Add trace syscall

Makefile

@@ -193,6 +193,7 @@ UPROGS=\
 	$U/_grind\
 	$U/_wc\
 	$U/_zombie\
+	$U/_trace\
 
 
 

kernel/proc.c

@@ -292,6 +292,9 @@ fork(void)
   // copy saved user registers.
   *(np->trapframe) = *(p->trapframe);
 
+  // Copy tracemask
+  np->tracemask = p->tracemask;
+
   // Cause fork to return 0 in the child.
   np->trapframe->a0 = 0;
 

kernel/proc.h

@@ -105,4 +105,5 @@ struct proc {
   struct file *ofile[NOFILE];  // Open files
   struct inode *cwd;           // Current directory
   char name[16];               // Process name (debugging)
+  int tracemask;               // Mask for syscall trace
 };

kernel/syscall.c

@@ -104,6 +104,7 @@ extern uint64 sys_unlink(void);
 extern uint64 sys_wait(void);
 extern uint64 sys_write(void);
 extern uint64 sys_uptime(void);
+extern uint64 sys_trace(void);
 
 static uint64 (*syscalls[])(void) = {
 [SYS_fork]    sys_fork,
@@ -127,6 +128,33 @@ static uint64 (*syscalls[])(void) = {
 [SYS_link]    sys_link,
 [SYS_mkdir]   sys_mkdir,
 [SYS_close]   sys_close,
+[SYS_trace]   sys_trace,
+};
+
+char *syscall_names[] = {
+  "",
+  "fork",   
+  "exit",   
+  "wait",   
+  "pipe",   
+  "read",   
+  "kill",   
+  "exec",   
+  "fstat",  
+  "chdir",  
+  "dup",    
+  "getpid", 
+  "sbrk",   
+  "sleep",  
+  "uptime", 
+  "open",   
+  "write",  
+  "mknod",  
+  "unlink", 
+  "link",   
+  "mkdir",  
+  "close",  
+  "trace",  
 };
 
 void
@@ -138,6 +166,8 @@ syscall(void)
   num = p->trapframe->a7;
   if(num > 0 && num < NELEM(syscalls) && syscalls[num]) {
     p->trapframe->a0 = syscalls[num]();
+    if(p->tracemask & (1 << (num)))
+      printf("%d: syscall %s -> %d\n", p->pid, syscall_names[num], p->trapframe->a0);
   } else {
     printf("%d %s: unknown sys call %d\n",
             p->pid, p->name, num);

kernel/syscall.h

@@ -20,3 +20,4 @@
 #define SYS_link   19
 #define SYS_mkdir  20
 #define SYS_close  21
+#define SYS_trace  22

kernel/sysproc.c

@@ -95,3 +95,12 @@ sys_uptime(void)
   release(&tickslock);
   return xticks;
 }
+
+uint64 sys_trace(void) {
+  int mask;
+
+  if(argint(0, &mask) < 0) return -1;
+
+  myproc()->tracemask = mask;
+  return 0;
+}

user/user.h

@@ -23,6 +23,7 @@ int getpid(void);
 char* sbrk(int);
 int sleep(int);
 int uptime(void);
+int trace(int);
 
 // ulib.c
 int stat(const char*, struct stat*);

user/usys.pl

@@ -36,3 +36,4 @@ sub entry {
 entry("sbrk");
 entry("sleep");
 entry("uptime");
+entry("trace");