Last change
on this file since 7464 was 3745, checked in by mdewsnip, 21 years ago |
Addition of MG package for search and retrieval
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Property svn:executable
set to
*
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Property svn:keywords
set to
Author Date Id Revision
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File size:
1.8 KB
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[3745] | 1 | /* ftruncate emulations that work on some System V's.
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| 2 | This file is in the public domain. */
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| 3 |
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| 4 | #ifdef HAVE_CONFIG_H
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| 5 | # ifdef __WIN32__ /* [RPAP - Feb 97: WIN32 Port] */
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| 6 | # include <win32cfg.h>
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| 7 | # else
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| 8 | # include <sysfuncs.h>
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| 9 | # endif
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| 10 | #endif
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| 11 |
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| 12 | #include <sys/types.h>
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| 13 | #include <fcntl.h>
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| 14 |
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| 15 | #ifdef F_CHSIZE
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| 16 |
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| 17 | int
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| 18 | ftruncate (fd, length)
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| 19 | int fd;
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| 20 | off_t length;
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| 21 | {
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| 22 | return fcntl (fd, F_CHSIZE, length);
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| 23 | }
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| 24 |
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| 25 | #else /* not F_CHSIZE */
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| 26 | #ifdef F_FREESP
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| 27 |
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| 28 | /* By William Kucharski <[email protected]>. */
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| 29 |
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| 30 | #include <sys/stat.h>
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| 31 | #include <errno.h>
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| 32 | #ifdef HAVE_UNISTD_H
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| 33 | #include <unistd.h>
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| 34 | #endif
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| 35 |
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| 36 | int
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| 37 | ftruncate (fd, length)
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| 38 | int fd;
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| 39 | off_t length;
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| 40 | {
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| 41 | struct flock fl;
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| 42 | struct stat filebuf;
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| 43 |
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| 44 | if (fstat (fd, &filebuf) < 0)
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| 45 | return -1;
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| 46 |
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| 47 | if (filebuf.st_size < length)
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| 48 | {
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| 49 | /* Extend file length. */
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| 50 | if (lseek (fd, (length - 1), SEEK_SET) < 0)
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| 51 | return -1;
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| 52 |
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| 53 | /* Write a "0" byte. */
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| 54 | if (write (fd, "", 1) != 1)
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| 55 | return -1;
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| 56 | }
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| 57 | else
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| 58 | {
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| 59 |
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| 60 | /* Truncate length. */
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| 61 |
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| 62 | fl.l_whence = 0;
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| 63 | fl.l_len = 0;
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| 64 | fl.l_start = length;
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| 65 | fl.l_type = F_WRLCK; /* write lock on file space */
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| 66 |
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| 67 | /* This relies on the *undocumented* F_FREESP argument to fcntl,
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| 68 | which truncates the file so that it ends at the position
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| 69 | indicated by fl.l_start. Will minor miracles never cease? */
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| 70 |
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| 71 | if (fcntl (fd, F_FREESP, &fl) < 0)
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| 72 | return -1;
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| 73 | }
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| 74 |
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| 75 | return 0;
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| 76 | }
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| 77 |
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| 78 | #else /* not F_CHSIZE nor F_FREESP */
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| 79 | #ifdef HAVE_CHSIZE
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| 80 |
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| 81 | int
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| 82 | ftruncate (fd, length)
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| 83 | int fd;
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| 84 | off_t length;
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| 85 | {
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| 86 | return chsize (fd, length);
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| 87 | }
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| 88 |
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| 89 | #else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
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| 90 |
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| 91 | #include <errno.h>
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| 92 | #ifndef errno
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| 93 | extern int errno;
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| 94 | #endif
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| 95 |
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| 96 | int
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| 97 | ftruncate (fd, length)
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| 98 | int fd;
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| 99 | off_t length;
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| 100 | {
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| 101 | errno = EIO;
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| 102 | return -1;
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| 103 | }
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| 104 |
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| 105 | #endif /* not HAVE_CHSIZE */
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| 106 | #endif /* not F_FREESP */
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| 107 | #endif /* not F_CHSIZE */
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