1
/* -*- coding: utf-8 -*- */
1
/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
9
* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
5
* Copyright © 2008-2017 Teddy Hogeborn
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* Copyright © 2008-2017 Björn Påhlsson
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* This file is part of Mandos.
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* Mandos is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* 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
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* WITHOUT ANY WARRANTY; without even the implied warranty of
15
17
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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18
* General Public License for more details.
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20
* You should have received a copy of the GNU General Public License
19
* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@fukt.bsnet.se>.
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* Contact the authors at <mandos@recompile.se>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
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28
#include <stddef.h> /* size_t, NULL */
28
#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
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EXIT_SUCCESS, realloc() */
29
#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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31
#include <stdbool.h> /* bool, true, false */
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(),
35
WEXITSTATUS(), wait(), pid_t,
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uid_t, gid_t, getuid(), getgid(),
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#include <stdio.h> /* fileno(), fprintf(),
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stderr, STDOUT_FILENO, fclose() */
34
#include <sys/types.h> /* fstat(), struct stat, waitpid(),
35
WIFEXITED(), WEXITSTATUS(), wait(),
36
pid_t, uid_t, gid_t, getuid(),
38
38
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
39
39
FD_SET(), FD_ISSET(), FD_CLR */
40
40
#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
42
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
41
WEXITSTATUS(), WTERMSIG() */
42
#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
43
43
#include <iso646.h> /* and, or, not */
44
#include <dirent.h> /* DIR, struct dirent, opendir(),
45
readdir(), closedir(), dirfd() */
46
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
47
fcntl(), setuid(), setgid(),
48
F_GETFD, F_SETFD, FD_CLOEXEC,
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access(), pipe(), fork(), close()
50
dup2(), STDOUT_FILENO, _exit(),
51
execv(), write(), read(),
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()
53
52
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
55
#include <string.h> /* strsep, strlen(), asprintf() */
53
FD_CLOEXEC, openat(), scandirat(),
55
#include <string.h> /* strsep, strlen(), strsignal(),
56
strcmp(), strncmp() */
56
57
#include <errno.h> /* errno */
57
58
#include <argp.h> /* struct argp_option, struct
58
59
argp_state, struct argp,
375
416
.doc = "Group ID the plugins will run as", .group = 3 },
376
417
{ .name = "debug", .key = 132,
377
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.doc = "Debug mode", .group = 4 },
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{ .name = "plugin-helper-dir", .key = 133,
421
.doc = "Specify a different plugin helper directory",
424
* These reproduce what we would get without ARGP_NO_HELP
426
{ .name = "help", .key = '?',
427
.doc = "Give this help list", .group = -1 },
428
{ .name = "usage", .key = -3,
429
.doc = "Give a short usage message", .group = -1 },
430
{ .name = "version", .key = 'V',
431
.doc = "Print program version", .group = -1 },
381
error_t parse_opt(int key, char *arg, __attribute__((unused))
382
struct argp_state *state){
435
__attribute__((nonnull(3)))
436
error_t parse_opt(int key, char *arg, struct argp_state *state){
385
441
case 'g': /* --global-options */
387
443
char *plugin_option;
388
444
while((plugin_option = strsep(&arg, ",")) != NULL){
389
if(plugin_option[0] == '\0'){
392
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if(not add_argument(getplugin(NULL), plugin_option)){
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perror("add_argument");
394
return ARGP_ERR_UNKNOWN;
399
452
case 'G': /* --global-env */
403
if(not add_environment(getplugin(NULL), arg, true)){
404
perror("add_environment");
453
if(add_environment(getplugin(NULL), arg, true)){
407
457
case 'o': /* --options-for */
409
char *plugin_name = strsep(&arg, ":");
410
if(plugin_name[0] == '\0'){
414
while((plugin_option = strsep(&arg, ",")) != NULL){
415
if(not add_argument(getplugin(plugin_name), plugin_option)){
416
perror("add_argument");
417
return ARGP_ERR_UNKNOWN;
459
char *option_list = strchr(arg, ':');
460
if(option_list == NULL){
461
argp_error(state, "No colon in \"%s\"", arg);
468
argp_error(state, "Empty plugin name");
473
while((option = strsep(&option_list, ",")) != NULL){
474
if(not add_argument(getplugin(arg), option)){
422
481
case 'E': /* --env-for */
427
483
char *envdef = strchr(arg, ':');
428
484
if(envdef == NULL){
485
argp_error(state, "No colon in \"%s\"", arg);
432
if(not add_environment(getplugin(arg), envdef+1, true)){
433
perror("add_environment");
492
argp_error(state, "Empty plugin name");
496
if(add_environment(getplugin(arg), envdef, true)){
437
501
case 'd': /* --disable */
439
503
plugin *p = getplugin(arg);
441
return ARGP_ERR_UNKNOWN;
446
510
case 'e': /* --enable */
448
512
plugin *p = getplugin(arg);
450
return ARGP_ERR_UNKNOWN;
455
519
case 128: /* --plugin-dir */
457
521
plugindir = strdup(arg);
458
if(plugindir == NULL){
522
if(plugindir != NULL){
462
526
case 129: /* --config-file */
463
527
/* This is already done by parse_opt_config_file() */
465
529
case 130: /* --userid */
467
tmpmax = strtoimax(arg, &tmp, 10);
530
tmp_id = strtoimax(arg, &tmp, 10);
468
531
if(errno != 0 or tmp == arg or *tmp != '\0'
469
or tmpmax != (uid_t)tmpmax){
470
fprintf(stderr, "Bad user ID number: \"%s\", using %"
471
PRIdMAX "\n", arg, (intmax_t)uid);
532
or tmp_id != (uid_t)tmp_id){
533
argp_error(state, "Bad user ID number: \"%s\", using %"
534
PRIdMAX, arg, (intmax_t)uid);
476
540
case 131: /* --groupid */
478
tmpmax = strtoimax(arg, &tmp, 10);
541
tmp_id = strtoimax(arg, &tmp, 10);
479
542
if(errno != 0 or tmp == arg or *tmp != '\0'
480
or tmpmax != (gid_t)tmpmax){
481
fprintf(stderr, "Bad group ID number: \"%s\", using %"
482
PRIdMAX "\n", arg, (intmax_t)gid);
543
or tmp_id != (gid_t)tmp_id){
544
argp_error(state, "Bad group ID number: \"%s\", using %"
545
PRIdMAX, arg, (intmax_t)gid);
487
551
case 132: /* --debug */
554
case 133: /* --plugin-helper-dir */
555
free(pluginhelperdir);
556
pluginhelperdir = strdup(arg);
557
if(pluginhelperdir != NULL){
562
* These reproduce what we would get without ARGP_NO_HELP
564
case '?': /* --help */
565
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
566
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
567
case -3: /* --usage */
568
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
569
argp_state_help(state, state->out_stream,
570
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
571
case 'V': /* --version */
572
fprintf(state->out_stream, "%s\n", argp_program_version);
491
576
* When adding more options before this line, remember to also add a
492
577
* "case" to the "parse_opt_config_file" function below.
597
693
new_arg = strdup(p);
598
694
if(new_arg == NULL){
600
exitstatus = EXIT_FAILURE;
695
error(0, errno, "strdup");
696
exitstatus = EX_OSERR;
605
701
custom_argc += 1;
606
custom_argv = realloc(custom_argv, sizeof(char *)
607
* ((unsigned int) custom_argc + 1));
608
if(custom_argv == NULL){
610
exitstatus = EXIT_FAILURE;
703
char **new_argv = realloc(custom_argv, sizeof(char *)
704
* ((size_t)custom_argc + 1));
705
if(new_argv == NULL){
706
error(0, errno, "realloc");
707
exitstatus = EX_OSERR;
712
custom_argv = new_argv;
614
715
custom_argv[custom_argc-1] = new_arg;
615
716
custom_argv[custom_argc] = NULL;
720
ret = fclose(conffp);
721
} while(ret == EOF and errno == EINTR);
723
error(0, errno, "fclose");
724
exitstatus = EX_IOERR;
620
729
/* Check for harmful errors and go to fallback. Other errors might
621
730
not affect opening plugins */
622
731
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
624
exitstatus = EXIT_FAILURE;
732
error(0, errno, "fopen");
733
exitstatus = EX_OSERR;
628
/* If there was any arguments from configuration file,
629
pass them to parser as command arguments */
737
/* If there were any arguments from the configuration file, pass
738
them to parser as command line arguments */
630
739
if(custom_argv != NULL){
631
ret = argp_parse(&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
633
if(ret == ARGP_ERR_UNKNOWN){
634
fprintf(stderr, "Unknown error while parsing arguments\n");
635
exitstatus = EXIT_FAILURE;
740
ret = argp_parse(&argp, custom_argc, custom_argv,
741
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
749
error(0, errno, "argp_parse");
750
exitstatus = EX_OSERR;
753
exitstatus = EX_CONFIG;
640
758
/* Parse actual command line arguments, to let them override the
642
ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
643
if(ret == ARGP_ERR_UNKNOWN){
644
fprintf(stderr, "Unknown error while parsing arguments\n");
645
exitstatus = EXIT_FAILURE;
760
ret = argp_parse(&argp, argc, argv,
761
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
769
error(0, errno, "argp_parse");
770
exitstatus = EX_OSERR;
773
exitstatus = EX_USAGE;
778
char *pluginhelperenv;
780
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
781
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
783
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
785
if(ret == -1 or not bret){
786
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
787
" environment variable to \"%s\" for all plugins\n",
788
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
791
free(pluginhelperenv);
650
for(plugin *p = plugin_list; p != NULL; p=p->next){
796
for(plugin *p = plugin_list; p != NULL; p = p->next){
651
797
fprintf(stderr, "Plugin: %s has %d arguments\n",
652
798
p->name ? p->name : "Global", p->argc - 1);
653
799
for(char **a = p->argv; *a != NULL; a++){
663
/* Strip permissions down to nobody */
810
/* Work around Debian bug #633582:
811
<https://bugs.debian.org/633582> */
812
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
813
if(plugindir_fd == -1){
815
error(0, errno, "open(\"" PDIR "\")");
818
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
820
error(0, errno, "fstat");
822
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
823
ret = fchown(plugindir_fd, uid, gid);
825
error(0, errno, "fchown");
833
/* Lower permissions */
836
error(0, errno, "setgid");
668
838
ret = setuid(uid);
673
if(plugindir == NULL){
676
dir = opendir(plugindir);
680
perror("Could not open plugin dir");
681
exitstatus = EXIT_FAILURE;
685
/* Set the FD_CLOEXEC flag on the directory, if possible */
840
error(0, errno, "setuid");
843
/* Open plugin directory with close_on_exec flag */
687
int dir_fd = dirfd(dir);
689
ret = set_cloexec_flag(dir_fd);
691
perror("set_cloexec_flag");
692
exitstatus = EXIT_FAILURE;
845
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
848
#else /* not O_CLOEXEC */
850
#endif /* not O_CLOEXEC */
853
error(0, errno, "Could not open plugin dir");
854
exitstatus = EX_UNAVAILABLE;
859
/* Set the FD_CLOEXEC flag on the directory */
860
ret = set_cloexec_flag(dir_fd);
862
error(0, errno, "set_cloexec_flag");
863
exitstatus = EX_OSERR;
866
#endif /* O_CLOEXEC */
869
int good_name(const struct dirent * const dirent){
870
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
871
"*.dpkg-old", "*.dpkg-bak",
872
"*.dpkg-divert", NULL };
874
#pragma GCC diagnostic push
875
#pragma GCC diagnostic ignored "-Wcast-qual"
877
for(const char **pat = (const char **)patterns;
878
*pat != NULL; pat++){
880
#pragma GCC diagnostic pop
882
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
885
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
886
" matching pattern %s\n", dirent->d_name, *pat);
894
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
896
if(numplugins == -1){
897
error(0, errno, "Could not scan plugin dir");
899
exitstatus = EX_OSERR;
698
903
FD_ZERO(&rfds_all);
700
905
/* Read and execute any executable in the plugin directory*/
702
dirst = readdir(dir);
704
/* All directory entries have been processed */
708
exitstatus = EXIT_FAILURE;
714
d_name_len = strlen(dirst->d_name);
716
/* Ignore dotfiles, backup files and other junk */
718
bool bad_name = false;
720
const char const *bad_prefixes[] = { ".", "#", NULL };
722
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
725
".dpkg-divert", NULL };
726
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
727
size_t pre_len = strlen(*pre);
728
if((d_name_len >= pre_len)
729
and strncmp((dirst->d_name), *pre, pre_len) == 0){
731
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
732
" with bad prefix %s\n", dirst->d_name, *pre);
741
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
742
size_t suf_len = strlen(*suf);
743
if((d_name_len >= suf_len)
744
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
747
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
748
" with bad suffix %s\n", dirst->d_name, *suf);
761
if(plugindir == NULL){
762
ret = asprintf(&filename, PDIR "/%s", dirst->d_name);
764
ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
906
for(int i = 0; i < numplugins; i++){
908
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
910
error(0, errno, "Could not open plugin");
771
ret = stat(filename, &st);
914
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
916
error(0, errno, "stat");
778
922
/* Ignore non-executable files */
779
if(not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
923
if(not S_ISREG(st.st_mode)
924
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
781
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
782
" with bad type or mode\n", filename);
927
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
928
" with bad type or mode\n",
929
plugindir != NULL ? plugindir : PDIR,
930
direntries[i]->d_name);
788
plugin *p = getplugin(dirst->d_name);
937
plugin *p = getplugin(direntries[i]->d_name);
939
error(0, errno, "getplugin");
796
946
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
947
direntries[i]->d_name);
806
957
for(char **a = g->argv + 1; *a != NULL; a++){
807
958
if(not add_argument(p, *a)){
808
perror("add_argument");
959
error(0, errno, "add_argument");
811
962
/* Add global environment variables */
812
963
for(char **e = g->environ; *e != NULL; e++){
813
964
if(not add_environment(p, *e, false)){
814
perror("add_environment");
965
error(0, errno, "add_environment");
819
/* If this plugin has any environment variables, we will call
820
using execve and need to duplicate the environment from this
970
/* If this plugin has any environment variables, we need to
971
duplicate the environment from this process, too. */
822
972
if(p->environ[0] != NULL){
823
973
for(char **e = environ; *e != NULL; e++){
824
974
if(not add_environment(p, *e, false)){
825
perror("add_environment");
975
error(0, errno, "add_environment");
982
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
983
#else /* O_CLOEXEC */
984
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
985
#endif /* O_CLOEXEC */
834
exitstatus = EXIT_FAILURE;
987
error(0, errno, "pipe");
988
exitstatus = EX_OSERR;
992
if(pipefd[0] >= FD_SETSIZE){
993
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
997
exitstatus = EX_OSERR;
837
1002
/* Ask OS to automatic close the pipe on exec */
838
1003
ret = set_cloexec_flag(pipefd[0]);
840
perror("set_cloexec_flag");
841
exitstatus = EXIT_FAILURE;
1005
error(0, errno, "set_cloexec_flag");
1008
exitstatus = EX_OSERR;
1009
free(direntries[i]);
844
1012
ret = set_cloexec_flag(pipefd[1]);
846
perror("set_cloexec_flag");
847
exitstatus = EXIT_FAILURE;
1014
error(0, errno, "set_cloexec_flag");
1017
exitstatus = EX_OSERR;
1018
free(direntries[i]);
1021
#endif /* not O_CLOEXEC */
850
1022
/* Block SIGCHLD until process is safely in process list */
851
ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
1023
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1024
&sigchld_action.sa_mask,
853
perror("sigprocmask");
854
exitstatus = EXIT_FAILURE;
1027
error(0, errno, "sigprocmask");
1028
exitstatus = EX_OSERR;
1029
free(direntries[i]);
857
1032
/* Starting a new process to be watched */
1036
} while(pid == -1 and errno == EINTR);
861
exitstatus = EXIT_FAILURE;
1038
error(0, errno, "fork");
1039
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1040
&sigchld_action.sa_mask, NULL));
1043
exitstatus = EX_OSERR;
1044
free(direntries[i]);
865
1048
/* this is the child process */
866
1049
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1051
error(0, errno, "sigaction");
871
1054
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
873
perror("sigprocmask");
1056
error(0, errno, "sigprocmask");
877
1060
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1062
error(0, errno, "dup2");
884
/* If dir has no file descriptor, we could not set FD_CLOEXEC
885
above and must now close it manually here. */
888
if(p->environ[0] == NULL){
889
if(execv(filename, p->argv) < 0){
894
if(execve(filename, p->argv, p->environ) < 0){
1066
if(fexecve(plugin_fd, p->argv,
1067
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1068
error(0, errno, "fexecve for %s/%s",
1069
plugindir != NULL ? plugindir : PDIR,
1070
direntries[i]->d_name);
901
1075
/* Parent process */
902
1076
close(pipefd[1]); /* Close unused write end of pipe */
904
plugin *new_plugin = getplugin(dirst->d_name);
1078
plugin *new_plugin = getplugin(direntries[i]->d_name);
905
1079
if(new_plugin == NULL){
907
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1080
error(0, errno, "getplugin");
1081
ret = (int)(TEMP_FAILURE_RETRY
1082
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
909
perror("sigprocmask");
1085
error(0, errno, "sigprocmask");
911
exitstatus = EXIT_FAILURE;
1087
exitstatus = EX_OSERR;
1088
free(direntries[i]);
1091
free(direntries[i]);
915
1093
new_plugin->pid = pid;
916
1094
new_plugin->fd = pipefd[0];
918
1096
/* Unblock SIGCHLD so signal handler can be run if this process
919
1097
has already completed */
920
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1098
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1099
&sigchld_action.sa_mask,
922
perror("sigprocmask");
923
exitstatus = EXIT_FAILURE;
1102
error(0, errno, "sigprocmask");
1103
exitstatus = EX_OSERR;