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Annotation of embedaddon/libiconv/srclib/safe-read.c, revision 1.1

1.1     ! misho       1: /* An interface to read and write that retries after interrupts.
        !             2: 
        !             3:    Copyright (C) 1993-1994, 1998, 2002-2006, 2009-2011 Free Software
        !             4:    Foundation, Inc.
        !             5: 
        !             6:    This program is free software: you can redistribute it and/or modify
        !             7:    it under the terms of the GNU General Public License as published by
        !             8:    the Free Software Foundation; either version 3 of the License, or
        !             9:    (at your option) any later version.
        !            10: 
        !            11:    This program is distributed in the hope that it will be useful,
        !            12:    but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            13:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            14:    GNU General Public License for more details.
        !            15: 
        !            16:    You should have received a copy of the GNU General Public License
        !            17:    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
        !            18: 
        !            19: #include <config.h>
        !            20: 
        !            21: /* Specification.  */
        !            22: #ifdef SAFE_WRITE
        !            23: # include "safe-write.h"
        !            24: #else
        !            25: # include "safe-read.h"
        !            26: #endif
        !            27: 
        !            28: /* Get ssize_t.  */
        !            29: #include <sys/types.h>
        !            30: #include <unistd.h>
        !            31: 
        !            32: #include <errno.h>
        !            33: 
        !            34: #ifdef EINTR
        !            35: # define IS_EINTR(x) ((x) == EINTR)
        !            36: #else
        !            37: # define IS_EINTR(x) 0
        !            38: #endif
        !            39: 
        !            40: #include <limits.h>
        !            41: 
        !            42: #ifdef SAFE_WRITE
        !            43: # define safe_rw safe_write
        !            44: # define rw write
        !            45: #else
        !            46: # define safe_rw safe_read
        !            47: # define rw read
        !            48: # undef const
        !            49: # define const /* empty */
        !            50: #endif
        !            51: 
        !            52: /* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
        !            53:    interrupted.  Return the actual number of bytes read(written), zero for EOF,
        !            54:    or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error.  */
        !            55: size_t
        !            56: safe_rw (int fd, void const *buf, size_t count)
        !            57: {
        !            58:   /* Work around a bug in Tru64 5.1.  Attempting to read more than
        !            59:      INT_MAX bytes fails with errno == EINVAL.  See
        !            60:      <http://lists.gnu.org/archive/html/bug-gnu-utils/2002-04/msg00010.html>.
        !            61:      When decreasing COUNT, keep it block-aligned.  */
        !            62:   enum { BUGGY_READ_MAXIMUM = INT_MAX & ~8191 };
        !            63: 
        !            64:   for (;;)
        !            65:     {
        !            66:       ssize_t result = rw (fd, buf, count);
        !            67: 
        !            68:       if (0 <= result)
        !            69:         return result;
        !            70:       else if (IS_EINTR (errno))
        !            71:         continue;
        !            72:       else if (errno == EINVAL && BUGGY_READ_MAXIMUM < count)
        !            73:         count = BUGGY_READ_MAXIMUM;
        !            74:       else
        !            75:         return result;
        !            76:     }
        !            77: }