Support exit status for exit/wait

One test case for returning a exit status
Passes usertests, but haven't used it to simplify tests

user/cat.c

@@ -12,12 +12,12 @@ cat(int fd)
   while((n = read(fd, buf, sizeof(buf))) > 0) {
     if (write(1, buf, n) != n) {
       printf("cat: write error\n");
-      exit();
+      exit(-1);
     }
   }
   if(n < 0){
     printf("cat: read error\n");
-    exit();
+    exit(-1);
   }
 }
 
@@ -28,16 +28,16 @@ main(int argc, char *argv[])
 
   if(argc <= 1){
     cat(0);
-    exit();
+    exit(-1);
   }
 
   for(i = 1; i < argc; i++){
     if((fd = open(argv[i], 0)) < 0){
       printf("cat: cannot open %s\n", argv[i]);
-      exit();
+      exit(-1);
     }
     cat(fd);
     close(fd);
   }
-  exit();
+  exit(0);
 }

user/echo.c

@@ -15,5 +15,5 @@ main(int argc, char *argv[])
       write(1, "\n", 1);
     }
   }
-  exit();
+  exit(0);
 }

user/forktest.c

@@ -25,24 +25,24 @@ forktest(void)
     if(pid < 0)
       break;
     if(pid == 0)
-      exit();
+      exit(0);
   }
 
   if(n == N){
     print("fork claimed to work N times!\n");
-    exit();
+    exit(-1);
   }
 
   for(; n > 0; n--){
-    if(wait() < 0){
+    if(wait(0) < 0){
       print("wait stopped early\n");
-      exit();
+      exit(-1);
     }
   }
 
-  if(wait() != -1){
+  if(wait(0) != -1){
     print("wait got too many\n");
-    exit();
+    exit(-1);
   }
 
   print("fork test OK\n");
@@ -52,5 +52,5 @@ int
 main(void)
 {
   forktest();
-  exit();
+  exit(0);
 }

user/grep.c

@@ -41,24 +41,24 @@ main(int argc, char *argv[])
 
   if(argc <= 1){
     fprintf(2, "usage: grep pattern [file ...]\n");
-    exit();
+    exit(-1);
   }
   pattern = argv[1];
 
   if(argc <= 2){
     grep(pattern, 0);
-    exit();
+    exit(0);
   }
 
   for(i = 2; i < argc; i++){
     if((fd = open(argv[i], 0)) < 0){
       printf("grep: cannot open %s\n", argv[i]);
-      exit();
+      exit(-1);
     }
     grep(pattern, fd);
     close(fd);
   }
-  exit();
+  exit(0);
 }
 
 // Regexp matcher from Kernighan & Pike,

user/init.c

@@ -24,14 +24,14 @@ main(void)
     pid = fork();
     if(pid < 0){
       printf("init: fork failed\n");
-      exit();
+      exit(-1);
     }
     if(pid == 0){
       exec("sh", argv);
       printf("init: exec sh failed\n");
-      exit();
+      exit(-1);
     }
-    while((wpid=wait()) >= 0 && wpid != pid){
+    while((wpid=wait(0)) >= 0 && wpid != pid){
       //printf("zombie!\n");
     }
   }

user/kill.c

@@ -9,9 +9,9 @@ main(int argc, char **argv)
 
   if(argc < 2){
     fprintf(2, "usage: kill pid...\n");
-    exit();
+    exit(-1);
   }
   for(i=1; i<argc; i++)
     kill(atoi(argv[i]));
-  exit();
+  exit(0);
 }

user/ln.c

@@ -7,9 +7,9 @@ main(int argc, char *argv[])
 {
   if(argc != 3){
     fprintf(2, "Usage: ln old new\n");
-    exit();
+    exit(-1);
   }
   if(link(argv[1], argv[2]) < 0)
     fprintf(2, "link %s %s: failed\n", argv[1], argv[2]);
-  exit();
+  exit(0);
 }

user/ls.c

@@ -77,9 +77,9 @@ main(int argc, char *argv[])
 
   if(argc < 2){
     ls(".");
-    exit();
+    exit(0);
   }
   for(i=1; i<argc; i++)
     ls(argv[i]);
-  exit();
+  exit(0);
 }

user/mkdir.c

@@ -9,7 +9,7 @@ main(int argc, char *argv[])
 
   if(argc < 2){
     fprintf(2, "Usage: mkdir files...\n");
-    exit();
+    exit(-1);
   }
 
   for(i = 1; i < argc; i++){
@@ -19,5 +19,5 @@ main(int argc, char *argv[])
     }
   }
 
-  exit();
+  exit(0);
 }

user/rm.c

@@ -9,7 +9,7 @@ main(int argc, char *argv[])
 
   if(argc < 2){
     fprintf(2, "Usage: rm files...\n");
-    exit();
+    exit(-1);
   }
 
   for(i = 1; i < argc; i++){
@@ -19,5 +19,5 @@ main(int argc, char *argv[])
     }
   }
 
-  exit();
+  exit(0);
 }

user/sh.c

@@ -65,7 +65,7 @@ runcmd(struct cmd *cmd)
   struct redircmd *rcmd;
 
   if(cmd == 0)
-    exit();
+    exit(-1);
 
   switch(cmd->type){
   default:
@@ -74,7 +74,7 @@ runcmd(struct cmd *cmd)
   case EXEC:
     ecmd = (struct execcmd*)cmd;
     if(ecmd->argv[0] == 0)
-      exit();
+      exit(-1);
     exec(ecmd->argv[0], ecmd->argv);
     fprintf(2, "exec %s failed\n", ecmd->argv[0]);
     break;
@@ -84,7 +84,7 @@ runcmd(struct cmd *cmd)
     close(rcmd->fd);
     if(open(rcmd->file, rcmd->mode) < 0){
       fprintf(2, "open %s failed\n", rcmd->file);
-      exit();
+      exit(-1);
     }
     runcmd(rcmd->cmd);
     break;
@@ -93,7 +93,7 @@ runcmd(struct cmd *cmd)
     lcmd = (struct listcmd*)cmd;
     if(fork1() == 0)
       runcmd(lcmd->left);
-    wait();
+    wait(0);
     runcmd(lcmd->right);
     break;
 
@@ -117,8 +117,8 @@ runcmd(struct cmd *cmd)
     }
     close(p[0]);
     close(p[1]);
-    wait();
-    wait();
+    wait(0);
+    wait(0);
     break;
 
   case BACK:
@@ -127,7 +127,7 @@ runcmd(struct cmd *cmd)
       runcmd(bcmd->cmd);
     break;
   }
-  exit();
+  exit(0);
 }
 
 int
@@ -166,16 +166,16 @@ main(void)
     }
     if(fork1() == 0)
       runcmd(parsecmd(buf));
-    wait();
+    wait(0);
   }
-  exit();
+  exit(0);
 }
 
 void
 panic(char *s)
 {
   fprintf(2, "%s\n", s);
-  exit();
+  exit(-1);
 }
 
 int

user/stressfs.c

@@ -43,7 +43,7 @@ main(int argc, char *argv[])
     read(fd, data, sizeof(data));
   close(fd);
 
-  wait();
+  wait(0);
 
-  exit();
+  exit(0);
 }

user/user.h

@@ -3,8 +3,8 @@ struct rtcdate;
 
 // system calls
 int fork(void);
-int exit(void) __attribute__((noreturn));
-int wait(void);
+int exit(int) __attribute__((noreturn));
+int wait(int*);
 int pipe(int*);
 int write(int, const void*, int);
 int read(int, void*, int);

user/wc.c

@@ -27,7 +27,7 @@ wc(int fd, char *name)
   }
   if(n < 0){
     printf("wc: read error\n");
-    exit();
+    exit(-1);
   }
   printf("%d %d %d %s\n", l, w, c, name);
 }
@@ -39,16 +39,16 @@ main(int argc, char *argv[])
 
   if(argc <= 1){
     wc(0, "");
-    exit();
+    exit(0);
   }
 
   for(i = 1; i < argc; i++){
     if((fd = open(argv[i], 0)) < 0){
       printf("wc: cannot open %s\n", argv[i]);
-      exit();
+      exit(-1);
     }
     wc(fd, argv[i]);
     close(fd);
   }
-  exit();
+  exit(0);
 }

user/zombie.c

@@ -10,5 +10,5 @@ main(void)
 {
   if(fork() > 0)
     sleep(5);  // Let child exit before parent.
-  exit();
+  exit(0);
 }