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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 <stdio.h> /* asprintf()*/
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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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EXIT_SUCCESS, malloc(), _exit(),
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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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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#include <sysexits.h> /* EX_OSERR, EX_UNAVAILABLE */
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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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static bool usplash_write(const char *cmd, const char *arg){
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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("TIMEOUT", "15") will write "TIMEOUT 15\0"
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* usplash_write("PULSATE", NULL) will write "PULSATE\0"
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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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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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ret = open("/dev/.initramfs/usplash_fifo", O_WRONLY);
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}while(fifo_fd == -1);
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const char *cmd_line;
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size_t cmd_line_len;
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char *cmd_line_alloc = NULL;
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cmd_line_len = strlen(cmd);
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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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if(ret == -1 and (errno != EINTR or interrupted_by_signal)){
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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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size_t written = 0;
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while(not interrupted_by_signal and written < cmd_line_len){
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sret = write(fifo_fd, cmd_line + written,
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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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if(errno != EINTR or interrupted_by_signal){
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free(cmd_line_alloc);
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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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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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/* 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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DIR *proc_dir = opendir("/proc");
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if(proc_dir == NULL){
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error(0, errno, "opendir");
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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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/* 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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error(0, errno, "asprintf");
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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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error(0, errno, "lstat");
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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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char *cmdline_filename;
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ret = asprintf(&cmdline_filename, "/proc/%s/cmdline",
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error(0, errno, "asprintf");
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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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error(0, errno, "open");
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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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/* 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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goto fail_find_usplash;
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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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goto fail_find_usplash;
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cmdline_len += (size_t)sret;
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error(0, errno, "close");
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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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error(0, errno, "closedir");
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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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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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pid_t usplash_pid = -1;
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bool usplash_accessed = false;
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int status = EXIT_FAILURE; /* Default failure exit status */
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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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char *prompt = makeprompt();
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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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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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/* 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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usplash_pid = find_usplash(&cmdline, &cmdline_len);
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if(usplash_pid == 0){
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status = EX_UNAVAILABLE;
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/* Set up the signal handler */
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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 = sigaddset(&new_action.sa_mask, SIGINT);
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error(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGHUP);
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error(0, errno, "sigaddset");
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ret = sigaddset(&new_action.sa_mask, SIGTERM);
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error(0, errno, "sigaddset");
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ret = sigaction(SIGINT, NULL, &old_action);
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error(0, errno, "sigaction");
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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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error(0, errno, "sigaction");
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ret = sigaction(SIGHUP, NULL, &old_action);
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error(0, errno, "sigaction");
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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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error(0, errno, "sigaction");
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ret = sigaction(SIGTERM, NULL, &old_action);
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error(0, errno, "sigaction");
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387
if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &new_action, NULL);
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error(0, errno, "sigaction");
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usplash_accessed = true;
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400
/* Write command to FIFO */
345
if(not interrupted_by_signal){
346
if(not usplash_write("TIMEOUT", "0")
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and (errno != EINTR)){
348
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)
354
and (errno != EINTR)){
355
perror("usplash_write");
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an_error_occured = true;
361
/* This is not really a loop; while() is used to be able to "break"
362
out of it; those breaks are marked "Big" */
363
while(not interrupted_by_signal and not an_error_occured){
370
fifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
374
an_error_occured = true;
377
if(interrupted_by_signal){
381
}while(fifo_fd == -1);
382
if(interrupted_by_signal or an_error_occured){
387
size_t buf_allocated = 0;
388
const size_t blocksize = 1024;
390
if(buf_len + blocksize > buf_allocated){
391
char *tmp = realloc(buf, buf_allocated + blocksize);
394
an_error_occured = true;
398
buf_allocated += blocksize;
401
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
405
an_error_occured = true;
408
if(interrupted_by_signal){
413
if(interrupted_by_signal or an_error_occured){
417
buf_len += (size_t)sret;
420
if(interrupted_by_signal or an_error_occured){
424
if(not usplash_write("TIMEOUT", "15")
425
and (errno != EINTR)){
426
perror("usplash_write");
427
an_error_occured = true;
429
if(interrupted_by_signal or an_error_occured){
433
/* Print password to stdout */
435
while(written < buf_len){
437
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
441
an_error_occured = true;
444
if(interrupted_by_signal){
449
if(interrupted_by_signal or an_error_occured){
452
written += (size_t)sret;
455
if(not interrupted_by_signal and not an_error_occured){
460
} /* end of non-loop while() */
462
/* If we got here, an error or interrupt must have happened */
401
if(not usplash_write(&fifo_fd, "TIMEOUT", "0")){
403
error(0, errno, "usplash_write");
409
if(interrupted_by_signal){
413
if(not usplash_write(&fifo_fd, "INPUTQUIET", prompt)){
415
error(0, errno, "usplash_write");
421
if(interrupted_by_signal){
428
/* Read reply from usplash */
430
outfifo_fd = open("/dev/.initramfs/usplash_outfifo", O_RDONLY);
431
if(outfifo_fd == -1){
433
error(0, errno, "open");
439
if(interrupted_by_signal){
444
size_t buf_allocated = 0;
445
const size_t blocksize = 1024;
447
/* Allocate more space */
448
if(buf_len + blocksize > buf_allocated){
449
char *tmp = realloc(buf, buf_allocated + blocksize);
452
error(0, errno, "realloc");
458
buf_allocated += blocksize;
460
sret = read(outfifo_fd, buf + buf_len,
461
buf_allocated - buf_len);
464
error(0, errno, "read");
467
TEMP_FAILURE_RETRY(close(outfifo_fd));
470
if(interrupted_by_signal){
474
buf_len += (size_t)sret;
476
ret = close(outfifo_fd);
479
error(0, errno, "close");
486
if(interrupted_by_signal){
490
if(not usplash_write(&fifo_fd, "TIMEOUT", "15")){
492
error(0, errno, "usplash_write");
498
if(interrupted_by_signal){
502
ret = close(fifo_fd);
505
error(0, errno, "close");
512
/* Print password to stdout */
514
while(written < buf_len){
516
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
519
error(0, errno, "write");
526
if(interrupted_by_signal){
529
written += (size_t)sret;
534
if(interrupted_by_signal){
547
/* If usplash was never accessed, we can stop now */
548
if(not usplash_accessed){
554
ret = (int)TEMP_FAILURE_RETRY(close(fifo_fd));
555
if(ret == -1 and errno != EINTR){
556
error(0, errno, "close");
561
/* Close output FIFO */
562
if(outfifo_fd != -1){
563
ret = (int)TEMP_FAILURE_RETRY(close(outfifo_fd));
565
error(0, errno, "close");
464
569
/* Create argc and argv for new usplash*/
465
570
int cmdline_argc = 0;