X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=lib%2Fmmap.c;h=87a2047f7038df21268eb32ce0ce958ec6ab8223;hb=2e2adfa5d7ac912434bef5b8a9b25cfb14d4a4a6;hp=46f5cd3add76ef0b9d8643fe415fdd45076eca34;hpb=5b53087fa5a07ff89d34cf3bf3bc1b28809f05c2;p=libucw.git

diff --git a/lib/mmap.c b/lib/mmap.c
index 46f5cd3a..87a2047f 100644
--- a/lib/mmap.c
+++ b/lib/mmap.c
@@ -1,25 +1,26 @@
 /*
  *	Sherlock Library -- Mapping of Files
  *
- *	(c) 1999 Martin Mares, <mj@atrey.karlin.mff.cuni.cz>
+ *	(c) 1999 Martin Mares <mj@ucw.cz>
  */
 
+#include "lib/lib.h"
+
 #include <stdio.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
 
-#include "lib/lib.h"
-
 #ifndef MAP_FAILED
+#warning System includes do not define MAP_FAILED.
 #define MAP_FAILED ((void *)-1L)
 #endif
 
 void *
-mmap_file(byte *name, unsigned *len)
+mmap_file(byte *name, unsigned *len, int writeable)
 {
-  int fd = open(name, O_RDONLY);
+  int fd = open(name, writeable ? O_RDWR : O_RDONLY);
   struct stat st;
   void *x;
 
@@ -31,10 +32,21 @@ mmap_file(byte *name, unsigned *len)
     {
       if (len)
 	*len = st.st_size;
-      x = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
-      if (x == MAP_FAILED)
-	x = NULL;
+      if (st.st_size)
+	{
+	  x = mmap(NULL, st.st_size, writeable ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_SHARED, fd, 0);
+	  if (x == MAP_FAILED)
+	    x = NULL;
+	}
+      else	/* For empty file, we can return any non-zero address */
+	return "";
     }
   close(fd);
   return x;
 }
+
+void
+munmap_file(void *start, unsigned len)
+{
+  munmap(start, len);
+}