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/* -*- coding: utf-8 -*- */
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* Plymouth - Read a password from Plymouth and output it
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* Copyright © 2010-2015 Teddy Hogeborn
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* Copyright © 2010-2015 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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* 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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* Contact the authors at <mandos@recompile.se>.
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#define _GNU_SOURCE /* asprintf(), TEMP_FAILURE_RETRY() */
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#include <signal.h> /* sig_atomic_t, struct sigaction,
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sigemptyset(), sigaddset(), SIGINT,
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#include <stdbool.h> /* bool, false, true */
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#include <fcntl.h> /* open(), O_RDONLY */
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#include <iso646.h> /* and, or, not*/
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#include <sys/types.h> /* size_t, ssize_t, pid_t, struct dirent,
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#include <sys/types.h> /* size_t, ssize_t, pid_t, struct
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#include <sys/wait.h> /* waitpid() */
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#include <stddef.h> /* NULL */
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#include <string.h> /* strchr(), memcmp() */
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#include <stdio.h> /* asprintf(), perror(), fopen(), fscanf() */
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#include <unistd.h> /* close(), readlink(), read(), fork()
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setsid(), chdir(), dup2()
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#include <stdio.h> /* asprintf(), perror(), fopen(),
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fscanf(), vasprintf(), fprintf(),
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#include <unistd.h> /* close(), readlink(), read(),
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fork(), setsid(), chdir(), dup2(),
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STDERR_FILENO, execv(), access() */
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#include <stdlib.h> /* free(), EXIT_FAILURE, realloc(),
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EXIT_SUCCESS, malloc(), _exit(),
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#include <dirent.h> /* scandir(), alphasort() */
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#include <inttypes.h> /* intmax_t, strtoumax(), SCNuMAX */
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#include <sys/stat.h> /* struct stat, lstat() */
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#include <sysexits.h> /* EX_OSERR */
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#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
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#include <error.h> /* error() */
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#include <errno.h> /* TEMP_FAILURE_RETRY */
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#include <argz.h> /* argz_count(), argz_extract() */
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#include <stdarg.h> /* va_list, va_start(), ... */
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sig_atomic_t interrupted_by_signal = 0;
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const char plymouth_pid[] = "/dev/.initramfs/plymouth.pid";
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/* Used by Ubuntu 11.04 (Natty Narwahl) */
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const char plymouth_old_pid[] = "/dev/.initramfs/plymouth.pid";
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/* Used by Ubuntu 11.10 (Oneiric Ocelot) */
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const char plymouth_pid[] = "/run/initramfs/plymouth.pid";
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const char plymouth_path[] = "/bin/plymouth";
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const char plymouthd_path[] = "/sbin/plymouthd";
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const char *plymouthd_default_argv[] = {"/sbin/plymouthd", "--mode=boot",
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const char *plymouthd_default_argv[] = {"/sbin/plymouthd",
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"--attach-to-session",
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"--pid-file=/dev/.initramfs/plymouth.pid",
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static void termination_handler(__attribute__((unused))int signum){
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interrupted_by_signal = 1;
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/* Function to use when printing errors */
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__attribute__((format (gnu_printf, 3, 4)))
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void error_plus(int status, int errnum, const char *formatstring,
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va_start(ap, formatstring);
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ret = vasprintf(&text, formatstring, ap);
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fprintf(stderr, "Mandos plugin %s: ",
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program_invocation_short_name);
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vfprintf(stderr, formatstring, ap);
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fprintf(stderr, ": ");
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fprintf(stderr, "%s\n", strerror(errnum));
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error(status, errno, "vasprintf while printing error");
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fprintf(stderr, "Mandos plugin ");
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error(status, errnum, "%s", text);
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/* Create prompt string */
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char *makeprompt(void){
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const char *const cryptsource = getenv("cryptsource");
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const char *const crypttarget = getenv("crypttarget");
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const char prompt_start[] = "Enter passphrase to unlock the disk";
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const char prompt_start[] = "Unlocking the disk";
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const char prompt_end[] = "Enter passphrase";
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if(cryptsource == NULL){
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if(crypttarget == NULL){
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ret = asprintf(&prompt, "%s: ", prompt_start);
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ret = asprintf(&prompt, "%s\n%s", prompt_start, prompt_end);
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ret = asprintf(&prompt, "%s (%s): ", prompt_start,
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ret = asprintf(&prompt, "%s (%s)\n%s", prompt_start,
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crypttarget, prompt_end);
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if(crypttarget == NULL){
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ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
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ret = asprintf(&prompt, "%s %s\n%s", prompt_start, cryptsource,
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ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
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cryptsource, crypttarget);
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ret = asprintf(&prompt, "%s %s (%s)\n%s", prompt_start,
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cryptsource, crypttarget, prompt_end);
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bool become_a_daemon(void){
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int ret = setuid(geteuid());
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error(0, errno, "setuid");
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error_plus(0, errno, "setuid");
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error(0, errno, "chdir");
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error_plus(0, errno, "chdir");
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
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error(0, errno, "dup2");
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error_plus(0, errno, "dup2");
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__attribute__((nonnull (2, 3)))
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bool exec_and_wait(pid_t *pid_return, const char *path,
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const char **argv, bool interruptable,
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const char * const *argv, bool interruptable,
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error(0, errno, "fork");
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error_plus(0, errno, "fork");
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error(0, errno, "waitpid");
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error_plus(0, errno, "waitpid");
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if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
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if(WIFEXITED(status) and (WEXITSTATUS(status) == 0)){
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__attribute__((nonnull))
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int is_plymouth(const struct dirent *proc_entry){
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maxvalue = strtoumax(proc_entry->d_name, &tmp, 10);
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proc_id = strtoumax(proc_entry->d_name, &tmp, 10);
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if(errno != 0 or *tmp != '\0' or maxvalue != (uintmax_t)((pid_t)maxvalue)){
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if(errno != 0 or *tmp != '\0'
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or proc_id != (uintmax_t)((pid_t)proc_id)){
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char exe_target[sizeof(plymouth_path)];
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char exe_target[sizeof(plymouthd_path)];
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ret = asprintf(&exe_link, "/proc/%s/exe", proc_entry->d_name);
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error(0, errno, "asprintf");
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error_plus(0, errno, "asprintf");
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struct stat exe_stat;
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ret = lstat(exe_link, &exe_stat);
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if(errno != ENOENT){
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error(0, errno, "lstat");
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error_plus(0, errno, "lstat");
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pid_t get_pid(void){
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uintmax_t proc_id = 0;
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FILE *pidfile = fopen(plymouth_pid, "r");
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uintmax_t maxvalue = 0;
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/* Try the new pid file location */
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if(pidfile != NULL){
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ret = fscanf(pidfile, "%" SCNuMAX, &maxvalue);
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ret = fscanf(pidfile, "%" SCNuMAX, &proc_id);
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struct dirent **direntries;
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/* Try the old pid file location */
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pidfile = fopen(plymouth_pid, "r");
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ret = fscanf(pidfile, "%" SCNuMAX, &proc_id);
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/* Look for a plymouth process */
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struct dirent **direntries = NULL;
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ret = scandir("/proc", &direntries, is_plymouth, alphasort);
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sscanf(direntries[0]->d_name, "%" SCNuMAX, &maxvalue);
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error_plus(0, errno, "scandir");
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ret = sscanf(direntries[0]->d_name, "%" SCNuMAX, &proc_id);
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error_plus(0, errno, "sscanf");
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/* scandir might preallocate for this variable (man page unclear).
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even if ret == 0, therefore we need to free it. */
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pid = (pid_t)maxvalue;
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if((uintmax_t)pid == maxvalue){
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pid = (pid_t)proc_id;
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if((uintmax_t)pid == proc_id){
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const char **getargv(pid_t pid){
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const char * const * getargv(pid_t pid){
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char *cmdline_filename;
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/* test -x /bin/plymouth */
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ret = access(plymouth_path, X_OK);
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/* Plymouth is probably not installed. Don't print an error
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message, just exit. */
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exit(EX_UNAVAILABLE);
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{ /* Add signal handlers */
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struct sigaction old_action,
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new_action = { .sa_handler = termination_handler,
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sigemptyset(&new_action.sa_mask);
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for(int *sig = (int[]){ SIGINT, SIGHUP, SIGTERM, 0 }; *sig != 0; sig++){
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for(int *sig = (int[]){ SIGINT, SIGHUP, SIGTERM, 0 };
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ret = sigaddset(&new_action.sa_mask, *sig);
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error(0, errno, "sigaddset");
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error_plus(EX_OSERR, errno, "sigaddset");
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ret = sigaction(*sig, NULL, &old_action);
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error(0, errno, "sigaction");
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error_plus(EX_OSERR, errno, "sigaction");
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(*sig, &new_action, NULL);
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error(0, errno, "sigaction");
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error_plus(EX_OSERR, errno, "sigaction");
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/* plymouth --ping */
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bret = exec_and_wait(&plymouth_command_pid, plymouth_path,
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(const char *[]){ (const char *)plymouth_path, (const char *)"--ping", (const char *)NULL},
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{ plymouth_path, "--ping", NULL },
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if(interrupted_by_signal){
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kill_and_wait(plymouth_command_pid);
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/* Plymouth is probably not running. Don't print an error
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message, just exit. */
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exit(EX_UNAVAILABLE);
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prompt = makeprompt();
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ret = asprintf(&prompt_arg, "--prompt=%s", prompt);
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error(0, errno, "asprintf");
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error_plus(EX_OSERR, errno, "asprintf");
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/* plymouth ask-for-password --prompt="$prompt" */
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bret = exec_and_wait(&plymouth_command_pid, plymouth_path,
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(const char *[]){plymouth_path, "ask-for-password", prompt_arg, NULL},
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bret = exec_and_wait(&plymouth_command_pid,
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plymouth_path, (const char *[])
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{ plymouth_path, "ask-for-password",
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free(prompt_arg);
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if(interrupted_by_signal){
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kill_and_wait(plymouth_command_pid);
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exit(EXIT_SUCCESS);
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if(not interrupted_by_signal){
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/* exec_and_wait failed for some other reason */
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kill_and_wait(plymouth_command_pid);
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const char **plymouthd_argv = NULL;
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const char * const *plymouthd_argv;
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pid_t pid = get_pid();
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error(0, 0, "plymouthd pid not found");
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error_plus(0, 0, "plymouthd pid not found");
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plymouthd_argv = plymouthd_default_argv;
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plymouthd_argv = getargv(pid);
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if(plymouthd_argv == NULL){
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plymouthd_argv = plymouthd_default_argv;
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bret = exec_and_wait(NULL, plymouth_path,
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(const char *[]){plymouth_path, "quit", NULL}, false, false);
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bret = exec_and_wait(NULL, plymouthd_path, plymouthd_argv, false, true);
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exec_and_wait(NULL, plymouth_path,
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(const char *[]){ plymouth_path, "show-splash", NULL }, false, false);
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bret = exec_and_wait(NULL, plymouth_path, (const char *[])
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{ plymouth_path, "quit", NULL },
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bret = exec_and_wait(NULL, plymouthd_path, plymouthd_argv,
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exec_and_wait(NULL, plymouth_path, (const char *[])
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{ plymouth_path, "show-splash", NULL },
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exit(EXIT_FAILURE);