@@ -1665,6 +1665,7 @@ ifdef NO_UNIX_SOCKETS
BASIC_CFLAGS += -DNO_UNIX_SOCKETS
else
LIB_OBJS += unix-socket.o
+ LIB_OBJS += unix-stream-server.o
endif
ifdef USE_WIN32_IPC
@@ -243,7 +243,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
add_compile_definitions(PROCFS_EXECUTABLE_PATH="/proc/self/exe" HAVE_DEV_TTY )
- list(APPEND compat_SOURCES unix-socket.c)
+ list(APPEND compat_SOURCES unix-socket.c unix-stream-server.c)
endif()
if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
new file mode 100644
@@ -0,0 +1,128 @@
+#include "cache.h"
+#include "lockfile.h"
+#include "unix-socket.h"
+#include "unix-stream-server.h"
+
+#define DEFAULT_LOCK_TIMEOUT (100)
+
+/*
+ * Try to connect to a unix domain socket at `path` (if it exists) and
+ * see if there is a server listening.
+ *
+ * We don't know if the socket exists, whether a server died and
+ * failed to cleanup, or whether we have a live server listening, so
+ * we "poke" it.
+ *
+ * We immediately hangup without sending/receiving any data because we
+ * don't know anything about the protocol spoken and don't want to
+ * block while writing/reading data. It is sufficient to just know
+ * that someone is listening.
+ */
+static int is_another_server_alive(const char *path,
+ const struct unix_stream_listen_opts *opts)
+{
+ int fd = unix_stream_connect(path, opts->disallow_chdir);
+ if (fd >= 0) {
+ close(fd);
+ return 1;
+ }
+
+ return 0;
+}
+
+int unix_stream_server__create(
+ const char *path,
+ const struct unix_stream_listen_opts *opts,
+ long timeout_ms,
+ struct unix_stream_server_socket **new_server_socket)
+{
+ struct lock_file lock = LOCK_INIT;
+ int fd_socket;
+ struct unix_stream_server_socket *server_socket;
+
+ *new_server_socket = NULL;
+
+ if (timeout_ms < 0)
+ timeout_ms = DEFAULT_LOCK_TIMEOUT;
+
+ /*
+ * Create a lock at "<path>.lock" if we can.
+ */
+ if (hold_lock_file_for_update_timeout(&lock, path, 0, timeout_ms) < 0)
+ return -1;
+
+ /*
+ * If another server is listening on "<path>" give up. We do not
+ * want to create a socket and steal future connections from them.
+ */
+ if (is_another_server_alive(path, opts)) {
+ rollback_lock_file(&lock);
+ errno = EADDRINUSE;
+ return -2;
+ }
+
+ /*
+ * Create and bind to a Unix domain socket at "<path>".
+ */
+ fd_socket = unix_stream_listen(path, opts);
+ if (fd_socket < 0) {
+ int saved_errno = errno;
+ rollback_lock_file(&lock);
+ errno = saved_errno;
+ return -1;
+ }
+
+ server_socket = xcalloc(1, sizeof(*server_socket));
+ server_socket->path_socket = strdup(path);
+ server_socket->fd_socket = fd_socket;
+ lstat(path, &server_socket->st_socket);
+
+ *new_server_socket = server_socket;
+
+ /*
+ * Always rollback (just delete) "<path>.lock" because we already created
+ * "<path>" as a socket and do not want to commit_lock to do the atomic
+ * rename trick.
+ */
+ rollback_lock_file(&lock);
+
+ return 0;
+}
+
+void unix_stream_server__free(
+ struct unix_stream_server_socket *server_socket)
+{
+ if (!server_socket)
+ return;
+
+ if (server_socket->fd_socket >= 0) {
+ if (!unix_stream_server__was_stolen(server_socket))
+ unlink(server_socket->path_socket);
+ close(server_socket->fd_socket);
+ }
+
+ free(server_socket->path_socket);
+ free(server_socket);
+}
+
+int unix_stream_server__was_stolen(
+ struct unix_stream_server_socket *server_socket)
+{
+ struct stat st_now;
+
+ if (!server_socket)
+ return 0;
+
+ if (lstat(server_socket->path_socket, &st_now) == -1)
+ return 1;
+
+ if (st_now.st_ino != server_socket->st_socket.st_ino)
+ return 1;
+ if (st_now.st_dev != server_socket->st_socket.st_dev)
+ return 1;
+
+ if (!S_ISSOCK(st_now.st_mode))
+ return 1;
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,36 @@
+#ifndef UNIX_STREAM_SERVER_H
+#define UNIX_STREAM_SERVER_H
+
+#include "unix-socket.h"
+
+struct unix_stream_server_socket {
+ char *path_socket;
+ struct stat st_socket;
+ int fd_socket;
+};
+
+/*
+ * Create a Unix Domain Socket at the given path under the protection
+ * of a '.lock' lockfile.
+ *
+ * Returns 0 on success, -1 on error, -2 if socket is in use.
+ */
+int unix_stream_server__create(
+ const char *path,
+ const struct unix_stream_listen_opts *opts,
+ long timeout_ms,
+ struct unix_stream_server_socket **server_socket);
+
+/*
+ * Close and delete the socket.
+ */
+void unix_stream_server__free(
+ struct unix_stream_server_socket *server_socket);
+
+/*
+ * Return 1 if the inode of the pathname to our socket changes.
+ */
+int unix_stream_server__was_stolen(
+ struct unix_stream_server_socket *server_socket);
+
+#endif /* UNIX_STREAM_SERVER_H */