1 files changed, 126 insertions, 0 deletions
diff --git a/shared/file-util.c b/shared/file-util.c
new file mode 100644
index 0000000..4170771
--- /dev/null
+++ b/shared/file-util.c
@@ -0,0 +1,126 @@
+/*
+ * Copyright © 2015 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+
+#include "file-util.h"
+
+static int
+current_time_str(char *str, size_t len, const char *fmt)
+{
+	time_t t;
+	struct tm *t_local;
+	int ret;
+
+	t = time(NULL);
+	t_local = localtime(&t);
+	if (!t_local) {
+		errno = ETIME;
+		return -1;
+	}
+
+	ret = strftime(str, len, fmt, t_local);
+	if (ret == 0) {
+		errno = ETIME;
+		return -1;
+	}
+
+	return ret;
+}
+
+static int
+create_file_excl(const char *fname)
+{
+	return open(fname, O_RDWR | O_CLOEXEC | O_CREAT | O_EXCL, 00666);
+}
+
+/** Create a unique file with date and time in the name
+ *
+ * \param path File path
+ * \param prefix File name prefix.
+ * \param suffix File name suffix.
+ * \param[out] name_out Buffer for the resulting file name.
+ * \param name_len Number of bytes usable in name_out.
+ * \return stdio FILE pointer, or NULL on failure.
+ *
+ * Create and open a new file with the name concatenated from
+ * path/prefix, date and time, and suffix. If a file with this name
+ * already exists, an counter number is added to the end of the
+ * date and time sub-string. The counter is increased until a free file
+ * name is found.
+ *
+ * Once creating the file succeeds, the name of the file is in name_out.
+ * On failure, the contents of name_out are undefined and errno is set.
+ */
+FILE *
+file_create_dated(const char *path, const char *prefix, const char *suffix,
+		  char *name_out, size_t name_len)
+{
+	char timestr[128];
+	int ret;
+	int fd;
+	int cnt = 0;
+	int with_path;
+
+	with_path = path && path[0];
+
+	if (current_time_str(timestr, sizeof(timestr), "%F_%H-%M-%S") < 0)
+		return NULL;
+
+	ret = snprintf(name_out, name_len, "%s%s%s%s%s",
+		       with_path ? path : "", with_path ? "/" : "",
+		       prefix, timestr, suffix);
+	if (ret < 0 || (size_t)ret >= name_len) {
+		errno = ENOBUFS;
+		return NULL;
+	}
+
+	fd = create_file_excl(name_out);
+
+	while (fd == -1 && errno == EEXIST) {
+		cnt++;
+
+		ret = snprintf(name_out, name_len, "%s%s%s%s-%d%s",
+			       with_path ? path : "", with_path ? "/" : "",
+			       prefix, timestr, cnt, suffix);
+		if (ret < 0 || (size_t)ret >= name_len) {
+			errno = ENOBUFS;
+			return NULL;
+		}
+
+		fd = create_file_excl(name_out);
+	}
+
+	if (fd == -1)
+		return NULL;
+
+	return fdopen(fd, "w");
+}