From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f181.google.com (mail-qk1-f181.google.com [209.85.222.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9AEEF29BD80 for ; Wed, 25 Feb 2026 20:17:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772050651; cv=none; b=rFvR2WFJS1Z9nWRoex17jPLmqivDxwxv71tEDny5usNLSoDFlHBquIpM5bHHV8ymUF6yA2yCwEYT5tp4vZaSZ72qqFIpjetTz7Yq6vuI0EGTWisGbUqryy5295W0nu1xnKfVVS+r/bs+LABccP1NZGmb/gRdX7wlcgFeRV5HvS4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772050651; c=relaxed/simple; bh=JOAUQgtalMHRhgdNV/YeiqvOLi3+yXa+k5LuMfKxqRU=; h=Message-Id:In-Reply-To:References:From:Date:Subject:Content-Type: MIME-Version:To:Cc; b=EgdV2e/eVUAqaalDd51/h9Yix/1+LKOi2Tlqy/rT7SBI5S9TW4pljLyTDUdZZDqV3oi1mGXc8ahln0FxV0TSO9AWQzh1EAedR4I8HqQXwx0wnqZz0yKB0QKzkZBYy18L7G8MsQYiKQ0BtYGjOfFf/Ah0QhmnOzS5T8XRRh6Cq70= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=FdRgwzx9; arc=none smtp.client-ip=209.85.222.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FdRgwzx9" Received: by mail-qk1-f181.google.com with SMTP id af79cd13be357-8cb3e22435fso109285185a.1 for ; Wed, 25 Feb 2026 12:17:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1772050649; x=1772655449; darn=vger.kernel.org; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:from:to:cc:subject:date :message-id:reply-to; bh=BbDNRmr8p87w3ZUQ1LQGNLGseO50776wwblaeHGbHPU=; b=FdRgwzx9+PuSSYOQpSBruB9T88ShPbbYeeuEO9y/gaBUQhRfWLfkAd/raEhaf1lN++ f2NYhErWyDmDlX59pcP82MkDVAlmsIMHHtZTPHnynHvBu1LnlbNEXpBqzzAr0dg1XLD7 fZK/RjBSkHC1P8qOztj+9HMkbbdWr5na0SxwrnGL4jHVwYz0WsW2AVfRFnbKNXpA04Mc AsiqnungoiXtjNVYMAt/SbsPOnH4ZC6roO0XIzuj8hiTmxkrCMludY8SpKht26NQscqb wUmqpg96C+7fbjxT9LVJzUdmd+S62aBaWw1KBnxPYu4WPXGRXabDo4rksDsfkN6MUQu6 4SWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772050649; x=1772655449; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=BbDNRmr8p87w3ZUQ1LQGNLGseO50776wwblaeHGbHPU=; b=wdZ3HAMWDSd3LfLsonI82US+z7xwhyXnWe/u33vXQemo5fW6mcA4q2yk+wN+4mbXUh 5p2JqPWgCtHDrlBTu9bpkrO1qBApLQBE9tsGlc5ZmPXP3alCneJdWxf21kpZagDr0yWA 5/4tEuqCpKZVMyAk+bS5DrCzWhrvMYrSelq69oMUjj0j5kvyf4nVegwyI35Bpx7Pntnn 24GiitK00MG2sa8G4oR3G8ZHXKLejwiimEINbo7wTHDQE3ELd5D0nArVfeJYhjtys4Oi 5dzkJO5qXP0A4JBC7jqQarL3fdobbiWtjktId9TeaCznPat4u12ENHlI0OwWosgc01xU D7og== X-Gm-Message-State: AOJu0YxbmPDPMz7dgnGiTyvHMXa+nwc6fybmuFttxIE/rQejxVkKKW6u 49RRSaZvaxY1bWvaoEN/Xv25UGqiTS2K+Qi3afBMW7ExP2RXWiA6LlY0nwwyFA== X-Gm-Gg: ATEYQzy2Zx+CcrtIOyd1t+StM3dVMfww8DZtD/FCevruICrHEef8ZycUIbhU/sRcuVF b44NAOfcZ8Js7wHXjDbEH5DAJRHyHIvANAwpLAkC/NWFK9mra+m2qAvogcB/3N1uML+2JQ+Qj9n 5Ga1it4gQuqjIJX8a4O7IU9AotWA1vcjNfNC6RygAoMq6DWqTY5Qn9qaN16x4TmdeB5UF2NetEU 5kII38RZ05vU2DIkQJA3ByyH2/cDcwaRMo659o6TWkTG1BuqrEkhitw5Lw5mICT3paUoXbdm+2H RXdrbBLldcL+YWuGLWuI/eriIOrx/zPUVEqr2V0QV+I9ovXQu35uVx0c9wryGL8lK0UEoD5jUSe bK1K8aYZi5sAewlAgjH8QMt3C4ZmRbylJmzQfzKxls+Q8lUq2IqUBK0bsKj26XT5YCtzFOMQaKn 1qaT8h8bz/fKCEtAQ/OnxXw11wjoiIAlic1Smr X-Received: by 2002:a05:620a:700c:b0:8c6:b05b:1f33 with SMTP id af79cd13be357-8cbbf35211emr50230885a.9.1772050649090; Wed, 25 Feb 2026 12:17:29 -0800 (PST) Received: from [127.0.0.1] ([135.119.235.86]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-899b3863174sm34841846d6.25.2026.02.25.12.17.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Feb 2026 12:17:28 -0800 (PST) Message-Id: <817489b3ea6a0831e4b815df1c4a0c0e100a2683.1772050636.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Paul Tarjan via GitGitGadget" Date: Wed, 25 Feb 2026 20:17:15 +0000 Subject: [PATCH v6 09/10] run-command: add close_fd_above_stderr option Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: git@vger.kernel.org Cc: Patrick Steinhardt , Paul Tarjan , Paul Tarjan From: Paul Tarjan Add a new option to struct child_process that closes file descriptors 3 and above in the child after forking but before exec. This prevents long-running child processes from inheriting pipe endpoints or other descriptors from the parent environment. The upper bound for the fd scan comes from sysconf(_SC_OPEN_MAX), capped at 4096 to avoid excessive iteration when the limit is set very high. Signed-off-by: Paul Tarjan --- run-command.c | 11 +++++++++++ run-command.h | 9 +++++++++ 2 files changed, 20 insertions(+) diff --git a/run-command.c b/run-command.c index e3e02475cc..cbadcf5ff8 100644 --- a/run-command.c +++ b/run-command.c @@ -832,6 +832,17 @@ fail_pipe: child_close(cmd->out); } + if (cmd->close_fd_above_stderr) { + long max_fd = sysconf(_SC_OPEN_MAX); + int fd; + if (max_fd < 0 || max_fd > 4096) + max_fd = 4096; + for (fd = 3; fd < max_fd; fd++) { + if (fd != child_notifier) + close(fd); + } + } + if (cmd->dir && chdir(cmd->dir)) child_die(CHILD_ERR_CHDIR); diff --git a/run-command.h b/run-command.h index 0df25e445f..a1aa1b1069 100644 --- a/run-command.h +++ b/run-command.h @@ -141,6 +141,15 @@ struct child_process { unsigned stdout_to_stderr:1; unsigned clean_on_exit:1; unsigned wait_after_clean:1; + + /** + * Close file descriptors 3 and above in the child after forking + * but before exec. This prevents the long-running child from + * inheriting pipe endpoints or other descriptors from the parent + * environment (e.g., the test harness). + */ + unsigned close_fd_above_stderr:1; + void (*clean_on_exit_handler)(struct child_process *process); }; -- gitgitgadget