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Annotation of coherent/g/usr/lib/uucp/tay104/unix/trunc.c, revision 1.1

1.1     ! root        1: /* trunc.c
        !             2:    Truncate a file to zero length.  */
        !             3: 
        !             4: #include "uucp.h"
        !             5: 
        !             6: #include "uudefs.h"
        !             7: #include "sysdep.h"
        !             8: #include "system.h"
        !             9: 
        !            10: #include <errno.h>
        !            11: 
        !            12: #if HAVE_FCNTL_H
        !            13: #include <fcntl.h>
        !            14: #else
        !            15: #if HAVE_SYS_FILE_H
        !            16: #include <sys/file.h>
        !            17: #endif
        !            18: #endif
        !            19: 
        !            20: #ifndef FD_CLOEXEC
        !            21: #define FD_CLOEXEC 1
        !            22: #endif
        !            23: 
        !            24: #ifndef SEEK_SET
        !            25: #define SEEK_SET 0
        !            26: #endif
        !            27: 
        !            28: /* External functions.  */
        !            29: #ifndef lseek
        !            30: extern off_t lseek ();
        !            31: #endif
        !            32: 
        !            33: /* Truncate a file to zero length.  If this fails, it closes and
        !            34:    removes the file.  We support a number of different means of
        !            35:    truncation, which is probably a waste of time since this function
        !            36:    is currently only called when the 'f' protocol resends a file.  */
        !            37: 
        !            38: #if HAVE_FTRUNCATE
        !            39: #undef HAVE_LTRUNC
        !            40: #define HAVE_LTRUNC 0
        !            41: #endif
        !            42: 
        !            43: #if ! HAVE_FTRUNCATE && ! HAVE_LTRUNC
        !            44: #ifdef F_CHSIZE
        !            45: #define HAVE_F_CHSIZE 1
        !            46: #else /* ! defined (F_CHSIZE) */
        !            47: #ifdef F_FREESP
        !            48: #define HAVE_F_FREESP 1
        !            49: #endif /* defined (F_FREESP) */
        !            50: #endif /* ! defined (F_CHSIZE) */
        !            51: #endif /* ! HAVE_FTRUNCATE && ! HAVE_LTRUNC */
        !            52: 
        !            53: openfile_t
        !            54: esysdep_truncate (e, zname)
        !            55:      openfile_t e;
        !            56:      const char *zname;
        !            57: {
        !            58:   int o;
        !            59: 
        !            60: #if HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP
        !            61:   int itrunc;
        !            62: 
        !            63:   if (! ffilerewind (e))
        !            64:     {
        !            65:       ulog (LOG_ERROR, "rewind: %s", strerror (errno));
        !            66:       (void) ffileclose (e);
        !            67:       (void) remove (zname);
        !            68:       return EFILECLOSED;
        !            69:     }
        !            70: 
        !            71: #if USE_STDIO
        !            72:   o = fileno (e);
        !            73: #else
        !            74:   o = e;
        !            75: #endif
        !            76: 
        !            77: #if HAVE_FTRUNCATE
        !            78:   itrunc = ftruncate (o, 0);
        !            79: #endif
        !            80: #if HAVE_LTRUNC
        !            81:   itrunc = ltrunc (o, (long) 0, SEEK_SET);
        !            82: #endif
        !            83: #if HAVE_F_CHSIZE
        !            84:   itrunc = fcntl (o, F_CHSIZE, (off_t) 0);
        !            85: #endif
        !            86: #if HAVE_F_FREESP
        !            87:   /* This selection is based on an implementation of ftruncate by
        !            88:      [email protected] (William Kucharski).  */
        !            89:   {
        !            90:     struct flock fl;
        !            91: 
        !            92:     fl.l_whence = 0;
        !            93:     fl.l_len = 0;
        !            94:     fl.l_start = 0;
        !            95:     fl.l_type = F_WRLCK;
        !            96: 
        !            97:     itrunc = fcntl (o, F_FREESP, &fl);
        !            98:   }
        !            99: #endif
        !           100: 
        !           101:   if (itrunc != 0)
        !           102:     {
        !           103: #if HAVE_FTRUNCATE
        !           104:       ulog (LOG_ERROR, "ftruncate: %s", strerror (errno));
        !           105: #endif
        !           106: #ifdef HAVE_LTRUNC
        !           107:       ulog (LOG_ERROR, "ltrunc: %s", strerror (errno));
        !           108: #endif
        !           109: #ifdef HAVE_F_CHSIZE
        !           110:       ulog (LOG_ERROR, "fcntl (F_CHSIZE): %s", strerror (errno));
        !           111: #endif
        !           112: #ifdef HAVE_F_FREESP
        !           113:       ulog (LOG_ERROR, "fcntl (F_FREESP): %s", strerror (errno));
        !           114: #endif
        !           115: 
        !           116:       (void) ffileclose (e);
        !           117:       (void) remove (zname);
        !           118:       return EFILECLOSED;
        !           119:     }
        !           120: 
        !           121:   return e;
        !           122: #else /* ! (HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP) */
        !           123:   (void) ffileclose (e);
        !           124:   (void) remove (zname);
        !           125: 
        !           126:   o = creat ((char *) zname, IPRIVATE_FILE_MODE);
        !           127: 
        !           128:   if (o == -1)
        !           129:     {
        !           130:       ulog (LOG_ERROR, "creat (%s): %s", zname, strerror (errno));
        !           131:       return EFILECLOSED;
        !           132:     }
        !           133: 
        !           134:   if (fcntl (o, F_SETFD, fcntl (o, F_GETFD, 0) | FD_CLOEXEC) < 0)
        !           135:     {
        !           136:       ulog (LOG_ERROR, "fcntl (FD_CLOEXEC): %s", strerror (errno));
        !           137:       (void) close (o);
        !           138:       return EFILECLOSED;
        !           139:     }
        !           140: 
        !           141: #if USE_STDIO
        !           142:   e = fdopen (o, (char *) BINWRITE);
        !           143: 
        !           144:   if (e == NULL)
        !           145:     {
        !           146:       ulog (LOG_ERROR, "fdopen (%s): %s", zname, strerror (errno));
        !           147:       (void) close (o);
        !           148:       (void) remove (zname);
        !           149:       return NULL;
        !           150:     }
        !           151: #else /* ! USE_STDIO */
        !           152:   e = o;
        !           153: #endif /* ! USE_STDIO */
        !           154: 
        !           155:   return e;
        !           156: #endif /* ! (HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP) */
        !           157: }

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