From patchwork Thu Mar 4 20:17:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Hostetler X-Patchwork-Id: 12116757 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C17CDC43332 for ; Thu, 4 Mar 2021 20:19:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B06E664F72 for ; Thu, 4 Mar 2021 20:19:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238942AbhCDUSc (ORCPT ); Thu, 4 Mar 2021 15:18:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238902AbhCDUSM (ORCPT ); Thu, 4 Mar 2021 15:18:12 -0500 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1B98C061762 for ; Thu, 4 Mar 2021 12:17:31 -0800 (PST) Received: by mail-wr1-x42d.google.com with SMTP id b18so22591880wrn.6 for ; Thu, 04 Mar 2021 12:17:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=n4uZto3Ixdp3JWQ2PwLctPd2qu7NdiwXcI9lyP9p3T4=; b=n705GU/aOCjXJyjPh7c84rqfJfoC+dDN9hZQb39BLiT+NmhZpHxbeFEy7zuvXkKmqe uwxIFCmGs8jhK8CsLHYN9xajDMNxlxfg/0ec2dndTF40GBDfBi4nP9mSQD3pVByy9wma ulpWWDoQH52tV9DNOFOjiAXdhluQkblTEFscRV/natzb69zYgM9ZJ+LxNlHVmKWnGYsu UQOpUVRbC9brVTK+Hlw/ZtKEHUWrb9w9D7nHko1OjmlJ0TsJGRd49+hPfQKJMI2wh2mH 3p9rIRYYKGO1UTsXvG67PgKpABC3IL1IV4YL860a2BmIeb+msXByNoLpNN3015xxKSPl t+aQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=n4uZto3Ixdp3JWQ2PwLctPd2qu7NdiwXcI9lyP9p3T4=; b=C42On7OCjhFo9Ak/GYysv88IQigj5q7d3QdrFlkx8X93l1VVHxgGyffxDBRqXrZw/K N65tkJBhXPk+DwCYxyY/61xQhu+fJxtr7HYy0ZX/27FYuA8ky7/VLbexwBzHC3SmhFnZ tybsX027M1m7e7VsA1RxsIwJ1qNhBAc1YmqHOf7UIc42u1zFFmMWJzJqtVCwHikMuNra PFsf84MN1QE1timOirkSWcxGfJljj8moixP41huuSfKx4zjE9VaI9dZrW7/E6vbeXPC8 wXHXW0JZmdxJE906udV6xMbfEmCbaIFAFUH6ZZiO3T3+aOa1JJf7CNUiraM8G31aT5NT n5YQ== X-Gm-Message-State: AOAM533WGLajlXUY5VJ9OpSRBveGw5eCIygIbxRonLY8ooeHUriUZH4D Nwl4bTliEdZkP6jl3V3bYHsXoPGwg3g= X-Google-Smtp-Source: ABdhPJxSCHO/DZM4ln/VAXbBrrKgPBLj26WHz0zJXZfk+ic2trcTErAJNUlNS5ICEUzDryx16vaWKw== X-Received: by 2002:adf:c389:: with SMTP id p9mr5737687wrf.410.1614889050646; Thu, 04 Mar 2021 12:17:30 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id a5sm560247wrs.35.2021.03.04.12.17.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Mar 2021 12:17:30 -0800 (PST) Message-Id: <4ae4429a70e408a1ab52a59370a4e6d10ca9a0fd.1614889047.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Thu, 04 Mar 2021 20:17:22 +0000 Subject: [PATCH 3/8] unix-stream-server: create unix-stream-server.c Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Jeff Hostetler , Jeff Hostetler Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Jeff Hostetler From: Jeff Hostetler Move unix_stream_server__listen_with_lock() and associated routines and data types out of unix-socket.[ch] and into their own source file. We added code to safely create a Unix domain socket using a lockfile in: 9406d12e14 (unix-socket: create `unix_stream_server__listen_with_lock()`, 2021-02-13). This code conceptually exists at a higher-level than the core unix_stream_connect() and unix_stream_listen() routines that it consumes and should be isolated for clarity. Signed-off-by: Jeff Hostetler --- Makefile | 1 + compat/simple-ipc/ipc-unix-socket.c | 1 + contrib/buildsystems/CMakeLists.txt | 2 +- unix-socket.c | 120 --------------------------- unix-socket.h | 26 ------ unix-stream-server.c | 124 ++++++++++++++++++++++++++++ unix-stream-server.h | 32 +++++++ 7 files changed, 159 insertions(+), 147 deletions(-) create mode 100644 unix-stream-server.c create mode 100644 unix-stream-server.h diff --git a/Makefile b/Makefile index 93f2e7ca9e1f..dfc37b0480e4 100644 --- a/Makefile +++ b/Makefile @@ -1678,6 +1678,7 @@ ifdef NO_UNIX_SOCKETS BASIC_CFLAGS += -DNO_UNIX_SOCKETS else LIB_OBJS += unix-socket.o + LIB_OBJS += unix-stream-server.o LIB_OBJS += compat/simple-ipc/ipc-shared.o LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o endif diff --git a/compat/simple-ipc/ipc-unix-socket.c b/compat/simple-ipc/ipc-unix-socket.c index b7fd0b34329e..b0264ca6cdc6 100644 --- a/compat/simple-ipc/ipc-unix-socket.c +++ b/compat/simple-ipc/ipc-unix-socket.c @@ -4,6 +4,7 @@ #include "pkt-line.h" #include "thread-utils.h" #include "unix-socket.h" +#include "unix-stream-server.h" #ifdef NO_UNIX_SOCKETS #error compat/simple-ipc/ipc-unix-socket.c requires Unix sockets diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt index 4c27a373414a..629a1817459b 100644 --- a/contrib/buildsystems/CMakeLists.txt +++ b/contrib/buildsystems/CMakeLists.txt @@ -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") diff --git a/unix-socket.c b/unix-socket.c index c9ea1de43bd2..e0be1badb58d 100644 --- a/unix-socket.c +++ b/unix-socket.c @@ -1,8 +1,6 @@ #include "cache.h" -#include "lockfile.h" #include "unix-socket.h" -#define DEFAULT_UNIX_STREAM_LISTEN_TIMEOUT (100) #define DEFAULT_UNIX_STREAM_LISTEN_BACKLOG (5) static int chdir_len(const char *orig, int len) @@ -136,121 +134,3 @@ int unix_stream_listen(const char *path, errno = saved_errno; return -1; } - -static int is_another_server_alive(const char *path, - const struct unix_stream_listen_opts *opts) -{ - struct stat st; - int fd; - - if (!lstat(path, &st) && S_ISSOCK(st.st_mode)) { - /* - * A socket-inode exists on disk at `path`, but we - * don't know whether it belongs to an active server - * or whether the last server died without cleaning - * up. - * - * Poke it with a trivial connection to try to find - * out. - */ - fd = unix_stream_connect(path, opts->disallow_chdir); - if (fd >= 0) { - close(fd); - return 1; - } - } - - return 0; -} - -struct unix_stream_server_socket *unix_stream_server__listen_with_lock( - const char *path, - const struct unix_stream_listen_opts *opts) -{ - struct lock_file lock = LOCK_INIT; - long timeout; - int fd_socket; - struct unix_stream_server_socket *server_socket; - - timeout = opts->timeout_ms; - if (opts->timeout_ms <= 0) - timeout = DEFAULT_UNIX_STREAM_LISTEN_TIMEOUT; - - /* - * Create a lock at ".lock" if we can. - */ - if (hold_lock_file_for_update_timeout(&lock, path, 0, timeout) < 0) { - error_errno(_("could not lock listener socket '%s'"), path); - return NULL; - } - - /* - * If another server is listening on "" give up. We do not - * want to create a socket and steal future connections from them. - */ - if (is_another_server_alive(path, opts)) { - errno = EADDRINUSE; - error_errno(_("listener socket already in use '%s'"), path); - rollback_lock_file(&lock); - return NULL; - } - - /* - * Create and bind to a Unix domain socket at "". - */ - fd_socket = unix_stream_listen(path, opts); - if (fd_socket < 0) { - error_errno(_("could not create listener socket '%s'"), path); - rollback_lock_file(&lock); - return NULL; - } - - 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); - - /* - * Always rollback (just delete) ".lock" because we already created - * "" as a socket and do not want to commit_lock to do the atomic - * rename trick. - */ - rollback_lock_file(&lock); - - return server_socket; -} - -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; - - /* We might also consider the ctime on some platforms. */ - - return 0; -} diff --git a/unix-socket.h b/unix-socket.h index bec925ee0213..b079e79cb3e1 100644 --- a/unix-socket.h +++ b/unix-socket.h @@ -18,30 +18,4 @@ int unix_stream_connect(const char *path, int disallow_chdir); int unix_stream_listen(const char *path, const struct unix_stream_listen_opts *opts); -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. - */ -struct unix_stream_server_socket *unix_stream_server__listen_with_lock( - const char *path, - const struct unix_stream_listen_opts *opts); - -/* - * 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_SOCKET_H */ diff --git a/unix-stream-server.c b/unix-stream-server.c new file mode 100644 index 000000000000..ad175ba731ca --- /dev/null +++ b/unix-stream-server.c @@ -0,0 +1,124 @@ +#include "cache.h" +#include "lockfile.h" +#include "unix-socket.h" +#include "unix-stream-server.h" + +#define DEFAULT_UNIX_STREAM_LISTEN_TIMEOUT (100) + +static int is_another_server_alive(const char *path, + const struct unix_stream_listen_opts *opts) +{ + struct stat st; + int fd; + + if (!lstat(path, &st) && S_ISSOCK(st.st_mode)) { + /* + * A socket-inode exists on disk at `path`, but we + * don't know whether it belongs to an active server + * or whether the last server died without cleaning + * up. + * + * Poke it with a trivial connection to try to find + * out. + */ + fd = unix_stream_connect(path, opts->disallow_chdir); + if (fd >= 0) { + close(fd); + return 1; + } + } + + return 0; +} + +struct unix_stream_server_socket *unix_stream_server__listen_with_lock( + const char *path, + const struct unix_stream_listen_opts *opts) +{ + struct lock_file lock = LOCK_INIT; + long timeout; + int fd_socket; + struct unix_stream_server_socket *server_socket; + + timeout = opts->timeout_ms; + if (opts->timeout_ms <= 0) + timeout = DEFAULT_UNIX_STREAM_LISTEN_TIMEOUT; + + /* + * Create a lock at ".lock" if we can. + */ + if (hold_lock_file_for_update_timeout(&lock, path, 0, timeout) < 0) { + error_errno(_("could not lock listener socket '%s'"), path); + return NULL; + } + + /* + * If another server is listening on "" give up. We do not + * want to create a socket and steal future connections from them. + */ + if (is_another_server_alive(path, opts)) { + errno = EADDRINUSE; + error_errno(_("listener socket already in use '%s'"), path); + rollback_lock_file(&lock); + return NULL; + } + + /* + * Create and bind to a Unix domain socket at "". + */ + fd_socket = unix_stream_listen(path, opts); + if (fd_socket < 0) { + error_errno(_("could not create listener socket '%s'"), path); + rollback_lock_file(&lock); + return NULL; + } + + 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); + + /* + * Always rollback (just delete) ".lock" because we already created + * "" as a socket and do not want to commit_lock to do the atomic + * rename trick. + */ + rollback_lock_file(&lock); + + return server_socket; +} + +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; + + /* We might also consider the ctime on some platforms. */ + + return 0; +} diff --git a/unix-stream-server.h b/unix-stream-server.h new file mode 100644 index 000000000000..745849e31c30 --- /dev/null +++ b/unix-stream-server.h @@ -0,0 +1,32 @@ +#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. + */ +struct unix_stream_server_socket *unix_stream_server__listen_with_lock( + const char *path, + const struct unix_stream_listen_opts *opts); + +/* + * 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 */