From 790892db657ac79b0ba5f7a69cc7e70eb4fed8e0 Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Thu, 8 Jun 2006 20:13:37 +0000 Subject: [PATCH] Ensure that cat works with any of the options, -A -v -e -E -T, when applied to files in /proc and /sys, even when the FIONREAD ioctl produces nonsensical results. Before this change, cat would produce no output (or truncated output), for some linux kernels. * src/cat.c (write_pending): New function, factored out of cat. (cat): Also interpret a negative ioctl/FIONREAD count as indicating that there are bytes to read. Some versions of linux-2.6.16 do that. Write any pending output before returning. Reported by Dan Jacobson in . * NEWS: Mention this bug fix. * tests/misc/cat-proc: New file. Test for the above. * tests/misc/Makefile.am (TESTS): Add cat-proc. --- ChangeLog | 18 +++++++++++++++++- NEWS | 4 ++++ src/cat.c | 32 ++++++++++++++++++++++++-------- tests/misc/Makefile.am | 1 + tests/misc/cat-proc | 42 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 88 insertions(+), 9 deletions(-) create mode 100755 tests/misc/cat-proc diff --git a/ChangeLog b/ChangeLog index 0036b94..805965d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,7 +1,23 @@ -2006-06-07 Paul Eggert +2006-06-08 Jim Meyering * Version 6.0-cvs. + Ensure that cat works with any of the options, -A -v -e -E -T, + when applied to files in /proc and /sys, even when the FIONREAD + ioctl produces nonsensical results. Before this change, cat would + produce no output (or truncated output), for some linux kernels. + + * src/cat.c (write_pending): New function, factored out of cat. + (cat): Also interpret a negative ioctl/FIONREAD count as indicating + that there are bytes to read. Some versions of linux-2.6.16 do that. + Write any pending output before returning. + Reported by Dan Jacobson in . + * NEWS: Mention this bug fix. + * tests/misc/cat-proc: New file. Test for the above. + * tests/misc/Makefile.am (TESTS): Add cat-proc. + +2006-06-07 Paul Eggert + * src/expr.c (eval4): Detect overflow properly when multiplying INTMAX_MIN * -1. diff --git a/NEWS b/NEWS index be511eb..fdca452 100644 --- a/NEWS +++ b/NEWS @@ -138,6 +138,10 @@ GNU coreutils NEWS -*- outline -*- ** Bug fixes + cat with any of the options, -A -v -e -E -T, when applied to a + file in /proc or /sys (linux-specific), would truncate its output, + usually printing nothing. + cp -p would fail in a /proc-less chroot, on some systems When `cp -RL' encounters the same directory more than once in the diff --git a/src/cat.c b/src/cat.c index b08e91e..ec2c528 100644 --- a/src/cat.c +++ b/src/cat.c @@ -1,5 +1,5 @@ /* cat -- concatenate files and print on the standard output. - Copyright (C) 88, 90, 91, 1995-2005 Free Software Foundation, Inc. + Copyright (C) 88, 90, 91, 1995-2006 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -195,6 +195,22 @@ simple_cat ( } } +/* Write any pending output to STDOUT_FILENO. + Pending is defined to be the *BPOUT - OUTBUF bytes starting at OUTBUF. + Then set *BPOUT to OUTPUT if it's not already that value. */ + +static inline void +write_pending (char *outbuf, char **bpout) +{ + size_t n_write = *bpout - outbuf; + if (0 < n_write) + { + if (full_write (STDOUT_FILENO, outbuf, n_write) != n_write) + error (EXIT_FAILURE, errno, _("write error")); + *bpout = outbuf; + } +} + /* Cat the file behind INPUT_DESC to the file behind OUTPUT_DESC. Return true if successful. Called if any option more than -u was specified. @@ -291,6 +307,7 @@ cat ( if (bpin > eob) { + bool input_pending = false; #ifdef FIONREAD int n_to_read = 0; @@ -318,15 +335,12 @@ cat ( return false; } } - if (n_to_read == 0) + if (n_to_read != 0) + input_pending = true; #endif - { - size_t n_write = bpout - outbuf; - if (full_write (STDOUT_FILENO, outbuf, n_write) != n_write) - error (EXIT_FAILURE, errno, _("write error")); - bpout = outbuf; - } + if (input_pending) + write_pending (outbuf, &bpout); /* Read more input into INBUF. */ @@ -334,11 +348,13 @@ cat ( if (n_read == SAFE_READ_ERROR) { error (0, errno, "%s", infile); + write_pending (outbuf, &bpout); newlines2 = newlines; return false; } if (n_read == 0) { + write_pending (outbuf, &bpout); newlines2 = newlines; return true; } diff --git a/tests/misc/Makefile.am b/tests/misc/Makefile.am index 5f6b07a..696b9fd 100644 --- a/tests/misc/Makefile.am +++ b/tests/misc/Makefile.am @@ -18,6 +18,7 @@ TESTS_ENVIRONMENT = \ # will execute the test script rather than the standard utility. TESTS = \ + cat-proc \ base64 \ basename \ close-stdout \ diff --git a/tests/misc/cat-proc b/tests/misc/cat-proc new file mode 100755 index 0000000..69e2065 --- /dev/null +++ b/tests/misc/cat-proc @@ -0,0 +1,42 @@ +#!/bin/sh +# Ensure that cat -E produces same output as cat, module `$'s, +# even when applied to a file in /proc. + +if test "$VERBOSE" = yes; then + set -x + cat --version +fi + +pwd=`pwd` +t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$ +trap 'status=$?; cd $pwd; chmod -R u+rwx $t0; rm -rf $t0 && exit $status' 0 +trap '(exit $?); exit $?' 1 2 13 15 + +framework_failure=0 +mkdir -p $tmp || framework_failure=1 +cd $tmp || framework_failure=1 + +if test $framework_failure = 1; then + echo "$0: failure in testing framework" 1>&2 + (exit 1); exit 1 +fi + +f=/proc/cpuinfo +test -f $f \ + || { + echo "$0: no $f skipping this test" 1>&2 + (exit 77); exit 77 + } + +fail=0 + +# Yes, parts of /proc/cpuinfo might change between cat runs. +# If that happens, consider choosing a file that's less likely to change, +# or just filter out the changing lines. +cat -E $f | tr -d '$' > out || fail=1 +cat $f | tr -d '$' > exp || fail=1 + +cmp out exp || fail=1 +test $fail = 1 && diff out exp 2> /dev/null + +(exit $fail); exit $fail -- 2.7.4