See ChangeLog entry 2005-11-07 for details.

os/utils.c

@@ -2238,3 +2238,53 @@ CheckUserAuthorization(void)
     }
 #endif
 }
+
+#ifdef __SCO__
+#include <fcntl.h>
+
+static void
+lockit (int fd, short what)
+{
+  struct flock lck;
+
+  lck.l_whence = 0;
+  lck.l_start = 0;
+  lck.l_len = 1;
+  lck.l_type = what;
+
+  (void)fcntl (fd, F_SETLKW, &lck);
+}
+
+/* SCO OpenServer 5 lacks pread/pwrite. Emulate them. */
+ssize_t
+pread (int fd, void *buf, size_t nbytes, off_t offset)
+{
+  off_t saved;
+  ssize_t ret;
+
+  lockit (fd, F_RDLCK);
+  saved = lseek (fd, 0, SEEK_CUR);
+  lseek (fd, offset, SEEK_SET);
+  ret = read (fd, buf, nbytes);
+  lseek (fd, saved, SEEK_SET);
+  lockit (fd, F_UNLCK);
+
+  return ret;
+}
+
+ssize_t
+pwrite (int fd, const void *buf, size_t nbytes, off_t offset)
+{
+  off_t saved;
+  ssize_t ret;
+
+  lockit (fd, F_WRLCK);
+  saved = lseek (fd, 0, SEEK_CUR);
+  lseek (fd, offset, SEEK_SET);
+  ret = write (fd, buf, nbytes);
+  lseek (fd, saved, SEEK_SET);
+  lockit (fd, F_UNLCK);
+
+  return ret;
+}
+#endif /* __SCO__ */