Merge branch 'cow' into net

Conflicts:
	.gitignore
	Makefile
	conf/lab.mk
	kernel/defs.h
	kernel/syscall.c
	kernel/vm.c
	user/pingpong.c
	user/user.h
	user/usys.pl

1 files changed, 27 insertions, 0 deletions

diff --git a/user/trace.c b/user/trace.c
new file mode 100644
index 0000000..dd77760
--- /dev/null
+++ b/user/trace.c
@@ -0,0 +1,27 @@
+#include "kernel/param.h"
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+int
+main(int argc, char *argv[])
+{
+  int i;
+  char *nargv[MAXARG];
+
+  if(argc < 3 || (argv[1][0] < '0' || argv[1][0] > '9')){
+    fprintf(2, "Usage: %s mask command\n", argv[0]);
+    exit(1);
+  }
+
+  if (trace(atoi(argv[1])) < 0) {
+    fprintf(2, "%s: trace failed\n", argv[0]);
+    exit(1);
+  }
+  
+  for(i = 2; i < argc && i < MAXARG; i++){
+    nargv[i-2] = argv[i];
+  }
+  exec(nargv[0], nargv);
+  exit(0);
+}