forkexectree

bd8db5d8 · Nickolai Zeldovich · 011b8409 · bd8db5d8 · bd8db5d8 · bd8db5d8
--- a/Makefile
+++ b/Makefile
@@ -182,6 +182,7 @@ UPROGS=\
 	_sleep\
 	_maptest\
 	_forktree\
+	_forkexectree\
 	_mapbench\
 fs.img: mkfs README $(UPROGS)

--- a/forkexectree.c
+++ b/forkexectree.c
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+#include "xv6-mtrace.h"
+#define NCHILD 2
+#define NDEPTH 7
+void
+forktree(uint depth)
+{
+  if (depth == 0) {
+    printf(1, "%d: forkexectree\n", getpid());
+    mtrace_enable_set(1, "xv6-forktree");
+  }
+  if (depth >= NDEPTH)
+    exit();
+  for (uint i = 0; i < NCHILD; i++) {
+    int pid = fork(0);
+    if (pid < 0) {
+      printf(1, "fork error\n");
+      exit();
+    }
+    if (pid == 0) {
+      depth++;
+      char depthbuf[16];
+      snprintf(depthbuf, sizeof(depthbuf), "%d", depth);
+      char *av[] = { "forkexectree", depthbuf };
+      exec("forkexectree", av);
+    }
+  }
+  for (uint i = 0; i < NCHILD; i++) {
+    if (wait() < 0) {
+      printf(1, "wait stopped early\n");
+      exit();
+    }
+  }
+  if (wait() != -1) {
+    printf(1, "wait got too many\n");
+    exit();
+  }
+  if (depth > 0)
+    exit();
+  struct mtrace_appdata_entry entry;
+  entry.u64 = 0;
+  mtrace_appdata_register(&entry);
+  mtrace_enable_set(0, "xv6-forktree");
+  printf(1, "%d: forkexectree OK\n", getpid());
+  halt();
+}
+int
+main(int ac, char **av)
+{
+  if (ac == 1) {
+    forktree(0);
+  } else {
+    forktree(atoi(av[1]));
+  }
+  exit();
+}
--- a/user.h
+++ b/user.h
@@ -33,6 +33,7 @@ void *memmove(void*, void*, int);
 char* strchr(const char*, char c);
 int strcmp(const char*, const char*);
 void printf(int, char*, ...);
+void snprintf(char *buf, uint n, char *fmt, ...);
 char* gets(char*, int max);
 uint strlen(char*);
 void* memset(void*, int, uint);