158 lines
3.2 KiB
C
158 lines
3.2 KiB
C
/* trunc.c
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Truncate a file to zero length. */
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#include "uucp.h"
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#include "uudefs.h"
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#include "sysdep.h"
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#include "system.h"
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#include <errno.h>
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#if HAVE_FCNTL_H
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#include <fcntl.h>
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#else
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#if HAVE_SYS_FILE_H
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#include <sys/file.h>
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#endif
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#endif
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#ifndef FD_CLOEXEC
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#define FD_CLOEXEC 1
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#endif
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#ifndef SEEK_SET
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#define SEEK_SET 0
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#endif
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/* External functions. */
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#ifndef lseek
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extern off_t lseek ();
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#endif
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/* Truncate a file to zero length. If this fails, it closes and
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removes the file. We support a number of different means of
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truncation, which is probably a waste of time since this function
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is currently only called when the 'f' protocol resends a file. */
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#if HAVE_FTRUNCATE
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#undef HAVE_LTRUNC
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#define HAVE_LTRUNC 0
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#endif
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#if ! HAVE_FTRUNCATE && ! HAVE_LTRUNC
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#ifdef F_CHSIZE
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#define HAVE_F_CHSIZE 1
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#else /* ! defined (F_CHSIZE) */
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#ifdef F_FREESP
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#define HAVE_F_FREESP 1
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#endif /* defined (F_FREESP) */
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#endif /* ! defined (F_CHSIZE) */
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#endif /* ! HAVE_FTRUNCATE && ! HAVE_LTRUNC */
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openfile_t
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esysdep_truncate (e, zname)
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openfile_t e;
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const char *zname;
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{
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int o;
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#if HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP
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int itrunc;
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if (! ffilerewind (e))
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{
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ulog (LOG_ERROR, "rewind: %s", strerror (errno));
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(void) ffileclose (e);
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(void) remove (zname);
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return EFILECLOSED;
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}
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#if USE_STDIO
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o = fileno (e);
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#else
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o = e;
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#endif
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#if HAVE_FTRUNCATE
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itrunc = ftruncate (o, 0);
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#endif
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#if HAVE_LTRUNC
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itrunc = ltrunc (o, (long) 0, SEEK_SET);
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#endif
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#if HAVE_F_CHSIZE
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itrunc = fcntl (o, F_CHSIZE, (off_t) 0);
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#endif
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#if HAVE_F_FREESP
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/* This selection is based on an implementation of ftruncate by
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kucharsk@Solbourne.com (William Kucharski). */
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{
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struct flock fl;
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fl.l_whence = 0;
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fl.l_len = 0;
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fl.l_start = 0;
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fl.l_type = F_WRLCK;
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itrunc = fcntl (o, F_FREESP, &fl);
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}
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#endif
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if (itrunc != 0)
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{
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#if HAVE_FTRUNCATE
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ulog (LOG_ERROR, "ftruncate: %s", strerror (errno));
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#endif
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#ifdef HAVE_LTRUNC
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ulog (LOG_ERROR, "ltrunc: %s", strerror (errno));
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#endif
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#ifdef HAVE_F_CHSIZE
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ulog (LOG_ERROR, "fcntl (F_CHSIZE): %s", strerror (errno));
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#endif
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#ifdef HAVE_F_FREESP
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ulog (LOG_ERROR, "fcntl (F_FREESP): %s", strerror (errno));
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#endif
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(void) ffileclose (e);
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(void) remove (zname);
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return EFILECLOSED;
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}
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return e;
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#else /* ! (HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP) */
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(void) ffileclose (e);
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(void) remove (zname);
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o = creat ((char *) zname, IPRIVATE_FILE_MODE);
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if (o == -1)
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{
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ulog (LOG_ERROR, "creat (%s): %s", zname, strerror (errno));
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return EFILECLOSED;
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}
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if (fcntl (o, F_SETFD, fcntl (o, F_GETFD, 0) | FD_CLOEXEC) < 0)
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{
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ulog (LOG_ERROR, "fcntl (FD_CLOEXEC): %s", strerror (errno));
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(void) close (o);
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return EFILECLOSED;
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}
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#if USE_STDIO
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e = fdopen (o, (char *) BINWRITE);
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if (e == NULL)
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{
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ulog (LOG_ERROR, "fdopen (%s): %s", zname, strerror (errno));
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(void) close (o);
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(void) remove (zname);
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return NULL;
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}
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#else /* ! USE_STDIO */
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e = o;
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#endif /* ! USE_STDIO */
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return e;
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#endif /* ! (HAVE_FTRUNCATE || HAVE_LTRUNC || HAVE_F_CHSIZE || HAVE_F_FREESP) */
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}
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