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/* -*- coding: utf-8 -*- */
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* Passprompt - Read a password from usplash and output it
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* Copyright © 2008 Teddy Hogeborn
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* Copyright © 2008 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 <https://www.fukt.bsnet.se/~belorn/> and
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* <https://www.fukt.bsnet.se/~teddy/>.
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#define _GNU_SOURCE /* asprintf() */
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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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SIG_IGN, kill(), SIGKILL */
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#include <stdbool.h> /* bool, false, true */
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#include <fcntl.h> /* open(), O_WRONLY, O_RDONLY */
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#include <iso646.h> /* and, or, not*/
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#include <errno.h> /* errno, EINTR */
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#include <sys/types.h> /* size_t, ssize_t, pid_t, DIR, struct
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#include <stddef.h> /* NULL */
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#include <string.h> /* strlen(), memcmp() */
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#include <stdio.h> /* asprintf(), perror() */
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#include <unistd.h> /* close(), write(), readlink(),
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read(), STDOUT_FILENO, sleep(),
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fork(), setuid(), geteuid(),
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setsid(), chdir(), dup2(),
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STDERR_FILENO, execv() */
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#include <stdlib.h> /* free(), EXIT_FAILURE, strtoul(),
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realloc(), EXIT_SUCCESS, malloc(),
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#include <stdlib.h> /* getenv() */
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
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sig_atomic_t interrupted_by_signal = 0;
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static void termination_handler(__attribute__((unused))int signum){
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interrupted_by_signal = 1;
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static bool usplash_write(const char *cmd, const char *arg){
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* usplash_write("TIMEOUT", "15") will write "TIMEOUT 15\0"
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* usplash_write("PULSATE", NULL) will write "PULSATE\0"
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fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
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if(fifo_fd == -1 and (errno != EINTR or interrupted_by_signal)){
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}while(fifo_fd == -1);
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char *cmd_line_alloc = NULL;
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cmd_line_len = strlen(cmd);
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ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
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if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
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cmd_line = cmd_line_alloc;
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cmd_line_len = (size_t)ret + 1;
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while(not interrupted_by_signal and written < cmd_line_len){
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ret = write(fifo_fd, cmd_line + written,
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cmd_line_len - written);
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if(errno != EINTR or interrupted_by_signal){
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free(cmd_line_alloc);
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written += (size_t)ret;
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free(cmd_line_alloc);
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ret = close(fifo_fd);
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if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
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if(interrupted_by_signal){
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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bool an_error_occured = false;
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/* Create prompt string */
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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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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 (%s): ", prompt_start,
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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 (%s): ", prompt_start,
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cryptsource, crypttarget);
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/* Find usplash process */
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pid_t usplash_pid = 0;
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char *cmdline = NULL;
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size_t cmdline_len = 0;
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const char usplash_name[] = "/sbin/usplash";
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DIR *proc_dir = opendir("/proc");
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if(proc_dir == NULL){
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for(struct dirent *proc_ent = readdir(proc_dir);
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proc_ent = readdir(proc_dir)){
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pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
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/* Find the executable name by doing readlink() on the
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/proc/<pid>/exe link */
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char exe_target[sizeof(usplash_name)];
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/* create file name string */
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ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
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/* Check that it refers to a symlink owned by root:root */
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struct stat exe_stat;
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ret = lstat(exe_link, &exe_stat);
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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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sret = readlink(exe_link, exe_target, sizeof(exe_target));
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if((sret == ((ssize_t)sizeof(exe_target)-1))
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and (memcmp(usplash_name, exe_target,
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sizeof(exe_target)-1) == 0)){
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/* Read and save the command line of usplash in "cmdline" */
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/* Open /proc/<pid>/cmdline */
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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cl_fd = open(cmdline_filename, O_RDONLY);
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free(cmdline_filename);
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free(cmdline_filename);
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size_t cmdline_allocated = 0;
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const size_t blocksize = 1024;
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if(cmdline_len + blocksize > cmdline_allocated){
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tmp = realloc(cmdline, cmdline_allocated + blocksize);
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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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cmdline_len += (size_t)sret;
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if(usplash_pid == 0){
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/* Set up the signal handler */
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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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sigaddset(&new_action.sa_mask, SIGINT);
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sigaddset(&new_action.sa_mask, SIGHUP);
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sigaddset(&new_action.sa_mask, SIGTERM);
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ret = sigaction(SIGINT, NULL, &old_action);
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &new_action, NULL);
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ret = sigaction(SIGHUP, NULL, &old_action);
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &new_action, NULL);
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ret = sigaction(SIGTERM, NULL, &old_action);
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &new_action, NULL);
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/* Write command to FIFO */
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if(not interrupted_by_signal){
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if(not usplash_write("TIMEOUT", "0")
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and (errno != EINTR)){
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perror("usplash_write");
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an_error_occured = true;
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if(not interrupted_by_signal and not an_error_occured){
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if(not usplash_write("INPUTQUIET", prompt)
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and (errno != EINTR)){
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perror("usplash_write");
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an_error_occured = true;
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/* This is not really a loop; while() is used to be able to "break"
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out of it; those breaks are marked "Big" */
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while(not interrupted_by_signal and not an_error_occured){
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fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
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an_error_occured = true;
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if(interrupted_by_signal){
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}while(fifo_fd == -1);
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if(interrupted_by_signal or an_error_occured){
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size_t buf_allocated = 0;
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const size_t blocksize = 1024;
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if(buf_len + blocksize > buf_allocated){
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char *tmp = realloc(buf, buf_allocated + blocksize);
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an_error_occured = true;
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buf_allocated += blocksize;
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sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
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an_error_occured = true;
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if(interrupted_by_signal){
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if(interrupted_by_signal or an_error_occured){
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buf_len += (size_t)sret;
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if(interrupted_by_signal or an_error_occured){
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if(not usplash_write("TIMEOUT", "15")
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and (errno != EINTR)){
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perror("usplash_write");
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an_error_occured = true;
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if(interrupted_by_signal or an_error_occured){
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/* Print password to stdout */
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while(written < buf_len){
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sret = write(STDOUT_FILENO, buf + written, buf_len - written);
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an_error_occured = true;
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if(interrupted_by_signal){
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if(interrupted_by_signal or an_error_occured){
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written += (size_t)sret;
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if(not interrupted_by_signal and not an_error_occured){
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} /* end of non-loop while() */
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/* If we got here, an error or interrupt must have happened */
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/* Create argc and argv for new usplash*/
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int cmdline_argc = 0;
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char **cmdline_argv = malloc(sizeof(char *));
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while(position < cmdline_len){
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char **tmp = realloc(cmdline_argv,
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* (size_t)(cmdline_argc + 2)));
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cmdline_argv[cmdline_argc] = cmdline + position;
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position += strlen(cmdline + position) + 1;
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cmdline_argv[cmdline_argc] = NULL;
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/* Kill old usplash */
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kill(usplash_pid, SIGTERM);
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while(kill(usplash_pid, 0) == 0){
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kill(usplash_pid, SIGKILL);
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pid_t new_usplash_pid = fork();
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if(new_usplash_pid == 0){
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/* Child; will become new usplash process */
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/* Make the effective user ID (root) the only user ID instead of
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the real user ID (mandos) */
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ret = setuid(geteuid());
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/* if(fork() != 0){ */
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/* _exit(EXIT_SUCCESS); */
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
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execv(usplash_name, cmdline_argv);
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if(not interrupted_by_signal){
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if(not usplash_write("PULSATE", NULL)
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and (errno != EINTR)){
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perror("usplash_write");
added
removed
plugins.d/usplash.c
