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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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#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* perror, fileno(), fprintf(),
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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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stat, waitpid(), WIFEXITED(),
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#include <inttypes.h> /* intmax_t, PRIdMAX, strtoimax() */
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_IOERR,
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EX_CONFIG, EX_UNAVAILABLE, EX_OK */
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#include <errno.h> /* errno */
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#include <error.h> /* error() */
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#define BUFFER_SIZE 256
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#define AFILE "/conf/conf.d/mandos/plugin-runner.conf"
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const char *argp_program_version = "plugin-runner " VERSION;
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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
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const char *argp_program_bug_address = "<mandos@recompile.se>";
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typedef struct plugin{
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char *name; /* can be NULL or any plugin name */
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/* Helper function for add_argument and add_environment */
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__attribute__((nonnull))
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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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sigemptyset(&sigchld_action.sa_mask);
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ret = sigaddset(&sigchld_action.sa_mask, SIGCHLD);
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error(0, errno, "sigaddset");
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exitstatus = EX_OSERR;
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ret = sigaction(SIGCHLD, &sigchld_action, &old_sigchld_action);
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error(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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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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new_arg = strdup(p);
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if(new_arg == NULL){
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error(0, errno, "strdup");
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exitstatus = EX_OSERR;
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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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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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/* Check for harmful errors and go to fallback. Other errors might
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not affect opening plugins */
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if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
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error(0, errno, "fopen");
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exitstatus = EX_OSERR;
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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");
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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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ret = setuid(uid);
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error(0, errno, "setuid");
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/* Open plugin directory with close_on_exec flag */
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/* Set the FD_CLOEXEC flag on the directory */
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ret = set_cloexec_flag(dir_fd);
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perror("set_cloexec_flag");
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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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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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for(char **a = g->argv + 1; *a != NULL; a++){
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if(not add_argument(p, *a)){
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perror("add_argument");
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error(0, errno, "add_argument");
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/* Add global environment variables */
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for(char **e = g->environ; *e != NULL; e++){
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if(not add_environment(p, *e, false)){
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perror("add_environment");
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error(0, errno, "add_environment");
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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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perror("add_environment");
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error(0, errno, "add_environment");
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ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
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error(0, errno, "pipe");
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exitstatus = EX_OSERR;
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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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perror("set_cloexec_flag");
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error(0, errno, "set_cloexec_flag");
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exitstatus = EX_OSERR;
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ret = set_cloexec_flag(pipefd[1]);
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perror("set_cloexec_flag");
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error(0, errno, "set_cloexec_flag");
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exitstatus = EX_OSERR;
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/* this is the child process */
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ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
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error(0, errno, "sigaction");
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_exit(EX_OSERR);
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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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error(0, errno, "sigprocmask");
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_exit(EX_OSERR);
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ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
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error(0, errno, "dup2");
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_exit(EX_OSERR);
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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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_exit(EX_OSERR);
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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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_exit(EX_OSERR);
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free(filename);
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plugin *new_plugin = getplugin(dirst->d_name);
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if(new_plugin == NULL){
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perror("getplugin");
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error(0, errno, "getplugin");
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ret = (int)(TEMP_FAILURE_RETRY
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(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
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perror("sigprocmask");
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error(0, errno, "sigprocmask");
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exitstatus = EX_OSERR;
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&sigchld_action.sa_mask,
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perror("sigprocmask");
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error(0, errno, "sigprocmask");
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exitstatus = EX_OSERR;
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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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fd_set rfds = rfds_all;
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int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
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if(select_ret == -1 and errno != EINTR){
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error(0, errno, "select");
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exitstatus = EX_OSERR;
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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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(sigprocmask(SIG_UNBLOCK,
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&sigchld_action.sa_mask, NULL)));
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perror("sigprocmask");
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error(0, errno, "sigprocmask");
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exitstatus = EX_OSERR;
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bool bret = print_out_password(proc->buffer,
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proc->buffer_length);
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perror("print_out_password");
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error(0, errno, "print_out_password");
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exitstatus = EX_IOERR;
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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 */
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bret = print_out_password(passwordbuffer, len);
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perror("print_out_password");
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error(0, errno, "print_out_password");
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exitstatus = EX_IOERR;
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/* Restore old signal handler */
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ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
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perror("sigaction");
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error(0, errno, "sigaction");
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exitstatus = EX_OSERR;