snapshot: find the correct binary name

This is somewhat of a neutral change; the existing /proc/*/maps check
works because our path name usually has the word 'model' in it. But
really, we should find the true, full path of the user program.

This should be extended to find more maps (e.g., for other libraries),
and it should be extended for Mac OSX too.

diff --git a/snapshot-interface.cc b/snapshot-interface.cc
index c22b8712b32937cbd415fb9f2ab7d1039e8c97a8..51fe2f08de1392dd6fe40cd3757edcf675367c60 100644 (file)
--- a/snapshot-interface.cc
+++ b/snapshot-interface.cc
@@ -12,7 +12,8 @@
 #include <inttypes.h>
 #include "common.h"
 
-
+/* MYBINARYNAME only works because our pathname usually includes 'model' (e.g.,
+ * /.../model-checker/test/userprog.o) */
 #define MYBINARYNAME "model"
 #define MYLIBRARYNAME "libmodel.so"
 #define MAPFILE "/proc/self/maps"
@@ -67,12 +68,22 @@ static void SnapshotGlobalSegments(){
        pclose(map);
 }
 #else
+
+static void get_binary_name(char *buf, size_t len)
+{
+       if (readlink("/proc/self/exe", buf, len) == -1) {
+               perror("readlink");
+               exit(EXIT_FAILURE);
+       }
+}
+
 /** The SnapshotGlobalSegments function computes the memory regions
  *     that may contain globals and then configures the snapshotting
  *     library to snapshot them.
  */
 static void SnapshotGlobalSegments(){
        char buf[9000];
+       char binary_name[800];
        FILE *map;
 
        map = fopen(MAPFILE, "r");
@@ -80,13 +91,14 @@ static void SnapshotGlobalSegments(){
                perror("fopen");
                exit(EXIT_FAILURE);
        }
+       get_binary_name(binary_name, sizeof(binary_name));
        while (fgets(buf, sizeof(buf), map)) {
                char regionname[200] = "";
                char r, w, x, p;
                void *begin, *end;
 
                sscanf(buf, "%p-%p %c%c%c%c %*x %*x:%*x %*u %200s\n", &begin, &end, &r, &w, &x, &p, regionname);
-               if (w == 'w' && (strstr(regionname, MYBINARYNAME) || strstr(regionname, MYLIBRARYNAME))) {
+               if (w == 'w' && (strstr(regionname, binary_name) || strstr(regionname, MYLIBRARYNAME))) {
                        size_t len = ((uintptr_t)end - (uintptr_t)begin) / PAGESIZE;
                        if (len != 0)
                                addMemoryRegionToSnapShot(begin, len);