Mercurial > hg > octave-nkf > gnulib-hg
changeset 17508:52cc408447aa
getdtablesize: work around cygwin issue
Cygwin 1.7.25 has a bug that even though it claims to support
RLIMIT_NOFILE inheritance, there is no enforcement of the soft
limit, and getdtablesize() automatically grows until it reaches
the hard limit which cannot be changed by setrlimit(). Best is
to just treat things as an invariant limit, as several other
modules assume that getdtablesize() will not change without an
intervening setrlimit().
* m4/getdtablesize.m4 (gl_FUNC_GETDTABLESIZE): Detect problem.
* modules/getdtablesize (configure.ac): Build replacement.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Set up a witness.
* modules/unistd (Makefile.am): Expose the witness.
* lib/unistd.in.h (getdtablesize): Declare replacement.
* lib/getdtablesize.c (rpl_getdtablesize): Work around it.
* tests/test-getdtablesize.c (main): Test it.
* doc/glibc-functions/getdtablesize.texi (getdtablesize): Document it.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Thu, 26 Sep 2013 11:26:29 -0600 |
parents | 9aea01bed17e |
children | 7fadcfb1189f |
files | ChangeLog doc/glibc-functions/getdtablesize.texi lib/getdtablesize.c lib/unistd.in.h m4/getdtablesize.m4 m4/unistd_h.m4 modules/getdtablesize modules/unistd tests/test-getdtablesize.c |
diffstat | 9 files changed, 92 insertions(+), 13 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2013-09-26 Eric Blake <eblake@redhat.com> + + getdtablesize: work around cygwin issue + * m4/getdtablesize.m4 (gl_FUNC_GETDTABLESIZE): Detect problem. + * modules/getdtablesize (configure.ac): Build replacement. + * m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Set up a witness. + * modules/unistd (Makefile.am): Expose the witness. + * lib/unistd.in.h (getdtablesize): Declare replacement. + * lib/getdtablesize.c (rpl_getdtablesize): Work around it. + * tests/test-getdtablesize.c (main): Test it. + * doc/glibc-functions/getdtablesize.texi (getdtablesize): Document it. + 2013-09-25 Mats Erik Andersson <gnu@gisladisker.se> pmccabe2html: escaping of special characters
--- a/doc/glibc-functions/getdtablesize.texi +++ b/doc/glibc-functions/getdtablesize.texi @@ -9,6 +9,11 @@ @item This function is missing on some platforms: mingw, MSVC 9. + +@item +This function does not represent the true @code{RLIMIT_NOFILE} soft +limit on some platforms: +Cygwin 1.7.25. @end itemize Portability problems not fixed by Gnulib:
--- a/lib/getdtablesize.c +++ b/lib/getdtablesize.c @@ -22,11 +22,11 @@ #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ -#include <stdio.h> +# include <stdio.h> -#include "msvc-inval.h" +# include "msvc-inval.h" -#if HAVE_MSVC_INVALID_PARAMETER_HANDLER +# if HAVE_MSVC_INVALID_PARAMETER_HANDLER static int _setmaxstdio_nothrow (int newmax) { @@ -44,10 +44,11 @@ return result; } -# define _setmaxstdio _setmaxstdio_nothrow -#endif +# define _setmaxstdio _setmaxstdio_nothrow +# endif -/* Cache for the previous getdtablesize () result. */ +/* Cache for the previous getdtablesize () result. Safe to cache because + Windows also lacks setrlimit. */ static int dtablesize; int @@ -83,4 +84,24 @@ return dtablesize; } +#elif HAVE_GETDTABLESIZE + +# include <sys/resource.h> +# undef getdtablesize + +int +rpl_getdtablesize(void) +{ + /* To date, this replacement is only compiled for Cygwin 1.7.25, + which auto-increased the RLIMIT_NOFILE soft limit until it + hits the compile-time constant hard limit of 3200. Although + that version of cygwin supported a child process inheriting + a smaller soft limit, the smaller limit is not enforced, so + we might as well just report the hard limit. */ + struct rlimit lim; + if (!getrlimit (RLIMIT_NOFILE, &lim) && lim.rlim_max != RLIM_INFINITY) + return lim.rlim_max; + return getdtablesize (); +} + #endif
--- a/lib/unistd.in.h +++ b/lib/unistd.in.h @@ -654,10 +654,19 @@ #if @GNULIB_GETDTABLESIZE@ /* Return the maximum number of file descriptors in the current process. In POSIX, this is same as sysconf (_SC_OPEN_MAX). */ -# if !@HAVE_GETDTABLESIZE@ +# if @REPLACE_GETDTABLESIZE@ +# if !(defined __cplusplus && defined GNULIB_NAMESPACE) +# undef getdtablesize +# define getdtablesize rpl_getdtablesize +# endif +_GL_FUNCDECL_RPL (getdtablesize, int, (void)); +_GL_CXXALIAS_RPL (getdtablesize, int, (void)); +# else +# if !@HAVE_GETDTABLESIZE@ _GL_FUNCDECL_SYS (getdtablesize, int, (void)); +# endif +_GL_CXXALIAS_SYS (getdtablesize, int, (void)); # endif -_GL_CXXALIAS_SYS (getdtablesize, int, (void)); _GL_CXXALIASWARN (getdtablesize); #elif defined GNULIB_POSIXCHECK # undef getdtablesize
--- a/m4/getdtablesize.m4 +++ b/m4/getdtablesize.m4 @@ -1,4 +1,4 @@ -# getdtablesize.m4 serial 4 +# getdtablesize.m4 serial 5 dnl Copyright (C) 2008-2013 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -7,8 +7,35 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE], [ AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) + AC_REQUIRE([AC_CANONICAL_HOST]) AC_CHECK_FUNCS_ONCE([getdtablesize]) - if test $ac_cv_func_getdtablesize != yes; then + if test $ac_cv_func_getdtablesize = yes; then + # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit + # up to an unchangeable hard limit; all other platforms correctly + # require setrlimit before getdtablesize() can report a larger value. + AC_CACHE_CHECK([whether getdtablesize works], + [gl_cv_func_getdtablesize_works], + [AC_RUN_IFELSE([ + AC_LANG_PROGRAM([[#include <unistd.h>]], + [int size = getdtablesize(); + if (dup2 (0, getdtablesize()) != -1) + return 1; + if (size != getdtablesize()) + return 2; + ])], + [gl_cv_func_getdtablesize_works=yes], + [gl_cv_func_getdtablesize_works=no], + [case "$host_os" in + cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows + gl_cv_func_getdtablesize_works="guessing no" ;; + *) gl_cv_func_getdtablesize_works="guessing yes" ;; + esac]) + ]) + case "$gl_cv_func_getdtablesize_works" in + *yes) ;; + *) REPLACE_GETDTABLESIZE=1 ;; + esac + else HAVE_GETDTABLESIZE=0 fi ])
--- a/m4/unistd_h.m4 +++ b/m4/unistd_h.m4 @@ -1,4 +1,4 @@ -# unistd_h.m4 serial 66 +# unistd_h.m4 serial 67 dnl Copyright (C) 2006-2013 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -160,6 +160,7 @@ REPLACE_FTRUNCATE=0; AC_SUBST([REPLACE_FTRUNCATE]) REPLACE_GETCWD=0; AC_SUBST([REPLACE_GETCWD]) REPLACE_GETDOMAINNAME=0; AC_SUBST([REPLACE_GETDOMAINNAME]) + REPLACE_GETDTABLESIZE=0; AC_SUBST([REPLACE_GETDTABLESIZE]) REPLACE_GETLOGIN_R=0; AC_SUBST([REPLACE_GETLOGIN_R]) REPLACE_GETGROUPS=0; AC_SUBST([REPLACE_GETGROUPS]) REPLACE_GETPAGESIZE=0; AC_SUBST([REPLACE_GETPAGESIZE])
--- a/modules/getdtablesize +++ b/modules/getdtablesize @@ -7,11 +7,12 @@ Depends-on: unistd +extensions msvc-inval [test $HAVE_GETDTABLESIZE = 0] configure.ac: gl_FUNC_GETDTABLESIZE -if test $HAVE_GETDTABLESIZE = 0; then +if test $HAVE_GETDTABLESIZE = 0 || test $REPLACE_GETDTABLESIZE = 1; then AC_LIBOBJ([getdtablesize]) gl_PREREQ_GETDTABLESIZE fi @@ -26,5 +27,5 @@ LGPLv2+ Maintainer: -Bruno Haible +Bruno Haible, Eric Blake
--- a/modules/unistd +++ b/modules/unistd @@ -137,6 +137,7 @@ -e 's|@''REPLACE_FTRUNCATE''@|$(REPLACE_FTRUNCATE)|g' \ -e 's|@''REPLACE_GETCWD''@|$(REPLACE_GETCWD)|g' \ -e 's|@''REPLACE_GETDOMAINNAME''@|$(REPLACE_GETDOMAINNAME)|g' \ + -e 's|@''REPLACE_GETDTABLESIZE''@|$(REPLACE_GETDTABLESIZE)|g' \ -e 's|@''REPLACE_GETLOGIN_R''@|$(REPLACE_GETLOGIN_R)|g' \ -e 's|@''REPLACE_GETGROUPS''@|$(REPLACE_GETGROUPS)|g' \ -e 's|@''REPLACE_GETPAGESIZE''@|$(REPLACE_GETPAGESIZE)|g' \