From fa915b528c85b90fd55839907f862a0d4cd273db Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Tue, 2 Oct 2012 16:50:57 -0600 Subject: [PATCH] pselect: reject invalid file descriptors Similar to the recent select fixes. * m4/pselect.m4 (gl_FUNC_PSELECT): Probe for FreeBSD bug. * lib/pselect.c (rpl_pselect) [!win32]: Work around it. * modules/pselect (Depends-on): Add dup2. * doc/posix-functions/pselect.texi (pselect): Document this. --- ChangeLog | 6 ++++++ doc/posix-functions/pselect.texi | 4 ++++ lib/pselect.c | 34 ++++++++++++++++++++++++++++++++++ m4/pselect.m4 | 40 +++++++++++++++++++++++++++++++++++++++- modules/pselect | 1 + 5 files changed, 84 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 94447ef4d..70fd40681 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ 2012-10-02 Eric Blake + pselect: reject invalid file descriptors + * m4/pselect.m4 (gl_FUNC_PSELECT): Probe for FreeBSD bug. + * lib/pselect.c (rpl_pselect) [!win32]: Work around it. + * modules/pselect (Depends-on): Add dup2. + * doc/posix-functions/pselect.texi (pselect): Document this. + select: reject invalid file descriptors * m4/select.m4 (gl_FUNC_SELECT): Probe for FreeBSD bug. * lib/select.c (rpl_select) [!win32]: Work around it. diff --git a/doc/posix-functions/pselect.texi b/doc/posix-functions/pselect.texi index 4c6f093a4..aa191cc23 100644 --- a/doc/posix-functions/pselect.texi +++ b/doc/posix-functions/pselect.texi @@ -11,6 +11,10 @@ Portability problems fixed by Gnulib: @item This function is missing on some platforms: OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1, Solaris 9, mingw, MSVC 9, Interix 3.5, BeOS. +@item +On some platforms, this function fails to detect invalid fds with +EBADF, but only if they lie beyond the current maximum open fd: +FreeBSD 8.2. @end itemize Portability problems not fixed by Gnulib: diff --git a/lib/pselect.c b/lib/pselect.c index 4e7a7ed86..b544c7c32 100644 --- a/lib/pselect.c +++ b/lib/pselect.c @@ -33,6 +33,8 @@ pointer parameter stands for no descriptors, an infinite timeout, or an unaffected signal mask. */ +#if !HAVE_PSELECT + int pselect (int nfds, fd_set *restrict rfds, fd_set *restrict wfds, fd_set *restrict xfds, @@ -74,3 +76,35 @@ pselect (int nfds, fd_set *restrict rfds, return select_result; } + +#else /* HAVE_PSELECT */ +# include +# undef pselect + +int +rpl_pselect (int nfds, fd_set *restrict rfds, + fd_set *restrict wfds, fd_set *restrict xfds, + struct timespec const *restrict timeout, + sigset_t const *restrict sigmask) +{ + int i; + + /* FreeBSD 8.2 has a bug: it does not always detect invalid fds. */ + if (nfds < 0 || nfds > FD_SETSIZE) + { + errno = EINVAL; + return -1; + } + for (i = 0; i < nfds; i++) + { + if (((rfds && FD_ISSET (i, rfds)) + || (wfds && FD_ISSET (i, wfds)) + || (xfds && FD_ISSET (i, xfds))) + && dup2 (i, i) != i) + return -1; + } + + return pselect (nfds, rfds, wfds, xfds, timeout, sigmask); +} + +#endif diff --git a/m4/pselect.m4 b/m4/pselect.m4 index 97bf12cd2..5edacd28f 100644 --- a/m4/pselect.m4 +++ b/m4/pselect.m4 @@ -1,4 +1,4 @@ -# pselect.m4 +# pselect.m4 serial 2 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -23,6 +23,44 @@ AC_DEFUN([gl_FUNC_PSELECT], return !p;]])], [gl_cv_sig_pselect=yes], [gl_cv_sig_pselect=no])]) + + dnl On FreeBSD 8.2, pselect() doesn't always reject bad fds. + AC_CACHE_CHECK([whether pselect detects invalid fds], + [gl_cv_func_pselect_detects_ebadf], + [ + AC_RUN_IFELSE([AC_LANG_PROGRAM([[ +#include +#include +#if HAVE_SYS_SELECT_H +# include +#endif +#include +#include +]],[[ + fd_set set; + dup2(0, 16); + FD_ZERO(&set); + FD_SET(16, &set); + close(16); + struct timespec timeout; + timeout.tv_sec = 0; + timeout.tv_nsec = 5000; + return pselect (17, &set, NULL, NULL, &timeout, NULL) != -1 || errno != EBADF; +]])], [gl_cv_func_pselect_detects_ebadf=yes], + [gl_cv_func_pselect_detects_ebadf=no], + [ + case "$host_os" in + # Guess yes on glibc systems. + *-gnu*) gl_cv_func_pselect_detects_ebadf="guessing yes" ;; + # If we don't know, assume the worst. + *) gl_cv_func_pselect_detects_ebadf="guessing no" ;; + esac + ]) + ]) + case $gl_cv_func_pselect_detects_ebadf in + *yes) ;; + *) REPLACE_PSELECT=1 ;; + esac fi if test $ac_cv_func_pselect = no || test $gl_cv_sig_pselect = no; then diff --git a/modules/pselect b/modules/pselect index 1ca08edea..9db819c9f 100644 --- a/modules/pselect +++ b/modules/pselect @@ -9,6 +9,7 @@ Depends-on: sys_select pthread_sigmask [test $HAVE_PSELECT = 0 || test $REPLACE_PSELECT = 1] select [test $HAVE_PSELECT = 0 || test $REPLACE_PSELECT = 1] +dup2 [test $REPLACE_PSELECT = 1] configure.ac: gl_FUNC_PSELECT -- 2.11.0