mirror of
https://github.com/libguestfs/libguestfs.git
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0f54df53d2
As part of our efforts to clean up and simplify libguestfs, removing gnulib deletes a large dependency that we mostly no longer use and causes problems for new users trying to build the library from source. A few modules from gnulib are still used (under a compatible license) and these are copied into gnulib/lib/
80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/* An interface to read and write that retries after interrupts.
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Copyright (C) 1993-1994, 1998, 2002-2006, 2009-2021 Free Software
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Foundation, Inc.
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(NB: I modified the original GPL boilerplate here to LGPLv2+. This
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is because of the weird way that gnulib uses licenses, where the
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real license is covered in the modules/X file. The real license
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for this file is LGPLv2+, not GPL. - RWMJ)
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <config.h>
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/* Specification. */
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#ifdef SAFE_WRITE
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# include "safe-write.h"
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#else
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# include "safe-read.h"
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#endif
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/* Get ssize_t. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <limits.h>
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#include <errno.h>
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#ifdef EINTR
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# define IS_EINTR(x) ((x) == EINTR)
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#else
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# define IS_EINTR(x) 0
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#endif
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enum { SYS_BUFSIZE_MAX = INT_MAX >> 20 << 20 };
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#ifdef SAFE_WRITE
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# define safe_rw safe_write
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# define rw write
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#else
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# define safe_rw safe_read
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# define rw read
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# undef const
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# define const /* empty */
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#endif
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/* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
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interrupted. Return the actual number of bytes read(written), zero for EOF,
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or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error. */
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size_t
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safe_rw (int fd, void const *buf, size_t count)
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{
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for (;;)
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{
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ssize_t result = rw (fd, buf, count);
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if (0 <= result)
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return result;
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else if (IS_EINTR (errno))
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continue;
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else if (errno == EINVAL && SYS_BUFSIZE_MAX < count)
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count = SYS_BUFSIZE_MAX;
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else
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return result;
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}
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}
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