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mirror of https://github.com/rd235/cado synced 2024-12-27 06:24:11 +01:00
cado/compute_digest.c
2016-08-09 17:46:05 +02:00

93 lines
2.6 KiB
C

/*
* scado: setuid in capability sauce.
* Copyright (C) 2016 Davide Berardi and Renzo Davoli, University of Bologna
*
* This file is part of cado.
*
* Cado 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 2
* 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/>.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <compute_digest.h>
#define BUFSIZE 1024
/* compute the hash digest for file whose descriptor is infd.
if outfd >= 0 copy the contents to the file whose descriptor is outfd.
the return value is the size of the file (or a negative value in case of error).
the size of ascii_digest must be at least DIGESTSTRLEN + 1*/
static ssize_t fcompute_digest(int infd, int outfd, char *ascii_digest) {
char buf[BUFSIZE];
unsigned char binary_digest[DIGESTLEN];
MHASH td;
ssize_t n;
ssize_t rv = 0;
td = mhash_init(DIGESTTYPE);
while ((n=read(infd,buf,BUFSIZE)) > 0) {
mhash(td, buf, n);
if (outfd >= 0) write(outfd, buf, n);
rv += n;
}
mhash_deinit(td, binary_digest);
if (n >= 0) {
int i;
for (i = 0; i < DIGESTLEN; i++, ascii_digest += 2)
sprintf(ascii_digest, "%.2x", binary_digest[i]);
*ascii_digest = 0;
}
return (n < 0) ? n : rv;
}
/* compute the hash digest of the file (the first arg is the pathname) */
ssize_t compute_digest(const char *path, char *digest) {
int fd=open(path, O_RDONLY);
if (fd >= 0) {
ssize_t rv = fcompute_digest(fd, -1, digest);
close(fd);
return rv;
} else
return -1;
}
/* compute the hash digest of the file (the first arg is the pathname)
while copying it in a temporary file. The second arg is a template for tmp files
as explained in mkstemp(3)
*/
ssize_t copytemp_digest(const char *inpath, char *outtemplate, char *digest) {
int infd=open(inpath, O_RDONLY);
int outfd;
mode_t oldmask;
ssize_t rv;
if (infd < 0)
return -1;
oldmask = umask(027);
outfd = mkstemp(outtemplate);
umask(oldmask);
if (outfd < 0)
return -1;
rv = fcompute_digest(infd, outfd, digest);
close(infd);
close(outfd);
return rv;
}