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/*
SSSD
Backup files
Copyright (C) Simo Sorce 2009
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/>.
*/
#include "util/util.h"
#include <fcntl.h>
#include <stddef.h>
#include <stdlib.h>
#define BUFFER_SIZE 65536
int backup_file(const char *src_file, int dbglvl)
{
TALLOC_CTX *tmp_ctx = NULL;
char buf[BUFFER_SIZE];
int src_fd = -1;
int dst_fd = -1;
char *dst_file;
ssize_t numread;
ssize_t written;
int ret, i;
src_fd = open(src_file, O_RDONLY);
if (src_fd < 0) {
ret = errno;
DEBUG(dbglvl, "Error (%d [%s]) opening source file %s\n",
ret, strerror(ret), src_file);
goto done;
}
tmp_ctx = talloc_new(NULL);
if (!tmp_ctx) {
ret = ENOMEM;
goto done;
}
/* try a few times to come up with a new backup file, then give up */
for (i = 0; i < 10; i++) {
if (i == 0) {
dst_file = talloc_asprintf(tmp_ctx, "%s.bak", src_file);
} else {
dst_file = talloc_asprintf(tmp_ctx, "%s.bak%d", src_file, i);
}
if (!dst_file) {
ret = ENOMEM;
goto done;
}
errno = 0;
dst_fd = open(dst_file, O_CREAT|O_EXCL|O_WRONLY, 0600);
ret = errno;
if (dst_fd >= 0) break;
if (ret != EEXIST) {
DEBUG(dbglvl, "Error (%d [%s]) opening destination file %s\n",
ret, strerror(ret), dst_file);
goto done;
}
}
if (ret != 0) {
DEBUG(dbglvl, "Error (%d [%s]) opening destination file %s\n",
ret, strerror(ret), dst_file);
goto done;
}
/* copy file contents */
while (1) {
errno = 0;
numread = sss_atomic_read_s(src_fd, buf, BUFFER_SIZE);
if (numread < 0) {
ret = errno;
DEBUG(dbglvl, "Error (%d [%s]) reading from source %s\n",
ret, strerror(ret), src_file);
goto done;
}
if (numread == 0) break;
errno = 0;
written = sss_atomic_write_s(dst_fd, buf, numread);
if (written == -1) {
ret = errno;
DEBUG(dbglvl, "Error (%d [%s]) writing to destination %s\n",
ret, strerror(ret), dst_file);
goto done;
}
if (written != numread) {
DEBUG(dbglvl, "Wrote %zd bytes expected %zd bytes\n",
written, numread);
ret = EIO;
goto done;
}
}
ret = EOK;
done:
if (src_fd != -1) close(src_fd);
if (dst_fd != -1) close(dst_fd);
talloc_free(tmp_ctx);
return ret;
}
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