other_patches

早期freebsd实现

*** PORT/db/recno/rec_open.c.orig	1993/10/13 02:01:31
--- PORT/db/recno/rec_open.c	1993/10/13 02:20:47
***************
*** 159,167 ****
--- 159,182 ----
  				SET(t, R_EOF);
  			else {
  				t->bt_msize = sb.st_size;
+ /*
+  * hack : 
+  *
+  * The Linux kernel mmap() semantics are broken :
+  * 
+  * Under Linux, read only private mappings cause write only and read/write 
+  * opens to fail with errno=ETXTBSY.  Shared read only mappings should work
+  * fine though, but I'm not familiar enough with the code to ascertain that
+  * a MAP_SHARED mapping would be safe so I use the non-mmap'd version 
+  * instead.
+  *
+  */
+ 
+ #if !defined(linux) 
  				if ((t->bt_smap = mmap(NULL, t->bt_msize,
  				    PROT_READ, MAP_PRIVATE, rfd,
  				    (off_t)0)) == (caddr_t)-1)
+ #endif
  					goto slow;
  				t->bt_cmap = t->bt_smap;
  				t->bt_emap = t->bt_smap + sb.st_size;