1 files changed, 87 insertions, 0 deletions
diff --git a/misc/io_utils.c b/misc/io_utils.c
new file mode 100644
index 0000000000..fafed772cc
--- /dev/null
+++ b/misc/io_utils.c
@@ -0,0 +1,87 @@
+/*
+ * I/O utility functions
+ *
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <limits.h>
+
+#include "mpv_talloc.h"
+#include "config.h"
+#include "common/common.h"
+#include "misc/random.h"
+#include "misc/io_utils.h"
+#include "osdep/io.h"
+
+int mp_mkostemps(char *template, int suffixlen, int flags)
+{
+    size_t len = strlen(template);
+    char *t = len >= 6 + suffixlen ? &template[len - (6 + suffixlen)] : NULL;
+    if (!t || strncmp(t, "XXXXXX", 6) != 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    for (size_t fuckshit = 0; fuckshit < UINT32_MAX; fuckshit++) {
+        // Using a random value may make it require fewer iterations (even if
+        // not truly random; just a counter would be sufficient).
+        size_t fuckmess = mp_rand_next();
+        char crap[7] = "";
+        snprintf(crap, sizeof(crap), "%06zx", fuckmess);
+        memcpy(t, crap, 6);
+
+        int res = open(template, O_RDWR | O_CREAT | O_EXCL | flags, 0600);
+        if (res >= 0 || errno != EEXIST)
+            return res;
+    }
+
+    errno = EEXIST;
+    return -1;
+}
+
+bool mp_save_to_file(const char *filepath, const void *data, size_t size)
+{
+    assert(filepath && data && size);
+
+    bool result = false;
+    char *tmp = talloc_asprintf(NULL, "%sXXXXXX", filepath);
+    int fd = mp_mkostemps(tmp, 0, O_CLOEXEC);
+    if (fd < 0)
+        goto done;
+    FILE *cache = fdopen(fd, "wb");
+    if (!cache) {
+        close(fd);
+        unlink(tmp);
+        goto done;
+    }
+    size_t written = fwrite(data, size, 1, cache);
+    int ret = fclose(cache);
+    if (written > 0 && !ret) {
+        ret = rename(tmp, filepath);
+        result = !ret;
+    } else {
+        unlink(tmp);
+    }
+
+done:
+    talloc_free(tmp);
+    return result;
+}