[trace] Get the tracee program name from the environment.

Support non-Linux systems which don't have a /proc/self/cmdline
by transferring the application name given to cairo-trace via
an environment variable CAIRO_TRACE_PROG_NAME.

2 files changed, 21 insertions, 13 deletions

diff --git a/util/cairo-trace/cairo-trace.in b/util/cairo-trace/cairo-trace.in
index 3e54d4ed..f2a5b8f5 100644
--- a/util/cairo-trace/cairo-trace.in
+++ b/util/cairo-trace/cairo-trace.in
@@ -85,7 +85,8 @@ if test $# -eq 0; then
     usage
 fi
 
-#echo $*
+CAIRO_TRACE_PROG_NAME="$1"
+export CAIRO_TRACE_PROG_NAME
 
 LD_PRELOAD=@libdir@/cairo/cairo-trace.so 
 export LD_PRELOAD
diff --git a/util/cairo-trace/trace.c b/util/cairo-trace/trace.c
index f8275a69..3c47aafc 100644
--- a/util/cairo-trace/trace.c
+++ b/util/cairo-trace/trace.c
@@ -651,22 +651,29 @@ _trace_printf (const char *fmt, ...)
 static void
 get_prog_name (char *buf, int length)
 {
-    FILE *file = fopen ("/proc/self/cmdline", "rb");
-    *buf = '\0';
-    if (file != NULL) {
-	char *slash;
+    char *slash;
+    FILE *file;
 
-	slash = fgets (buf, length, file);
-	fclose (file);
-	if (slash == NULL)
-	    return;
+    memset (buf, 0, length);
+    if (length == 0)
+	return;
 
-	slash = strrchr (buf, '/');
-	if (slash != NULL) {
-	    int len = strlen (slash+1);
-	    memmove (buf, slash+1, len+1);
+    file = fopen ("/proc/self/cmdline", "rb");
+    if (file != NULL) {
+	fgets (buf, length, file);
+	fclose (file);
+    } else {
+	char const *name = getenv ("CAIRO_TRACE_PROG_NAME");
+	if (name != NULL) {
+	    strncpy (buf, name, length-1);
 	}
     }
+
+    slash = strrchr (buf, '/');
+    if (slash != NULL) {
+	size_t len = strlen (slash+1);
+	memmove (buf, slash+1, len+1);
+    }
 }
 
 static void