From 8e29cc911e8bd3267d1367444e3c4a829001fd4f Mon Sep 17 00:00:00 2001 From: Assaf Gordon Date: Sun, 17 Apr 2016 02:28:13 -0400 Subject: [PATCH] seq: detect and report I/O errors immediately Ensure I/O errors are detected (and terminate seq), preventing seq from infloop (or running for long time with a large range) upon write errors or ignored SIGPIPE. Examples: seq 1 inf > /dev/full (seq_fast) seq 1.1 0.1 inf >/dev/full (print_numbers) * src/seq.c (io_error): A new function to diagnose appropriate stdio errors and exit the program with failure status. (seq_fast, print_numbers): Explicitly check for write errors and terminate the program with diagnostic. * tests/misc/seq-io-errors.sh: Test error detection with /dev/full. * tests/misc/seq-epipe.sh: Test error detection with broken pipes. * tests/local.mk: Add new tests. * NEWS: Mention the fix. --- NEWS | 3 +++ src/seq.c | 24 ++++++++++++++++++----- tests/local.mk | 2 ++ tests/misc/seq-epipe.sh | 46 +++++++++++++++++++++++++++++++++++++++++++++ tests/misc/seq-io-errors.sh | 46 +++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 116 insertions(+), 5 deletions(-) create mode 100755 tests/misc/seq-epipe.sh create mode 100755 tests/misc/seq-io-errors.sh diff --git a/NEWS b/NEWS index 4cb5caf..e420716 100644 --- a/NEWS +++ b/NEWS @@ -15,6 +15,9 @@ GNU coreutils NEWS -*- outline -*- stty --help no longer outputs extraneous gettext header lines for translated languages. [bug introduced in coreutils-8.24] + seq now immediately exits upon write errors. + [This bug was present in "the beginning".] + ** Changes in behavior seq no longer accepts 0 value as increment, and now also rejects NaN diff --git a/src/seq.c b/src/seq.c index de92bc2..1b9da40 100644 --- a/src/seq.c +++ b/src/seq.c @@ -278,6 +278,15 @@ long_double_format (char const *fmt, struct layout *layout) } } +static void ATTRIBUTE_NORETURN +io_error (void) +{ + /* FIXME: consider option to silently ignore errno=EPIPE */ + error (0, errno, _("standard output")); + clearerr (stdout); + exit (EXIT_FAILURE); +} + /* Actually print the sequence of numbers in the specified range, with the given or default stepping and format. */ @@ -295,7 +304,8 @@ print_numbers (char const *fmt, struct layout layout, for (i = 1; ; i++) { long double x0 = x; - printf (fmt, x); + if (printf (fmt, x) < 0) + io_error (); if (out_of_range) break; x = first + i * step; @@ -336,10 +346,12 @@ print_numbers (char const *fmt, struct layout layout, break; } - fputs (separator, stdout); + if (fputs (separator, stdout) == EOF) + io_error (); } - fputs (terminator, stdout); + if (fputs (terminator, stdout) == EOF) + io_error (); } } @@ -506,14 +518,16 @@ seq_fast (char const *a, char const *b) output buffer so far, and reset to start of buffer. */ if (buf_end - (p_len + 1) < bufp) { - fwrite (buf, bufp - buf, 1, stdout); + if (fwrite (buf, bufp - buf, 1, stdout) != 1) + io_error (); bufp = buf; } } /* Write any remaining buffered output, and the terminator. */ *bufp++ = *terminator; - fwrite (buf, bufp - buf, 1, stdout); + if (fwrite (buf, bufp - buf, 1, stdout) != 1) + io_error (); IF_LINT (free (buf)); } diff --git a/tests/local.mk b/tests/local.mk index a83c3d0..7bea2c3 100644 --- a/tests/local.mk +++ b/tests/local.mk @@ -235,6 +235,8 @@ all_tests = \ tests/misc/ptx.pl \ tests/misc/test.pl \ tests/misc/seq.pl \ + tests/misc/seq-epipe.sh \ + tests/misc/seq-io-errors.sh \ tests/misc/seq-long-double.sh \ tests/misc/seq-precision.sh \ tests/misc/head.pl \ diff --git a/tests/misc/seq-epipe.sh b/tests/misc/seq-epipe.sh new file mode 100755 index 0000000..21e9322 --- /dev/null +++ b/tests/misc/seq-epipe.sh @@ -0,0 +1,46 @@ +#!/bin/sh +# Test for proper detection of EPIPE with ignored SIGPIPE + +# Copyright (C) 2016 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 +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src +print_ver_ seq + +# upon EPIPE with signals ignored, 'seq' should exit with an error. +(trap '' PIPE; + timeout 10 sh -c '( (seq inf 2>err ; echo $?>code) | head -n1)'>/dev/null) + +# Exit-code must be 1, indicating 'write error' +cat << \EOF > exp || framework_failure_ +1 +EOF +if test -e code ; then + compare exp code || fail=1 +else + # 'exitcode' file was not created + warn_ "missing exit code file (seq failed to detect EPIPE?)" + fail=1 +fi + +# The error message must begin with "standard output:" +# (but don't hard-code the strerror text) +compare_dev_null_ /dev/null err +if ! grep -qE '^seq: standard output: .+$' err ; then + warn_ "seq emitted incorrect error on EPIPE" + fail=1 +fi + +Exit $fail diff --git a/tests/misc/seq-io-errors.sh b/tests/misc/seq-io-errors.sh new file mode 100755 index 0000000..8007187 --- /dev/null +++ b/tests/misc/seq-io-errors.sh @@ -0,0 +1,46 @@ +#!/bin/sh +# Test for proper detection of I/O errors in seq + +# Copyright (C) 2016 Free Software Foundation, Inc. + +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src +print_ver_ seq + +if ! test -w /dev/full || ! test -c /dev/full; then + skip_ '/dev/full is required' +fi + +# Run 'seq' with a timeout, preventing infinite-loop run. +# expected returned codes: +# 1 - seq detected an I/O error and exited with an error. +# 124 - timed-out (seq likely infloop) +# other - unexpected error +timed_seq_fail() { timeout 10 seq "$@" >/dev/full 2>/dev/null; } + + +# Test infinite sequence, using fast-path method (seq_fast). +returns_ 1 timed_seq_fail 1 inf || fail=1 + +# Test infinite sequence, using slow-path method (print_numbers). +returns_ 1 timed_seq_fail 1.1 .1 inf || fail=1 + +# Test non-infinite sequence, using slow-path method (print_numbers). +# (despite being non-infinite, the entire sequence should take long time to +# print. Thus, either an I/O error is detected immediately, or seq will +# timeout). +returns_ 1 timed_seq_fail 1 0.0001 99999999 || fail=1 + +Exit $fail -- 2.7.0