1 files changed, 122 insertions, 0 deletions
diff --git a/src/util/backup_file.c b/src/util/backup_file.c
new file mode 100644
index 000000000..cf9ddf303
--- /dev/null
+++ b/src/util/backup_file.c
@@ -0,0 +1,122 @@
+/*
+ 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 count;
+    ssize_t num;
+    ssize_t pos;
+    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) {
+        num = read(src_fd, buf, BUFFER_SIZE);
+        if (num < 0) {
+            if (errno == EINTR) continue;
+            ret = errno;
+            DEBUG(dbglvl, ("Error (%d [%s]) reading from source %s\n",
+                           ret, strerror(ret), src_file));
+            goto done;
+        }
+        if (num == 0) break;
+
+        count = num;
+
+        while (count > 0) {
+            pos = 0;
+            errno = 0;
+            num = write(dst_fd, &buf[pos], count);
+            if (num < 0) {
+                if (errno == EINTR) continue;
+                ret = errno;
+                DEBUG(dbglvl, ("Error (%d [%s]) writing to destination %s\n",
+                               ret, strerror(ret), dst_file));
+                goto done;
+            }
+            pos += num;
+            count -= num;
+        }
+    }
+
+    ret = EOK;
+
+done:
+    if (src_fd != -1) close(src_fd);
+    if (dst_fd != -1) close(dst_fd);
+    talloc_free(tmp_ctx);
+    return ret;
+}