[PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[David Jack Olrik]

Signed-off-by: David Jack Olrik <david@olrik.dk>
---
 git-instaweb.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/git-instaweb.sh b/git-instaweb.sh
index b79c6b6..da8eb3f 100755
--- a/git-instaweb.sh
+++ b/git-instaweb.sh
@@ -30,7 +30,7 @@ test -z "$port" && port=1234
 
 start_httpd () {
 	httpd_only="`echo $httpd | cut -f1 -d' '`"
-	if test "`expr index $httpd_only /`" -eq '1' || \
+	if test "`echo $httpd_only | cut -c 1`" = '/' || \
 				which $httpd_only >/dev/null
 	then
 		$httpd $fqgitdir/gitweb/httpd.conf
-- 
1.5.3.rc6

Re: [PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[Uwe Kleine-König]

Hello,

David Jack Olrik wrote:
> -	if test "`expr index $httpd_only /`" -eq '1' || \
> +	if test "`echo $httpd_only | cut -c 1`" = '/' || \
>  				which $httpd_only >/dev/null

I wonder why not use:

	if expr "z$httpd_only" : "z/" >/dev/null

Best regards
Uwe

-- 
Uwe Kleine-König

exit vi, lesson II:
: w q ! <CR>

NB: write the current file

Re: [PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[David Jack Olrik]

On 22/08/2007, at 14.21, Uwe Kleine-König wrote:

> David Jack Olrik wrote:
>> -	if test "`expr index $httpd_only /`" -eq '1' || \
>> +	if test "`echo $httpd_only | cut -c 1`" = '/' || \
>>  				which $httpd_only >/dev/null
>
> I wonder why not use:
>
> 	if expr "z$httpd_only" : "z/" >/dev/null

You'd then need to check against 2 instead of 1, which I find less
obvious as we are testing for a '/' at the begining of the string.

-- 
Best regards,
David Jack Olrik <david@olrik.dk>             http://david.olrik.dk
GnuPG fingerprint C290 0A4A 0CCC CBA8 2B37 E18D 01D2 F6EF 2E61 9894
["The first rule of Perl club is  You do not talk about Perl club"]

Re: [PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[Uwe Kleine-König]

David Jack Olrik wrote:
> 
> On 22/08/2007, at 14.21, Uwe Kleine-König wrote:
> 
> >David Jack Olrik wrote:
> >>-	if test "`expr index $httpd_only /`" -eq '1' || \
> >>+	if test "`echo $httpd_only | cut -c 1`" = '/' || \
> >> 				which $httpd_only >/dev/null
> >
> >I wonder why not use:
> >
> >	if expr "z$httpd_only" : "z/" >/dev/null
> 
> You'd then need to check against 2 instead of 1, which I find less
> obvious as we are testing for a '/' at the begining of the string.
If I understood the problem right you only need to test for the exit
code, that is the program test is not required at all.

Best regards
Uwe

-- 
Uwe Kleine-König

http://www.google.com/search?q=5%2B7

[PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[David Jack Olrik]

On 22/08/2007, at 15.23, Uwe Kleine-König wrote:

> > You'd then need to check against 2 instead of 1, which I find less
> > obvious as we are testing for a '/' at the begining of the string.
> If I understood the problem right you only need to test for the exit
> code, that is the program test is not required at all.

Ah, yes that's true. The following should make it more clear that we are
looking at the first character.

    if expr "$httpd_only" : "\/" >/dev/null


Signed-off-by: David Jack Olrik <david@olrik.dk>
---
 git-instaweb.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/git-instaweb.sh b/git-instaweb.sh
index b79c6b6..85646f1 100755
--- a/git-instaweb.sh
+++ b/git-instaweb.sh
@@ -30,7 +30,7 @@ test -z "$port" && port=1234
 
 start_httpd () {
 	httpd_only="`echo $httpd | cut -f1 -d' '`"
-	if test "`expr index $httpd_only /`" -eq '1' || \
+	if expr "$httpd_only" : "\/" >/dev/null || \
 				which $httpd_only >/dev/null
 	then
 		$httpd $fqgitdir/gitweb/httpd.conf
-- 
1.5.3.rc6

Re: [PATCH] Fixed non portable use of expr, and incorrect use of test -eq for string comparison.

[martin f krafft]

[-- Attachment #1: Type: text/plain, Size: 1056 bytes --]

also sprach David Jack Olrik <david@olrik.dk> [2007.08.22.1402 +0200]:
> -	if test "`expr index $httpd_only /`" -eq '1' || \
> +	if test "`echo $httpd_only | cut -c 1`" = '/' || \

how about

  if [ "$httpd_only" != "${httpd_only#/}" ]; then

that should do the same and does so without external processes.

>  				which $httpd_only >/dev/null

This is also not really portable. I suggest the use of

  command -v $http_only

first, that's shell-internal as well, and second, it's
/more/ portable than which, but also not entirely.

http://www.debian.org/doc/developers-reference/ch-best-pkging-practices.en.html#s-bpp-debian-maint-scripts

-- 
martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:" net@madduck
 
"of course the music is a great difficulty.
 you see, if one plays good music, people don't listen,
 and if one plays bad music people don't talk."
                                                        -- oscar wilde
 
spamtraps: madduck.bogus@madduck.net

[-- Attachment #2: Digital signature (see http://martin-krafft.net/gpg/) --]
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Re: [PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[Junio C Hamano]

David Jack Olrik <david@olrik.dk> writes:

> On 22/08/2007, at 15.23, Uwe Kleine-König wrote:
>
>> > You'd then need to check against 2 instead of 1, which I find less
>> > obvious as we are testing for a '/' at the begining of the string.
>> If I understood the problem right you only need to test for the exit
>> code, that is the program test is not required at all.
>
> Ah, yes that's true. The following should make it more clear that we are
> looking at the first character.
>
>     if expr "$httpd_only" : "\/" >/dev/null

Then why not avoid the fork with something like:

	case "$httpd_only" in
        /*)
                ... begins with slash ...
	esac

By the way, I do not know if the use of "which" there is
portable.  Have Solaris folks tried this program ever?

How about doing it this way?

 * No need to use "cut"; just let IFS do its job.

 * No need to use "which"; we will need to do a discovery with
   custom paths anyway, so use the same logic for discovery from
   the normal $PATH as well.

 * The original code wanted to allow the httpd command that
   comes to the function to have arguments and preserve it but
   did so only for the case where the command was not specified
   with a full pathname.  Allow it for full-path case as well
   for consistency.

 * The original code returned without checking for error when
   httpd was specified without a full path, and checked and
   complained when it was.  Check the error exit for both cases.

---

 git-instaweb.sh |   42 ++++++++++++++++++++++++++----------------
 1 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/git-instaweb.sh b/git-instaweb.sh
index b79c6b6..a17c9b3 100755
--- a/git-instaweb.sh
+++ b/git-instaweb.sh
@@ -29,32 +29,42 @@ test -z "$browser" && browser='firefox'
 test -z "$port" && port=1234
 
 start_httpd () {
-	httpd_only="`echo $httpd | cut -f1 -d' '`"
-	if test "`expr index $httpd_only /`" -eq '1' || \
-				which $httpd_only >/dev/null
-	then
-		$httpd $fqgitdir/gitweb/httpd.conf
-	else
+	set x $httpd
+	shift
+
+	httpd=
+	case "$1" in
+	/*)
+		: full path -- no discovery
+		httpd="$1"
+		;;
+	*)
 		# many httpds are installed in /usr/sbin or /usr/local/sbin
 		# these days and those are not in most users $PATHs
-		for i in /usr/local/sbin /usr/sbin
+		paths="$PATH:/usr/sbin:/usr/local/sbin"
+		oIFS="$IFS"
+		IFS=:
+		for p in $paths
 		do
-			if test -x "$i/$httpd_only"
+			if test -x "$p/$1"
 			then
-				# don't quote $httpd, there can be
-				# arguments to it (-f)
-				$i/$httpd "$fqgitdir/gitweb/httpd.conf"
-				return
+				httpd="$p/$1"
+				break
 			fi
 		done
-		echo "$httpd_only not found. Install $httpd_only or use" \
-		     "--httpd to specify another http daemon."
+		IFS="$oIFS"
+		;;
+	esac
+	if test -z "$httpd"
+	then
+		echo "$1 not found. Install $1 or use --httpd to specify another http daemon."
 		exit 1
 	fi
-	if test $? != 0; then
+	shift
+	"$httpd" "$@" "$fqgitdir/gitweb/httpd.conf" || {
 		echo "Could not execute http daemon $httpd."
 		exit 1
-	fi
+	}
 }
 
 stop_httpd () {

Re: [PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[Uwe Kleine-König]

Hello,

David Jack Olrik wrote:
> On 22/08/2007, at 15.23, Uwe Kleine-König wrote:
> 
> > > You'd then need to check against 2 instead of 1, which I find less
> > > obvious as we are testing for a '/' at the begining of the string.
> > If I understood the problem right you only need to test for the exit
> > code, that is the program test is not required at all.
> 
> Ah, yes that's true. The following should make it more clear that we are
> looking at the first character.
> 
>     if expr "$httpd_only" : "\/" >/dev/null
yet another note:  I used expr "z$http_only" on purpose.  Look what
happens here:

	$ httpd_only=substr
	$ expr "$httpd_only" : "\/"
	expr: syntax error

Once more, Solaris is more exacting:

	$ /usr/bin/expr "/" : "\/"
	expr: syntax error

(This works fine with GNU expr.)

So better use "z$variable" because (up to now) there is no operator that
starts with a 'z'.

Best regards
Uwe

-- 
Uwe Kleine-König

fib where fib = 0 : 1 : zipWith (+) fib (tail fib)

Re: [PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[Uwe Kleine-König]

Hello Junio,

Junio C Hamano wrote:
> By the way, I do not know if the use of "which" there is
> portable.  Have Solaris folks tried this program ever?
I don't count myself to "Solaris folks", even though I still use it to
read and write my email.  But anyhow I know some of the pitfalls...

	login@~ > /bin/bash --version
	GNU bash, version 3.00.16(1)-release (sparc-sun-solaris2.10)
	Copyright (C) 2004 Free Software Foundation, Inc.

	login@~ > /bin/bash

	zeisberg@login ~$ which httpd && echo successful
	no httpd in /home/zeisberg/bin /home/zeisberg/usr/bin /opt/bin
	/usr/local/graphics/bin /usr/local/gnu/bin /usr/local/bin
	/usr/local/X11R6/bin /usr/xpg4/bin /usr/bin /usr/ccs/bin /usr/sbin
	/usr/ucb /usr/openwin/bin
	successful

That is, with httpd_only=httpd I get:

	$ if expr "z$httpd_only" : "z/" >/dev/null || \
		which $httpd_only >/dev/null
	then
		$httpd_only arg1 arg2
	fi
	bash: httpd: command not found

Best regards
Uwe

-- 
Uwe Kleine-König

If a lawyer and an IRS agent were both drowning, and you could only save
one of them, would you go to lunch or read the paper?

Re: [PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[Junio C Hamano]

Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> writes:

> Junio C Hamano wrote:
>> By the way, I do not know if the use of "which" there is
>> portable.  Have Solaris folks tried this program ever?
> I don't count myself to "Solaris folks", even though I still use it to
> read and write my email.  But anyhow I know some of the pitfalls...
>
> 	login@~ > /bin/bash --version
> 	GNU bash, version 3.00.16(1)-release (sparc-sun-solaris2.10)
> 	Copyright (C) 2004 Free Software Foundation, Inc.
>
> 	login@~ > /bin/bash
>
> 	zeisberg@login ~$ which httpd && echo successful
> 	no httpd in /home/zeisberg/bin /home/zeisberg/usr/bin /opt/bin
> 	/usr/local/graphics/bin /usr/local/gnu/bin /usr/local/bin
> 	/usr/local/X11R6/bin /usr/xpg4/bin /usr/bin /usr/ccs/bin /usr/sbin
> 	/usr/ucb /usr/openwin/bin
> 	successful

Thanks.  Somebody else tried:

	found=`which "$command"`
        if test -n "$found"
        then
        	... use $found as the full path to the command
	fi

and got burned because "no httpd in ..." comes to the stdout!
I did not exactly recall if there was an issue with the exit
status, but your demonstration shows that the status is also
useless.

We _could_ do something ugly and pointless like:

	test -f `which "$command"`

but I'd say I prefer the alternative I sent out at that point.

Re: [PATCH] Fixed non portable use of expr and removed incorrect use of test -eq for string comparison

[Uwe Kleine-König]

Hello Junio,

Junio C Hamano wrote:
> Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> writes:
> 
> > Junio C Hamano wrote:
> >> By the way, I do not know if the use of "which" there is
> >> portable.  Have Solaris folks tried this program ever?
> > I don't count myself to "Solaris folks", even though I still use it to
> > read and write my email.  But anyhow I know some of the pitfalls...
> >
> > 	login@~ > /bin/bash --version
> > 	GNU bash, version 3.00.16(1)-release (sparc-sun-solaris2.10)
> > 	Copyright (C) 2004 Free Software Foundation, Inc.
> >
> > 	login@~ > /bin/bash
> >
> > 	zeisberg@login ~$ which httpd && echo successful
> > 	no httpd in /home/zeisberg/bin /home/zeisberg/usr/bin /opt/bin
> > 	/usr/local/graphics/bin /usr/local/gnu/bin /usr/local/bin
> > 	/usr/local/X11R6/bin /usr/xpg4/bin /usr/bin /usr/ccs/bin /usr/sbin
> > 	/usr/ucb /usr/openwin/bin
> > 	successful
> 
> Thanks.  Somebody else tried:
> 
> 	found=`which "$command"`
>         if test -n "$found"
>         then
>         	... use $found as the full path to the command
> 	fi
> 
> and got burned because "no httpd in ..." comes to the stdout!
That was someting I planed to mention in my email but obviously I
forgot.

> I did not exactly recall if there was an issue with the exit
> status, but your demonstration shows that the status is also
> useless.
> 
> We _could_ do something ugly and pointless like:
> 
> 	test -f `which "$command"`
> 
> but I'd say I prefer the alternative I sent out at that point.
Ack.

-- 
Uwe Kleine-König

http://www.google.com/search?q=gravity+on+earth%3D