1
/* -*- coding: utf-8 -*- */
1
/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
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3
* Mandos plugin runner - Run Mandos plugins
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* 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 © 2008-2018 Teddy Hogeborn
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* Copyright © 2008-2018 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
11
* 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
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* (at your option) any later version.
15
* Mandos is distributed in the hope that it will be useful, but
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16
* 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>.
23
* 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(),
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WEXITSTATUS(), wait(), pid_t,
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uid_t, gid_t, getuid(), getgid(),
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(),
36
pid_t, uid_t, gid_t, getuid(),
38
38
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
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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()
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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(),
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setgid(), setuid(), S_ISREG(),
49
faccessat() pipe2(), fork(),
50
_exit(), dup2(), fexecve(), read()
53
52
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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#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
417
.doc = "Group ID the plugins will run as", .group = 3 },
376
418
{ .name = "debug", .key = 132,
377
419
.doc = "Debug mode", .group = 4 },
420
{ .name = "plugin-helper-dir", .key = 133,
422
.doc = "Specify a different plugin helper directory",
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* These reproduce what we would get without ARGP_NO_HELP
427
{ .name = "help", .key = '?',
428
.doc = "Give this help list", .group = -1 },
429
{ .name = "usage", .key = -3,
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.doc = "Give a short usage message", .group = -1 },
431
{ .name = "version", .key = 'V',
432
.doc = "Print program version", .group = -1 },
381
error_t parse_opt(int key, char *arg, __attribute__((unused))
382
struct argp_state *state){
436
__attribute__((nonnull(3)))
437
error_t parse_opt(int key, char *arg, struct argp_state *state){
385
442
case 'g': /* --global-options */
387
444
char *plugin_option;
388
445
while((plugin_option = strsep(&arg, ",")) != NULL){
389
if(plugin_option[0] == '\0'){
392
446
if(not add_argument(getplugin(NULL), plugin_option)){
393
perror("add_argument");
394
return ARGP_ERR_UNKNOWN;
399
453
case 'G': /* --global-env */
403
if(not add_environment(getplugin(NULL), arg, true)){
404
perror("add_environment");
454
if(add_environment(getplugin(NULL), arg, true)){
407
458
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;
460
char *option_list = strchr(arg, ':');
461
if(option_list == NULL){
462
argp_error(state, "No colon in \"%s\"", arg);
469
argp_error(state, "Empty plugin name");
474
while((option = strsep(&option_list, ",")) != NULL){
475
if(not add_argument(getplugin(arg), option)){
422
482
case 'E': /* --env-for */
427
484
char *envdef = strchr(arg, ':');
428
485
if(envdef == NULL){
486
argp_error(state, "No colon in \"%s\"", arg);
432
if(not add_environment(getplugin(arg), envdef+1, true)){
433
perror("add_environment");
493
argp_error(state, "Empty plugin name");
497
if(add_environment(getplugin(arg), envdef, true)){
437
502
case 'd': /* --disable */
439
504
plugin *p = getplugin(arg);
441
return ARGP_ERR_UNKNOWN;
446
511
case 'e': /* --enable */
448
513
plugin *p = getplugin(arg);
450
return ARGP_ERR_UNKNOWN;
455
520
case 128: /* --plugin-dir */
457
522
plugindir = strdup(arg);
458
if(plugindir == NULL){
523
if(plugindir != NULL){
462
527
case 129: /* --config-file */
463
528
/* This is already done by parse_opt_config_file() */
465
530
case 130: /* --userid */
467
tmpmax = strtoimax(arg, &tmp, 10);
531
tmp_id = strtoimax(arg, &tmp, 10);
468
532
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);
533
or tmp_id != (uid_t)tmp_id){
534
argp_error(state, "Bad user ID number: \"%s\", using %"
535
PRIdMAX, arg, (intmax_t)uid);
476
541
case 131: /* --groupid */
478
tmpmax = strtoimax(arg, &tmp, 10);
542
tmp_id = strtoimax(arg, &tmp, 10);
479
543
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);
544
or tmp_id != (gid_t)tmp_id){
545
argp_error(state, "Bad group ID number: \"%s\", using %"
546
PRIdMAX, arg, (intmax_t)gid);
487
552
case 132: /* --debug */
555
case 133: /* --plugin-helper-dir */
556
free(pluginhelperdir);
557
pluginhelperdir = strdup(arg);
558
if(pluginhelperdir != NULL){
563
* These reproduce what we would get without ARGP_NO_HELP
565
case '?': /* --help */
566
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
567
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
568
__builtin_unreachable();
569
case -3: /* --usage */
570
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
571
argp_state_help(state, state->out_stream,
572
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
573
__builtin_unreachable();
574
case 'V': /* --version */
575
fprintf(state->out_stream, "%s\n", argp_program_version);
491
579
* When adding more options before this line, remember to also add a
492
580
* "case" to the "parse_opt_config_file" function below.
597
701
new_arg = strdup(p);
598
702
if(new_arg == NULL){
600
exitstatus = EXIT_FAILURE;
703
error(0, errno, "strdup");
704
exitstatus = EX_OSERR;
605
709
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;
711
char **new_argv = realloc(custom_argv, sizeof(char *)
712
* ((size_t)custom_argc + 1));
713
if(new_argv == NULL){
714
error(0, errno, "realloc");
715
exitstatus = EX_OSERR;
720
custom_argv = new_argv;
614
723
custom_argv[custom_argc-1] = new_arg;
615
custom_argv[custom_argc] = NULL;
724
custom_argv[custom_argc] = NULL;
728
ret = fclose(conffp);
729
} while(ret == EOF and errno == EINTR);
731
error(0, errno, "fclose");
732
exitstatus = EX_IOERR;
620
737
/* Check for harmful errors and go to fallback. Other errors might
621
738
not affect opening plugins */
622
739
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
624
exitstatus = EXIT_FAILURE;
740
error(0, errno, "fopen");
741
exitstatus = EX_OSERR;
628
/* If there was any arguments from configuration file,
629
pass them to parser as command arguments */
745
/* If there were any arguments from the configuration file, pass
746
them to parser as command line arguments */
630
747
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;
748
ret = argp_parse(&argp, custom_argc, custom_argv,
749
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
757
error(0, errno, "argp_parse");
758
exitstatus = EX_OSERR;
761
exitstatus = EX_CONFIG;
640
766
/* 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;
768
ret = argp_parse(&argp, argc, argv,
769
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
777
error(0, errno, "argp_parse");
778
exitstatus = EX_OSERR;
781
exitstatus = EX_USAGE;
786
char *pluginhelperenv;
788
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
789
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
791
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
793
if(ret == -1 or not bret){
794
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
795
" environment variable to \"%s\" for all plugins\n",
796
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
799
free(pluginhelperenv);
650
for(plugin *p = plugin_list; p != NULL; p=p->next){
804
for(plugin *p = plugin_list; p != NULL; p = p->next){
651
805
fprintf(stderr, "Plugin: %s has %d arguments\n",
652
806
p->name ? p->name : "Global", p->argc - 1);
653
807
for(char **a = p->argv; *a != NULL; a++){
663
/* Strip permissions down to nobody */
818
/* Work around Debian bug #633582:
819
<https://bugs.debian.org/633582> */
820
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
821
if(plugindir_fd == -1){
823
error(0, errno, "open(\"" PDIR "\")");
826
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
828
error(0, errno, "fstat");
830
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
831
ret = fchown(plugindir_fd, uid, gid);
833
error(0, errno, "fchown");
841
/* Lower permissions */
844
error(0, errno, "setgid");
668
846
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 */
848
error(0, errno, "setuid");
851
/* 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;
853
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
856
#else /* not O_CLOEXEC */
858
#endif /* not O_CLOEXEC */
861
error(0, errno, "Could not open plugin dir");
862
exitstatus = EX_UNAVAILABLE;
867
/* Set the FD_CLOEXEC flag on the directory */
868
ret = set_cloexec_flag(dir_fd);
870
error(0, errno, "set_cloexec_flag");
871
exitstatus = EX_OSERR;
874
#endif /* O_CLOEXEC */
877
int good_name(const struct dirent * const dirent){
878
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
879
"*.dpkg-old", "*.dpkg-bak",
880
"*.dpkg-divert", NULL };
882
#pragma GCC diagnostic push
883
#pragma GCC diagnostic ignored "-Wcast-qual"
885
for(const char **pat = (const char **)patterns;
886
*pat != NULL; pat++){
888
#pragma GCC diagnostic pop
890
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
893
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
894
" matching pattern %s\n", dirent->d_name, *pat);
902
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
904
if(numplugins == -1){
905
error(0, errno, "Could not scan plugin dir");
907
exitstatus = EX_OSERR;
698
911
FD_ZERO(&rfds_all);
700
913
/* 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);
914
for(int i = 0; i < numplugins; i++){
916
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
918
error(0, errno, "Could not open plugin");
771
ret = stat(filename, &st);
922
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
924
error(0, errno, "stat");
778
930
/* Ignore non-executable files */
779
if(not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
931
if(not S_ISREG(st.st_mode)
932
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);
935
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
936
" with bad type or mode\n",
937
plugindir != NULL ? plugindir : PDIR,
938
direntries[i]->d_name);
788
plugin *p = getplugin(dirst->d_name);
945
plugin *p = getplugin(direntries[i]->d_name);
947
error(0, errno, "getplugin");
796
954
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
955
direntries[i]->d_name);
806
965
for(char **a = g->argv + 1; *a != NULL; a++){
807
966
if(not add_argument(p, *a)){
808
perror("add_argument");
967
error(0, errno, "add_argument");
811
970
/* Add global environment variables */
812
971
for(char **e = g->environ; *e != NULL; e++){
813
972
if(not add_environment(p, *e, false)){
814
perror("add_environment");
973
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
978
/* If this plugin has any environment variables, we need to
979
duplicate the environment from this process, too. */
822
980
if(p->environ[0] != NULL){
823
981
for(char **e = environ; *e != NULL; e++){
824
982
if(not add_environment(p, *e, false)){
825
perror("add_environment");
983
error(0, errno, "add_environment");
990
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
991
#else /* O_CLOEXEC */
992
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
993
#endif /* O_CLOEXEC */
834
exitstatus = EXIT_FAILURE;
995
error(0, errno, "pipe");
996
exitstatus = EX_OSERR;
1000
if(pipefd[0] >= FD_SETSIZE){
1001
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1005
exitstatus = EX_OSERR;
1006
free(direntries[i]);
837
1010
/* Ask OS to automatic close the pipe on exec */
838
1011
ret = set_cloexec_flag(pipefd[0]);
840
perror("set_cloexec_flag");
841
exitstatus = EXIT_FAILURE;
1013
error(0, errno, "set_cloexec_flag");
1016
exitstatus = EX_OSERR;
1017
free(direntries[i]);
844
1020
ret = set_cloexec_flag(pipefd[1]);
846
perror("set_cloexec_flag");
847
exitstatus = EXIT_FAILURE;
1022
error(0, errno, "set_cloexec_flag");
1025
exitstatus = EX_OSERR;
1026
free(direntries[i]);
1029
#endif /* not O_CLOEXEC */
850
1030
/* Block SIGCHLD until process is safely in process list */
851
ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
1031
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1032
&sigchld_action.sa_mask,
853
perror("sigprocmask");
854
exitstatus = EXIT_FAILURE;
1035
error(0, errno, "sigprocmask");
1036
exitstatus = EX_OSERR;
1037
free(direntries[i]);
857
1040
/* Starting a new process to be watched */
1044
} while(pid == -1 and errno == EINTR);
861
exitstatus = EXIT_FAILURE;
1046
error(0, errno, "fork");
1047
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1048
&sigchld_action.sa_mask, NULL));
1051
exitstatus = EX_OSERR;
1052
free(direntries[i]);
865
1056
/* this is the child process */
866
1057
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1059
error(0, errno, "sigaction");
871
1062
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
873
perror("sigprocmask");
1064
error(0, errno, "sigprocmask");
877
1068
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1070
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){
1074
if(fexecve(plugin_fd, p->argv,
1075
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1076
error(0, errno, "fexecve for %s/%s",
1077
plugindir != NULL ? plugindir : PDIR,
1078
direntries[i]->d_name);
901
1083
/* Parent process */
902
1084
close(pipefd[1]); /* Close unused write end of pipe */
904
plugin *new_plugin = getplugin(dirst->d_name);
1086
plugin *new_plugin = getplugin(direntries[i]->d_name);
905
1087
if(new_plugin == NULL){
907
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1088
error(0, errno, "getplugin");
1089
ret = (int)(TEMP_FAILURE_RETRY
1090
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
909
perror("sigprocmask");
1093
error(0, errno, "sigprocmask");
911
exitstatus = EXIT_FAILURE;
1095
exitstatus = EX_OSERR;
1096
free(direntries[i]);
1099
free(direntries[i]);
915
1101
new_plugin->pid = pid;
916
1102
new_plugin->fd = pipefd[0];
1105
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1106
new_plugin->name, (intmax_t) (new_plugin->pid));
918
1109
/* Unblock SIGCHLD so signal handler can be run if this process
919
1110
has already completed */
920
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1111
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1112
&sigchld_action.sa_mask,
922
perror("sigprocmask");
923
exitstatus = EXIT_FAILURE;
1115
error(0, errno, "sigprocmask");
1116
exitstatus = EX_OSERR;