From patchwork Wed Mar 20 16:16:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrey Drobyshev X-Patchwork-Id: 13598004 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C3DB5C54E58 for ; Wed, 20 Mar 2024 16:17:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rmyci-0007ZS-7w; Wed, 20 Mar 2024 12:17:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rmycc-0007TD-Be for qemu-devel@nongnu.org; Wed, 20 Mar 2024 12:16:59 -0400 Received: from relay.virtuozzo.com ([130.117.225.111]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rmyca-0003sn-Fg for qemu-devel@nongnu.org; Wed, 20 Mar 2024 12:16:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Message-Id:Date:Subject :From; bh=Ktcfn+truaHsgdVNaP0RGvkmq8oZrw57gpLOr+xG5Wc=; b=ek3tKiMNEnaNeMOADsG ChCXOKkdo7PKHra4hM/eSRrJ1Ln4zQxN9D4mJ8BmtFuDJpEwW/MpjPxkIDAIL7/rx1sGWJ/FJIpax aH5v4XWk9ymkK48gvajMuNMeNQ5SWV24LlL8V21CktTF2H3mY6EN6GH0ZzKOmQLKuSWklcy8HRVc8 aqYVPJrjf9AW1xmQ8b1fgjDtOI4OwngULIrHJ3lRwUjZ9/ajNFhyoO7CSJypK76iUKIsgYRqba2NJ BZIYQFK8NToHaNklcvJrHES7KxribORfp2m1K+ywpM7s4/47jh7tzFGJevmdS6fFXzAPoHWgilJkO L9KoNH5xAirwu2A==; Received: from [130.117.225.1] (helo=dev005.ch-qa.vzint.dev) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1rmyaM-006TNN-1j; Wed, 20 Mar 2024 17:16:37 +0100 From: Andrey Drobyshev To: qemu-devel@nongnu.org Cc: berrange@redhat.com, michael.roth@amd.com, kkostiuk@redhat.com, marcandre.lureau@redhat.com, philmd@linaro.org, andrey.drobyshev@virtuozzo.com, den@virtuozzo.com Subject: [PATCH v4 2/7] qga: introduce ga_run_command() helper for guest cmd execution Date: Wed, 20 Mar 2024 18:16:43 +0200 Message-Id: <20240320161648.158226-3-andrey.drobyshev@virtuozzo.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20240320161648.158226-1-andrey.drobyshev@virtuozzo.com> References: <20240320161648.158226-1-andrey.drobyshev@virtuozzo.com> MIME-Version: 1.0 Received-SPF: pass client-ip=130.117.225.111; envelope-from=andrey.drobyshev@virtuozzo.com; helo=relay.virtuozzo.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org When executing guest commands in *nix environment, we repeat the same fork/exec pattern multiple times. Let's just separate it into a single helper which would also be able to feed input data into the launched process' stdin. This way we can avoid code duplication. To keep the history more bisectable, let's replace qmp commands implementations one by one. Also add G_GNUC_UNUSED attribute to the helper and remove it in the next commit. Originally-by: Yuri Pudgorodskiy Signed-off-by: Andrey Drobyshev Reviewed-by: Daniel P. Berrangé --- qga/commands-posix.c | 150 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 7df2d72e9f..9b1bdf194c 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -76,6 +76,156 @@ static void ga_wait_child(pid_t pid, int *status, Error **errp) g_assert(rpid == pid); } +static ssize_t ga_pipe_read_str(int fd[2], char **str) +{ + ssize_t n, len = 0; + char buf[1024]; + + close(fd[1]); + fd[1] = -1; + while ((n = read(fd[0], buf, sizeof(buf))) != 0) { + if (n < 0) { + if (errno == EINTR) { + continue; + } else { + len = -errno; + break; + } + } + *str = g_realloc(*str, len + n + 1); + memcpy(*str + len, buf, n); + len += n; + *str[len] = '\0'; + } + close(fd[0]); + fd[0] = -1; + + return len; +} + +/* + * Helper to run command with input/output redirection, + * sending string to stdin and taking error message from + * stdout/err. + */ +G_GNUC_UNUSED +static int ga_run_command(const char *argv[], const char *in_str, + const char *action, Error **errp) +{ + pid_t pid; + int status; + int retcode = -1; + int infd[2] = { -1, -1 }; + int outfd[2] = { -1, -1 }; + char *str = NULL; + ssize_t len = 0; + + if ((in_str && !g_unix_open_pipe(infd, FD_CLOEXEC, NULL)) || + !g_unix_open_pipe(outfd, FD_CLOEXEC, NULL)) { + error_setg(errp, "cannot create pipe FDs"); + goto out; + } + + pid = fork(); + if (pid == 0) { + char *cherr = NULL; + + setsid(); + + if (in_str) { + /* Redirect stdin to infd. */ + close(infd[1]); + dup2(infd[0], 0); + close(infd[0]); + } else { + reopen_fd_to_null(0); + } + + /* Redirect stdout/stderr to outfd. */ + close(outfd[0]); + dup2(outfd[1], 1); + dup2(outfd[1], 2); + close(outfd[1]); + + execvp(argv[0], (char *const *)argv); + + /* Write the cause of failed exec to pipe for the parent to read it. */ + cherr = g_strdup_printf("failed to exec '%s'", argv[0]); + perror(cherr); + g_free(cherr); + _exit(EXIT_FAILURE); + } else if (pid < 0) { + error_setg_errno(errp, errno, "failed to create child process"); + goto out; + } + + if (in_str) { + close(infd[0]); + infd[0] = -1; + if (qemu_write_full(infd[1], in_str, strlen(in_str)) != + strlen(in_str)) { + error_setg_errno(errp, errno, "%s: cannot write to stdin pipe", + action); + goto out; + } + close(infd[1]); + infd[1] = -1; + } + + len = ga_pipe_read_str(outfd, &str); + if (len < 0) { + error_setg_errno(errp, -len, "%s: cannot read from stdout/stderr pipe", + action); + goto out; + } + + ga_wait_child(pid, &status, errp); + if (*errp) { + goto out; + } + + if (!WIFEXITED(status)) { + if (len) { + error_setg(errp, "child process has terminated abnormally: %s", + str); + } else { + error_setg(errp, "child process has terminated abnormally"); + } + goto out; + } + + retcode = WEXITSTATUS(status); + + if (WEXITSTATUS(status)) { + if (len) { + error_setg(errp, "child process has failed to %s: %s", + action, str); + } else { + error_setg(errp, "child process has failed to %s: exit status %d", + action, WEXITSTATUS(status)); + } + goto out; + } + +out: + g_free(str); + + if (infd[0] != -1) { + close(infd[0]); + } + if (infd[1] != -1) { + close(infd[1]); + } + if (outfd[0] != -1) { + close(outfd[0]); + } + if (outfd[1] != -1) { + close(outfd[1]); + } + + return retcode; +} + void qmp_guest_shutdown(const char *mode, Error **errp) { const char *shutdown_flag;