Re: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
On 05/11/2014 02:48 PM, Paul Eggert wrote:
Following up to the grep snapshot announcement in:
http://lists.gnu.org/archive/html/platform-testers/2014-05/msg0.html
That snapshot failed to build the shell scripts egrep and fgrep properly
on Solaris 10, because it set SHELL = /bin/sh in src/Makefile, which
caused the makefile to put #!/bin/sh at the top of the shell scripts,
which breaks because the shell scripts use a construct '${0%/*}' that
Solaris 10 /bin/sh doesn't grok. The build should have used SHELL =
/bin/bash, which is what grep does with my test builds.
In autoconf.git, there are zero hits for:
git grep -F '0%/*'
However, in grep.git, there is:
src/egrep.sh:if test -x ${0%/*}/@grep@; then
src/egrep.sh: PATH=${0%/*}:$PATH
The culprit is grep itself, not autoconf.
--
Eric Blake eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org
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Re: bug#17471: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
On Sun, May 11, 2014 at 1:48 PM, Paul Eggert egg...@cs.ucla.edu wrote:
Following up to the grep snapshot announcement in:
http://lists.gnu.org/archive/html/platform-testers/2014-05/msg0.html
That snapshot failed to build the shell scripts egrep and fgrep properly on
Solaris 10, because it set SHELL = /bin/sh in src/Makefile, which caused
the makefile to put #!/bin/sh at the top of the shell scripts, which
breaks because the shell scripts use a construct '${0%/*}' that Solaris 10
/bin/sh doesn't grok. The build should have used SHELL = /bin/bash, which
is what grep does with my test builds.
We could work around the problem by avoiding that shell construct, but I'd
rather fix the build machinery because this bug could affect any package
that uses POSIX shell scripts. The snapshot was built with an experimental
version of Autoconf (2.69.117-1717), whereas I had tested with the latest
stable version (2.69 as shipped with Fedora 20). The two versions differ in
how they compute the name of a working shell, so it appears that there's a
bug in the experimental version of Autoconf.
A quick workaround for grep is to build the next snapshot with Autoconf
2.69. In the long run, though, we should fix the Autoconf bug. I'll CC:
this to bug-autoconf to give them a heads-up.
Hi Paul,
Thanks for reporting that.
I would like our egrep and fgrep scripts to work even on systems with
a non-POSIX shell and no bash to fall back on. Our tests/init.sh
code tries hard to find a sufficiently functional shell (including a
test for the ${VAR%GLOB} construct), and making it work in spite of
Solaris's /bin/sh was tricky, and we had to be willing to give up and
skip tests altogether, in the event that no sufficiently featureful
shell is found. Here, we don't have that luxury.
Ideally, these wrapper shell scripts would not have to fork an extra
process to perform this trivial string manipulation, but I can live
with the extra overhead, expecially for scripts like these that merely
provide support for obsolescent-named programs.
I think the attach patch is sufficiently portable to do what I want.
Does anyone see a way to make it more efficient with a POSIX shell?
0001-egrep-fgrep-make-wrappers-portable-to-non-POSIX-shel.patch
Description: Binary data
Re: bug#17471: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
On Sun, May 11, 2014 at 1:48 PM, Paul Eggert egg...@cs.ucla.edu wrote:
Following up to the grep snapshot announcement in:
http://lists.gnu.org/archive/html/platform-testers/2014-05/msg0.html
That snapshot failed to build the shell scripts egrep and fgrep properly on
Solaris 10, because it set SHELL = /bin/sh in src/Makefile, which caused
the makefile to put #!/bin/sh at the top of the shell scripts, which
breaks because the shell scripts use a construct '${0%/*}' that Solaris 10
/bin/sh doesn't grok. The build should have used SHELL = /bin/bash, which
is what grep does with my test builds.
We could work around the problem by avoiding that shell construct, but I'd
rather fix the build machinery because this bug could affect any package
that uses POSIX shell scripts. The snapshot was built with an experimental
version of Autoconf (2.69.117-1717), whereas I had tested with the latest
stable version (2.69 as shipped with Fedora 20). The two versions differ in
how they compute the name of a working shell, so it appears that there's a
bug in the experimental version of Autoconf.
A quick workaround for grep is to build the next snapshot with Autoconf
2.69. In the long run, though, we should fix the Autoconf bug. I'll CC:
this to bug-autoconf to give them a heads-up.
Hi Paul,
Thanks for reporting that.
I would like our egrep and fgrep scripts to work even on systems with
an old shell and no bash to fall back on. Our tests/init.sh code
tries hard to find a sufficiently functional shell (including a test
for the ${VAR%GLOB} construct), and making it work in spite of
Solaris's /bin/sh was tricky... plus, we had to be willing to give up
and skip tests altogether, in the event that no sufficiently
functional shell is found. Here, we don't have that luxury.
Ideally, these wrapper shell scripts would not have to fork an extra
process to perform this trivial string manipulation, but I can live
with the extra overhead, especially for scripts like these that merely
provide support for obsolescent programs.
I think the attached patch is sufficiently portable to work everywhere.
Does anyone see a (simple+clean) way to make it more efficient for the
common case in which @SHELL@ is a more functional shell?
Re: bug#17471: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
On 2014-05-12 10:33 -0700, Jim Meyering wrote:
[...]
I think the attach patch is sufficiently portable to do what I want.
Does anyone see a way to make it more efficient with a POSIX shell?
From e2a305bff2be376f6dd29e52a1d32636e0c22706 Mon Sep 17 00:00:00 2001
From: Jim Meyering meyer...@fb.com
Date: Mon, 12 May 2014 10:33:09 -0700
Subject: [PATCH] egrep, fgrep: make wrappers portable to non-POSIX shells
* src/egrep.sh (grep): Use sed in a subshell in place of the
POSIX sh construct, ${0%/*}. The latter is not portable to
Solaris 10. Reported by Paul Eggert in http://debbugs.gnu.org/17471
---
src/egrep.sh | 7 ---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/src/egrep.sh b/src/egrep.sh
index f1b4146..0a374aa 100644
--- a/src/egrep.sh
+++ b/src/egrep.sh
@@ -2,9 +2,10 @@
grep=grep
case $0 in
*/*)
-if test -x ${0%/*}/@grep@; then
- PATH=${0%/*}:$PATH
- grep=@grep@
+dirname=`echo $0|sed 's,//*[^/]*$,,'`
I'd write
dirname=`expr x$0 : x'\(.*\)/'`
but mainly for style reasons...
+if test -x $dirname/'@grep@'; then
+ PATH=$dirname:$PATH
+ grep='@grep@'
fi;;
esac
exec $grep @option@ $@
Cheers,
--
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)
Re: bug#17471: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
On 05/12/2014 10:33 AM, Jim Meyering wrote:
Does anyone see a way to make it more efficient with a POSIX shell?
Yes. Eric's earlier message convinced me that grep shouldn't rely on
Autoconf guaranteeing a shell that supports substrings in parameter
expansion, so I came up with the attached patch (which keeps the shell
efficient with a POSIX shell) and pushed it before I got around to
reading your message. I tested on Solaris 10 with the shell
artificially set to /bin/sh, so I'm marking this as done.
From an Autoconf point of view it might be nice to have a good way to
say I need a POSIX shell or at least I need a shell that does
substrings, but that's merely a wishlist item.
From 0ca1f6d79514189ef8db6e931f285cbaec9789ec Mon Sep 17 00:00:00 2001
From: Paul Eggert egg...@cs.ucla.edu
Date: Mon, 12 May 2014 11:38:28 -0700
Subject: [PATCH] egrep, fgrep: port to Solaris 10 /bin/sh
This old shell doesn't grok ${0%/*}; see: http://bugs.gnu.org/17471
* src/Makefile.am (egrep fgrep): Don't assume the shell does substrings.
* src/egrep.sh (dir): New var, so that the substring calculation is
done only once (which is a small win even with newer shells),
and so that the calculation is easier to edit on older shells.
---
src/Makefile.am | 7 +++
src/egrep.sh| 5 +++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/src/Makefile.am b/src/Makefile.am
index f8c9415..e2c82a4 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -47,7 +47,14 @@ EXTRA_DIST = dosbuf.c egrep.sh
egrep fgrep: egrep.sh Makefile
$(AM_V_GEN)grep=`echo grep | sed -e '$(transform)'` \
case $@ in egrep) option=-E;; fgrep) option=-F;; esac \
+ shell_does_substrings='set x/y d=$${1%/*} test $$d = x' \
+ if $(SHELL) -c $$shell_does_substrings 2/dev/null; then \
+ edit_substring='s,X,X,'; \
+ else \
+ edit_substring='s,\$${0%/\*},`expr X$$0 : '\''X\\(.*\\)/'\''`,g'; \
+ fi \
sed -e 's|[@]SHELL@|$(SHELL)|g' \
+ -e $$edit_substring \
-e s|[@]grep@|$$grep|g \
-e s|[@]option@|$$option|g $(srcdir)/egrep.sh $@-t
$(AM_V_at)chmod +x $@-t
diff --git a/src/egrep.sh b/src/egrep.sh
index f1b4146..1a03d2a 100644
--- a/src/egrep.sh
+++ b/src/egrep.sh
@@ -2,8 +2,9 @@
grep=grep
case $0 in
*/*)
-if test -x ${0%/*}/@grep@; then
- PATH=${0%/*}:$PATH
+dir=${0%/*}
+if test -x $dir/@grep@; then
+ PATH=$dir:$PATH
grep=@grep@
fi;;
esac
--
1.9.0
Re: bug#17471: On Solaris 10, grep snapshot apparently hit by bleeding-edge Autoconf bug
Thanks for dealing with that. The only potential problem I see with your patch would be when one runs configure with a perverse program name transformation, e.g., --program-transform-name='s/^/$/', introducing a shell metacharacter (or leading/trailing white space!) in the resulting name. In that case, the lack of single quotes around @grep@ would be fatal. Fixing that is not high priority. Anyone who does that to grep deserves the result :-)
