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Summary:ASTERISK-16343: [patch] Configure sets ac_cv_fork_works=no incorrectly for uclibc
Reporter:Philip Prindeville (pprindeville)Labels:
Date Opened:2010-07-09 12:47:27Date Closed:2010-07-17 12:43:50
Priority:MinorRegression?Yes
Status:Closed/CompleteComponents:Core/BuildSystem
Versions:Frequency of
Occurrence
Related
Issues:
Environment:Attachments:( 0) asterisk-1.6-fork.patch
Description:The generated top-level configure contains:

if test "x$ac_cv_func_fork_works" = xcross; then
case $host in
 *-*-amigaos* | *-*-msdosdjgpp* | *-*-uclinux* | *-*-linux-uclibc* )
   # Override, as these systems have only a dummy fork() stub
   ac_cv_func_fork_works=no
   ;;

this is wrong.  The linux-uclibc fork() works just fine.

Comments:By: Leif Madsen (lmadsen) 2010-07-09 13:16:20

This is not major -- the number of people affected by this is relatively low.
By: Philip Prindeville (pprindeville) 2010-07-09 13:39:34

Sorry, I was told that build issues were considered "major".
By: Leif Madsen (lmadsen) 2010-07-09 14:26:25

(02:20:25 PM) jparker: I made that change.  I don't recall why.  The change was explicitly to add what he's asking to remove.
By: abelbeck (abelbeck) 2010-07-09 17:25:53

This issue was discovered in the trunk branch of AstLinux (cross-compile using uclibc).  Philip (the reporter here) implemented  Tilghman's comments on bugid 17464, whereby properly setting 'configure's $host variable.  Since *-*-linux-uclibc* was now matched, ac_cv_fork_works is set to 'no', previously (for many years) it was always guessed to be 'yes' and worked fine with uclibc.

It appears that back in r59573, in asterisk 1.4.3, the *-*-linux-uclibc* match was added.

The above patch works for me, and the command line option -f could always be used to disable fork if so desired.
By: Michael Keuter (mkeuter) 2010-07-10 03:54:24

The patch also works for me in Astlinux-trunk (for Asterisk 1.6.2.9 + Asterisk trunk).
By: Philip Prindeville (pprindeville) 2010-07-10 15:55:59

And I'm now running it against trunk (r275254).
By: Tilghman Lesher (tilghman) 2010-07-16 22:55:18

You'll need to report this upstream to the GNU autoconf project.  While we can create an alternate test, this patch isn't it:  it needs to be generated from the configure.ac script.
By: Philip Prindeville (pprindeville) 2010-07-17 00:25:11

I'm confused: above jparker admitted that this was a test made directly to asterisk, not in autoconf.  A quick look at autoconf 2.65's lib/autoconf/functions.m4 file confirms this.
By: Philip Prindeville (pprindeville) 2010-07-17 00:34:53

Just to follow up, here's the relevant portion of that file:

 1763  # AC_FUNC_FORK
 1764  # -------------
 1765  AN_FUNCTION([fork],  [AC_FUNC_FORK])
 1766  AN_FUNCTION([vfork], [AC_FUNC_FORK])
 1767  AC_DEFUN([AC_FUNC_FORK],
 1768  [AC_REQUIRE([AC_TYPE_PID_T])dnl
 1769  AC_CHECK_HEADERS(vfork.h)
 1770  AC_CHECK_FUNCS(fork vfork)
 1771  if test "x$ac_cv_func_fork" = xyes; then
 1772    _AC_FUNC_FORK
 1773  else  1774    ac_cv_func_fork_works=$ac_cv_func_fork
 1775  fi
 1776  if test "x$ac_cv_func_fork_works" = xcross; then
 1777    case $host in
 1778      *-*-amigaos* | *-*-msdosdjgpp*)
 1779        # Override, as these systems have only a dummy fork() stub
 1780        ac_cv_func_fork_works=no
 1781        ;;
 1782      *)  1783        ac_cv_func_fork_works=yes
 1784        ;;
 1785    esac
 1786    AC_MSG_WARN([result $ac_cv_func_fork_works guessed because of cross co
mpilation])
 1787  fi
 1788  ac_cv_func_vfork_works=$ac_cv_func_vfork
 1789  if test "x$ac_cv_func_vfork" = xyes; then
 1790    _AC_FUNC_VFORK
 1791  fi;
 1792  if test "x$ac_cv_func_fork_works" = xcross; then
 1793    ac_cv_func_vfork_works=$ac_cv_func_vfork
 1794    AC_MSG_WARN([result $ac_cv_func_vfork_works guessed because of cross c
ompilation])
 1795  fi
 1796  
 1797  if test "x$ac_cv_func_vfork_works" = xyes; then
 1798    AC_DEFINE(HAVE_WORKING_VFORK, 1, [Define to 1 if `vfork' works.])
 1799  else
 1800    AC_DEFINE(vfork, fork, [Define as `fork' if `vfork' does not work.])
 1801  fi
 1802  if test "x$ac_cv_func_fork_works" = xyes; then
 1803    AC_DEFINE(HAVE_WORKING_FORK, 1, [Define to 1 if `fork' works.])
 1804  fi
 1805  ])# AC_FUNC_FORK

As you see, only amigaos and msdosdjgpp fail to support fork().
By: Tilghman Lesher (tilghman) 2010-07-17 11:45:08

Then your patch needs to be against configure.ac, not configure.
By: Philip Prindeville (pprindeville) 2010-07-17 11:53:31

Have you looked at the patch?

It contains hunks for 3 different files:

configure
autoconf/ast_func_fork.m4
menuselect/acinclude.m4

I think I'm starting to understand why getting a fix approved sometimes takes as long as it does.
By: Digium Subversion (svnbot) 2010-07-17 11:59:11

Repository: asterisk
Revision: 277738

U   branches/1.4/autoconf/ast_func_fork.m4
U   branches/1.4/configure

------------------------------------------------------------------------
r277738 | tilghman | 2010-07-17 11:59:10 -0500 (Sat, 17 Jul 2010) | 5 lines

Remove uclibc cross-compile triplet, as uclibc has a working fork()... it's only uclinux that does not.

(closes issue ASTERISK-16343)
Reported by: pprindeville

------------------------------------------------------------------------

http://svn.digium.com/view/asterisk?view=rev&revision=277738
By: Digium Subversion (svnbot) 2010-07-17 12:42:31

Repository: asterisk
Revision: 277775

_U  trunk/
U   trunk/autoconf/ast_func_fork.m4
U   trunk/configure
U   trunk/include/asterisk/autoconfig.h.in

------------------------------------------------------------------------
r277775 | tilghman | 2010-07-17 12:42:31 -0500 (Sat, 17 Jul 2010) | 12 lines

Merged revisions 277738 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
 r277738 | tilghman | 2010-07-17 11:59:11 -0500 (Sat, 17 Jul 2010) | 5 lines
 
 Remove uclibc cross-compile triplet, as uclibc has a working fork()... it's only uclinux that does not.
 
 (closes issue ASTERISK-16343)
  Reported by: pprindeville
........

------------------------------------------------------------------------

http://svn.digium.com/view/asterisk?view=rev&revision=277775
By: Digium Subversion (svnbot) 2010-07-17 12:43:49

Repository: asterisk
Revision: 277776

_U  branches/1.6.2/
U   branches/1.6.2/autoconf/ast_func_fork.m4
U   branches/1.6.2/configure
U   branches/1.6.2/include/asterisk/autoconfig.h.in

------------------------------------------------------------------------
r277776 | tilghman | 2010-07-17 12:43:49 -0500 (Sat, 17 Jul 2010) | 19 lines

Merged revisions 277775 via svnmerge from
https://origsvn.digium.com/svn/asterisk/trunk

................
 r277775 | tilghman | 2010-07-17 12:42:32 -0500 (Sat, 17 Jul 2010) | 12 lines
 
 Merged revisions 277738 via svnmerge from
 https://origsvn.digium.com/svn/asterisk/branches/1.4
 
 ........
   r277738 | tilghman | 2010-07-17 11:59:11 -0500 (Sat, 17 Jul 2010) | 5 lines
   
   Remove uclibc cross-compile triplet, as uclibc has a working fork()... it's only uclinux that does not.
   
   (closes issue ASTERISK-16343)
    Reported by: pprindeville
 ........
................

------------------------------------------------------------------------

http://svn.digium.com/view/asterisk?view=rev&revision=277776