tests/misc/printf-surprise.sh

   1 #!/bin/sh
   2 # Detect printf(3) failure even when it doesn't set stream error indicator
   3
   4 # Copyright (C) 2007-2016 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 <http://www.gnu.org/licenses/>.
  18
  19 prog=printf
  20
  21 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  22 print_ver_ printf
  23
  24 vm=$(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
  51 mkfifo_or_skip_ fifo
  52
  53 # Disable MALLOC_PERTURB_, to avoid triggering this bug
  54 # http://bugs.debian.org/481543#77
  55 export MALLOC_PERTURB_=0
  56
  57 # Terminate any background process
  58 cleanup_() { kill $pid 2>/dev/null && wait $pid; }
  59
  60 head -c 10 fifo > out & pid=$!
  61
  62 # Trigger large mem allocation failure
  63 ( ulimit -v $vm && env $prog %20000000f 0 2>err-msg > fifo )
  64 exit=$?
  65
  66 # Map this longer, and rarer, diagnostic to the common one.
  67 # printf: cannot perform formatted output: Cannot allocate memory" \
  68 sed 's/cannot perform .*/write error/' err-msg > k && mv k err-msg
  69 err_msg=$(tr '\n' : < err-msg)
  70
  71 # By some bug, on Solaris 11 (5.11 snv_86), err_msg ends up
  72 # containing '1> fifo:printf: write error:'.  Recognize that, too.
  73
  74 case $err_msg in
  75   "$prog: write error:"*) diagnostic=y ;;
  76   "1> fifo:$prog: write error:") diagnostic=y ;;
  77   '') diagnostic=n ;;
  78   *) diagnostic=unexpected ;;
  79 esac
  80 n_out=$(wc -c < out)
  81
  82 case $n_out:$diagnostic:$exit in
  83   10:n:0) ;; # ok, succeeds w/no diagnostic: FreeBSD 6.1
  84   0:y:1)  ;; # ok, glibc-2.8 and newer, when printf(3) fails with ENOMEM
  85
  86   # With MALLOC_PERTURB_=0, this no longer happens.
  87   # *:139)     # segfault; known bug at least in debian unstable's libc6 2.7-11
  88   #    echo 1>&2 "$0: bug in snprintf causes low-mem use of printf to segfault"
  89   #    fail=77;;
  90
  91   # 10:y) ;; # Fail: doesn't happen: nobody succeeds with a diagnostic
  92   # 0:n)  ;; # Fail pre-patch: no output, no diag
  93   *) fail=1;;
  94 esac
  95
  96 Exit $fail