MySQL Bugs: #4825: mysql 4.0.20 fails to ./configure at "checking for ps"

Bug #4825	mysql 4.0.20 fails to ./configure at "checking for ps"
Submitted:	30 Jul 2004 11:43	Modified:	30 Jul 2004 14:42
Reporter:	[ name withheld ]	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: Compiling	Severity:	S2 (Serious)
Version:	4.0.20	OS:	Linux (Linux)
Assigned to:	Sergei Golubchik	CPU Architecture:	Any

Description:
Please see:

http://bugs.gentoo.org/show_bug.cgi?id=58872

for the full info.

Basically, the line:

if $PS p $$ 2> /dev/null | grep $0 > /dev/null

in configure, should be changed to:

if $PS p $$ 2> /dev/null | grep -- $0 > /dev/null

because ps returns "-bash" instead of "bash" on my system, which causes grep to fail.

How to repeat:
I'm not yet sure what causes it on the box in question, but I would guess that grsecurity adds the - to some processes in the ps output.

Suggested fix:
change:

if $PS p $$ 2> /dev/null | grep $0 > /dev/null

to:

if $PS p $$ 2> /dev/null | grep -- $0 > /dev/null

in configure

Sorry, but I cannot understand how it can fail because of the reason you described.

ps prepends - to indicate login shell:

> ps p $$
  PID TTY      STAT   TIME COMMAND
31368 pts/9    S      0:00 -bash

But when you run it from the script there can be no - there because the shell is not login shell (also it will be shown as sh, not bash).

but even if it would be -bash in the ps output it cannot cause problems for grep, because it's

grep $0

and $0 is the name of the script - that is configure - and not the output of the ps

(and, of course, MySQL compiles just fine on the linux box where I run the ps command from above)

You're quite correct about it grepping for ./configure and not -bash.

It turns out that because I had restricted /bin/ps execute permissions to root and the wheel group, and because Gentoo's Portage runs configure/make as the user "portage", configure could not execute ps.

Sorry for the confusion, but should -- not be added to grep for safety?

It would only help the the script will be renamed to something that start with "-" so it's not very probable scenario.

But actually I'm worried about the portability of "grep --" - for example configure script from GNU autoconf (which was carefully tuned for maximal portability) never uses "--"

What about grep -e "$0" (note the quotes around "$0", in case the script is renamed to something that contains a character in $IFS)?

GNU Emacs M-x grep suggests -e on the command line, so I assume it is portable. At least the Solaris grep(1) man page documents it:

  -e pattern_list
      Used to specify one or more patterns to match. If more than one pattern
      is specified in pattern_list, they must be separated by newline charac-
      ters (carriage returns). The -e option is useful for specifying a pat-
      tern that begins with a - (dash).

I don't know if there is a grep(1) switch for treating the argument as a fixed string and not a regexp.