3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* 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
6
* 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
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
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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>.
25
26
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
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asprintf(), O_CLOEXEC */
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(), reallocarray(), realloc(),
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EXIT_SUCCESS, exit() */
30
31
#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* perror, fileno(), fprintf(),
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stderr, STDOUT_FILENO */
33
#include <sys/types.h> /* DIR, fdopendir(), stat(), struct
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stat, waitpid(), WIFEXITED(),
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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(),
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WIFEXITED(), WEXITSTATUS(), wait(),
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pid_t, uid_t, gid_t, getuid(),
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#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(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
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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, fdopendir(),
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readdir(), closedir(), dirfd() */
47
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
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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(),
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#include <dirent.h> /* struct dirent, scandirat() */
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#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(),
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faccessat() pipe2(), fork(),
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_exit(), dup2(), fexecve(), read()
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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#include <string.h> /* strsep, strlen(), asprintf(),
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FD_CLOEXEC, openat(), scandirat(),
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#include <string.h> /* strsep, strlen(), strsignal(),
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strcmp(), strncmp() */
58
57
#include <errno.h> /* errno */
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58
#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
485
524
plugin *p = getplugin(arg);
487
526
p->disabled = false;
491
531
case 128: /* --plugin-dir */
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plugindir = strdup(arg);
534
if(plugindir != NULL){
495
538
case 129: /* --config-file */
496
539
/* This is already done by parse_opt_config_file() */
498
541
case 130: /* --userid */
499
tmpmax = strtoimax(arg, &tmp, 10);
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tmp_id = strtoimax(arg, &tmp, 10);
500
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if(errno != 0 or tmp == arg or *tmp != '\0'
501
or tmpmax != (uid_t)tmpmax){
544
or tmp_id != (uid_t)tmp_id){
502
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argp_error(state, "Bad user ID number: \"%s\", using %"
503
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PRIdMAX, arg, (intmax_t)uid);
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case 131: /* --groupid */
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tmpmax = strtoimax(arg, &tmp, 10);
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tmp_id = strtoimax(arg, &tmp, 10);
510
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if(errno != 0 or tmp == arg or *tmp != '\0'
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or tmpmax != (gid_t)tmpmax){
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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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case 132: /* --debug */
566
case 133: /* --plugin-helper-dir */
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free(pluginhelperdir);
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pluginhelperdir = strdup(arg);
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if(pluginhelperdir != NULL){
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* These reproduce what we would get without ARGP_NO_HELP
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case '?': /* --help */
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state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
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argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
579
__builtin_unreachable();
527
580
case -3: /* --usage */
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state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
529
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argp_state_help(state, state->out_stream,
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ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
584
__builtin_unreachable();
531
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case 'V': /* --version */
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fprintf(state->out_stream, "%s\n", argp_program_version);
533
587
exit(EXIT_SUCCESS);
742
/* Strip permissions down to nobody */
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){
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error(0, errno, "open(\"" PDIR "\")");
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ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
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error(0, errno, "fstat");
852
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
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ret = fchown(plugindir_fd, uid, gid);
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error(0, errno, "fchown");
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/* Lower permissions */
866
error(0, errno, "setgid");
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ret = setuid(uid);
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error(0, errno, "setuid");
752
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/* Open plugin directory with close_on_exec flag */
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if(plugindir == NULL){
756
dir_fd = open(PDIR, O_RDONLY |
759
#else /* not O_CLOEXEC */
761
#endif /* not O_CLOEXEC */
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dir_fd = open(plugindir, O_RDONLY |
767
#else /* not O_CLOEXEC */
769
#endif /* not O_CLOEXEC */
875
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
878
#else /* not O_CLOEXEC */
880
#endif /* not O_CLOEXEC */
772
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if(dir_fd == -1){
773
perror("Could not open plugin dir");
774
exitstatus = EXIT_FAILURE;
883
error(0, errno, "Could not open plugin dir");
884
exitstatus = EX_UNAVAILABLE;
779
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/* Set the FD_CLOEXEC flag on the directory */
780
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ret = set_cloexec_flag(dir_fd);
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perror("set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(dir_fd));
784
exitstatus = EXIT_FAILURE;
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error(0, errno, "set_cloexec_flag");
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exitstatus = EX_OSERR;
787
896
#endif /* O_CLOEXEC */
789
dir = fdopendir(dir_fd);
791
perror("Could not open plugin dir");
792
TEMP_FAILURE_RETRY(close(dir_fd));
793
exitstatus = EXIT_FAILURE;
899
int good_name(const struct dirent * const dirent){
900
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
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"*.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\""
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" matching pattern %s\n", dirent->d_name, *pat);
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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;
798
933
FD_ZERO(&rfds_all);
800
935
/* Read and execute any executable in the plugin directory*/
803
dirst = readdir(dir);
804
} while(dirst == NULL and errno == EINTR);
806
/* All directory entries have been processed */
810
exitstatus = EXIT_FAILURE;
816
d_name_len = strlen(dirst->d_name);
818
/* Ignore dotfiles, backup files and other junk */
820
bool bad_name = false;
822
const char const *bad_prefixes[] = { ".", "#", NULL };
824
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
827
".dpkg-divert", NULL };
828
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
829
size_t pre_len = strlen(*pre);
830
if((d_name_len >= pre_len)
831
and strncmp((dirst->d_name), *pre, pre_len) == 0){
833
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
834
" with bad prefix %s\n", dirst->d_name, *pre);
843
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
844
size_t suf_len = strlen(*suf);
845
if((d_name_len >= suf_len)
846
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
849
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
850
" with bad suffix %s\n", dirst->d_name, *suf);
863
if(plugindir == NULL){
864
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
867
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
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");
876
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
944
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
946
error(0, errno, "stat");
883
952
/* Ignore non-executable files */
884
953
if(not S_ISREG(st.st_mode)
885
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
954
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
887
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
888
" with bad type or mode\n", filename);
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);
894
plugin *p = getplugin(dirst->d_name);
967
plugin *p = getplugin(direntries[i]->d_name);
969
error(0, errno, "getplugin");
902
976
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
977
direntries[i]->d_name);
912
987
for(char **a = g->argv + 1; *a != NULL; a++){
913
988
if(not add_argument(p, *a)){
914
perror("add_argument");
989
error(0, errno, "add_argument");
917
992
/* Add global environment variables */
918
993
for(char **e = g->environ; *e != NULL; e++){
919
994
if(not add_environment(p, *e, false)){
920
perror("add_environment");
995
error(0, errno, "add_environment");
925
/* If this plugin has any environment variables, we will call
926
using execve and need to duplicate the environment from this
1000
/* If this plugin has any environment variables, we need to
1001
duplicate the environment from this process, too. */
928
1002
if(p->environ[0] != NULL){
929
1003
for(char **e = environ; *e != NULL; e++){
930
1004
if(not add_environment(p, *e, false)){
931
perror("add_environment");
1005
error(0, errno, "add_environment");
937
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 */
940
exitstatus = EXIT_FAILURE;
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]);
943
1032
/* Ask OS to automatic close the pipe on exec */
944
1033
ret = set_cloexec_flag(pipefd[0]);
946
perror("set_cloexec_flag");
947
exitstatus = EXIT_FAILURE;
1035
error(0, errno, "set_cloexec_flag");
1038
exitstatus = EX_OSERR;
1039
free(direntries[i]);
950
1042
ret = set_cloexec_flag(pipefd[1]);
952
perror("set_cloexec_flag");
953
exitstatus = EXIT_FAILURE;
1044
error(0, errno, "set_cloexec_flag");
1047
exitstatus = EX_OSERR;
1048
free(direntries[i]);
1051
#endif /* not O_CLOEXEC */
956
1052
/* Block SIGCHLD until process is safely in process list */
957
1053
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
958
1054
&sigchld_action.sa_mask,
961
perror("sigprocmask");
962
exitstatus = EXIT_FAILURE;
1057
error(0, errno, "sigprocmask");
1058
exitstatus = EX_OSERR;
1059
free(direntries[i]);
965
1062
/* Starting a new process to be watched */
969
1066
} while(pid == -1 and errno == EINTR);
972
exitstatus = EXIT_FAILURE;
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]);
976
1078
/* this is the child process */
977
1079
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1081
error(0, errno, "sigaction");
982
1084
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
984
perror("sigprocmask");
1086
error(0, errno, "sigprocmask");
988
1090
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1092
error(0, errno, "dup2");
995
/* If dir has no file descriptor, we could not set FD_CLOEXEC
996
above and must now close it manually here. */
999
if(p->environ[0] == NULL){
1000
if(execv(filename, p->argv) < 0){
1002
_exit(EXIT_FAILURE);
1005
if(execve(filename, p->argv, p->environ) < 0){
1007
_exit(EXIT_FAILURE);
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);
1010
1103
/* no return */
1012
1105
/* Parent process */
1013
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
1016
plugin *new_plugin = getplugin(dirst->d_name);
1106
close(pipefd[1]); /* Close unused write end of pipe */
1108
plugin *new_plugin = getplugin(direntries[i]->d_name);
1017
1109
if(new_plugin == NULL){
1018
perror("getplugin");
1110
error(0, errno, "getplugin");
1019
1111
ret = (int)(TEMP_FAILURE_RETRY
1020
1112
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1023
perror("sigprocmask");
1115
error(0, errno, "sigprocmask");
1025
exitstatus = EXIT_FAILURE;
1117
exitstatus = EX_OSERR;
1118
free(direntries[i]);
1121
free(direntries[i]);
1029
1123
new_plugin->pid = pid;
1030
1124
new_plugin->fd = pipefd[0];
1127
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1128
new_plugin->name, (intmax_t) (new_plugin->pid));
1032
1131
/* Unblock SIGCHLD so signal handler can be run if this process
1033
1132
has already completed */
1034
1133
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1035
1134
&sigchld_action.sa_mask,
1038
perror("sigprocmask");
1039
exitstatus = EXIT_FAILURE;
1137
error(0, errno, "sigprocmask");
1138
exitstatus = EX_OSERR;
1043
FD_SET(new_plugin->fd, &rfds_all); /* Spurious warning from
1142
FD_SET(new_plugin->fd, &rfds_all);
1046
1144
if(maxfd < new_plugin->fd){
1047
1145
maxfd = new_plugin->fd;
1051
TEMP_FAILURE_RETRY(closedir(dir));
1053
1153
free_plugin(getplugin(NULL));
1055
1155
for(plugin *p = plugin_list; p != NULL; p = p->next){
1141
1237
bool bret = print_out_password(proc->buffer,
1142
1238
proc->buffer_length);
1144
perror("print_out_password");
1145
exitstatus = EXIT_FAILURE;
1240
error(0, errno, "print_out_password");
1241
exitstatus = EX_IOERR;
1150
1246
/* This process has not completed. Does it have any output? */
1151
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){ /* Spurious
1247
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){
1154
1248
/* This process had nothing to say at this time */
1155
1249
proc = proc->next;
1158
1252
/* Before reading, make the process' data buffer large enough */
1159
1253
if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
1160
proc->buffer = realloc(proc->buffer, proc->buffer_size
1161
+ (size_t) BUFFER_SIZE);
1162
if(proc->buffer == NULL){
1164
exitstatus = EXIT_FAILURE;
1254
char *new_buffer = realloc(proc->buffer, proc->buffer_size
1255
+ (size_t) BUFFER_SIZE);
1256
if(new_buffer == NULL){
1257
error(0, errno, "malloc");
1258
exitstatus = EX_OSERR;
1261
proc->buffer = new_buffer;
1167
1262
proc->buffer_size += BUFFER_SIZE;
1169
1264
/* Read from the process */