3
3
* Mandos plugin runner - Run Mandos plugins
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.
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* This program is distributed in the hope that it will be useful, but
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
14
16
* WITHOUT ANY WARRANTY; without even the implied warranty of
15
17
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16
18
* General Public License for more details.
18
20
* You should have received a copy of the GNU General Public License
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
22
* Contact the authors at <mandos@fukt.bsnet.se>.
23
* Contact the authors at <mandos@recompile.se>.
25
26
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
27
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(),
32
#include <stdio.h> /* fileno(), fprintf(),
33
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(),
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WEXITSTATUS(), WTERMSIG(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
41
WEXITSTATUS(), WTERMSIG() */
42
#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
44
43
#include <iso646.h> /* and, or, not */
45
#include <dirent.h> /* DIR, struct dirent, opendir(),
46
readdir(), closedir(), dirfd() */
47
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
48
fcntl(), setuid(), setgid(),
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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(),
44
#include <dirent.h> /* struct dirent, scandirat() */
45
#include <unistd.h> /* fcntl(), F_GETFD, F_SETFD,
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FD_CLOEXEC, write(), STDOUT_FILENO,
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struct stat, fstat(), close(),
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setgid(), setuid(), S_ISREG(),
49
faccessat() pipe2(), fork(),
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_exit(), dup2(), fexecve(), read()
54
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
56
#include <string.h> /* strsep, strlen(), asprintf(),
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strsignal(), strcmp(), strncmp() */
53
FD_CLOEXEC, openat(), scandirat(),
55
#include <string.h> /* strsep, strlen(), strsignal(),
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strcmp(), strncmp() */
58
57
#include <errno.h> /* errno */
59
58
#include <argp.h> /* struct argp_option, struct
60
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argp_state, struct argp,
393
416
.doc = "Group ID the plugins will run as", .group = 3 },
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{ .name = "debug", .key = 132,
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.doc = "Debug mode", .group = 4 },
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{ .name = "plugin-helper-dir", .key = 133,
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.doc = "Specify a different plugin helper directory",
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* These reproduce what we would get without ARGP_NO_HELP
426
{ .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 },
399
error_t parse_opt(int key, char *arg, __attribute__((unused))
400
struct argp_state *state){
435
__attribute__((nonnull(3)))
436
error_t parse_opt(int key, char *arg, struct argp_state *state){
404
441
case 'g': /* --global-options */
406
443
char *plugin_option;
407
444
while((plugin_option = strsep(&arg, ",")) != NULL){
408
if(plugin_option[0] == '\0'){
411
445
if(not add_argument(getplugin(NULL), plugin_option)){
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perror("add_argument");
413
return ARGP_ERR_UNKNOWN;
418
452
case 'G': /* --global-env */
422
if(not add_environment(getplugin(NULL), arg, true)){
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perror("add_environment");
453
if(add_environment(getplugin(NULL), arg, true)){
426
457
case 'o': /* --options-for */
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;
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)){
441
481
case 'E': /* --env-for */
446
483
char *envdef = strchr(arg, ':');
447
484
if(envdef == NULL){
485
argp_error(state, "No colon in \"%s\"", arg);
451
if(not add_environment(getplugin(arg), envdef+1, true)){
452
perror("add_environment");
492
argp_error(state, "Empty plugin name");
496
if(add_environment(getplugin(arg), envdef, true)){
456
501
case 'd': /* --disable */
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503
plugin *p = getplugin(arg);
460
return ARGP_ERR_UNKNOWN;
465
510
case 'e': /* --enable */
467
512
plugin *p = getplugin(arg);
469
return ARGP_ERR_UNKNOWN;
474
519
case 128: /* --plugin-dir */
476
521
plugindir = strdup(arg);
477
if(plugindir == NULL){
522
if(plugindir != NULL){
481
526
case 129: /* --config-file */
482
527
/* This is already done by parse_opt_config_file() */
484
529
case 130: /* --userid */
486
tmpmax = strtoimax(arg, &tmp, 10);
530
tmp_id = strtoimax(arg, &tmp, 10);
487
531
if(errno != 0 or tmp == arg or *tmp != '\0'
488
or tmpmax != (uid_t)tmpmax){
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fprintf(stderr, "Bad user ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)uid);
532
or tmp_id != (uid_t)tmp_id){
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argp_error(state, "Bad user ID number: \"%s\", using %"
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PRIdMAX, arg, (intmax_t)uid);
495
540
case 131: /* --groupid */
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tmpmax = strtoimax(arg, &tmp, 10);
541
tmp_id = strtoimax(arg, &tmp, 10);
498
542
if(errno != 0 or tmp == arg or *tmp != '\0'
499
or tmpmax != (gid_t)tmpmax){
500
fprintf(stderr, "Bad group ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)gid);
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or tmp_id != (gid_t)tmp_id){
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argp_error(state, "Bad group ID number: \"%s\", using %"
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PRIdMAX, arg, (intmax_t)gid);
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551
case 132: /* --debug */
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case 133: /* --plugin-helper-dir */
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free(pluginhelperdir);
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pluginhelperdir = strdup(arg);
557
if(pluginhelperdir != NULL){
562
* These reproduce what we would get without ARGP_NO_HELP
564
case '?': /* --help */
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state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
566
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
567
__builtin_unreachable();
568
case -3: /* --usage */
569
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
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argp_state_help(state, state->out_stream,
571
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
572
__builtin_unreachable();
573
case 'V': /* --version */
574
fprintf(state->out_stream, "%s\n", argp_program_version);
510
578
* When adding more options before this line, remember to also add a
511
579
* "case" to the "parse_opt_config_file" function below.
647
732
/* Check for harmful errors and go to fallback. Other errors might
648
733
not affect opening plugins */
649
734
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
651
exitstatus = EXIT_FAILURE;
735
error(0, errno, "fopen");
736
exitstatus = EX_OSERR;
655
/* If there was any arguments from configuration file,
656
pass them to parser as command arguments */
740
/* If there were any arguments from the configuration file, pass
741
them to parser as command line arguments */
657
742
if(custom_argv != NULL){
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;
743
ret = argp_parse(&argp, custom_argc, custom_argv,
744
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
752
error(0, errno, "argp_parse");
753
exitstatus = EX_OSERR;
756
exitstatus = EX_CONFIG;
667
761
/* Parse actual command line arguments, to let them override the
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;
763
ret = argp_parse(&argp, argc, argv,
764
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
772
error(0, errno, "argp_parse");
773
exitstatus = EX_OSERR;
776
exitstatus = EX_USAGE;
781
char *pluginhelperenv;
783
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
784
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
786
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
788
if(ret == -1 or not bret){
789
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
790
" environment variable to \"%s\" for all plugins\n",
791
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
794
free(pluginhelperenv);
677
for(plugin *p = plugin_list; p != NULL; p=p->next){
799
for(plugin *p = plugin_list; p != NULL; p = p->next){
678
800
fprintf(stderr, "Plugin: %s has %d arguments\n",
679
801
p->name ? p->name : "Global", p->argc - 1);
680
802
for(char **a = p->argv; *a != NULL; a++){
690
/* Strip permissions down to nobody */
813
/* Work around Debian bug #633582:
814
<https://bugs.debian.org/633582> */
815
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
816
if(plugindir_fd == -1){
818
error(0, errno, "open(\"" PDIR "\")");
821
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
823
error(0, errno, "fstat");
825
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
826
ret = fchown(plugindir_fd, uid, gid);
828
error(0, errno, "fchown");
836
/* Lower permissions */
839
error(0, errno, "setgid");
695
841
ret = setuid(uid);
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 */
843
error(0, errno, "setuid");
846
/* Open plugin directory with close_on_exec flag */
714
int dir_fd = dirfd(dir);
716
ret = set_cloexec_flag(dir_fd);
718
perror("set_cloexec_flag");
719
exitstatus = EXIT_FAILURE;
848
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
851
#else /* not O_CLOEXEC */
853
#endif /* not O_CLOEXEC */
856
error(0, errno, "Could not open plugin dir");
857
exitstatus = EX_UNAVAILABLE;
862
/* Set the FD_CLOEXEC flag on the directory */
863
ret = set_cloexec_flag(dir_fd);
865
error(0, errno, "set_cloexec_flag");
866
exitstatus = EX_OSERR;
869
#endif /* O_CLOEXEC */
872
int good_name(const struct dirent * const dirent){
873
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
874
"*.dpkg-old", "*.dpkg-bak",
875
"*.dpkg-divert", NULL };
877
#pragma GCC diagnostic push
878
#pragma GCC diagnostic ignored "-Wcast-qual"
880
for(const char **pat = (const char **)patterns;
881
*pat != NULL; pat++){
883
#pragma GCC diagnostic pop
885
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
888
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
889
" matching pattern %s\n", dirent->d_name, *pat);
897
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
899
if(numplugins == -1){
900
error(0, errno, "Could not scan plugin dir");
902
exitstatus = EX_OSERR;
725
906
FD_ZERO(&rfds_all);
727
908
/* Read and execute any executable in the plugin directory*/
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,
909
for(int i = 0; i < numplugins; i++){
911
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
913
error(0, errno, "Could not open plugin");
802
ret = TEMP_FAILURE_RETRY(stat(filename, &st));
917
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
919
error(0, errno, "stat");
809
925
/* Ignore non-executable files */
810
926
if(not S_ISREG(st.st_mode)
811
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
927
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
813
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
814
" with bad type or mode\n", filename);
930
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
931
" with bad type or mode\n",
932
plugindir != NULL ? plugindir : PDIR,
933
direntries[i]->d_name);
820
plugin *p = getplugin(dirst->d_name);
940
plugin *p = getplugin(direntries[i]->d_name);
942
error(0, errno, "getplugin");
828
949
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
950
direntries[i]->d_name);
838
960
for(char **a = g->argv + 1; *a != NULL; a++){
839
961
if(not add_argument(p, *a)){
840
perror("add_argument");
962
error(0, errno, "add_argument");
843
965
/* Add global environment variables */
844
966
for(char **e = g->environ; *e != NULL; e++){
845
967
if(not add_environment(p, *e, false)){
846
perror("add_environment");
968
error(0, errno, "add_environment");
851
/* If this plugin has any environment variables, we will call
852
using execve and need to duplicate the environment from this
973
/* If this plugin has any environment variables, we need to
974
duplicate the environment from this process, too. */
854
975
if(p->environ[0] != NULL){
855
976
for(char **e = environ; *e != NULL; e++){
856
977
if(not add_environment(p, *e, false)){
857
perror("add_environment");
978
error(0, errno, "add_environment");
863
ret = TEMP_FAILURE_RETRY(pipe(pipefd));
985
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
986
#else /* O_CLOEXEC */
987
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
988
#endif /* O_CLOEXEC */
866
exitstatus = EXIT_FAILURE;
990
error(0, errno, "pipe");
991
exitstatus = EX_OSERR;
995
if(pipefd[0] >= FD_SETSIZE){
996
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1000
exitstatus = EX_OSERR;
1001
free(direntries[i]);
869
1005
/* Ask OS to automatic close the pipe on exec */
870
1006
ret = set_cloexec_flag(pipefd[0]);
872
perror("set_cloexec_flag");
873
exitstatus = EXIT_FAILURE;
1008
error(0, errno, "set_cloexec_flag");
1011
exitstatus = EX_OSERR;
1012
free(direntries[i]);
876
1015
ret = set_cloexec_flag(pipefd[1]);
878
perror("set_cloexec_flag");
879
exitstatus = EXIT_FAILURE;
1017
error(0, errno, "set_cloexec_flag");
1020
exitstatus = EX_OSERR;
1021
free(direntries[i]);
1024
#endif /* not O_CLOEXEC */
882
1025
/* Block SIGCHLD until process is safely in process list */
883
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
884
&sigchld_action.sa_mask,
1026
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1027
&sigchld_action.sa_mask,
887
perror("sigprocmask");
888
exitstatus = EXIT_FAILURE;
1030
error(0, errno, "sigprocmask");
1031
exitstatus = EX_OSERR;
1032
free(direntries[i]);
891
1035
/* Starting a new process to be watched */
895
1039
} while(pid == -1 and errno == EINTR);
898
exitstatus = EXIT_FAILURE;
1041
error(0, errno, "fork");
1042
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1043
&sigchld_action.sa_mask, NULL));
1046
exitstatus = EX_OSERR;
1047
free(direntries[i]);
902
1051
/* this is the child process */
903
1052
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1054
error(0, errno, "sigaction");
908
1057
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
910
perror("sigprocmask");
1059
error(0, errno, "sigprocmask");
914
1063
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1065
error(0, errno, "dup2");
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){
1069
if(fexecve(plugin_fd, p->argv,
1070
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1071
error(0, errno, "fexecve for %s/%s",
1072
plugindir != NULL ? plugindir : PDIR,
1073
direntries[i]->d_name);
938
1078
/* Parent process */
939
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
942
plugin *new_plugin = getplugin(dirst->d_name);
1079
close(pipefd[1]); /* Close unused write end of pipe */
1081
plugin *new_plugin = getplugin(direntries[i]->d_name);
943
1082
if(new_plugin == NULL){
945
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
946
&sigchld_action.sa_mask,
1083
error(0, errno, "getplugin");
1084
ret = (int)(TEMP_FAILURE_RETRY
1085
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
949
perror("sigprocmask");
1088
error(0, errno, "sigprocmask");
951
exitstatus = EXIT_FAILURE;
1090
exitstatus = EX_OSERR;
1091
free(direntries[i]);
1094
free(direntries[i]);
955
1096
new_plugin->pid = pid;
956
1097
new_plugin->fd = pipefd[0];
1100
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1101
new_plugin->name, (intmax_t) (new_plugin->pid));
958
1104
/* Unblock SIGCHLD so signal handler can be run if this process
959
1105
has already completed */
960
ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
961
&sigchld_action.sa_mask,
1106
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1107
&sigchld_action.sa_mask,
964
perror("sigprocmask");
965
exitstatus = EXIT_FAILURE;
1110
error(0, errno, "sigprocmask");
1111
exitstatus = EX_OSERR;