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* 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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* Copyright © 2008-2013 Teddy Hogeborn
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* Copyright © 2008-2013 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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* along with this program. If not, see
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* <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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asprintf(), O_CLOEXEC */
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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 */
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#include <sys/types.h> /* DIR, fdopendir(), stat(), struct
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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/wait.h> /* wait(), waitpid(), WIFEXITED(),
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WEXITSTATUS(), WTERMSIG(),
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#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
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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 <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 <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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_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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strsignal(), strcmp(), strncmp() */
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FD_CLOEXEC, openat() */
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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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#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
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/* Helper function for add_argument and add_environment */
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__attribute__((nonnull, warn_unused_result))
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static bool add_to_char_array(const char *new, char ***array,
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/* Resize the pointed-to array to hold one more pointer */
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char **new_array = NULL;
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*array = realloc(*array, sizeof(char *)
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* (size_t) ((*len) + 2));
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} while(*array == NULL and errno == EINTR);
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new_array = realloc(*array, sizeof(char *)
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* (size_t) ((*len) + 2));
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} while(new_array == NULL and errno == EINTR);
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/* Malloc check */
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if(new_array == NULL){
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/* Make a copy of the new string */
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/* namelen = length of name of environment variable */
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size_t namelen = (size_t)(strchrnul(def, '=') - def);
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/* Search for this environment variable */
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for(char **e = p->environ; *e != NULL; e++){
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if(strncmp(*e, def, namelen + 1) == 0){
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for(char **envdef = p->environ; *envdef != NULL; envdef++){
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if(strncmp(*envdef, def, namelen + 1) == 0){
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/* It already exists */
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new = realloc(*e, strlen(def) + 1);
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} while(new == NULL and errno == EINTR);
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new_envdef = realloc(*envdef, strlen(def) + 1);
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} while(new_envdef == NULL and errno == EINTR);
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if(new_envdef == NULL){
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*envdef = new_envdef;
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strcpy(*envdef, def);
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plugin *p = getplugin(arg);
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p->disabled = false;
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case 128: /* --plugin-dir */
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plugindir = strdup(arg);
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if(plugindir != NULL){
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case 129: /* --config-file */
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/* This is already done by parse_opt_config_file() */
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case 130: /* --userid */
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tmpmax = strtoimax(arg, &tmp, 10);
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tmp_id = strtoimax(arg, &tmp, 10);
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if(errno != 0 or tmp == arg or *tmp != '\0'
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or tmpmax != (uid_t)tmpmax){
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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);
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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);
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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 */
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custom_argc += 1;
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custom_argv = realloc(custom_argv, sizeof(char *)
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* ((unsigned int) custom_argc + 1));
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if(custom_argv == NULL){
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error(0, errno, "realloc");
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exitstatus = EX_OSERR;
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char **new_argv = realloc(custom_argv, sizeof(char *)
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if(new_argv == NULL){
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error(0, errno, "realloc");
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exitstatus = EX_OSERR;
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custom_argv = new_argv;
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custom_argv[custom_argc-1] = new_arg;
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custom_argv[custom_argc] = NULL;
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/* Strip permissions down to nobody */
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/* Work around Debian bug #633582:
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<http://bugs.debian.org/633582> */
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int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
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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");
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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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TEMP_FAILURE_RETRY(close(plugindir_fd));
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/* Lower permissions */
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error(0, errno, "setgid");
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/* Open plugin directory with close_on_exec flag */
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if(plugindir == NULL){
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dir_fd = open(PDIR, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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dir_fd = open(plugindir, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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if(dir_fd == -1){
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error(0, errno, "Could not open plugin dir");
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exitstatus = EX_UNAVAILABLE;
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bool bad_name = false;
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const char const *bad_prefixes[] = { ".", "#", NULL };
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const char * const bad_prefixes[] = { ".", "#", NULL };
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const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
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const char * const bad_suffixes[] = { "~", "#", ".dpkg-new",
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".dpkg-divert", NULL };
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for(const char **pre = bad_prefixes; *pre != NULL; pre++){
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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 **pre = (const char **)bad_prefixes;
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*pre != NULL; pre++){
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#pragma GCC diagnostic pop
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size_t pre_len = strlen(*pre);
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if((d_name_len >= pre_len)
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and strncmp((dirst->d_name), *pre, pre_len) == 0){
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for(const char **suf = bad_suffixes; *suf != NULL; suf++){
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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 **suf = (const char **)bad_suffixes;
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*suf != NULL; suf++){
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#pragma GCC diagnostic pop
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size_t suf_len = strlen(*suf);
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if((d_name_len >= suf_len)
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and (strcmp((dirst->d_name) + d_name_len-suf_len, *suf)
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if(plugindir == NULL){
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ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
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ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
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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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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, "asprintf");
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
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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(access(filename, X_OK)) != 0)){
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or (TEMP_FAILURE_RETRY(faccessat(dir_fd, dirst->d_name, X_OK,
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fprintf(stderr, "Ignoring plugin dir entry \"%s\""
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" with bad type or mode\n", filename);
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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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TEMP_FAILURE_RETRY(close(plugin_fd));
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plugin *p = getplugin(dirst->d_name);
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error(0, errno, "getplugin");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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/* If this plugin has any environment variables, we will call
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using execve and need to duplicate the environment from this
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/* If this plugin has any environment variables, we need to
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duplicate the environment from this process, too. */
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if(p->environ[0] != NULL){
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for(char **e = environ; *e != NULL; e++){
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if(not add_environment(p, *e, false)){
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above and must now close it manually here. */
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if(p->environ[0] == NULL){
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if(execv(filename, p->argv) < 0){
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error(0, errno, "execv for %s", filename);
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if(execve(filename, p->argv, p->environ) < 0){
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error(0, errno, "execve for %s", filename);
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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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/* 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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if(new_plugin == NULL){
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error(0, errno, "getplugin");
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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_SET(new_plugin->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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if(maxfd < new_plugin->fd){
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maxfd = new_plugin->fd;
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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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/* Block signal while modifying process_list */
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ret = (int)TEMP_FAILURE_RETRY(sigprocmask
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/* This process has not completed. Does it have any output? */
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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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if(proc->eof or not FD_ISSET(proc->fd, &rfds)){ /* Spurious
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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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/* This process had nothing to say at this time */
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proc = proc->next;
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/* Before reading, make the process' data buffer large enough */
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if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
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proc->buffer = realloc(proc->buffer, proc->buffer_size
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+ (size_t) BUFFER_SIZE);
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if(proc->buffer == NULL){
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char *new_buffer = realloc(proc->buffer, proc->buffer_size
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+ (size_t) BUFFER_SIZE);
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if(new_buffer == NULL){
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error(0, errno, "malloc");
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exitstatus = EX_OSERR;
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proc->buffer = new_buffer;
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proc->buffer_size += BUFFER_SIZE;
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/* Read from the process */