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* Mandos plugin runner - Run Mandos plugins
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* Copyright © 2008-2014 Teddy Hogeborn
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* Copyright © 2008-2014 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* 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
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* 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
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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
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* (at your option) any later version.
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* 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
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* 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@recompile.se>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
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#include <stddef.h> /* size_t, NULL */
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#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* fileno(), fprintf(),
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stderr, STDOUT_FILENO, fclose() */
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#include <sys/types.h> /* DIR, fdopendir(), fstat(), 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 <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 */
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#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
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WEXITSTATUS(), WTERMSIG(),
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WEXITSTATUS(), WTERMSIG() */
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#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
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#include <iso646.h> /* and, or, not */
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#include <dirent.h> /* DIR, struct dirent, fdopendir(),
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readdir(), closedir(), dirfd() */
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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() pipe(), fork(),
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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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FD_CLOEXEC, openat() */
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FD_CLOEXEC, openat(), scandirat(),
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#include <string.h> /* strsep, strlen(), strsignal(),
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strcmp(), strncmp() */
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#include <errno.h> /* errno */
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char *pluginhelperenv;
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ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
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pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
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bret = add_environment(getplugin(NULL), pluginhelperenv, true);
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if(ret == -1 or not bret){
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error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
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" environment variable to \"%s\" for all plugins\n",
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pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
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free(pluginhelperenv);
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for(plugin *p = plugin_list; p != NULL; p=p->next){
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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fprintf(stderr, "Plugin: %s has %d arguments\n",
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p->name ? p->name : "Global", p->argc - 1);
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for(char **a = p->argv; *a != NULL; a++){
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ret = set_cloexec_flag(dir_fd);
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(dir_fd));
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exitstatus = EX_OSERR;
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#endif /* O_CLOEXEC */
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dir = fdopendir(dir_fd);
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error(0, errno, "Could not open plugin dir");
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TEMP_FAILURE_RETRY(close(dir_fd));
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exitstatus = EX_OSERR;
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int good_name(const struct dirent * const dirent){
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const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
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"*.dpkg-old", "*.dpkg-bak",
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"*.dpkg-divert", NULL };
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wcast-qual"
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for(const char **pat = (const char **)patterns;
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*pat != NULL; pat++){
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#pragma GCC diagnostic pop
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if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
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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,
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if(numplugins == -1){
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error(0, errno, "Could not scan plugin dir");
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exitstatus = EX_OSERR;
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FD_ZERO(&rfds_all);
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/* Read and execute any executable in the plugin directory*/
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dirst = readdir(dir);
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} while(dirst == NULL and errno == EINTR);
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/* All directory entries have been processed */
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error(0, errno, "readdir");
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exitstatus = EX_IOERR;
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/* Ignore dotfiles, backup files and other junk */
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bool bad_name = false;
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const char * const patterns[] = { ".*", "#*#", "*~",
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"*.dpkg-new", "*.dpkg-old",
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"*.dpkg-bak", "*.dpkg-divert",
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wcast-qual"
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for(const char **pat = (const char **)patterns;
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*pat != NULL; pat++){
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#pragma GCC diagnostic pop
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if(fnmatch(*pat, dirst->d_name,
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FNM_FILE_NAME | FNM_PERIOD) != FNM_NOMATCH){
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fprintf(stderr, "Ignoring plugin dir entry \"%s\""
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" matching pattern %s\n", dirst->d_name, *pat);
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int plugin_fd = openat(dir_fd, dirst->d_name, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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for(int i = 0; i < numplugins; i++){
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int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
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if(plugin_fd == -1){
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error(0, errno, "Could not open plugin");
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/* Set the FD_CLOEXEC flag on the plugin FD */
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ret = set_cloexec_flag(plugin_fd);
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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#endif /* O_CLOEXEC */
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ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
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error(0, errno, "stat");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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/* Ignore non-executable files */
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if(not S_ISREG(st.st_mode)
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or (TEMP_FAILURE_RETRY(faccessat(dir_fd, dirst->d_name, X_OK,
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or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
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fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
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" with bad type or mode\n",
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plugindir != NULL ? plugindir : PDIR, dirst->d_name);
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plugindir != NULL ? plugindir : PDIR,
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direntries[i]->d_name);
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TEMP_FAILURE_RETRY(close(plugin_fd));
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plugin *p = getplugin(dirst->d_name);
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plugin *p = getplugin(direntries[i]->d_name);
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error(0, errno, "getplugin");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
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direntries[i]->d_name);
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TEMP_FAILURE_RETRY(close(plugin_fd));
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ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
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#else /* O_CLOEXEC */
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ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
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#endif /* O_CLOEXEC */
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error(0, errno, "pipe");
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exitstatus = EX_OSERR;
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if(pipefd[0] >= FD_SETSIZE){
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fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
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TEMP_FAILURE_RETRY(close(pipefd[0]));
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TEMP_FAILURE_RETRY(close(pipefd[1]));
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exitstatus = EX_OSERR;
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free(direntries[i]);
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/* Ask OS to automatic close the pipe on exec */
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ret = set_cloexec_flag(pipefd[0]);
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(pipefd[0]));
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TEMP_FAILURE_RETRY(close(pipefd[1]));
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exitstatus = EX_OSERR;
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free(direntries[i]);
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ret = set_cloexec_flag(pipefd[1]);
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(pipefd[0]));
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TEMP_FAILURE_RETRY(close(pipefd[1]));
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exitstatus = EX_OSERR;
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free(direntries[i]);
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#endif /* not O_CLOEXEC */
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/* Block SIGCHLD until process is safely in process list */
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ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
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&sigchld_action.sa_mask,
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_exit(EX_OSERR);
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/* If dir has no file descriptor, we could not set FD_CLOEXEC
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above and must now close it manually here. */
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if(fexecve(plugin_fd, p->argv,
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(p->environ[0] != NULL) ? p->environ : environ) < 0){
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error(0, errno, "fexecve for %s/%s",
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plugindir != NULL ? plugindir : PDIR, dirst->d_name);
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plugindir != NULL ? plugindir : PDIR,
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direntries[i]->d_name);
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_exit(EX_OSERR);
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/* no return */
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/* Parent process */
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TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
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TEMP_FAILURE_RETRY(close(plugin_fd));
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plugin *new_plugin = getplugin(dirst->d_name);
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close(pipefd[1]); /* Close unused write end of pipe */
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plugin *new_plugin = getplugin(direntries[i]->d_name);
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if(new_plugin == NULL){
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error(0, errno, "getplugin");
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ret = (int)(TEMP_FAILURE_RETRY
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(intmax_t) (proc->pid),
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WTERMSIG(proc->status),
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strsignal(WTERMSIG(proc->status)));
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} else if(WCOREDUMP(proc->status)){
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fprintf(stderr, "Plugin %s [%" PRIdMAX "] dumped"
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" core\n", proc->name, (intmax_t) (proc->pid));
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/* Remove the plugin */
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#if defined (__GNUC__) and defined (__GLIBC__)
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#if not __GLIBC_PREREQ(2, 16)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wsign-conversion"
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FD_CLR(proc->fd, &rfds_all); /* Spurious warning from
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-Wconversion in GNU libc
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#if defined (__GNUC__) and defined (__GLIBC__)
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#if not __GLIBC_PREREQ(2, 16)
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#pragma GCC diagnostic pop
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FD_CLR(proc->fd, &rfds_all);
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/* Block signal while modifying process_list */
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ret = (int)TEMP_FAILURE_RETRY(sigprocmask