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66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* safe-read.c -- an interface to read that retries after interrupts
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Copyright (C) 1993, 1994 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <sys/types.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <errno.h>
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#ifndef STDC_HEADERS
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extern int errno;
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#endif
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/* Read LEN bytes at PTR from descriptor DESC, for file FILENAME,
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retrying if necessary. Return a negative value if an error occurs,
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otherwise return the actual number of bytes read,
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which must be LEN unless end-of-file was reached. */
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The canonical source for this function is in the gcc distribution
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in file cccp.c. So don't make any changes here. */
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static int
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safe_read (desc, ptr, len)
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int desc;
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char *ptr;
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int len;
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{
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int left = len;
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while (left > 0) {
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int nchars = read (desc, ptr, left);
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if (nchars < 0)
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{
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#ifdef EINTR
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if (errno == EINTR)
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continue;
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#endif
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return nchars;
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}
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if (nchars == 0)
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break;
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ptr += nchars;
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left -= nchars;
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}
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return len - left;
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}
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