From patchwork Thu Jul 1 14:47:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Hostetler X-Patchwork-Id: 12354317 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 A2D2AC11F6C for ; Thu, 1 Jul 2021 14:48:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A3C16140C for ; Thu, 1 Jul 2021 14:48:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233016AbhGAOug (ORCPT ); Thu, 1 Jul 2021 10:50:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232907AbhGAOu1 (ORCPT ); Thu, 1 Jul 2021 10:50:27 -0400 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 423C6C0613E1 for ; Thu, 1 Jul 2021 07:47:55 -0700 (PDT) Received: by mail-wr1-x42c.google.com with SMTP id i8so8665864wrc.0 for ; Thu, 01 Jul 2021 07:47:55 -0700 (PDT) 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=UfZUXel1p6AOKNdy1ef02UiRKIjcEL1X8er7dQKR42M=; b=W0YGGiO21Mdxh1rXRTHfDs9JPCDmO559ehggERJWYfYZDVLyzjHayur2yRA4nLW4EE I9qDvD7+YZHME7Mv8rP1OsvhfAqxU5okvNDe440+qBlNRbJsN95PSQx9tmwGqFk289MS 5MI3PXxbFRpNXoHWYwa4ydvmGMQeaC/+u9iUh6ajvYDhuuf46eicqvtul4zQ8GO4TalH g+t3K5EUIX2AeMakpr6vN4S/qH+/gR9hOSdPlm5h893cMWzgG+zAH2V/h5iOlpSrzWhJ muC4L57Rso+fLjDsxohkj9Scjq6X1Iita40VQhXSTDGSxmy+sT/71aFC+VU8o36/QUYB ze1g== 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=UfZUXel1p6AOKNdy1ef02UiRKIjcEL1X8er7dQKR42M=; b=qPcZPHFe8JwBkNc9h2IeNacJpvtIRRsFyULe6g3IUD+MbSsCpYQ6ZgpP/frkFh36pg 3UEooRn/lV0e9oa8ikKzA57YdmYmQLUsyRiVe8sBQb1v2XuYTOOZmPCGd4PKDTUQBD0c 00uTunC8PcA8tubIl5yCkQYbz9v0kz+Uaoxc8mtgeNCS67QtvyWm032RnCdyjrf21rbw x9ecRwSf9nlCuzMlEw8nRJQgh+ehZOBMal/wgYEJrZTOKakBxZjc+NpTar5rNleVRsTw kDrACgFdj+TqxwEDGnaWwIQujFxghpfovUk9EiiyXZPDHaq8ridqGEEXEZokQmrr8Df1 7apA== X-Gm-Message-State: AOAM532CTgBys+FQpaQZKpil3UUlpulS4CO8XfmSY3kZP25SMsSpvk4V rJTLGQRvYosQpA9M4HwnyjYgkfgocB4= X-Google-Smtp-Source: ABdhPJw2LkpQfWpv7I91AtezUZUN+HVaobQEiDFVz7y2Hh36CJo+lGtLY9xyBsAExm7fAqieiUWzLg== X-Received: by 2002:adf:82a1:: with SMTP id 30mr2683wrc.31.1625150873805; Thu, 01 Jul 2021 07:47:53 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id f2sm127500wrq.69.2021.07.01.07.47.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Jul 2021 07:47:53 -0700 (PDT) Message-Id: <9fe902aad87f1192705fb69ea212a2d066d0286d.1625150864.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Thu, 01 Jul 2021 14:47:24 +0000 Subject: [PATCH v3 14/34] fsmonitor--daemon: implement 'start' command Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Johannes Schindelin , Jeff Hostetler , Derrick Stolee , Jeff Hostetler , Jeff Hostetler Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Jeff Hostetler From: Jeff Hostetler Implement 'git fsmonitor--daemon start' command. This command tries to start a daemon in the background. It creates a background process to run the daemon. The updated daemon does not actually do anything yet because the platform backends are still just stubs. Signed-off-by: Jeff Hostetler --- builtin/fsmonitor--daemon.c | 208 ++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c index a265c962ccc..7fcf960652f 100644 --- a/builtin/fsmonitor--daemon.c +++ b/builtin/fsmonitor--daemon.c @@ -9,6 +9,7 @@ #include "khash.h" static const char * const builtin_fsmonitor__daemon_usage[] = { + N_("git fsmonitor--daemon start []"), N_("git fsmonitor--daemon run []"), N_("git fsmonitor--daemon stop"), N_("git fsmonitor--daemon status"), @@ -22,6 +23,9 @@ static const char * const builtin_fsmonitor__daemon_usage[] = { #define FSMONITOR__IPC_THREADS "fsmonitor.ipcthreads" static int fsmonitor__ipc_threads = 8; +#define FSMONITOR__START_TIMEOUT "fsmonitor.starttimeout" +static int fsmonitor__start_timeout_sec = 60; + static int fsmonitor_config(const char *var, const char *value, void *cb) { if (!strcmp(var, FSMONITOR__IPC_THREADS)) { @@ -33,6 +37,15 @@ static int fsmonitor_config(const char *var, const char *value, void *cb) return 0; } + if (!strcmp(var, FSMONITOR__START_TIMEOUT)) { + int i = git_config_int(var, value); + if (i < 0) + return error(_("value of '%s' out of range: %d"), + FSMONITOR__START_TIMEOUT, i); + fsmonitor__start_timeout_sec = i; + return 0; + } + return git_default_config(var, value, cb); } @@ -256,6 +269,194 @@ static int try_to_run_foreground_daemon(void) return !!fsmonitor_run_daemon(); } +#ifdef GIT_WINDOWS_NATIVE +/* + * Create a background process to run the daemon. It should be completely + * disassociated from the terminal. + * + * Conceptually like `daemonize()` but different because Windows does not + * have `fork(2)`. Spawn a normal Windows child process but without the + * limitations of `start_command()` and `finish_command()`. + * + * The child process execs the "git fsmonitor--daemon run" command. + * + * The current process returns so that the caller can wait for the child + * to startup before exiting. + */ +static int spawn_background_fsmonitor_daemon(pid_t *pid) +{ + char git_exe[MAX_PATH]; + struct strvec args = STRVEC_INIT; + int in, out; + + GetModuleFileNameA(NULL, git_exe, MAX_PATH); + + in = open("/dev/null", O_RDONLY); + out = open("/dev/null", O_WRONLY); + + strvec_push(&args, git_exe); + strvec_push(&args, "fsmonitor--daemon"); + strvec_push(&args, "run"); + strvec_pushf(&args, "--ipc-threads=%d", fsmonitor__ipc_threads); + + *pid = mingw_spawnvpe(args.v[0], args.v, NULL, NULL, in, out, out); + close(in); + close(out); + + strvec_clear(&args); + + if (*pid < 0) + return error(_("could not spawn fsmonitor--daemon in the background")); + + return 0; +} +#else +/* + * Create a background process to run the daemon. It should be completely + * disassociated from the terminal. + * + * This is adapted from `daemonize()`. Use `fork()` to directly + * create and run the daemon in the child process. + * + * The fork-child can just call the run code; it does not need to exec + * it. + * + * The fork-parent returns the child PID so that we can wait for the + * child to startup before exiting. + */ +static int spawn_background_fsmonitor_daemon(pid_t *pid) +{ + *pid = fork(); + + switch (*pid) { + case 0: + if (setsid() == -1) + error_errno(_("setsid failed")); + close(0); + close(1); + close(2); + sanitize_stdfds(); + + return !!fsmonitor_run_daemon(); + + case -1: + return error_errno(_("could not spawn fsmonitor--daemon in the background")); + + default: + return 0; + } +} +#endif + +/* + * This is adapted from `wait_or_whine()`. Watch the child process and + * let it get started and begin listening for requests on the socket + * before reporting our success. + */ +static int wait_for_background_startup(pid_t pid_child) +{ + int status; + pid_t pid_seen; + enum ipc_active_state s; + time_t time_limit, now; + + time(&time_limit); + time_limit += fsmonitor__start_timeout_sec; + + for (;;) { + pid_seen = waitpid(pid_child, &status, WNOHANG); + + if (pid_seen == -1) + return error_errno(_("waitpid failed")); + else if (pid_seen == 0) { + /* + * The child is still running (this should be + * the normal case). Try to connect to it on + * the socket and see if it is ready for + * business. + * + * If there is another daemon already running, + * our child will fail to start (possibly + * after a timeout on the lock), but we don't + * care (who responds) if the socket is live. + */ + s = fsmonitor_ipc__get_state(); + if (s == IPC_STATE__LISTENING) + return 0; + + time(&now); + if (now > time_limit) + return error(_("fsmonitor--daemon not online yet")); + } else if (pid_seen == pid_child) { + /* + * The new child daemon process shutdown while + * it was starting up, so it is not listening + * on the socket. + * + * Try to ping the socket in the odd chance + * that another daemon started (or was already + * running) while our child was starting. + * + * Again, we don't care who services the socket. + */ + s = fsmonitor_ipc__get_state(); + if (s == IPC_STATE__LISTENING) + return 0; + + /* + * We don't care about the WEXITSTATUS() nor + * any of the WIF*(status) values because + * `cmd_fsmonitor__daemon()` does the `!!result` + * trick on all function return values. + * + * So it is sufficient to just report the + * early shutdown as an error. + */ + return error(_("fsmonitor--daemon failed to start")); + } else + return error(_("waitpid is confused")); + } +} + +static int try_to_start_background_daemon(void) +{ + pid_t pid_child; + int ret; + + /* + * Before we try to create a background daemon process, see + * if a daemon process is already listening. This makes it + * easier for us to report an already-listening error to the + * console, since our spawn/daemon can only report the success + * of creating the background process (and not whether it + * immediately exited). + */ + if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING) + die("fsmonitor--daemon is already running '%s'", + the_repository->worktree); + + printf(_("starting fsmonitor-daemon in '%s'\n"), + the_repository->worktree); + fflush(stdout); + + /* + * Run the actual daemon in a background process. + */ + ret = spawn_background_fsmonitor_daemon(&pid_child); + if (pid_child <= 0) + return ret; + + /* + * Wait (with timeout) for the background child process get + * started and begin listening on the socket/pipe. This makes + * the "start" command more synchronous and more reliable in + * tests. + */ + ret = wait_for_background_startup(pid_child); + + return ret; +} + int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix) { const char *subcmd; @@ -264,6 +465,10 @@ int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix) OPT_INTEGER(0, "ipc-threads", &fsmonitor__ipc_threads, N_("use ipc worker threads")), + OPT_INTEGER(0, "start-timeout", + &fsmonitor__start_timeout_sec, + N_("Max seconds to wait for background daemon startup")), + OPT_END() }; @@ -285,6 +490,9 @@ int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix) die(_("invalid 'ipc-threads' value (%d)"), fsmonitor__ipc_threads); + if (!strcmp(subcmd, "start")) + return !!try_to_start_background_daemon(); + if (!strcmp(subcmd, "run")) return !!try_to_run_foreground_daemon();