/mandos/release

#define _GNU_SOURCE		/* TEMP_FAILURE_RETRY() */

#include <sys/types.h>		/* ssize_t */

#include <sys/stat.h>		/* mkfifo(), S_IRUSR, S_IWUSR */

#include <iso646.h>		/* and */

#include <errno.h>		/* errno, EEXIST */

#include <stdio.h>		/* perror() */

#include <stdlib.h>		/* EXIT_FAILURE, NULL, size_t, free(), 

				   realloc(), EXIT_SUCCESS */

#include <fcntl.h>		/* open(), O_RDONLY */

#include <unistd.h>		/* read(), close(), write(),

				   STDOUT_FILENO */

int main(__attribute__((unused))int argc,

	 __attribute__((unused))char **argv){

  int ret = 0;

  ssize_t sret;

  /* Create FIFO */

  const char passfifo[] = "/lib/cryptsetup/passfifo";

  ret = TEMP_FAILURE_RETRY(mkfifo(passfifo, S_IRUSR | S_IWUSR));

  if(ret == -1 and errno != EEXIST){

    perror("mkfifo");

    return EXIT_FAILURE;

  }

  /* Open FIFO */

  int fifo_fd = TEMP_FAILURE_RETRY(open(passfifo, O_RDONLY));

  if(fifo_fd == -1){

    perror("open");

    return EXIT_FAILURE;

  }

  /* Read from FIFO */

  char *buf = NULL;

  size_t buf_len = 0;

  {

    size_t buf_allocated = 0;

    const size_t blocksize = 1024;

    do{

      if(buf_len + blocksize > buf_allocated){

	char *tmp = realloc(buf, buf_allocated + blocksize);

	if(tmp == NULL){

	  perror("realloc");

	  free(buf);

	  return EXIT_FAILURE;

	}

	buf = tmp;

	buf_allocated += blocksize;

      }

      sret = TEMP_FAILURE_RETRY(read(fifo_fd, buf + buf_len,

				     buf_allocated - buf_len));

      if(sret == -1){

	perror("read");

	free(buf);

	return EXIT_FAILURE;

      }

      buf_len += (size_t)sret;

    }while(sret != 0);

  }

  /* Close FIFO */

  TEMP_FAILURE_RETRY(close(fifo_fd));

  /* Print password to stdout */

  size_t written = 0;

  while(written < buf_len){

    sret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buf + written,

				    buf_len - written));

    if(sret == -1){

      perror("write");

      free(buf);

      return EXIT_FAILURE;

    }

    written += (size_t)sret;

  }

  free(buf);

  return EXIT_SUCCESS;

}