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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 © 2007-2008 Teddy Hogeborn & 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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#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
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EXIT_SUCCESS, realloc() */
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#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* perror, fileno(), fprintf(),
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stderr, STDOUT_FILENO */
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#include <stdio.h> /* perror, popen(), fileno(),
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fprintf(), stderr, STDOUT_FILENO */
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#include <sys/types.h> /* DIR, opendir(), stat(), struct
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stat, waitpid(), WIFEXITED(),
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WEXITSTATUS(), wait(), pid_t,
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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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dup2, STDOUT_FILENO, _exit(),
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execv(), write(), read(),
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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sigprocmask(), SIG_BLOCK, SIGCHLD,
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SIG_UNBLOCK, kill() */
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#include <errno.h> /* errno, EBADF */
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#include <inttypes.h> /* intmax_t, SCNdMAX, PRIdMAX, */
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#define BUFFER_SIZE 256
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#define PDIR "/lib/mandos/plugins.d"
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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_version = "plugin-runner 1.0";
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const char *argp_program_bug_address = "<mandos@fukt.bsnet.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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or if none is found, creates a new one */
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static plugin *getplugin(char *name){
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/* Check for exiting plugin with that name */
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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or (p->name and name and (strcmp(p->name, name) == 0))){
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for (plugin *p = plugin_list; p != NULL; p = p->next){
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if ((p->name == name)
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or (p->name and name and (strcmp(p->name, name) == 0))){
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/* Create a new plugin */
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plugin *new_plugin = malloc(sizeof(plugin));
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if(new_plugin == NULL){
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if (new_plugin == NULL){
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char *copy_name = NULL;
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if(name != NULL){
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copy_name = strdup(name);
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if(copy_name == NULL){
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*new_plugin = (plugin){ .name = copy_name,
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.next = plugin_list };
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*new_plugin = (plugin) { .name = copy_name,
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.next = plugin_list };
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new_plugin->argv = malloc(sizeof(char *) * 2);
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if(new_plugin->argv == NULL){
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if (new_plugin->argv == NULL){
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free(new_plugin);
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* Descriptor Flags".
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* *Note File Descriptor Flags:(libc)Descriptor Flags.
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static int set_cloexec_flag(int fd){
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static int set_cloexec_flag(int fd)
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int ret = fcntl(fd, F_GETFD, 0);
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/* If reading the flags failed, return error indication now. */
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/* Mark processes as completed when they exit, and save their exit
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static void handle_sigchld(__attribute__((unused)) int sig){
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void handle_sigchld(__attribute__((unused)) int sig){
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plugin *proc = plugin_list;
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/* Prints out a password to stdout */
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static bool print_out_password(const char *buffer, size_t length){
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bool print_out_password(const char *buffer, size_t length){
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if(length>0 and buffer[length-1] == '\n'){
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for(size_t written = 0; written < length; written += (size_t)ret){
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ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buffer + written,
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length - written));
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error_t parse_opt(int key, char *arg, __attribute__((unused))
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struct argp_state *state){
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error_t parse_opt (int key, char *arg, __attribute__((unused))
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struct argp_state *state) {
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case 'g': /* --global-options */
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while((p = strsep(&arg, ",")) != NULL){
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if(p[0] == '\0'){
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/* This is already done by parse_opt_config_file() */
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case 130: /* --userid */
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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (uid_t)tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad user ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)uid);
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uid = (uid_t)strtol(arg, NULL, 10);
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case 131: /* --groupid */
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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (gid_t)tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad group ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)gid);
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gid = (gid_t)strtol(arg, NULL, 10);
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case 132: /* --debug */
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* When adding more options before this line, remember to also add a
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* "case" to the "parse_opt_config_file" function below.
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case ARGP_KEY_ARG:
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/* Cryptsetup always passes an argument, which is an empty
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string if "none" was specified in /etc/crypttab. So if
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argument was empty, we ignore it silently. */
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fprintf(stderr, "Ignoring unknown argument \"%s\"\n", arg);
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fprintf(stderr, "Ignoring unknown argument \"%s\"\n", arg);
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case ARGP_KEY_END:
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/* This option parser is the same as parse_opt() above, except it
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ignores everything but the --config-file option. */
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error_t parse_opt_config_file(int key, char *arg,
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__attribute__((unused))
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struct argp_state *state){
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error_t parse_opt_config_file (int key, char *arg,
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__attribute__((unused))
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struct argp_state *state) {
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case 'g': /* --global-options */
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case 'G': /* --global-env */
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case 'o': /* --options-for */
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.doc = "Mandos plugin runner -- Run plugins" };
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/* Parse using parse_opt_config_file() in order to get the custom
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/* Parse using the parse_opt_config_file in order to get the custom
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config file location, if any. */
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ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if(ret == ARGP_ERR_UNKNOWN){
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ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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char *org_line = NULL;
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char *p, *arg, *new_arg, *line;
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const char whitespace_delims[] = " \r\t\f\v\n";
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const char comment_delim[] = "#";
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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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if (errno == EMFILE or errno == ENFILE or errno == ENOMEM){
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exitstatus = EXIT_FAILURE;
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/* If there was any arguments from configuration file,
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pass them to parser as command arguments */
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if(custom_argv != NULL){
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ret = argp_parse(&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
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if(ret == ARGP_ERR_UNKNOWN){
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ret = argp_parse (&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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/* Parse actual command line arguments, to let them override the
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ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if(ret == ARGP_ERR_UNKNOWN){
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ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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for(char **a = p->argv; *a != NULL; a++){
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fprintf(stderr, "\tArg: %s\n", *a);
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fprintf(stderr, "...and %d environment variables\n", p->envc);
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fprintf(stderr, "...and %u environment variables\n", p->envc);
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for(char **a = p->environ; *a != NULL; a++){
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fprintf(stderr, "\t%s\n", *a);
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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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size_t pre_len = strlen(*pre);
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if(plugindir == NULL){
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ret = asprintf(&filename, PDIR "/%s", dirst->d_name);
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ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
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ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
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perror("asprintf");
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ret = stat(filename, &st);
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/* Ignore non-executable files */
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if(not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
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if (not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
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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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/* Block SIGCHLD until process is safely in process list */
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ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
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ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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perror("sigaction");
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_exit(EXIT_FAILURE);
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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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_exit(EXIT_FAILURE);
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ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
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close(pipefd[1]); /* Close unused write end of pipe */
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plugin *new_plugin = getplugin(dirst->d_name);
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if(new_plugin == NULL){
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if (new_plugin == NULL){
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perror("getplugin");
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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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/* Unblock SIGCHLD so signal handler can be run if this process
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has already completed */
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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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FD_SET(new_plugin->fd, &rfds_all);
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if(maxfd < new_plugin->fd){
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if (maxfd < new_plugin->fd){
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maxfd = new_plugin->fd;
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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free_plugin_list();
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/* Main loop while running plugins exist */
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while(plugin_list){
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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){
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if (select_ret == -1){
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perror("select");
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exitstatus = EXIT_FAILURE;
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if(WIFEXITED(proc->status)){
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fprintf(stderr, "Plugin %" PRIdMAX " exited with status"
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" %d\n", (intmax_t) (proc->pid),
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fprintf(stderr, "Plugin %u exited with status %d\n",
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(unsigned int) (proc->pid),
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WEXITSTATUS(proc->status));
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} else if(WIFSIGNALED(proc->status)){
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fprintf(stderr, "Plugin %" PRIdMAX " killed by signal"
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" %d\n", (intmax_t) (proc->pid),
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} else if(WIFSIGNALED(proc->status)) {
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fprintf(stderr, "Plugin %u killed by signal %d\n",
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(unsigned int) (proc->pid),
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WTERMSIG(proc->status));
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} else if(WCOREDUMP(proc->status)){
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fprintf(stderr, "Plugin %" PRIdMAX " dumped core\n",
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(intmax_t) (proc->pid));
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fprintf(stderr, "Plugin %d dumped core\n",
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(unsigned int) (proc->pid));
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/* We are done modifying process list, so unblock signal */
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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if(plugin_list == NULL){
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plugin *next_plugin = proc->next;
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free_plugin(proc);
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proc = next_plugin;
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/* We are done modifying process list, so unblock signal */
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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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if(plugin_list == NULL){
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/* This process exited nicely, so print its buffer */
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bool bret = print_out_password(proc->buffer,
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proc->buffer_length);
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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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if (proc->buffer == NULL){
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perror("malloc");
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exitstatus = EXIT_FAILURE;
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proc->buffer_size += BUFFER_SIZE;
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/* Read from the process */
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sret = read(proc->fd, proc->buffer + proc->buffer_length,
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ret = read(proc->fd, proc->buffer + proc->buffer_length,
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/* Read error from this process; ignore the error */
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proc = proc->next;
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proc->eof = true;
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proc->buffer_length += (size_t) sret;
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proc->buffer_length += (size_t) ret;
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fprintf(stderr, "Going to fallback mode using getpass(3)\n");
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char *passwordbuffer = getpass("Password: ");
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size_t len = strlen(passwordbuffer);
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/* Strip trailing newline */
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if(len > 0 and passwordbuffer[len-1] == '\n'){
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passwordbuffer[len-1] = '\0'; /* not strictly necessary */
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bret = print_out_password(passwordbuffer, len);
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bret = print_out_password(passwordbuffer, strlen(passwordbuffer));
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perror("print_out_password");
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exitstatus = EXIT_FAILURE;