X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Futils.c;h=ff6d1c22337200e69e24807b1c871530ce6ea09e;hb=7e66b1b0255bbe6b5a55a83d3ff182ba3d4300ee;hp=bf93386c46147eca75e33c59a13b9f8214f49ba4;hpb=fbb9748b6dc509542c4a82960da36d7b03a3a66b;p=lttng-tools.git

diff --git a/src/common/utils.c b/src/common/utils.c
index bf93386c4..ff6d1c223 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -30,6 +30,7 @@
 #include <inttypes.h>
 #include <grp.h>
 #include <pwd.h>
+#include <sys/file.h>
 
 #include <common/common.h>
 #include <common/runas.h>
@@ -468,6 +469,44 @@ error:
 	return ret;
 }
 
+/*
+ * Create lock file to the given path and filename.
+ * Returns the associated file descriptor, -1 on error.
+ */
+LTTNG_HIDDEN
+int utils_create_lock_file(const char *filepath)
+{
+	int ret;
+	int fd;
+
+	assert(filepath);
+
+	fd = open(filepath, O_CREAT,
+		O_WRONLY | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+	if (fd < 0) {
+		PERROR("open lock file %s", filepath);
+		ret = -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.
+	 */
+	ret = flock(fd, LOCK_EX | LOCK_NB);
+	if (ret) {
+		WARN("Could not get lock file %s, another instance is running.",
+			filepath);
+		close(fd);
+		fd = ret;
+		goto error;
+	}
+
+error:
+	return fd;
+}
+
 /*
  * Recursively create directory using the given path and mode.
  *
@@ -822,11 +861,28 @@ LTTNG_HIDDEN
 char *utils_get_home_dir(void)
 {
 	char *val = NULL;
+	struct passwd *pwd;
+
 	val = getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
 	if (val != NULL) {
-		return val;
+		goto end;
+	}
+	val = getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
+	if (val != NULL) {
+		goto end;
+	}
+
+	/* Fallback on the password file entry. */
+	pwd = getpwuid(getuid());
+	if (!pwd) {
+		goto end;
 	}
-	return getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
+	val = pwd->pw_dir;
+
+	DBG3("Home directory is '%s'", val);
+
+end:
+	return val;
 }
 
 /**