diff options
Diffstat (limited to 'lib/safe-read.c')
| -rw-r--r-- | lib/safe-read.c | 46 |
1 files changed, 22 insertions, 24 deletions
diff --git a/lib/safe-read.c b/lib/safe-read.c index c21d1cf1..9caf8466 100644 --- a/lib/safe-read.c +++ b/lib/safe-read.c @@ -1,5 +1,7 @@ /* An interface to read and write that retries after interrupts. - Copyright (C) 1993, 1994, 1998, 2002-2003 Free Software Foundation, Inc. + + Copyright (C) 1993, 1994, 1998, 2002, 2003, 2004, 2005 Free Software + Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -13,9 +15,9 @@ You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, - Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ -#if HAVE_CONFIG_H +#ifdef HAVE_CONFIG_H # include <config.h> #endif @@ -28,14 +30,9 @@ /* Get ssize_t. */ #include <sys/types.h> -#if HAVE_UNISTD_H -# include <unistd.h> -#endif +#include <unistd.h> #include <errno.h> -#ifndef errno -extern int errno; -#endif #ifdef EINTR # define IS_EINTR(x) ((x) == EINTR) @@ -61,22 +58,23 @@ extern int errno; size_t safe_rw (int fd, void const *buf, size_t count) { - ssize_t result; + /* Work around a bug in Tru64 5.1. Attempting to read more than + INT_MAX bytes fails with errno == EINVAL. See + <http://lists.gnu.org/archive/html/bug-gnu-utils/2002-04/msg00010.html>. + When decreasing COUNT, keep it block-aligned. */ + enum { BUGGY_READ_MAXIMUM = INT_MAX & ~8191 }; - /* POSIX limits COUNT to SSIZE_MAX, but we limit it further, requiring - that COUNT <= INT_MAX, to avoid triggering a bug in Tru64 5.1. - When decreasing COUNT, keep the file pointer block-aligned. - Note that in any case, read(write) may succeed, yet read(write) - fewer than COUNT bytes, so the caller must be prepared to handle - partial results. */ - if (count > INT_MAX) - count = INT_MAX & ~8191; - - do + for (;;) { - result = rw (fd, buf, count); - } - while (result < 0 && IS_EINTR (errno)); + ssize_t result = rw (fd, buf, count); - return (size_t) result; + if (0 <= result) + return result; + else if (IS_EINTR (errno)) + continue; + else if (errno == EINVAL && BUGGY_READ_MAXIMUM < count) + count = BUGGY_READ_MAXIMUM; + else + return result; + } } |