Add new ptrace event tracing mechanism

fs/binfmt_aout.c

@@ -425,8 +425,12 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 	regs->gp = ex.a_gpvalue;
 #endif
 	start_thread(regs, ex.a_entry, current->mm->start_stack);
-	if (current->ptrace & PT_PTRACED)
-		send_sig(SIGTRAP, current, 0);
+	if (unlikely(current->ptrace & PT_PTRACED)) {
+		if (current->ptrace & PT_TRACE_EXEC)
+			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
+		else
+			send_sig(SIGTRAP, current, 0);
+	}
 	return 0;
 }
 

fs/binfmt_elf.c

@@ -792,8 +792,12 @@ static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 #endif
 
 	start_thread(regs, elf_entry, bprm->p);
-	if (current->ptrace & PT_PTRACED)
-		send_sig(SIGTRAP, current, 0);
+	if (unlikely(current->ptrace & PT_PTRACED)) {
+		if (current->ptrace & PT_TRACE_EXEC)
+			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
+		else
+			send_sig(SIGTRAP, current, 0);
+	}
 	retval = 0;
 out:
 	return retval;

include/linux/ptrace.h

@@ -25,9 +25,20 @@
 
 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
 #define PTRACE_SETOPTIONS	0x4200
+#define PTRACE_GETEVENTMSG	0x4201
 
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD	0x00000001
+#define PTRACE_O_TRACEFORK	0x00000002
+#define PTRACE_O_TRACEVFORK	0x00000004
+#define PTRACE_O_TRACECLONE	0x00000008
+#define PTRACE_O_TRACEEXEC	0x00000010
+
+/* Wait extended result codes for the above trace options.  */
+#define PTRACE_EVENT_FORK	1
+#define PTRACE_EVENT_VFORK	2
+#define PTRACE_EVENT_CLONE	3
+#define PTRACE_EVENT_EXEC	4
 
 #include <asm/ptrace.h>
 #include <linux/sched.h>
@@ -39,6 +50,7 @@ extern int ptrace_detach(struct task_struct *, unsigned int);
 extern void ptrace_disable(struct task_struct *);
 extern int ptrace_check_attach(struct task_struct *task, int kill);
 extern int ptrace_request(struct task_struct *child, long request, long addr, long data);
+extern void ptrace_notify(int exit_code);
 extern void __ptrace_link(struct task_struct *child,
 				struct task_struct *new_parent);
 extern void __ptrace_unlink(struct task_struct *child);

include/linux/sched.h

@@ -397,6 +397,8 @@ struct task_struct {
 /* journalling filesystem info */
 	void *journal_info;
 	struct dentry *proc_dentry;
+
+	unsigned long ptrace_message;
 };
 
 extern void __put_task_struct(struct task_struct *tsk);
@@ -435,6 +437,10 @@ do { if (atomic_dec_and_test(&(tsk)->usage)) __put_task_struct(tsk); } while(0)
 #define PT_DTRACE	0x00000002	/* delayed trace (used on m68k, i386) */
 #define PT_TRACESYSGOOD	0x00000004
 #define PT_PTRACE_CAP	0x00000008	/* ptracer can follow suid-exec */
+#define PT_TRACE_FORK	0x00000010
+#define PT_TRACE_VFORK	0x00000020
+#define PT_TRACE_CLONE	0x00000040
+#define PT_TRACE_EXEC	0x00000080
 
 /*
  * Limit the stack by to some sane default: root can always

kernel/fork.c

@@ -923,6 +923,22 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	goto fork_out;
 }
 
+static inline int fork_traceflag (unsigned clone_flags)
+{
+	if (clone_flags & (CLONE_UNTRACED | CLONE_IDLETASK))
+		return 0;
+	else if (clone_flags & CLONE_VFORK) {
+		if (current->ptrace & PT_TRACE_VFORK)
+			return PTRACE_EVENT_VFORK;
+	} else if ((clone_flags & CSIGNAL) != SIGCHLD) {
+		if (current->ptrace & PT_TRACE_CLONE)
+			return PTRACE_EVENT_CLONE;
+	} else if (current->ptrace & PT_TRACE_FORK)
+		return PTRACE_EVENT_FORK;
+
+	return 0;
+}
+
 /*
  *  Ok, this is the main fork-routine.
  *
@@ -936,6 +952,13 @@ struct task_struct *do_fork(unsigned long clone_flags,
 			    int *user_tid)
 {
 	struct task_struct *p;
+	int trace = 0;
+
+	if (unlikely(current->ptrace)) {
+		trace = fork_traceflag (clone_flags);
+		if (trace)
+			clone_flags |= CLONE_PTRACE;
+	}
 
 	p = copy_process(clone_flags, stack_start, regs, stack_size, user_tid);
 	if (!IS_ERR(p)) {
@@ -951,6 +974,12 @@ struct task_struct *do_fork(unsigned long clone_flags,
 
 		wake_up_forked_process(p);		/* do this last */
 		++total_forks;
+
+		if (unlikely (trace)) {
+			current->ptrace_message = (unsigned long) p->pid;
+			ptrace_notify ((trace << 8) | SIGTRAP);
+		}
+
 		if (clone_flags & CLONE_VFORK)
 			wait_for_completion(&vfork);
 		else

kernel/ptrace.c

@@ -249,14 +249,37 @@ int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int
 	return copied;
 }
 
-int ptrace_setoptions(struct task_struct *child, long data)
+static int ptrace_setoptions(struct task_struct *child, long data)
 {
 	if (data & PTRACE_O_TRACESYSGOOD)
 		child->ptrace |= PT_TRACESYSGOOD;
 	else
 		child->ptrace &= ~PT_TRACESYSGOOD;
 
-	if ((data & PTRACE_O_TRACESYSGOOD) != data)
+	if (data & PTRACE_O_TRACEFORK)
+		child->ptrace |= PT_TRACE_FORK;
+	else
+		child->ptrace &= ~PT_TRACE_FORK;
+
+	if (data & PTRACE_O_TRACEVFORK)
+		child->ptrace |= PT_TRACE_VFORK;
+	else
+		child->ptrace &= ~PT_TRACE_VFORK;
+
+	if (data & PTRACE_O_TRACECLONE)
+		child->ptrace |= PT_TRACE_CLONE;
+	else
+		child->ptrace &= ~PT_TRACE_CLONE;
+
+	if (data & PTRACE_O_TRACEEXEC)
+		child->ptrace |= PT_TRACE_EXEC;
+	else
+		child->ptrace &= ~PT_TRACE_EXEC;
+
+	if ((data & (PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEFORK
+		    | PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE
+		    | PTRACE_O_TRACEEXEC))
+	    != data)
 		return -EINVAL;
 
 	return 0;
@@ -274,9 +297,23 @@ int ptrace_request(struct task_struct *child, long request,
 	case PTRACE_SETOPTIONS:
 		ret = ptrace_setoptions(child, data);
 		break;
+	case PTRACE_GETEVENTMSG:
+		ret = put_user(child->ptrace_message, (unsigned long *) data);
+		break;
 	default:
 		break;
 	}
 
 	return ret;
 }
+
+void ptrace_notify(int exit_code)
+{
+	BUG_ON (!(current->ptrace & PT_PTRACED));
+
+	/* Let the debugger run.  */
+	current->exit_code = exit_code;
+	set_current_state(TASK_STOPPED);
+	notify_parent(current, SIGCHLD);
+	schedule();
+}