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#define _GNU_SOURCE /* asprintf() */
#include <signal.h> /* sig_atomic_t, struct sigaction,
sigemptyset(), sigaddset(),
sigaction, SIGINT, SIG_IGN, SIGHUP,
SIGTERM, kill(), SIGKILL */
#include <stddef.h> /* NULL */
#include <stdlib.h> /* getenv() */
#include <stdio.h> /* asprintf(), perror() */
#include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS,
strtoul(), free() */
#include <sys/types.h> /* pid_t, DIR, struct dirent,
ssize_t */
#include <dirent.h> /* opendir(), readdir(), closedir() */
#include <unistd.h> /* readlink(), fork(), execl(),
_exit */
#include <string.h> /* memcmp() */
#include <iso646.h> /* and */
#include <stdbool.h> /* bool, false, true */
#include <errno.h> /* errno */
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
WEXITSTATUS() */
#include <fcntl.h> /* open(), O_RDONLY */
sig_atomic_t interrupted_by_signal = 0;
static void termination_handler(__attribute__((unused))int signum){
interrupted_by_signal = 1;
}
int main(__attribute__((unused))int argc,
__attribute__((unused))char **argv){
int ret = 0;
ssize_t sret;
bool an_error_occured = false;
/* Create prompt string */
char *prompt = NULL;
{
const char *const cryptsource = getenv("cryptsource");
const char *const crypttarget = getenv("crypttarget");
const char *const prompt_start = "Enter passphrase to unlock the disk";
if(cryptsource == NULL){
if(crypttarget == NULL){
ret = asprintf(&prompt, "%s: ", prompt_start);
} else {
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
crypttarget);
}
} else {
if(crypttarget == NULL){
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
} else {
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
cryptsource, crypttarget);
}
}
if(ret == -1){
return EXIT_FAILURE;
}
}
/* Find usplash process */
pid_t usplash_pid = 0;
char *cmdline = NULL;
size_t cmdline_len = 0;
{
const char usplash_name[] = "/sbin/usplash";
DIR *proc_dir = opendir("/proc");
if(proc_dir == NULL){
free(prompt);
perror("opendir");
return EXIT_FAILURE;
}
for(struct dirent *proc_ent = readdir(proc_dir);
proc_ent != NULL;
proc_ent = readdir(proc_dir)){
pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
if(pid == 0){
/* Not a process */
continue;
}
/* Find the executable name by doing readlink() on the
/proc/<pid>/exe link */
char exe_target[sizeof(usplash_name)];
{
char *exe_link;
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
if(ret == -1){
perror("asprintf");
free(prompt);
closedir(proc_dir);
return EXIT_FAILURE;
}
sret = readlink(exe_link, exe_target, sizeof(exe_target));
free(exe_link);
}
if((sret == ((ssize_t)sizeof(exe_target)-1))
and (memcmp(usplash_name, exe_target,
sizeof(exe_target)-1) == 0)){
usplash_pid = pid;
/* Read and save the command line of usplash in "cmdline" */
{
/* Open /proc/<pid>/cmdline */
int cl_fd;
{
char *cmdline_filename;
ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
proc_ent->d_name);
if(ret == -1){
perror("asprintf");
free(prompt);
closedir(proc_dir);
return EXIT_FAILURE;
}
cl_fd = open(cmdline_filename, O_RDONLY);
if(cl_fd == -1){
perror("open");
free(cmdline_filename);
free(prompt);
closedir(proc_dir);
return EXIT_FAILURE;
}
free(cmdline_filename);
}
size_t cmdline_allocated = 0;
char *tmp;
const size_t blocksize = 1024;
do{
if(cmdline_len + blocksize > cmdline_allocated){
tmp = realloc(cmdline, cmdline_allocated + blocksize);
if(tmp == NULL){
perror("realloc");
free(cmdline);
free(prompt);
closedir(proc_dir);
return EXIT_FAILURE;
}
cmdline = tmp;
cmdline_allocated += blocksize;
}
sret = read(cl_fd, cmdline + cmdline_len,
cmdline_allocated - cmdline_len);
if(sret == -1){
perror("read");
free(cmdline);
free(prompt);
closedir(proc_dir);
return EXIT_FAILURE;
}
cmdline_len += (size_t)sret;
} while(sret != 0);
close(cl_fd);
}
break;
}
}
closedir(proc_dir);
}
if(usplash_pid == 0){
free(prompt);
return EXIT_FAILURE;
}
/* Set up the signal handler */
{
struct sigaction old_action,
new_action = { .sa_handler = termination_handler,
.sa_flags = 0 };
sigemptyset(&new_action.sa_mask);
sigaddset(&new_action.sa_mask, SIGINT);
sigaddset(&new_action.sa_mask, SIGHUP);
sigaddset(&new_action.sa_mask, SIGTERM);
ret = sigaction(SIGINT, NULL, &old_action);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
if (old_action.sa_handler != SIG_IGN){
ret = sigaction(SIGINT, &new_action, NULL);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
}
ret = sigaction(SIGHUP, NULL, &old_action);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
if (old_action.sa_handler != SIG_IGN){
ret = sigaction(SIGHUP, &new_action, NULL);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
}
ret = sigaction(SIGTERM, NULL, &old_action);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
if (old_action.sa_handler != SIG_IGN){
ret = sigaction(SIGTERM, &new_action, NULL);
if(ret == -1){
perror("sigaction");
free(prompt);
return EXIT_FAILURE;
}
}
}
/* Write command to FIFO */
if(not interrupted_by_signal){
int fifo_fd = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
if(fifo_fd == -1){
perror("open");
free(prompt);
return EXIT_FAILURE;
}
char *command;
ret = asprintf(&command, "INPUTQUIET %s", prompt);
if(ret == -1){
perror("asprintf");
free(prompt);
return EXIT_FAILURE;
}
free(prompt);
size_t command_len = (size_t)ret + 1;
size_t written = 0;
while(not interrupted_by_signal and written < command_len){
ret = write(fifo_fd, command + written, command_len - written);
if(ret == -1){
if(interrupted_by_signal){
break;
}
perror("write");
if(written == 0){
free(command);
return EXIT_FAILURE;
}
an_error_occured = true;
break;
}
written += (size_t)ret;
}
ret = close(fifo_fd);
if(ret == -1 and not interrupted_by_signal){
an_error_occured = true;
}
free(command);
}else{
free(prompt);
}
{
char *buf = NULL;
size_t buf_len = 0;
/* Read from FIFO */
if(not interrupted_by_signal and not an_error_occured){
int fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
if(fifo_fd == -1 and not interrupted_by_signal){
perror("open");
return EXIT_FAILURE;
}
size_t buf_allocated = 0;
const int blocksize = 1024;
do{
if(buf_len + blocksize > buf_allocated){
char *tmp = realloc(buf, buf_allocated + blocksize);
if(tmp == NULL){
perror("realloc");
an_error_occured = true;
break;
}
buf = tmp;
buf_allocated += blocksize;
}
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
if(sret == -1){
perror("read");
an_error_occured = true;
break;
}
buf_len += (size_t)sret;
}while(not interrupted_by_signal and sret != 0);
close(fifo_fd);
}
/* Print password to stdout */
if(not interrupted_by_signal and not an_error_occured){
size_t written = 0;
do{
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
if(sret == -1 and not interrupted_by_signal){
perror("write");
an_error_occured = true;
break;
}
written += (size_t)sret;
}while(written < buf_len);
if(not interrupted_by_signal and not an_error_occured){
return EXIT_SUCCESS;
}
}
}
kill(usplash_pid, SIGTERM);
int cmdline_argc = 0;
char **cmdline_argv = malloc(sizeof(char *));
/* Create argv and argc for new usplash*/
{
ptrdiff_t position = 0;
while((size_t)position < cmdline_len){
char **tmp = realloc(cmdline_argv,
(sizeof(char *) * (size_t)(cmdline_argc + 2)));
if(tmp == NULL){
perror("realloc");
free(cmdline_argv);
return EXIT_FAILURE;
}
cmdline_argv = tmp;
cmdline_argv[cmdline_argc] = cmdline + position;
cmdline_argc++;
position = (char *)rawmemchr(cmdline + position, '\0')
- cmdline + 1;
}
cmdline_argv[cmdline_argc] = NULL;
}
pid_t new_usplash_pid = fork();
if(new_usplash_pid == 0){
/* Child; will become new usplash process */
while(kill(usplash_pid, 0)){
sleep(2);
kill(usplash_pid, SIGKILL);
sleep(1);
}
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
if(ret == -1){
perror("dup2");
_exit(EXIT_FAILURE);
}
execv("/sbin/usplash", cmdline_argv);
}
return EXIT_FAILURE;
}
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