zgrep: fix shell portability bug with -f; fix mishandling of "-e -"

* tests/zgrep-f: Check for "zgrep -e -" bug, too.
* zgrep.in: Don't assume that if the shell redirects fd 6, then
this redirection is visible to the subsidiary grep.  POSIX doesn't
guarantee this visibility except for file descriptors 0, 1, and 2,
and ksh does not support it.  Problem reported by Thomas Schulz in
<http://lists.gnu.org/archive/html/bug-gzip/2010-11/msg00000.html>.
Also, fix a related bug: "-e -" was mishandled.  These two bugs
were introduced by commit 5b54db4546b84ec97ff57a62f8ddb98faacf77f2
dated 2009-10-09.
(escape): Change the convention: do not assume that a stray X
is present at the end of the last line.  All uses changed.
There was no longer any need for this convention, and fixing this
made it a bit easier to use 'sed' in a later part of the fix.

diff --git a/tests/zgrep-f b/tests/zgrep-f
index ba76bfd9714dd7e4f7a5136247fd0e508e320291..ec8cf77d88ab56823bfc852d5dd7683f639bc0c7 100644 (file)
--- a/tests/zgrep-f
+++ b/tests/zgrep-f
@@ -31,4 +31,7 @@ zgrep -f - haystack.gz < n > out 2>&1 || fail=1
 
 compare out n || fail=1
 
+# This failed with gzip 1.4.
+echo a-b | zgrep -e - > /dev/null || fail=1
+
 Exit $fail

diff --git a/zgrep.in b/zgrep.in
index 6afa62cf64851eb253b8160db95985b18237ee21..68396dbfcbbbf8de623d53c5aa77b5c11f993e89 100644 (file)
--- a/zgrep.in
+++ b/zgrep.in
@@ -47,14 +47,13 @@ OPTIONs are the same as for 'grep'.
 Report bugs to <bug-gzip@gnu.org>."
 
 # sed script to escape all ' for the shell, and then (to handle trailing
-# newlines correctly) turn trailing X on last line into '.
+# newlines correctly) append ' to the last line.
 escape='
   s/'\''/'\''\\'\'''\''/g
-  $s/X$/'\''/
+  $s/$/'\''/
 '
 operands=
 have_pat=0
-pat_on_stdin=0
 files_with_matches=0
 files_without_matches=0
 no_filename=0
@@ -67,7 +66,7 @@ while test $# -ne 0; do
 
   case $option in
   (-[0123456789EFGHIKLPRTUVZabchilnoqrsuvwxyz]?*)
-    arg2=-\'$(expr "X${option}X" : 'X-.[0-9]*\(.*\)' | sed "$escape")
+    arg2=-\'$(expr "X$option" : 'X-.[0-9]*\(.*\)' | sed "$escape")
     eval "set -- $arg2 "'${1+"$@"}'
     option=$(expr "X$option" : 'X\(-.[0-9]*\)');;
   (--binary-*=* | --[lm]a*=* | --reg*=*)
@@ -75,11 +74,23 @@ while test $# -ne 0; do
   (-[ABCDXdefm] | binary-* | --file | --[lm]a* | --reg*)
     case ${1?"$option option requires an argument"} in
     (*\'*)
-      optarg=" '"$(printf '%sX\n' "$1" | sed "$escape");;
+      optarg=" '"$(printf '%s\n' "$1" | sed "$escape");;
     (*)
       optarg=" '$1'";;
     esac
     shift;;
+  (-f?*\'*)
+    optarg=" '"$(expr "X$option" : 'X-f\(.*\)' | sed "$escape")
+    option=-f;;
+  (-f?*)
+    optarg=" '"$(expr "X$option" : 'X-f\(.*\)')\'
+    option=-f;;
+  (--file=*\'*)
+    optarg=" '"$(expr "X$option" : 'X--file=\(.*\)' | sed "$escape")
+    option=--file;;
+  (--file=*)
+    optarg=" '"$(expr "X$option" : 'X--file=\(.*\)')\'
+    option=--file;;
   (--)
     break;;
   (-?*)
@@ -87,7 +98,7 @@ while test $# -ne 0; do
   (*)
     case $option in
     (*\'*)
-      operands="$operands '"$(printf '%sX\n' "$option" | sed "$escape");;
+      operands="$operands '"$(printf '%s\n' "$option" | sed "$escape");;
     (*)
       operands="$operands '$option'";;
     esac
@@ -99,33 +110,18 @@ while test $# -ne 0; do
   (-[drRzZ] | --di* | --exc* | --inc* | --rec* | --nu*)
     printf >&2 '%s: %s: option not supported\n' "$0" "$option"
     exit 2;;
-  (-[ef]* | --file | --file=* | --reg*)
+  (-e* | --reg*)
+    have_pat=1;;
+  (-f | --file)
     # The pattern is coming from a file rather than the command-line.
     # If the file is actually stdin then we need to do a little
-    # magic, (since we use stdin to pass the gzip output to grep).
-    # So find a free fd and change the argument to then use this
-    # file descriptor for the pattern.
+    # magic, since we use stdin to pass the gzip output to grep.
+    # Turn the -f option into an -e option by copying the file's
+    # contents into OPTARG.
     case $optarg in
     (" '-'" | " '/dev/stdin'" | " '/dev/fd/0'")
-      pat_on_stdin=1
-      eval 'test -e .' 2>/dev/null \
-        && eval 'exists(){ test -e "$@"; }' \
-        || eval 'exists(){ test -r "$@" || test -w "$@"; }'
-      # Start search from 6 since the script already uses 3 and 5
-      fd=6
-      pat_fd=
-      while : ; do
-        if ! exists /proc/$$/fd/$fd; then
-          pat_fd=$fd
-          break;
-        fi
-        fd=$(expr $fd + 1)
-        if test $fd = 255; then
-          printf >&2 '%s: no free file descriptor\n' "$0"
-          exit 2
-        fi
-      done
-      optarg=/dev/fd/$pat_fd;
+      option=-e
+      optarg=" '"$(sed "$escape") || exit 2;;
     esac
     have_pat=1;;
   (--h | --he | --hel | --help)
@@ -149,7 +145,7 @@ while test $# -ne 0; do
 
   case $option in
   (*\'?*)
-    option=\'$(expr "X${option}X" : 'X\(.*\)' | sed "$escape");;
+    option=\'$(printf '%s\n' "$option" | sed "$escape");;
   (*)
     option="'$option'";;
   esac
@@ -162,7 +158,7 @@ eval "set -- $operands "'${1+"$@"}'
 if test $have_pat -eq 0; then
   case ${1?"missing pattern; try \`$0 --help' for help"} in
   (*\'*)
-    grep="$grep -- '"$(printf '%sX\n' "$1" | sed "$escape");;
+    grep="$grep -- '"$(printf '%s\n' "$1" | sed "$escape");;
   (*)
     grep="$grep -- '$1'";;
   esac
@@ -181,9 +177,6 @@ do
   # Fail if gzip or grep (or sed) fails.
   gzip_status=$(
     exec 5>&1
-    if test $pat_on_stdin -eq 1; then
-      eval "exec $pat_fd<&0"
-    fi
     (gzip -cdfq -- "$i" 5>&-; echo $? >&5) 3>&- |
     if test $files_with_matches -eq 1; then
       eval "$grep" >/dev/null && { printf '%s\n' "$i" || exit 2; }