+
+#if defined(__linux__) || defined(__CYGWIN__)
+
+#define LTTNG_SOCK_CREDS SCM_CREDENTIALS
+
+typedef struct ucred lttng_sock_cred;
+
+#define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
+#define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
+#define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
+
+#define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
+#define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
+#define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
+
+#elif (defined(__FreeBSD__) || defined(__sun__) || defined(__APPLE__))
+
+struct lttng_sock_cred {
+ uid_t uid;
+ gid_t gid;
+ pid_t pid;
+};
+
+typedef struct lttng_sock_cred lttng_sock_cred;
+
+#define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
+#define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
+#define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
+
+#define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
+#define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
+#define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
+
+#ifdef __APPLE__
+
+static inline
+int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
+{
+ /* The getsockopt LOCAL_PEERPID option is available since macOS 10.8. */
+ return getsockopt(socket_fd, SOL_LOCAL, LOCAL_PEERPID, pid,
+ &((socklen_t) {sizeof(*pid)}));
+}
+
+#elif defined(__sun__)
+
+/* Use the getpeerucreds interface on Solaris. */
+static inline
+int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
+{
+ int ret = 0;
+ ucred_t *ucred = NULL;
+
+ ret = getpeerucred(s, &ucred);
+ if (ret == -1) {
+ goto end;
+ }
+
+ ret = ucred_getpid(ucred);
+ if (ret == -1) {
+ goto free;
+ }
+
+ *pid = ret;
+ ret = 0;
+free:
+ ucred_free(ucred);
+end:
+ return ret;
+}
+
+#elif defined(__FreeBSD__)
+
+#include <sys/ucred.h>
+
+static inline
+int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
+{
+ int ret;
+ struct xucred sock_creds = {};
+
+ /* Only available in FreeBSD 13.0 and up. */
+ ret = getsockopt(socket_fd, SOL_LOCAL, LOCAL_PEERCRED, &sock_creds,
+ &((socklen_t) {sizeof(sock_creds)}));
+ if (ret) {
+ goto end;
+ }
+
+ *pid = sock_creds.cr_pid;
+end:
+ return ret;
+}
+
+#endif /* __APPLE__ */
+
+
+static inline
+int lttng_get_unix_socket_peer_creds(int socket_fd, struct lttng_sock_cred *creds)
+{
+ int ret;
+
+ /* This is a BSD extension that is supported by Cygwin. */
+ ret = getpeereid(socket_fd, &creds->uid, &creds->gid);
+ if (ret) {
+ goto end;
+ }
+
+ /*
+ * Getting a peer's PID is a bit more troublesome as it is platform
+ * specific.
+ */
+ ret = lttng_get_unix_socket_peer_pid(socket_fd, &creds->pid);
+end:
+ return ret;
+}
+
+#else
+#error "Please add support for your OS."
+#endif /* __linux__ , __FreeBSD__, __APPLE__ */
+