Kevin Cernekee wrote:
On Android, sysconf (_SC_OPEN_MAX) always returns the constant OPEN_MAX (256)
Ouch, that sounds like a POSIX conformance bug. I see enh posted an Android patch but we should probably fix this in gnulib too. I also noticed a porting problem on AIX 7.1 and installed the attached patch. I have the sneaking suspicion this will also fix the problem on (unfixed) Android; could you give it a try? Thanks.
>From b84e03dc80ff70342e5b7a1702b51d120efb95fc Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Tue, 17 Feb 2015 18:34:17 -0800 Subject: [PATCH] dup2, fcntl: port to AIX * m4/dup2.m4 (gl_FUNC_DUP2): * m4/fcntl.m4 (gl_FUNC_FCNTL): Prefer getrusage (RLIM_NOFILE ...)/rlim_cur to sysconf (_SC_OPEN_MAX). The former works on AIX 7.1 but the latter does not. Also, this may work better with Android; see: http://lists.gnu.org/archive/html/bug-gnulib/2015-02/msg00100.html --- ChangeLog | 10 +++++++++ m4/dup2.m4 | 72 ++++++++++++++++++++++++++++++++----------------------------- m4/fcntl.m4 | 40 ++++++++++++++++++---------------- 3 files changed, 70 insertions(+), 52 deletions(-) diff --git a/ChangeLog b/ChangeLog index 5083e95..f3b7b3a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,13 @@ +2015-02-17 Paul Eggert <egg...@cs.ucla.edu> + + dup2, fcntl: port to AIX + * m4/dup2.m4 (gl_FUNC_DUP2): + * m4/fcntl.m4 (gl_FUNC_FCNTL): + Prefer getrusage (RLIM_NOFILE ...)/rlim_cur to sysconf (_SC_OPEN_MAX). + The former works on AIX 7.1 but the latter does not. + Also, this may work better with Android; see: + http://lists.gnu.org/archive/html/bug-gnulib/2015-02/msg00100.html + 2015-02-16 Paul Eggert <egg...@cs.ucla.edu> getdtablesize, dup2, fcntl: port to Android diff --git a/m4/dup2.m4 b/m4/dup2.m4 index c47ef27..fec42b0 100644 --- a/m4/dup2.m4 +++ b/m4/dup2.m4 @@ -19,40 +19,44 @@ AC_DEFUN([gl_FUNC_DUP2], if test $HAVE_DUP2 = 1; then AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works], [AC_RUN_IFELSE([ - AC_LANG_PROGRAM([[#include <unistd.h> -#include <fcntl.h> -#include <limits.h> -#include <errno.h>]], - [int result = 0; - int bad_fd = INT_MAX; -#ifdef _SC_OPEN_MAX - long int open_max = sysconf (_SC_OPEN_MAX); - if (0 <= open_max && open_max <= INT_MAX) - bad_fd = open_max; -#endif -#ifdef FD_CLOEXEC - if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1) - result |= 1; -#endif - if (dup2 (1, 1) == 0) - result |= 2; -#ifdef FD_CLOEXEC - if (fcntl (1, F_GETFD) != FD_CLOEXEC) - result |= 4; -#endif - close (0); - if (dup2 (0, 0) != -1) - result |= 8; - /* Many gnulib modules require POSIX conformance of EBADF. */ - if (dup2 (2, bad_fd) == -1 && errno != EBADF) - result |= 16; - /* Flush out some cygwin core dumps. */ - if (dup2 (2, -1) != -1 || errno != EBADF) - result |= 32; - dup2 (2, 255); - dup2 (2, 256); - return result; - ]) + AC_LANG_PROGRAM( + [[#include <errno.h> + #include <fcntl.h> + #include <limits.h> + #include <sys/resource.h> + #include <unistd.h> + ]], + [[int result = 0; + int bad_fd = INT_MAX; + struct rlimit rlim; + if (getrlimit (RLIMIT_NOFILE, &rlim) == 0 + && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX + && rlim.rlim_cur != RLIM_INFINITY + && rlim.rlim_cur != RLIM_SAVED_MAX + && rlim.rlim_cur != RLIM_SAVED_CUR) + bad_fd = rlim.rlim_cur; + #ifdef FD_CLOEXEC + if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1) + result |= 1; + #endif + if (dup2 (1, 1) == 0) + result |= 2; + #ifdef FD_CLOEXEC + if (fcntl (1, F_GETFD) != FD_CLOEXEC) + result |= 4; + #endif + close (0); + if (dup2 (0, 0) != -1) + result |= 8; + /* Many gnulib modules require POSIX conformance of EBADF. */ + if (dup2 (2, bad_fd) == -1 && errno != EBADF) + result |= 16; + /* Flush out some cygwin core dumps. */ + if (dup2 (2, -1) != -1 || errno != EBADF) + result |= 32; + dup2 (2, 255); + dup2 (2, 256); + return result;]]) ], [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no], [case "$host_os" in diff --git a/m4/fcntl.m4 b/m4/fcntl.m4 index 9c044dc..1fce0f7 100644 --- a/m4/fcntl.m4 +++ b/m4/fcntl.m4 @@ -27,24 +27,28 @@ AC_DEFUN([gl_FUNC_FCNTL], dnl haiku alpha 2 F_DUPFD has wrong errno AC_CACHE_CHECK([whether fcntl handles F_DUPFD correctly], [gl_cv_func_fcntl_f_dupfd_works], - [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ -#include <limits.h> -#include <unistd.h> -#include <fcntl.h> -#include <errno.h> -]], [[int result = 0; - int bad_fd = INT_MAX; -#ifdef _SC_OPEN_MAX - long int open_max = sysconf (_SC_OPEN_MAX); - if (0 <= open_max && open_max <= INT_MAX) - bad_fd = open_max; -#endif - if (fcntl (0, F_DUPFD, -1) != -1) result |= 1; - if (errno != EINVAL) result |= 2; - if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4; - if (errno != EINVAL) result |= 8; - return result; - ]])], + [AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <errno.h> + #include <fcntl.h> + #include <limits.h> + #include <sys/resource.h> + #include <unistd.h> + ]], + [[int result = 0; + int bad_fd = INT_MAX; + struct rlimit rlim; + if (getrlimit (RLIMIT_NOFILE, &rlim) == 0 + && 0 <= rlim.rlim_cur && rlim.rlim_cur <= INT_MAX + && rlim.rlim_cur != RLIM_INFINITY + && rlim.rlim_cur != RLIM_SAVED_MAX + && rlim.rlim_cur != RLIM_SAVED_CUR) + bad_fd = rlim.rlim_cur; + if (fcntl (0, F_DUPFD, -1) != -1) result |= 1; + if (errno != EINVAL) result |= 2; + if (fcntl (0, F_DUPFD, bad_fd) != -1) result |= 4; + if (errno != EINVAL) result |= 8; + return result;]])], [gl_cv_func_fcntl_f_dupfd_works=yes], [gl_cv_func_fcntl_f_dupfd_works=no], [# Guess that it works on glibc systems -- 2.1.0
