Implement --shm-path option for UST sessions (per-uid channels)

[lttng-tools.git] / src / bin / lttng-sessiond / ust-registry.c

diff --git a/src/bin/lttng-sessiond/ust-registry.c b/src/bin/lttng-sessiond/ust-registry.c
index 1a00e9349fb2f04c6052a5222acaf7d927fdd471..26f306d52d516ac6091e74a1cb26ef73821dbbbd 100644 (file)
--- a/src/bin/lttng-sessiond/ust-registry.c
+++ b/src/bin/lttng-sessiond/ust-registry.c
@@ -546,7 +546,10 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
                uint32_t long_alignment,
                int byte_order,
                uint32_t major,
-               uint32_t minor)
+               uint32_t minor,
+               const char *shm_path,
+               uid_t euid,
+               gid_t egid)
 {
        int ret;
        struct ust_registry_session *session;
@@ -567,6 +570,38 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
        session->uint64_t_alignment = uint64_t_alignment;
        session->long_alignment = long_alignment;
        session->byte_order = byte_order;
+       session->metadata_fd = -1;
+       if (shm_path[0]) {
+               strncpy(session->shm_path, shm_path,
+                       sizeof(session->shm_path));
+               session->shm_path[sizeof(session->shm_path) - 1] = '\0';
+               strncpy(session->metadata_path, shm_path,
+                       sizeof(session->metadata_path));
+               session->metadata_path[sizeof(session->metadata_path) - 1] = '\0';
+               strncat(session->metadata_path, "/metadata",
+                       sizeof(session->metadata_path)
+                               - strlen(session->metadata_path) - 1);
+       }
+       if (session->shm_path[0]) {
+               ret = run_as_mkdir_recursive(session->shm_path,
+                       S_IRWXU | S_IRWXG,
+                       euid, egid);
+               if (ret) {
+                       PERROR("run_as_mkdir_recursive");
+                       goto error;
+               }
+       }
+       if (session->metadata_path[0]) {
+               /* Create metadata file */
+               ret = open(session->metadata_path,
+                       O_WRONLY | O_CREAT | O_EXCL,
+                       S_IRUSR | S_IWUSR);
+               if (ret < 0) {
+                       PERROR("Opening metadata file");
+                       goto error;
+               }
+               session->metadata_fd = ret;
+       }
 
        session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!session->channels) {
@@ -631,4 +666,14 @@ void ust_registry_session_destroy(struct ust_registry_session *reg)
        }
 
        free(reg->metadata);
+       if (reg->metadata_fd >= 0) {
+               ret = close(reg->metadata_fd);
+               if (ret) {
+                       PERROR("close");
+               }
+               ret = unlink(reg->metadata_path);
+               if (ret) {
+                       PERROR("unlink");
+               }
+       }
 }