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/*
* Copyright (C) 2013 Jeremy Kerr <jk@ozlabs.org>
*
* 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; version 2 of the License.
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <talloc/talloc.h>
#include "file.h"
static const int max_file_size = 1024 * 1024;
int read_file(void *ctx, const char *filename, char **bufp, int *lenp)
{
struct stat statbuf;
int rc, fd, i, len;
char *buf;
fd = open(filename, O_RDONLY);
if (fd < 0)
return -1;
rc = fstat(fd, &statbuf);
if (rc < 0)
goto err_close;
len = statbuf.st_size;
if (len > max_file_size)
goto err_close;
buf = talloc_array(ctx, char, len + 1);
if (!buf)
goto err_close;
for (i = 0; i < len; i += rc) {
rc = read(fd, buf + i, len - i);
/* unexpected EOF: trim and return */
if (rc == 0) {
len = i;
break;
}
if (rc < 0)
goto err_free;
}
buf[len] = '\0';
close(fd);
*bufp = buf;
*lenp = len;
return 0;
err_free:
talloc_free(buf);
err_close:
close(fd);
return -1;
}
static int write_fd(int fd, char *buf, int len)
{
int i, rc;
for (i = 0; i < len; i += rc) {
rc = write(fd, buf + i, len - i);
if (rc < 0 && errno != -EINTR)
return rc;
}
return 0;
}
int replace_file(const char *filename, char *buf, int len)
{
char *tempfile;
mode_t oldmask;
int rc, fd;
tempfile = talloc_asprintf(NULL, "%s.XXXXXX", filename);
oldmask = umask(0644);
fd = mkstemp(tempfile);
umask(oldmask);
if (fd < 0) {
talloc_free(tempfile);
return fd;
}
rc = write_fd(fd, buf, len);
if (rc) {
unlink(tempfile);
} else {
rc = rename(tempfile, filename);
}
talloc_free(tempfile);
fchmod(fd, 0644);
close(fd);
return rc;
}
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