From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 12F6538515EC; Tue, 20 Jul 2021 15:55:28 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 12F6538515EC From: "enometh at meer dot net" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/101510] std::filesystem::create_directory on an existing symlink to a directory Date: Tue, 20 Jul 2021 15:55:27 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 11.1.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: enometh at meer dot net X-Bugzilla-Status: WAITING X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: redi at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Jul 2021 15:55:28 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101510 --- Comment #5 from Madhu --- * "redi at gcc dot gnu.org" Wrote on Tue, 20 Jul 2021 11:46:32 +0000 > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101510 > > --- Comment #2 from Jonathan Wakely --- > (In reply to Madhu from comment #0) >> cppreference.com states >> >> ``` >> bool create_directory( const std::filesystem::path& p ); >> >> Creates the directory p as if by POSIX mkdir() with a second argument of >> static_cast(std::filesystem::perms::all) (the parent directory must >> already exist). If the function fails because p resolves to an existing >> directory, no error is reported. Otherwise on failure an error is report= ed. >> ``` >> >> This should accomodate situations when `p' resolves to an existing direc= tory >> when `p' it is a symbolic link. >> >> However create_directory(p) fails when p is a symbolic link which points >> to an existing directory. >> >> The standard usage pattern is to call mkdir(p) - and if it fails on EEXI= ST >> to stat(2) p - following symlinks, and check if is a directory. The patt= ern >> is used to ensure that `p' can be treated as a directory for further >> operations and this includes p being a symbolic link to a directory) > > You can do this with create_directory. If create_directory(p) doesn't thr= ow an > exception, then is_directory(p) is true. Or without exceptions: > > std::error_code ec; > create_directory(p, ec); > if (!ec) > { > // p resolves to a directory > } > It looks like I did indeed get the semantics wrong I was going by the usage from databasePath() in https://github.com/WebKit/WebKit/blob/main/Source/WebKit/NetworkProcess/Web= Storage/LocalStorageDatabaseTracker.cpp#L142 which calls ensureDatabaseDirectoryExists() in https://github.com/WebKit/WebKit/blob/main/Source/WebCore/platform/sql/SQLi= teFileSystem.cpp#L59 which calls makeAllDirectories() https://github.com/WebKit/WebKit/blob/main/Source/WTF/wtf/FileSystem.cpp#L7= 33 The check is for only on the boolean value of ec, which is wrong according to the spec, Thanks! Instead of precipitately filing the bug here I should have filed it with WebKit.=