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authorPeter Wemm <peter@FreeBSD.org>1996-08-20 23:46:10 +0000
committerPeter Wemm <peter@FreeBSD.org>1996-08-20 23:46:10 +0000
commit18576028af9c8455e19c9f51d94b87e08d1e6bd7 (patch)
tree70187fdf5be4cbefd0baf46bddac7e5e32c13c24 /contrib/cvs/lib/ftruncate.c
parentbd3a9cd23c621022280b2b8d4e66a5141b4e88e0 (diff)
Import of slightly trimmed cvs-1.8 distribution. Generated files
and non-unix code has been left out.
Notes
Notes: svn path=/vendor/cvs/dist/; revision=17721
Diffstat (limited to 'contrib/cvs/lib/ftruncate.c')
-rw-r--r--contrib/cvs/lib/ftruncate.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/contrib/cvs/lib/ftruncate.c b/contrib/cvs/lib/ftruncate.c
new file mode 100644
index 000000000000..13f20a382849
--- /dev/null
+++ b/contrib/cvs/lib/ftruncate.c
@@ -0,0 +1,76 @@
+/* ftruncate emulations that work on some System V's.
+ This file is in the public domain. */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/types.h>
+#include <fcntl.h>
+
+#ifdef F_CHSIZE
+int
+ftruncate (fd, length)
+ int fd;
+ off_t length;
+{
+ return fcntl (fd, F_CHSIZE, length);
+}
+#else
+#ifdef F_FREESP
+/* The following function was written by
+ kucharsk@Solbourne.com (William Kucharski) */
+
+#include <sys/stat.h>
+#include <errno.h>
+#include <unistd.h>
+
+int
+ftruncate (fd, length)
+ int fd;
+ off_t length;
+{
+ struct flock fl;
+ struct stat filebuf;
+
+ if (fstat (fd, &filebuf) < 0)
+ return -1;
+
+ if (filebuf.st_size < length)
+ {
+ /* Extend file length. */
+ if (lseek (fd, (length - 1), SEEK_SET) < 0)
+ return -1;
+
+ /* Write a "0" byte. */
+ if (write (fd, "", 1) != 1)
+ return -1;
+ }
+ else
+ {
+ /* Truncate length. */
+ fl.l_whence = 0;
+ fl.l_len = 0;
+ fl.l_start = length;
+ fl.l_type = F_WRLCK; /* Write lock on file space. */
+
+ /* This relies on the UNDOCUMENTED F_FREESP argument to
+ fcntl, which truncates the file so that it ends at the
+ position indicated by fl.l_start.
+ Will minor miracles never cease? */
+ if (fcntl (fd, F_FREESP, &fl) < 0)
+ return -1;
+ }
+
+ return 0;
+}
+#else
+int
+ftruncate (fd, length)
+ int fd;
+ off_t length;
+{
+ return chsize (fd, length);
+}
+#endif
+#endif