From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.2 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by inbox.vuxu.org (OpenSMTPD) with SMTP id 9a2c4551 for ; Mon, 10 Feb 2020 14:57:11 +0000 (UTC) Received: (qmail 26170 invoked by uid 550); 10 Feb 2020 14:57:09 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 26150 invoked from network); 10 Feb 2020 14:57:08 -0000 Date: Mon, 10 Feb 2020 09:56:55 -0500 From: Rich Felker To: Alexander Scherbatiy Cc: musl@lists.openwall.com Message-ID: <20200210145655.GQ1663@brightrain.aerifal.cx> References: <20200207210331.GK1663@brightrain.aerifal.cx> <20200208161908.GN1663@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: Rich Felker Subject: Re: [musl] fopen with "e" mode to close file descriptor in exec... functions On Mon, Feb 10, 2020 at 12:57:00PM +0300, Alexander Scherbatiy wrote: > Just a question about lsof options. On Ubuntu "lsof -q" gives: "lsof: > illegal option character: q". > Shouldn't busybox "lsof -p" give the similar error message? > > Is there an open request to support "lsof -p" option in busybox? You could just install the full lsof with "apk add lsof". But there's also a busybox bugtracker you could request it on. I think at least if they're not going to support the options, busybox should error out on them rather than ignoring them. Rich > On 08.02.2020 19:19, Rich Felker wrote: > > On Sat, Feb 08, 2020 at 10:45:10AM +0300, Alexander Scherbatiy wrote: > >> Below are steps to reproduce it in docker, logs from docker and strace log. > >> > >>> docker run --rm -it alpine:3.11.3 ash > >>> apk add gcc > >>> apk add libc-dev > >> Copy the posix_spawn_sample.c code below (note it uses "ash" in 'char > >> *argv[] = {"ash", ,,,}' for posix_spawn on Alpine Linux ) > >> > >>> gcc -o posix_spawn_sample posix_spawn_sample.c > >>> ./posix_spawn_sample > >> --- output --- > >> / # ./posix_spawn_sample > >> Child pid: 17 > >> PID=17 > >> 1 /bin/busybox /dev/pts/0 > >> 1 /bin/busybox /dev/pts/0 > >> 1 /bin/busybox /dev/pts/0 > >> 1 /bin/busybox /dev/tty > >> 16 /posix_spawn_sample /dev/pts/0 > >> 16 /posix_spawn_sample /dev/pts/0 > >> 16 /posix_spawn_sample /dev/pts/0 > >> 16 /posix_spawn_sample /test.log > >> ---------------- > >> > >> Note that "test.log" file is listed by "lsof -p PID" command. > > It's listed as being owned by pid 16, the parent, not pid 17, the > > child. That's expected. At first I didn't understand why lsof -p is > > showing these additional pids (parent and init) in addition to the > > requested one. But it seems since you're using Docker those are the > > *only* pids running, and you just hit the issue that busybox lsof does > > not support -p (or any options at all) and always lists all open files > > for all processes. > > > > It would be a lot better to have your test do like I suggested and ls > > -l /proc/$$/fd rather than running lsof. Then you will very clearly > > that the log file is not open. Or even run an interactive shell as the > > child so you can explore /proc yourself from it. > > > > Rich