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ftruncate. * ftruncate.c: New file, from gnulib. * output.cc (posix_fallocate): Define dummy version if not HAVE_POSIX_FALLOCATE. (Output_file::map): Call posix_fallocate rather than lseek and write. * gold.h (ftruncate): Declare if not HAVE_FTRUNCATE. * configure, Makefile.in, config.in: Rebuild.cgen-1_1-branch
Ian Lance Taylor
17 years ago
8 changed files with 248 additions and 11 deletions
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/* ftruncate emulations that work on some System V's.
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This file is in the public domain. */ |
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#include <config.h> |
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/* Specification. */ |
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#include <unistd.h> |
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#include <sys/types.h> |
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#include <fcntl.h> |
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#ifdef F_CHSIZE |
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int |
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ftruncate (int fd, off_t length) |
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{ |
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return fcntl (fd, F_CHSIZE, length); |
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} |
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#else /* not F_CHSIZE */ |
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# ifdef F_FREESP |
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/* By William Kucharski <kucharsk@netcom.com>. */ |
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# include <sys/stat.h> |
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# include <errno.h> |
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int |
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ftruncate (int fd, off_t length) |
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{ |
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struct flock fl; |
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struct stat filebuf; |
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if (fstat (fd, &filebuf) < 0) |
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return -1; |
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if (filebuf.st_size < length) |
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{ |
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/* Extend file length. */ |
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if (lseek (fd, (length - 1), SEEK_SET) < 0) |
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return -1; |
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/* Write a "0" byte. */ |
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if (write (fd, "", 1) != 1) |
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return -1; |
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} |
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else |
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{ |
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/* Truncate length. */ |
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fl.l_whence = 0; |
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fl.l_len = 0; |
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fl.l_start = length; |
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fl.l_type = F_WRLCK; /* write lock on file space */ |
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/* This relies on the *undocumented* F_FREESP argument to fcntl,
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which truncates the file so that it ends at the position |
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indicated by fl.l_start. Will minor miracles never cease? */ |
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if (fcntl (fd, F_FREESP, &fl) < 0) |
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return -1; |
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} |
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return 0; |
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} |
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# else /* not F_CHSIZE nor F_FREESP */ |
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# if HAVE_CHSIZE /* native Windows, e.g. mingw */ |
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int |
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ftruncate (int fd, off_t length) |
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{ |
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return chsize (fd, length); |
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} |
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# else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */ |
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# include <errno.h> |
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int |
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ftruncate (int fd, off_t length) |
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{ |
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errno = EIO; |
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return -1; |
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} |
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# endif /* not HAVE_CHSIZE */ |
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# endif /* not F_FREESP */ |
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#endif /* not F_CHSIZE */ |
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