[ltt-dev] [UST PATCH 1/6] Make app socket directories per-user v2

[Nils Carlson]

Changes since v1:
	* Document memory allocation

Make a separate app socket directories for each user, providing
some basic security and also the possibility of consistent cleanup.

Signed-off-by: Nils Carlson <nils.carlson at ericsson.com>
---
 libust/tracectl.c    |   34 +++++++++++++++++++---------------
 libustcomm/ustcomm.c |   34 +++++++++++++++++++++++++++++-----
 libustcomm/ustcomm.h |    4 ++++
 3 files changed, 52 insertions(+), 20 deletions(-)

diff --git a/libust/tracectl.c b/libust/tracectl.c
index 33c7280..ae92b7e 100644
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -1221,37 +1221,41 @@ static void auto_probe_connect(struct marker *m)
 
 static struct ustcomm_sock * init_app_socket(int epoll_fd)
 {
-	char *name;
+	char *dir_name, *sock_name;
 	int result;
-	struct ustcomm_sock *sock;
+	struct ustcomm_sock *sock = NULL;
 
-	result = asprintf(&name, "%s/%d", SOCK_DIR, (int)getpid());
+	dir_name = ustcomm_user_sock_dir();
+	if (!dir_name)
+		return NULL;
+
+	result = asprintf(&sock_name, "%s/%d", dir_name, (int)getpid());
 	if (result < 0) {
 		ERR("string overflow allocating socket name, "
 		    "UST thread bailing");
-		return NULL;
+		goto free_dir_name;
 	}
 
-	result = ensure_dir_exists(SOCK_DIR);
+	result = ensure_dir_exists(dir_name);
 	if (result == -1) {
 		ERR("Unable to create socket directory %s, UST thread bailing",
-		    SOCK_DIR);
-		goto free_name;
+		    dir_name);
+		goto free_sock_name;
 	}
 
-	sock = ustcomm_init_named_socket(name, epoll_fd);
+	sock = ustcomm_init_named_socket(sock_name, epoll_fd);
 	if (!sock) {
 		ERR("Error initializing named socket (%s). Check that directory"
-		    "exists and that it is writable. UST thread bailing", name);
-		goto free_name;
+		    "exists and that it is writable. UST thread bailing", sock_name);
+		goto free_sock_name;
 	}
 
-	free(name);
-	return sock;
+free_sock_name:
+	free(sock_name);
+free_dir_name:
+	free(dir_name);
 
-free_name:
-	free(name);
-	return NULL;
+	return sock;
 }
 
 static void __attribute__((constructor)) init()
diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
index 43f4289..dce1e52 100644
--- a/libustcomm/ustcomm.c
+++ b/libustcomm/ustcomm.c
@@ -533,6 +533,21 @@ close_sock:
 	return -1;
 }
 
+/* Returns the current users socket directory, must be freed */
+char *ustcomm_user_sock_dir(void)
+{
+	int result;
+	char *sock_dir = NULL;
+
+	result = asprintf(&sock_dir, "%s%s", USER_SOCK_DIR,
+			  cuserid(NULL));
+	if (result < 0) {
+		ERR("string overflow allocating directory name");
+		return NULL;
+	}
+
+	return sock_dir;
+}
 
 /* Open a connection to a traceable app.
  *
@@ -545,21 +560,30 @@ int ustcomm_connect_app(pid_t pid, int *app_fd)
 {
 	int result;
 	int retval = 0;
-	char *name;
+	char *dir_name, *sock_name;
+
+	dir_name = ustcomm_user_sock_dir();
+	if (!dir_name)
+		return -ENOMEM;
 
-	result = asprintf(&name, "%s/%d", SOCK_DIR, pid);
+	result = asprintf(&sock_name, "%s/%d", dir_name, pid);
 	if (result < 0) {
 		ERR("failed to allocate socket name");
-		return -1;
+		retval = -1;
+		goto free_dir_name;
 	}
 
-	result = ustcomm_connect_path(name, app_fd);
+	result = ustcomm_connect_path(sock_name, app_fd);
 	if (result < 0) {
 		ERR("failed to connect to app");
 		retval = -1;
+		goto free_sock_name;
 	}
 
-	free(name);
+free_sock_name:
+	free(sock_name);
+free_dir_name:
+	free(dir_name);
 
 	return retval;
 }
diff --git a/libustcomm/ustcomm.h b/libustcomm/ustcomm.h
index 0ec04fc..db38119 100644
--- a/libustcomm/ustcomm.h
+++ b/libustcomm/ustcomm.h
@@ -25,6 +25,7 @@
 #include <ust/kcompat/kcompat.h>
 
 #define SOCK_DIR "/tmp/ust-app-socks"
+#define USER_SOCK_DIR "/tmp/ust-socks-"
 
 struct ustcomm_sock {
 	struct cds_list_head list;
@@ -156,6 +157,9 @@ extern int ustcomm_req(int sock,
 		       char *res_data);
 
 extern int ustcomm_request_consumer(pid_t pid, const char *channel);
+
+/* Returns the current users socket directory, must be freed */
+extern char *ustcomm_user_sock_dir(void);
 extern int ustcomm_connect_app(pid_t pid, int *app_fd);
 extern int ustcomm_connect_path(const char *path, int *connection_fd);
 
-- 
1.7.1