1#!/bin/sh
2# Detect printf(3) failure even when it doesn't set stream error indicator
3
4# Copyright (C) 2007-2023 Free Software Foundation, Inc.
5
6# This program is free software: you can redistribute it and/or modify
7# it under the terms of the GNU General Public License as published by
8# the Free Software Foundation, either version 3 of the License, or
9# (at your option) any later version.
10
11# This program is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14# GNU General Public License for more details.
15
16# You should have received a copy of the GNU General Public License
17# along with this program.  If not, see <https://www.gnu.org/licenses/>.
18
19prog=printf
20
21. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
22print_ver_ printf
23
24vm=$(get_min_ulimit_v_ env $prog %20f 0) \
25  || skip_ "this shell lacks ulimit support"
26
27# Up to coreutils-6.9, "printf %.Nf 0" would encounter an ENOMEM internal
28# error from glibc's printf(3) function whenever N was large relative to
29# the size of available memory.  As of Oct 2007, that internal stream-
30# related failure was not reflected (for any libc I know of) in the usual
31# stream error indicator that is tested by ferror.  The result was that
32# while the printf command obviously failed (generated no output),
33# it mistakenly exited successfully (exit status of 0).
34
35# Testing it is tricky, because there is so much variance
36# in quality for this corner of printf(3) implementations.
37# Most implementations do attempt to allocate N bytes of storage.
38# Using the maximum value for N (2^31-1) causes glibc-2.7 to try to
39# allocate almost 2^64 bytes, while freeBSD 6.1's implementation
40# correctly outputs almost 2GB worth of 0's, which takes too long.
41# We want to test implementations that allocate N bytes, but without
42# triggering the above extremes.
43
44# Some other versions of glibc-2.7 have a snprintf function that segfaults
45# when an internal (technically unnecessary!) memory allocation fails.
46
47# The compromise is to limit virtual memory to something reasonable,
48# and to make an N-byte-allocating-printf require more than that, thus
49# triggering the printf(3) misbehavior -- which, btw, is required by ISO C99.
50
51mkfifo_or_skip_ fifo
52trap_sigpipe_or_skip_
53
54# Disable MALLOC_PERTURB_, to avoid triggering this bug
55# https://bugs.debian.org/481543#77
56export MALLOC_PERTURB_=0
57
58# Terminate any background process
59cleanup_() { kill $pid 2>/dev/null && wait $pid; }
60
61head -c 10 fifo > out & pid=$!
62
63# Trigger large mem allocation failure
64( trap '' PIPE && ulimit -v $vm && env $prog %20000000f 0 2>err-msg > fifo )
65exit=$?
66
67# Map this longer, and rarer, diagnostic to the common one.
68# printf: cannot perform formatted output: Cannot allocate memory"
69sed 's/cannot perform .*/write error/' err-msg > k && mv k err-msg
70err_msg=$(tr '\n' : < err-msg)
71
72# By some bug, on Solaris 11 (5.11 snv_86), err_msg ends up
73# containing '1> fifo:printf: write error:'.  Recognize that, too.
74
75case $err_msg in
76  "$prog: write error:"*) diagnostic=y ;;
77  "1> fifo:$prog: write error:") diagnostic=y ;;
78  '') diagnostic=n ;;
79  *) diagnostic=unexpected ;;
80esac
81n_out=$(wc -c < out)
82
83case $n_out:$diagnostic:$exit in
84  10:n:0) ;; # ok, succeeds w/no diagnostic: FreeBSD 6.1
85  10:y:1) ;; # ok, fails with EPIPE diagnostic: musl libc
86  0:y:1)  ;; # ok, glibc-2.8 and newer, when printf(3) fails with ENOMEM
87
88  # With MALLOC_PERTURB_=0, this no longer happens.
89  # *:139)     # segfault; known bug at least in debian unstable's libc6 2.7-11
90  #    echo 1>&2 "$0: bug in snprintf causes low-mem use of printf to segfault"
91  #    fail=77;;
92
93  # 10:y) ;; # Fail: doesn't happen: nobody succeeds with a diagnostic
94  # 0:n)  ;; # Fail pre-patch: no output, no diag
95  *) fail=1;;
96esac
97
98Exit $fail
99