callgraph

commit cfa67f131264dad5f192ef5092660eb9dd078286
parent 6eedc7c9a0c90735f0edfb1092b731bff5ccfe3d
Author: lostd <lostd@2f30.org>
Date:   Thu, 14 Nov 2013 22:35:29 +0200

Use a fixed callgraph.dot output file and don't overwrite it

Diffstat:
M
README
 | 
7
++-----
M
libcallgraph.c
 | 
12
++----------
M
symbolize.sh
 | 
7
++++---

3 files changed, 8 insertions(+), 18 deletions(-)
diff --git a/README b/README
@@ -13,16 +13,13 @@ example, modify its Makefile to include:
 
 	make
 
-Set the environment variable CGRAPH_OUT to the name of the .dot file.
-
-	export CGRAPH_OUT=callgraph.dot
-
 At this point you just run the program taking care for the library file
 to be in the library path.
 
 	LD_LIBRARY_PATH=$PWD ./prog [ARGS]
 
-Once the program terminates, you have to feed it to the symbolizer.
+Once the program terminates, you may want to replace addresses in the
+generated callgraph.dot file with function names, using the symbolizer.
 
 	./symbolize.sh ./prog
 
diff --git a/libcallgraph.c b/libcallgraph.c
@@ -65,16 +65,8 @@ writelog(int fildes, const void *buf, size_t nbyte)
 __attribute__ ((constructor)) static void
 init_logging(void)
 {
-     char *f;
-
-     f = getenv("CGRAPH_OUT");
-     if (!f) {
-          fprintf(stderr, "cgraph: CGRAPH_OUT is not set!\n");
-          _Exit(EXIT_FAILURE);
-     }
-
-     fd = open(f, O_WRONLY | O_CREAT, 0644);
-     if (fd < 0 || ftruncate(fd, 0) < 0) {
+     fd = open("callgraph.dot", O_WRONLY | O_CREAT | O_EXCL, 0644);
+     if (fd == -1) {
           perror("cgraph");
           _Exit(EXIT_FAILURE);
      }
diff --git a/symbolize.sh b/symbolize.sh
@@ -7,9 +7,10 @@ if [ ! -n "$1" ]; then
 	exit 1
 fi
 
-env | grep CGRAPH_OUT= &>/dev/null
-if [ ! "$?" -eq 0 -o "$CGRAPH_OUT" = "" ]; then
-	echo "CGRAPH_OUT is not set!" 1>&2
+CGRAPH_OUT=callgraph.dot
+
+if [ ! -f "$CGRAPH_OUT" ]; then
+	echo "$CGRAPH_OUT does not exist!" 1>&2
 	exit 1
 fi