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/* -*- coding: utf-8 -*- */
/*
* Passprompt - Read a password from a FIFO and output it
*
* Copyright © 2008,2009 Teddy Hogeborn
* Copyright © 2008,2009 Björn Påhlsson
*
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* <http://www.gnu.org/licenses/>.
*
* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
* <https://www.fukt.bsnet.se/~teddy/>.
*/
#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;
}
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