#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
+#include <linux/signal.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
SET_LINKS(child);
}
+/*
+ * Turn a tracing stop into a normal stop now, since with no tracer there
+ * would be no way to wake it up with SIGCONT or SIGKILL. If there was a
+ * signal sent that would resume the child, but didn't because it was in
+ * TASK_TRACED, resume it now.
+ * Requires that irqs be disabled.
+ */
+void ptrace_untrace(task_t *child)
+{
+ spin_lock(&child->sighand->siglock);
+ if (child->state == TASK_TRACED) {
+ if (child->signal->flags & SIGNAL_STOP_STOPPED) {
+ child->state = TASK_STOPPED;
+ } else {
+ signal_wake_up(child, 1);
+ }
+ }
+ spin_unlock(&child->sighand->siglock);
+}
+
/*
* unptrace a task: move it back to its original parent and
* remove it from the ptrace list.
if (!child->ptrace)
BUG();
child->ptrace = 0;
- if (list_empty(&child->ptrace_list))
- return;
- list_del_init(&child->ptrace_list);
- REMOVE_LINKS(child);
- child->parent = child->real_parent;
- SET_LINKS(child);
+ if (!list_empty(&child->ptrace_list)) {
+ list_del_init(&child->ptrace_list);
+ REMOVE_LINKS(child);
+ child->parent = child->real_parent;
+ SET_LINKS(child);
+ }
+
+ if (child->state == TASK_TRACED)
+ ptrace_untrace(child);
}
/*
*/
int ptrace_check_attach(struct task_struct *child, int kill)
{
- if (!(child->ptrace & PT_PTRACED))
- return -ESRCH;
+ int ret = -ESRCH;
- if (child->parent != current)
- return -ESRCH;
+ /*
+ * We take the read lock around doing both checks to close a
+ * possible race where someone else was tracing our child and
+ * detached between these two checks. After this locked check,
+ * we are sure that this is our traced child and that can only
+ * be changed by us so it's not changing right after this.
+ */
+ read_lock(&tasklist_lock);
+ if ((child->ptrace & PT_PTRACED) && child->parent == current &&
+ (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
+ && child->signal != NULL) {
+ ret = 0;
+ spin_lock_irq(&child->sighand->siglock);
+ if (child->state == TASK_STOPPED) {
+ child->state = TASK_TRACED;
+ } else if (child->state != TASK_TRACED && !kill) {
+ ret = -ESRCH;
+ }
+ spin_unlock_irq(&child->sighand->siglock);
+ }
+ read_unlock(&tasklist_lock);
- if (!kill) {
- if (child->state != TASK_STOPPED)
- return -ESRCH;
+ if (!ret && !kill) {
wait_task_inactive(child);
}
/* All systems go.. */
- return 0;
+ return ret;
}
int ptrace_attach(struct task_struct *task)
(current->gid != task->sgid) ||
(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
goto bad;
- rmb();
+ smp_rmb();
if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
goto bad;
/* the same process cannot be attached many times */
goto bad;
/* Go */
- task->ptrace |= PT_PTRACED;
+ task->ptrace |= PT_PTRACED | ((task->real_parent != current)
+ ? PT_ATTACHED : 0);
if (capable(CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
task_unlock(task);
int ptrace_detach(struct task_struct *child, unsigned int data)
{
- if ((unsigned long) data > _NSIG)
+ if (!valid_signal(data))
return -EIO;
/* Architecture-specific hardware disable .. */
write_lock_irq(&tasklist_lock);
__ptrace_unlink(child);
/* .. and wake it up. */
- if (child->state != TASK_ZOMBIE)
+ if (child->exit_state != EXIT_ZOMBIE)
wake_up_process(child);
write_unlock_irq(&tasklist_lock);
if (bytes > PAGE_SIZE-offset)
bytes = PAGE_SIZE-offset;
- flush_cache_page(vma, addr);
-
maddr = kmap(page);
if (write) {
copy_to_user_page(vma, page, addr,
static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)
{
- if (child->last_siginfo == NULL)
- return -EINVAL;
- return copy_siginfo_to_user(data, child->last_siginfo);
+ siginfo_t lastinfo;
+ int error = -ESRCH;
+
+ read_lock(&tasklist_lock);
+ if (likely(child->sighand != NULL)) {
+ error = -EINVAL;
+ spin_lock_irq(&child->sighand->siglock);
+ if (likely(child->last_siginfo != NULL)) {
+ lastinfo = *child->last_siginfo;
+ error = 0;
+ }
+ spin_unlock_irq(&child->sighand->siglock);
+ }
+ read_unlock(&tasklist_lock);
+ if (!error)
+ return copy_siginfo_to_user(data, &lastinfo);
+ return error;
}
static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
{
- if (child->last_siginfo == NULL)
- return -EINVAL;
- if (copy_from_user(child->last_siginfo, data, sizeof (siginfo_t)) != 0)
+ siginfo_t newinfo;
+ int error = -ESRCH;
+
+ if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
return -EFAULT;
- return 0;
+
+ read_lock(&tasklist_lock);
+ if (likely(child->sighand != NULL)) {
+ error = -EINVAL;
+ spin_lock_irq(&child->sighand->siglock);
+ if (likely(child->last_siginfo != NULL)) {
+ *child->last_siginfo = newinfo;
+ error = 0;
+ }
+ spin_unlock_irq(&child->sighand->siglock);
+ }
+ read_unlock(&tasklist_lock);
+ return error;
}
int ptrace_request(struct task_struct *child, long request,
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();
-
- /*
- * Signals sent while we were stopped might set TIF_SIGPENDING.
- */
-
- spin_lock_irq(¤t->sighand->siglock);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-}
-
-EXPORT_SYMBOL(ptrace_notify);
git://git.onelab.eu / linux-2.6.git / blobdiff