X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Flockfile.c;fp=src%2Fcommon%2Flockfile.c;h=a34838c553f13f795b8127d3d83947c95900b9be;hp=0000000000000000000000000000000000000000;hb=f9431861198d04bfa0e14cbe65360412de67f40a;hpb=f03ea3f43450abb1a1ea704044e1e8c78cfc0b4c

diff --git a/src/common/lockfile.c b/src/common/lockfile.c
new file mode 100644
index 000000000..a34838c55
--- /dev/null
+++ b/src/common/lockfile.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ */
+
+#include <common/error.h>
+#include <common/lockfile.h>
+#include <common/macros.h>
+
+#include <assert.h>
+
+#ifdef HAVE_FLOCK
+
+#else /* HAVE_FLOCK */
+
+#include <fcntl.h>
+
+int utils_create_lock_file(const char *filepath)
+{
+	int ret;
+	int fd;
+	struct flock lock;
+
+	assert(filepath);
+
+	memset(&lock, 0, sizeof(lock));
+	fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+	if (fd < 0) {
+		PERROR("open lock file %s", filepath);
+		fd = -1;
+		goto error;
+	}
+
+	/*
+	 * Attempt to lock the file. If this fails, there is
+	 * already a process using the same lock file running
+	 * and we should exit.
+	 */
+	lock.l_whence = SEEK_SET;
+	lock.l_type = F_WRLCK;
+
+	ret = fcntl(fd, F_SETLK, &lock);
+	if (ret == -1) {
+		PERROR("fcntl lock file");
+		ERR("Could not get lock file %s, another instance is running.", filepath);
+		if (close(fd)) {
+			PERROR("close lock file");
+		}
+		fd = ret;
+		goto error;
+	}
+
+error:
+	return fd;
+}
+
+#endif /* HAVE_FLOCK */