/mandos/release

#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 <errno.h>		/* errno */

#include <sys/wait.h>		/* waitpid(), WIFEXITED(),

				   WEXITSTATUS() */

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, char **argv){

  int ret = 0;

  /* Create prompt string */

  char *prompt = NULL;

  {

    const char *const cryptsource = getenv("cryptsource");

    const char *const crypttarget = getenv("crypttarget");

    const char *const prompt_start = "getpass "

      "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 splashy process */

  pid_t splashy_pid = 0;

  {

    const char splashy_name[] = "/sbin/splashy";

    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_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;

      }

      char exe_target[sizeof(splashy_name)];

      ssize_t sret = readlink(exe_link, exe_target,

			      sizeof(exe_target));

      free(exe_link);

      if((sret == ((ssize_t)sizeof(exe_target)-1))

	 and (memcmp(splashy_name, exe_target,

		     sizeof(exe_target)-1) == 0)){

	splashy_pid = pid;

	break;

      }

    }

    closedir(proc_dir);

  }

  if(splashy_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;

      }

    }

  }

  /* Fork off the splashy command to prompt for password */

  pid_t splashy_command_pid = 0;

  if(not interrupted_by_signal){

    splashy_command_pid = fork();

    if(splashy_command_pid == -1){

      if(not interrupted_by_signal){

	perror("fork");

      }

      return EXIT_FAILURE;

    }

    /* Child */

    if(splashy_command_pid == 0){

      const char splashy_command[] = "/sbin/splashy_update";

      ret = execl(splashy_command, splashy_command, prompt,

		  (char *)NULL);

      if(not interrupted_by_signal and errno != ENOENT){

	/* Don't report "File not found", since splashy might not be

	   installed. */

	perror("execl");

      }

      free(prompt);

      return EXIT_FAILURE;

    }

  }

  /* Parent */

  free(prompt);

  /* Wait for command to complete */

  int status;

  while(not interrupted_by_signal){

    waitpid(splashy_command_pid, &status, 0);

    if(not interrupted_by_signal

       and WIFEXITED(status) and WEXITSTATUS(status)==0){

      return EXIT_SUCCESS;

    }

  }

  kill(splashy_pid, SIGTERM);

  if(interrupted_by_signal){

    kill(splashy_command_pid, SIGTERM);

  }

  pid_t new_splashy_pid = fork();

  if(new_splashy_pid == 0){

    /* Child; will become new splashy process */

    while(kill(splashy_pid, 0)){

      sleep(2);

      kill(splashy_pid, SIGKILL);

      sleep(1);

    }

    ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */

    if(ret == -1){

      perror("dup2");

      _exit(EXIT_FAILURE);

    }

    execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);

  }

  return EXIT_FAILURE;

}