case closed

Makefile

@@ -192,6 +192,7 @@ UPROGS=\
 	$U/_pingpong\
 	$U/_primes\
 	$U/_find\
+	$U/_xargs\
 
 
 
@@ -339,7 +340,9 @@ grade:
 	@echo $(MAKE) clean
 	@$(MAKE) clean || \
           (echo "'make clean' failed.  HINT: Do you have another running instance of xv6?" && exit 1)
-	./grade-lab-$(LAB) $(GRADEFLAGS)
+	# ./grade-lab-$(LAB) $(GRADEFLAGS)
+	python grade-lab-$(LAB)
+	
 
 ##
 ## FOR submissions

time.txt

@@ -0,0 +1 @@
+3

user/xargs.c

@@ -0,0 +1,59 @@
+#include "kernel/param.h"
+#include "kernel/stat.h"
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char *argv[]) {
+  if (argc < 2) {
+    fprintf(2, "Usage: xargs command\n");
+    exit(1);
+  }
+
+  char *cmd[argc + 1];
+  int index = 0, data = 0;
+  for (int i = 1; i < argc; ++i) {
+    cmd[index++] = argv[i];
+  }
+
+  char buffer[MAXARG];
+  char line[MAXARG] = {0};
+  int line_pos = 0;
+
+  while ((data = read(0, buffer, MAXARG)) > 0) {
+    for (int i = 0; i < data; ++i) {
+      if (buffer[i] == '\n' || buffer[i] == ' ') {
+        line[line_pos] = 0;
+        if (line_pos > 0) {
+          char *arg = malloc(line_pos + 1);
+          strcpy(arg, line);
+          cmd[index++] = arg;
+        }
+        line_pos = 0;
+
+        if (buffer[i] == '\n') {
+          cmd[index] = 0;
+          if (fork() == 0) {
+            exec(cmd[0], cmd);
+            exit(1);
+          }
+          wait(0);
+          index = argc - 1;
+        }
+      } else {
+        line[line_pos++] = buffer[i];
+      }
+    }
+  }
+
+  // bug fixed
+  if (line_pos > 0) {
+    line[line_pos] = 0;
+    cmd[index++] = line;
+    cmd[index] = 0;
+    if (fork() == 0) {
+      exec(cmd[0], cmd);
+    }
+    wait(0);
+  }
+  exit(0);
+}