Your message dated Wed, 13 Mar 2013 16:04:11 +0100 with message-id <[email protected]> and subject line Re: file: "stdin: no read permission" if read from empty pipe has caused the Debian Bug report #508963, regarding file: "stdin: no read permission" if read from empty pipe to be marked as done.
This means that you claim that the problem has been dealt with. If this is not the case it is now your responsibility to reopen the Bug report if necessary, and/or fix the problem forthwith. (NB: If you are a system administrator and have no idea what this message is talking about, this may indicate a serious mail system misconfiguration somewhere. Please contact [email protected] immediately.) -- 508963: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=508963 Debian Bug Tracking System Contact [email protected] with problems
--- Begin Message ---Package: file Version: 4.26-2 Severity: normal file normally does sensible things with an empty file, e.g. $ touch empty; file empty empty: empty $ file - < empty /dev/stdin: empty but produces a confusing error message if you try to feed it an empty file via a pipe: $ cat empty | file /dev/stdin: no read permission I find this difference in strace logs suggestive: -fstat(0, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 +fstat(0, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0 read(0, ""..., 98304) = 0 +access(NULL, W_OK) = -1 EFAULT (Bad address) +access(NULL, X_OK) = -1 EFAULT (Bad address) -write(1, "/dev/stdin: empty\n"..., 18) = 18 +write(1, "/dev/stdin: no read permission\n"..., 31) = 31 I don't know what file is trying to do here (and I note that it is almost always wrong to use access()), but perhaps it is assuming that a failure of access() must be because of a lack of permissions, ignoring the possibility of a bad pointer ... I see it call access() with a sensible pathname if I try to use it on /etc/shadow from an unprivileged account; this also seems wrong -- it should take the EACCES result from the open() as authoritative -- but that might give some clues where things are going wrong in the code. -- System Information: Debian Release: 5.0 APT prefers unstable APT policy: (990, 'unstable'), (500, 'testing'), (1, 'experimental') Architecture: amd64 (x86_64) Kernel: Linux 2.6.26-1-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/bash Versions of packages file depends on: ii libc6 2.7-16 GNU C Library: Shared libraries ii libmagic1 4.26-2 File type determination library us ii zlib1g 1:1.2.3.3.dfsg-12 compression library - runtime file recommends no packages. file suggests no packages. -- no debconf information
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--- Begin Message ---file is not supposed to be used as '$whatever | file -' but as '$whatever | file --files-from -'. -- Address: Daniel Baumann, Donnerbuehlweg 3, CH-3012 Bern Email: [email protected] Internet: http://people.progress-technologies.net/~daniel.baumann/
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