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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 Teddy Hogeborn
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* Copyright © 2010 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@fukt.bsnet.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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SIGHUP, SIGTERM, sigaction(),
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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
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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(),
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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, 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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sig_atomic_t interrupted_by_signal = 0;
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const char plymouth_pid[] = "/dev/.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",
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"--attach-to-session",
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static void termination_handler(__attribute__((unused))int signum){
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if(interrupted_by_signal){
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interrupted_by_signal = 1;
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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[] = "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\n%s", prompt_start, prompt_end);
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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\n%s", prompt_start, cryptsource,
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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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void kill_and_wait(pid_t pid){
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TEMP_FAILURE_RETRY(kill(pid, SIGTERM));
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TEMP_FAILURE_RETRY(waitpid(pid, NULL, 0));
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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(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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bool exec_and_wait(pid_t *pid_return, const char *path,
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const char **argv, bool interruptable,
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error(0, errno, "fork");
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if(not become_a_daemon()){
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char **new_argv = NULL;
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for (; argv[i]!=NULL; i++){
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tmp = realloc(new_argv, sizeof(const char *) * ((size_t)i + 1));
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error(0, errno, "realloc");
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new_argv[i] = strdup(argv[i]);
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execv(path, (char *const *)new_argv);
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error(0, errno, "execv");
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if(pid_return != NULL){
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ret = waitpid(pid, &status, 0);
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} while(ret == -1 and errno == EINTR
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and ((not interrupted_by_signal)
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or (not interruptable)));
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if(interrupted_by_signal and interruptable){
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error(0, errno, "waitpid");
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if(WIFEXITED(status) and (WEXITSTATUS(status) == 0)){
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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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if(errno != 0 or *tmp != '\0'
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or maxvalue != (uintmax_t)((pid_t)maxvalue)){
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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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struct stat exe_stat;
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ret = lstat(exe_link, &exe_stat);
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error(0, errno, "lstat");
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if(not S_ISLNK(exe_stat.st_mode)
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or exe_stat.st_uid != 0
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or exe_stat.st_gid != 0){
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ssize_t sret = readlink(exe_link, exe_target, sizeof(exe_target));
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if((sret != (ssize_t)sizeof(plymouthd_path)-1) or
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(memcmp(plymouthd_path, exe_target,
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sizeof(plymouthd_path)-1) != 0)){
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FILE *pidfile = fopen(plymouth_pid, "r");
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uintmax_t maxvalue = 0;
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ret = fscanf(pidfile, "%" SCNuMAX, &maxvalue);
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struct dirent **direntries;
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ret = scandir("/proc", &direntries, is_plymouth, alphasort);
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error(0, errno, "scandir");
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ret = sscanf(direntries[0]->d_name, "%" SCNuMAX, &maxvalue);
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error(0, errno, "sscanf");
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pid = (pid_t)maxvalue;
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if((uintmax_t)pid == maxvalue){
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const char **getargv(pid_t pid){
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%" PRIuMAX "/cmdline",
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error(0, errno, "asprintf");
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/* Open /proc/<pid>/cmdline */
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cl_fd = open(cmdline_filename, O_RDONLY);
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free(cmdline_filename);
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error(0, errno, "open");
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size_t cmdline_allocated = 0;
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size_t cmdline_len = 0;
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char *cmdline = NULL;
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const size_t blocksize = 1024;
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/* Allocate more space? */
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if(cmdline_len + blocksize > cmdline_allocated){
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tmp = realloc(cmdline, cmdline_allocated + blocksize);
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error(0, errno, "realloc");
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cmdline_allocated += blocksize;
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sret = read(cl_fd, cmdline + cmdline_len,
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cmdline_allocated - cmdline_len);
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error(0, errno, "read");
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cmdline_len += (size_t)sret;
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error(0, errno, "close");
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/* we got cmdline and cmdline_len, ignore rest... */
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char **argv = malloc((argz_count(cmdline, cmdline_len) + 1)
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* sizeof(char *)); /* Get number of args */
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error(0, errno, "argv = malloc()");
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argz_extract(cmdline, cmdline_len, argv); /* Create argv */
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return (const char **)argv;
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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pid_t plymouth_command_pid;
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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 };
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ret = sigaddset(&new_action.sa_mask, *sig);
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error(EX_OSERR, errno, "sigaddset");
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ret = sigaction(*sig, NULL, &old_action);
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error(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(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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{ 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(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,
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plymouth_path, (const char *[])
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{ plymouth_path, "ask-for-password",
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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;
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pid_t pid = get_pid();
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error(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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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 },
added
removed
plugins.d/plymouth.c
