1
#define _GNU_SOURCE /* asprintf() */
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/* -*- coding: utf-8 -*- */
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* Usplash - Read a password from usplash and output it
5
* Copyright © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 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() */
2
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
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sigemptyset(), sigaddset(),
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sigaction, SIGINT, SIG_IGN, SIGHUP,
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SIGTERM, kill(), SIGKILL */
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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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36
#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, realloc(),
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EXIT_SUCCESS, malloc(), _exit() */
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#include <stdlib.h> /* getenv() */
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#include <stdio.h> /* asprintf(), perror() */
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#include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS,
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#include <sys/types.h> /* pid_t, DIR, struct dirent,
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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#include <unistd.h> /* readlink(), fork(), execl(),
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#include <string.h> /* memcmp() */
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#include <iso646.h> /* and */
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#include <stdbool.h> /* bool, false, true */
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#include <errno.h> /* errno */
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#include <sys/wait.h> /* waitpid(), WIFEXITED(),
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#include <fcntl.h> /* open(), O_RDONLY */
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#include <inttypes.h> /* intmax_t, strtoimax() */
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#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
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51
sig_atomic_t interrupted_by_signal = 0;
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const char usplash_name[] = "/sbin/usplash";
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static void termination_handler(__attribute__((unused))int signum){
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static void termination_handler(int signum){
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if(interrupted_by_signal){
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interrupted_by_signal = 1;
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signal_received = signum;
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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 *const 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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static bool usplash_write(int *fifo_fd_r,
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const char *cmd, const char *arg){
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* usplash_write(&fd, "TIMEOUT", "15") will write "TIMEOUT 15\0"
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* usplash_write(&fd, "PULSATE", NULL) will write "PULSATE\0"
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ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
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/* Find usplash process */
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pid_t usplash_pid = 0;
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char *cmd_line_alloc = NULL;
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cmd_line_len = strlen(cmd) + 1;
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ret = asprintf(&cmd_line_alloc, "%s %s", cmd, arg);
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TEMP_FAILURE_RETRY(close(*fifo_fd_r));
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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(written < cmd_line_len){
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sret = write(*fifo_fd_r, cmd_line + written,
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cmd_line_len - written);
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TEMP_FAILURE_RETRY(close(*fifo_fd_r));
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free(cmd_line_alloc);
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written += (size_t)sret;
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free(cmd_line_alloc);
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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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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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pid_t find_usplash(char **cmdline_r, size_t *cmdline_len_r){
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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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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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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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tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
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if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
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or tmpmax != (pid_t)tmpmax){
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/* Not a process */
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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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/* 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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goto fail_find_usplash;
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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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goto fail_find_usplash;
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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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/* Compare executable name */
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if((sret != ((ssize_t)sizeof(exe_target)-1))
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or (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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ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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perror("asprintf");
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sret = readlink(exe_link, exe_target, sizeof(exe_target));
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goto fail_find_usplash;
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cl_fd = open(cmdline_filename, O_RDONLY);
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free(cmdline_filename);
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goto fail_find_usplash;
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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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/* 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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goto fail_find_usplash;
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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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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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goto fail_find_usplash;
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cmdline_len += (size_t)sret;
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goto fail_find_usplash;
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/* Close directory */
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ret = closedir(proc_dir);
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goto fail_find_usplash;
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*cmdline_r = cmdline;
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*cmdline_len_r = cmdline_len;
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if(proc_dir != NULL){
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284
closedir(proc_dir);
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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pid_t usplash_pid = -1;
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bool usplash_accessed = false;
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char *prompt = makeprompt();
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/* Find usplash process */
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char *cmdline = NULL;
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size_t cmdline_len = 0;
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usplash_pid = find_usplash(&cmdline, &cmdline_len);
160
310
if(usplash_pid == 0){
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314
/* Set up the signal handler */
168
317
new_action = { .sa_handler = termination_handler,
170
319
sigemptyset(&new_action.sa_mask);
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sigaddset(&new_action.sa_mask, SIGINT);
172
sigaddset(&new_action.sa_mask, SIGHUP);
173
sigaddset(&new_action.sa_mask, SIGTERM);
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ret = sigaddset(&new_action.sa_mask, SIGINT);
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ret = sigaddset(&new_action.sa_mask, SIGHUP);
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ret = sigaddset(&new_action.sa_mask, SIGTERM);
174
335
ret = sigaction(SIGINT, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN){
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if(old_action.sa_handler != SIG_IGN){
181
343
ret = sigaction(SIGINT, &new_action, NULL);
188
351
ret = sigaction(SIGHUP, NULL, &old_action);
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if (old_action.sa_handler != SIG_IGN){
358
if(old_action.sa_handler != SIG_IGN){
195
359
ret = sigaction(SIGHUP, &new_action, NULL);
202
367
ret = sigaction(SIGTERM, NULL, &old_action);
208
if (old_action.sa_handler != SIG_IGN){
374
if(old_action.sa_handler != SIG_IGN){
209
375
ret = sigaction(SIGTERM, &new_action, NULL);
385
usplash_accessed = true;
218
386
/* Write command to FIFO */
219
if(not interrupted_by_signal){
220
int fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
387
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
389
perror("usplash_write");
394
if(interrupted_by_signal){
398
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
400
perror("usplash_write");
405
if(interrupted_by_signal){
412
/* Read reply from usplash */
414
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
415
if(outfifo_fd == -1){
227
ret = asprintf(&command, "INPUTQUIET %s", prompt);
235
size_t command_len = (size_t)ret + 1;
237
while(not interrupted_by_signal and written < command_len){
238
ret = write(fifo_fd, command + written, command_len - written);
240
if(interrupted_by_signal){
248
an_error_occured = true;
251
written += (size_t)ret;
253
ret = close(fifo_fd);
254
if(ret == -1 and not interrupted_by_signal){
255
an_error_occured = true;
267
if(not interrupted_by_signal and not an_error_occured){
268
int fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
269
if(fifo_fd == -1 and not interrupted_by_signal){
273
size_t buf_allocated = 0;
274
const int blocksize = 1024;
276
if(buf_len + blocksize > buf_allocated){
277
char *tmp = realloc(buf, buf_allocated + blocksize);
280
an_error_occured = true;
284
buf_allocated += blocksize;
286
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
289
an_error_occured = true;
292
buf_len += (size_t)sret;
293
}while(not interrupted_by_signal and sret != 0);
297
/* Print password to stdout */
298
if(not interrupted_by_signal and not an_error_occured){
301
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
302
if(sret == -1 and not interrupted_by_signal){
422
if(interrupted_by_signal){
427
size_t buf_allocated = 0;
428
const size_t blocksize = 1024;
430
/* Allocate more space */
431
if(buf_len + blocksize > buf_allocated){
432
char *tmp = realloc(buf, buf_allocated + blocksize);
440
buf_allocated += blocksize;
442
sret = read(outfifo_fd, buf + buf_len,
443
buf_allocated - buf_len);
448
TEMP_FAILURE_RETRY(close(outfifo_fd));
451
if(interrupted_by_signal){
455
buf_len += (size_t)sret;
457
ret = close(outfifo_fd);
466
if(interrupted_by_signal){
470
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
472
perror("usplash_write");
477
if(interrupted_by_signal){
481
ret = close(fifo_fd);
490
/* Print password to stdout */
492
while(written < buf_len){
494
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
304
an_error_occured = true;
307
written += (size_t)sret;
308
}while(written < buf_len);
309
if(not interrupted_by_signal and not an_error_occured){
315
kill(usplash_pid, SIGTERM);
503
if(interrupted_by_signal){
506
written += (size_t)sret;
511
if(interrupted_by_signal){
524
/* If usplash was never accessed, we can stop now */
525
if(not usplash_accessed){
531
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
532
if(ret == -1 and errno != EINTR){
538
/* Close output FIFO */
539
if(outfifo_fd != -1){
540
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
546
/* Create argc and argv for new usplash*/
317
547
int cmdline_argc = 0;
318
548
char **cmdline_argv = malloc(sizeof(char *));
319
/* Create argv and argc for new usplash*/
321
ptrdiff_t position = 0;
322
while((size_t)position < cmdline_len){
551
while(position < cmdline_len){
323
552
char **tmp = realloc(cmdline_argv,
324
(sizeof(char *) * (size_t)(cmdline_argc + 2)));
554
* (size_t)(cmdline_argc + 2)));
326
556
perror("realloc");
327
557
free(cmdline_argv);