From patchwork Wed Apr 29 17:36:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Blau X-Patchwork-Id: 11518039 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1004A92C for ; Wed, 29 Apr 2020 17:36:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7D2720B1F for ; Wed, 29 Apr 2020 17:36:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ttaylorr-com.20150623.gappssmtp.com header.i=@ttaylorr-com.20150623.gappssmtp.com header.b="p7MDWin9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726847AbgD2Rgi (ORCPT ); Wed, 29 Apr 2020 13:36:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726423AbgD2Rgh (ORCPT ); Wed, 29 Apr 2020 13:36:37 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C661FC03C1AE for ; Wed, 29 Apr 2020 10:36:37 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id fu13so1034121pjb.5 for ; Wed, 29 Apr 2020 10:36:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=m8WPRTZAA4ifjAR9b5/RmtGZJzGpRFy5RWTfVKbAGNM=; b=p7MDWin97u9/qwvuq817NQxJIQDjBLWEyMAy2uycqaoXZ6EVvt1ivwNOONDZJ3FeHJ xX+5Ee57JpsgvuZcDGIFyy6lXHmFKvbsrOkzvmAlzZVkktTuaVy79J9OnHzJjNRsZppB kTAHE1G5uv12Ew+nwvIr3dulq363l+sJ2HTvJQOKZXlnMAsnb56xJI5HTsK+Q47sBg1/ IyIFa8BX2ohwh6/DtdVefBv7pupeCG3cIc/CkPBnt3GU37wu39+2xKb0S2/ciXc8QIGF RA8Npq6ZcVFWl404euaMtzrIAAK1xr8pZlVxwLWa0p3vjFgD0gxf3d3JWVa9uQbfimmh m/+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=m8WPRTZAA4ifjAR9b5/RmtGZJzGpRFy5RWTfVKbAGNM=; b=JbeN0xJgA0Fx6tsFQg57lJdG+tjtv+rZB/bVWE+liGyuPZ3xDao8dFAi3kgJwBa/21 zZYf1J0t245mP7Mi3MdeTQb9knk4AlGdLhGpEFsb66lSIRY9PyJlXvuAsGiEjY0yOsoK 9XVxJueBFKvlb/gCgcbzbfPGVDiXKmup4dz9Om2UcFokrxjUN/kVrKhjkXDNKgbc0Iy0 w07qEa0aPAjRlALq6ka4krv3qvl+tX0/5hPdiT/YYHydwDceE6axqrDX1CdCO37grhJx ZoC2tOC6UvDUCF5UgC8O1s2HewWm/5BG+Xf0LHvZ9CQEd1phlsZ8KBRXJ919Dg7z86ol 97Fg== X-Gm-Message-State: AGi0PuaO9zxKV8yrPBpGMiIarX+56ct+SeAV8SvCGQJGyMTk50vXggJm McXHn4W+0fHKt7QBNBq0bqCcUt1sCKa4aQ== X-Google-Smtp-Source: APiQypI/hHhUfvIfeMokZKBdG7vGt9THszpzHOIIFtbSqQrfB+aaLzZKN8ofe/tZQ8hxoPvY/4Vq9A== X-Received: by 2002:a17:90a:25ea:: with SMTP id k97mr4547408pje.122.1588181796784; Wed, 29 Apr 2020 10:36:36 -0700 (PDT) Received: from localhost ([8.44.146.30]) by smtp.gmail.com with ESMTPSA id y7sm1541901pfq.21.2020.04.29.10.36.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2020 10:36:36 -0700 (PDT) Date: Wed, 29 Apr 2020 11:36:35 -0600 From: Taylor Blau To: git@vger.kernel.org Cc: peff@peff.net, dstolee@microsoft.com, gitster@pobox.com, mhagger@alum.mit.edu Subject: [PATCH v3 2/5] lockfile.c: introduce 'hold_lock_file_for_update_mode' Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org We use 'hold_lock_file_for_update' (and the '_timeout') variant to acquire a lock when updating references, the commit-graph file, and so on. In particular, the commit-graph machinery uses this to acquire a temporary file that is used to write a non-split commit-graph. In a subsequent commit, an issue in the commit-graph machinery produces graph files that have a different permission based on whether or not they are part of a multi-layer graph will be addressed. To do so, the commit-graph machinery will need a version of 'hold_lock_file_for_update' that takes the permission bits from the caller. Introduce such a function in this patch for both the 'hold_lock_file_for_update' and 'hold_lock_file_for_update_timeout' functions, and leave the existing functions alone by inlining their definitions in terms of the new mode variants. Note that, like in the previous commit, 'hold_lock_file_for_update_mode' is not guarenteed to set the given mode, since it may be modified by both the umask and 'core.sharedRepository'. Note also that even though the commit-graph machinery only calls 'hold_lock_file_for_update', that this is defined in terms of 'hold_lock_file_for_update_timeout', and so both need an additional mode parameter here. Signed-off-by: Taylor Blau --- lockfile.c | 18 ++++++++++-------- lockfile.h | 32 ++++++++++++++++++++++++++++---- 2 files changed, 38 insertions(+), 12 deletions(-) diff --git a/lockfile.c b/lockfile.c index 8e8ab4f29f..cc9a4b8428 100644 --- a/lockfile.c +++ b/lockfile.c @@ -70,7 +70,8 @@ static void resolve_symlink(struct strbuf *path) } /* Make sure errno contains a meaningful value on error */ -static int lock_file(struct lock_file *lk, const char *path, int flags) +static int lock_file(struct lock_file *lk, const char *path, int flags, + int mode) { struct strbuf filename = STRBUF_INIT; @@ -79,7 +80,7 @@ static int lock_file(struct lock_file *lk, const char *path, int flags) resolve_symlink(&filename); strbuf_addstr(&filename, LOCK_SUFFIX); - lk->tempfile = create_tempfile(filename.buf); + lk->tempfile = create_tempfile_mode(filename.buf, mode); strbuf_release(&filename); return lk->tempfile ? lk->tempfile->fd : -1; } @@ -99,7 +100,7 @@ static int lock_file(struct lock_file *lk, const char *path, int flags) * exactly once. If timeout_ms is -1, try indefinitely. */ static int lock_file_timeout(struct lock_file *lk, const char *path, - int flags, long timeout_ms) + int flags, long timeout_ms, int mode) { int n = 1; int multiplier = 1; @@ -107,7 +108,7 @@ static int lock_file_timeout(struct lock_file *lk, const char *path, static int random_initialized = 0; if (timeout_ms == 0) - return lock_file(lk, path, flags); + return lock_file(lk, path, flags, mode); if (!random_initialized) { srand((unsigned int)getpid()); @@ -121,7 +122,7 @@ static int lock_file_timeout(struct lock_file *lk, const char *path, long backoff_ms, wait_ms; int fd; - fd = lock_file(lk, path, flags); + fd = lock_file(lk, path, flags, mode); if (fd >= 0) return fd; /* success */ @@ -169,10 +170,11 @@ NORETURN void unable_to_lock_die(const char *path, int err) } /* This should return a meaningful errno on failure */ -int hold_lock_file_for_update_timeout(struct lock_file *lk, const char *path, - int flags, long timeout_ms) +int hold_lock_file_for_update_timeout_mode(struct lock_file *lk, + const char *path, int flags, + long timeout_ms, int mode) { - int fd = lock_file_timeout(lk, path, flags, timeout_ms); + int fd = lock_file_timeout(lk, path, flags, timeout_ms, mode); if (fd < 0) { if (flags & LOCK_DIE_ON_ERROR) unable_to_lock_die(path, errno); diff --git a/lockfile.h b/lockfile.h index 9843053ce8..db93e6ba73 100644 --- a/lockfile.h +++ b/lockfile.h @@ -90,6 +90,15 @@ * functions. In particular, the state diagram and the cleanup * machinery are all implemented in the tempfile module. * + * Permission bits + * --------------- + * + * If you call either `hold_lock_file_for_update_mode` or + * `hold_lock_file_for_update_timeout_mode`, you can specify a suggested + * mode for the underlying temporary file. Note that the file isn't + * guaranteed to have this exact mode, since it may be limited by either + * the umask, 'core.sharedRepository', or both. See `adjust_shared_perm` + * for more. * * Error handling * -------------- @@ -156,12 +165,20 @@ struct lock_file { * file descriptor for writing to it, or -1 on error. If the file is * currently locked, retry with quadratic backoff for at least * timeout_ms milliseconds. If timeout_ms is 0, try exactly once; if - * timeout_ms is -1, retry indefinitely. The flags argument and error - * handling are described above. + * timeout_ms is -1, retry indefinitely. The flags argument, error + * handling, and mode are described above. */ -int hold_lock_file_for_update_timeout( +int hold_lock_file_for_update_timeout_mode( struct lock_file *lk, const char *path, - int flags, long timeout_ms); + int flags, long timeout_ms, int mode); + +static inline int hold_lock_file_for_update_timeout( + struct lock_file *lk, const char *path, + int flags, long timeout_ms) +{ + return hold_lock_file_for_update_timeout_mode(lk, path, flags, + timeout_ms, 0666); +} /* * Attempt to create a lockfile for the file at `path` and return a @@ -175,6 +192,13 @@ static inline int hold_lock_file_for_update( return hold_lock_file_for_update_timeout(lk, path, flags, 0); } +static inline int hold_lock_file_for_update_mode( + struct lock_file *lk, const char *path, + int flags, int mode) +{ + return hold_lock_file_for_update_timeout_mode(lk, path, flags, 0, mode); +} + /* * Return a nonzero value iff `lk` is currently locked. */