
ret = setuid(uid);
870
error(0, errno, "setuid");
873
/* Open plugin directory with close_on_exec flag */
700
if(plugindir == NULL){
703
dir = opendir(plugindir);
707
perror("Could not open plugin dir");
708
exitstatus = EXIT_FAILURE;
712
/* Set the FD_CLOEXEC flag on the directory, if possible */
875
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
878
#else /* not O_CLOEXEC */
880
#endif /* not O_CLOEXEC */
883
error(0, errno, "Could not open plugin dir");
884
exitstatus = EX_UNAVAILABLE;
889
/* Set the FD_CLOEXEC flag on the directory */
890
ret = set_cloexec_flag(dir_fd);
892
error(0, errno, "set_cloexec_flag");
893
exitstatus = EX_OSERR;
896
#endif /* O_CLOEXEC */
899
int good_name(const struct dirent * const dirent){
900
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
901
"*.dpkg-old", "*.dpkg-bak",
902
"*.dpkg-divert", NULL };
904
#pragma GCC diagnostic push
905
#pragma GCC diagnostic ignored "-Wcast-qual"
907
for(const char **pat = (const char **)patterns;
908
*pat != NULL; pat++){
910
#pragma GCC diagnostic pop
912
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
915
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
916
" matching pattern %s\n", dirent->d_name, *pat);
714
int dir_fd = dirfd(dir);
716
ret = set_cloexec_flag(dir_fd);
718
perror("set_cloexec_flag");
719
exitstatus = EXIT_FAILURE;
924
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
926
if(numplugins == -1){
927
error(0, errno, "Could not scan plugin dir");
929
exitstatus = EX_OSERR;
933
725
FD_ZERO(&rfds_all);
935
727
/* Read and execute any executable in the plugin directory*/
936
for(int i = 0; i < numplugins; i++){
938
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
940
error(0, errno, "Could not open plugin");
730
dirst = readdir(dir);
731
} while(dirst == NULL and errno == EINTR);
733
/* All directory entries have been processed */
737
exitstatus = EXIT_FAILURE;
743
d_name_len = strlen(dirst->d_name);
745
/* Ignore dotfiles, backup files and other junk */
747
bool bad_name = false;
749
const char const *bad_prefixes[] = { ".", "#", NULL };
751
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
754
".dpkg-divert", NULL };
755
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
756
size_t pre_len = strlen(*pre);
757
if((d_name_len >= pre_len)
758
and strncmp((dirst->d_name), *pre, pre_len) == 0){
760
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
761
" with bad prefix %s\n", dirst->d_name, *pre);
770
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
771
size_t suf_len = strlen(*suf);
772
if((d_name_len >= suf_len)
773
and (strcmp((dirst->d_name) + d_name_len-suf_len, *suf)
776
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
777
" with bad suffix %s\n", dirst->d_name, *suf);
790
if(plugindir == NULL){
791
ret = TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
794
ret = TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s", plugindir,
944
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
802
ret = TEMP_FAILURE_RETRY(stat(filename, &st));
946
error(0, errno, "stat");
952
809
/* Ignore non-executable files */
953
810
if(not S_ISREG(st.st_mode)
954
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
811
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
957
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
958
" with bad type or mode\n",
959
plugindir != NULL ? plugindir : PDIR,
960
direntries[i]->d_name);
813
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
814
" with bad type or mode\n", filename);
967
plugin *p = getplugin(direntries[i]->d_name);
820
plugin *p = getplugin(dirst->d_name);
969
error(0, errno, "getplugin");
976
828
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
977
direntries[i]->d_name);
987
838
for(char **a = g->argv + 1; *a != NULL; a++){
988
839
if(not add_argument(p, *a)){
989
error(0, errno, "add_argument");
840
perror("add_argument");
992
843
/* Add global environment variables */
993
844
for(char **e = g->environ; *e != NULL; e++){
994
845
if(not add_environment(p, *e, false)){
995
error(0, errno, "add_environment");
846
perror("add_environment");
1000
/* If this plugin has any environment variables, we need to
1001
duplicate the environment from this process, too. */
851
/* If this plugin has any environment variables, we will call
852
using execve and need to duplicate the environment from this
1002
854
if(p->environ[0] != NULL){
1003
855
for(char **e = environ; *e != NULL; e++){
1004
856
if(not add_environment(p, *e, false)){
1005
error(0, errno, "add_environment");
857
perror("add_environment");
1012
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
1013
#else /* O_CLOEXEC */
1014
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
1015
#endif /* O_CLOEXEC */
863
ret = TEMP_FAILURE_RETRY(pipe(pipefd));
1017
error(0, errno, "pipe");
1018
exitstatus = EX_OSERR;
1019
free(direntries[i]);
1022
if(pipefd[0] >= FD_SETSIZE){
1023
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1027
exitstatus = EX_OSERR;
1028
free(direntries[i]);
866
exitstatus = EXIT_FAILURE;
1032
869
/* Ask OS to automatic close the pipe on exec */
1033
870
ret = set_cloexec_flag(pipefd[0]);
1035
error(0, errno, "set_cloexec_flag");
1038
exitstatus = EX_OSERR;
1039
free(direntries[i]);
872
perror("set_cloexec_flag");
873
exitstatus = EXIT_FAILURE;
1042
876
ret = set_cloexec_flag(pipefd[1]);
1044
error(0, errno, "set_cloexec_flag");
1047
exitstatus = EX_OSERR;
1048
free(direntries[i]);
878
perror("set_cloexec_flag");
879
exitstatus = EXIT_FAILURE;
1051
#endif /* not O_CLOEXEC */
1052
882
/* Block SIGCHLD until process is safely in process list */
1053
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1054
&sigchld_action.sa_mask,
883
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
884
&sigchld_action.sa_mask,
1057
error(0, errno, "sigprocmask");
1058
exitstatus = EX_OSERR;
1059
free(direntries[i]);
887
perror("sigprocmask");
888
exitstatus = EXIT_FAILURE;
1062
891
/* Starting a new process to be watched */
1066
895
} while(pid == -1 and errno == EINTR);
1068
error(0, errno, "fork");
1069
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1070
&sigchld_action.sa_mask, NULL));
1073
exitstatus = EX_OSERR;
1074
free(direntries[i]);
898
exitstatus = EXIT_FAILURE;
1078
902
/* this is the child process */
1079
903
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1081
error(0, errno, "sigaction");
1084
908
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1086
error(0, errno, "sigprocmask");
910
perror("sigprocmask");
1090
914
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1092
error(0, errno, "dup2");
1096
if(fexecve(plugin_fd, p->argv,
1097
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1098
error(0, errno, "fexecve for %s/%s",
1099
plugindir != NULL ? plugindir : PDIR,
1100
direntries[i]->d_name);
921
/* If dir has no file descriptor, we could not set FD_CLOEXEC
922
above and must now close it manually here. */
925
if(p->environ[0] == NULL){
926
if(execv(filename, p->argv) < 0){
931
if(execve(filename, p->argv, p->environ) < 0){
1105
938
/* Parent process */
1106
close(pipefd[1]); /* Close unused write end of pipe */
1108
plugin *new_plugin = getplugin(direntries[i]->d_name);
939
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
942
plugin *new_plugin = getplugin(dirst->d_name);
1109
943
if(new_plugin == NULL){
1110
error(0, errno, "getplugin");
1111
ret = (int)(TEMP_FAILURE_RETRY
1112
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
945
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
946
&sigchld_action.sa_mask,
1115
error(0, errno, "sigprocmask");
949
perror("sigprocmask");
1117
exitstatus = EX_OSERR;
1118
free(direntries[i]);
951
exitstatus = EXIT_FAILURE;
1121
free(direntries[i]);
1123
955
new_plugin->pid = pid;
1124
956
new_plugin->fd = pipefd[0];
1127
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1128
new_plugin->name, (intmax_t) (new_plugin->pid));
1131
958
/* Unblock SIGCHLD so signal handler can be run if this process
1132
959
has already completed */
1133
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1134
&sigchld_action.sa_mask,
960
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
961
&sigchld_action.sa_mask,
1137
error(0, errno, "sigprocmask");
1138
exitstatus = EX_OSERR;
964
perror("sigprocmask");
965
exitstatus = EXIT_FAILURE;