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Message-ID: <20091124200212.GA5818@redhat.com>
Date: Tue, 24 Nov 2009 21:02:12 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Alexey Dobriyan <adobriyan@...il.com>,
Ananth Mavinakayanahalli <ananth@...ibm.com>,
Christoph Hellwig <hch@...radead.org>,
"Frank Ch. Eigler" <fche@...hat.com>, Ingo Molnar <mingo@...e.hu>,
Peter Zijlstra <peterz@...radead.org>,
Roland McGrath <roland@...hat.com>
Cc: linux-kernel@...r.kernel.org, utrace-devel@...hat.com
Subject: [RFC,PATCH 12/14] reorder the code in kernel/ptrace.c
No functional changes, preparation for the next patch.
Move the code which can be shared with ptrace-utrace up, before
__ptrace_link(). This way ptrace-utrace needs a single #ifdef in
ptrace.c.
Signed-off-by: Roland McGrath <roland@...hat.com>
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
kernel/ptrace.c | 556 ++++++++++++++++++++++++++++----------------------------
1 file changed, 278 insertions(+), 278 deletions(-)
--- V1/kernel/ptrace.c~12_REORDER_PTRACE_C 2009-11-24 20:30:16.000000000 +0100
+++ V1/kernel/ptrace.c 2009-11-24 20:30:16.000000000 +0100
@@ -23,6 +23,284 @@
#include <linux/syscalls.h>
#include <linux/uaccess.h>
+int __ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+ const struct cred *cred = current_cred(), *tcred;
+
+ /* May we inspect the given task?
+ * This check is used both for attaching with ptrace
+ * and for allowing access to sensitive information in /proc.
+ *
+ * ptrace_attach denies several cases that /proc allows
+ * because setting up the necessary parent/child relationship
+ * or halting the specified task is impossible.
+ */
+ int dumpable = 0;
+ /* Don't let security modules deny introspection */
+ if (task == current)
+ return 0;
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if ((cred->uid != tcred->euid ||
+ cred->uid != tcred->suid ||
+ cred->uid != tcred->uid ||
+ cred->gid != tcred->egid ||
+ cred->gid != tcred->sgid ||
+ cred->gid != tcred->gid) &&
+ !capable(CAP_SYS_PTRACE)) {
+ rcu_read_unlock();
+ return -EPERM;
+ }
+ rcu_read_unlock();
+ smp_rmb();
+ if (task->mm)
+ dumpable = get_dumpable(task->mm);
+ if (!dumpable && !capable(CAP_SYS_PTRACE))
+ return -EPERM;
+
+ return security_ptrace_access_check(task, mode);
+}
+
+bool ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+ int err;
+ task_lock(task);
+ err = __ptrace_may_access(task, mode);
+ task_unlock(task);
+ return !err;
+}
+
+/*
+ * Called with irqs disabled, returns true if childs should reap themselves.
+ */
+static int ignoring_children(struct sighand_struct *sigh)
+{
+ int ret;
+ spin_lock(&sigh->siglock);
+ ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
+ (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
+ spin_unlock(&sigh->siglock);
+ return ret;
+}
+
+/*
+ * Called with tasklist_lock held for writing.
+ * Unlink a traced task, and clean it up if it was a traced zombie.
+ * Return true if it needs to be reaped with release_task().
+ * (We can't call release_task() here because we already hold tasklist_lock.)
+ *
+ * If it's a zombie, our attachedness prevented normal parent notification
+ * or self-reaping. Do notification now if it would have happened earlier.
+ * If it should reap itself, return true.
+ *
+ * If it's our own child, there is no notification to do. But if our normal
+ * children self-reap, then this child was prevented by ptrace and we must
+ * reap it now, in that case we must also wake up sub-threads sleeping in
+ * do_wait().
+ */
+bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
+{
+ __ptrace_unlink(p);
+
+ if (p->exit_state == EXIT_ZOMBIE) {
+ if (!task_detached(p) && thread_group_empty(p)) {
+ if (!same_thread_group(p->real_parent, tracer))
+ do_notify_parent(p, p->exit_signal);
+ else if (ignoring_children(tracer->sighand)) {
+ __wake_up_parent(p, tracer);
+ p->exit_signal = -1;
+ }
+ }
+ if (task_detached(p)) {
+ /* Mark it as in the process of being reaped. */
+ p->exit_state = EXIT_DEAD;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
+{
+ int copied = 0;
+
+ while (len > 0) {
+ char buf[128];
+ int this_len, retval;
+
+ this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+ retval = access_process_vm(tsk, src, buf, this_len, 0);
+ if (!retval) {
+ if (copied)
+ break;
+ return -EIO;
+ }
+ if (copy_to_user(dst, buf, retval))
+ return -EFAULT;
+ copied += retval;
+ src += retval;
+ dst += retval;
+ len -= retval;
+ }
+ return copied;
+}
+
+int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
+{
+ int copied = 0;
+
+ while (len > 0) {
+ char buf[128];
+ int this_len, retval;
+
+ this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+ if (copy_from_user(buf, src, this_len))
+ return -EFAULT;
+ retval = access_process_vm(tsk, dst, buf, this_len, 1);
+ if (!retval) {
+ if (copied)
+ break;
+ return -EIO;
+ }
+ copied += retval;
+ src += retval;
+ dst += retval;
+ len -= retval;
+ }
+ return copied;
+}
+
+static struct task_struct *ptrace_get_task_struct(pid_t pid)
+{
+ struct task_struct *child;
+
+ rcu_read_lock();
+ child = find_task_by_vpid(pid);
+ if (child)
+ get_task_struct(child);
+ rcu_read_unlock();
+
+ if (!child)
+ return ERR_PTR(-ESRCH);
+ return child;
+}
+
+#ifndef arch_ptrace_attach
+#define arch_ptrace_attach(child) do { } while (0)
+#endif
+
+SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
+{
+ struct task_struct *child;
+ long ret;
+
+ /*
+ * This lock_kernel fixes a subtle race with suid exec
+ */
+ lock_kernel();
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ if (!ret)
+ arch_ptrace_attach(current);
+ goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH) {
+ ret = ptrace_attach(child);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ ret = arch_ptrace(child, request, addr, data);
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ unlock_kernel();
+ return ret;
+}
+
+int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
+{
+ unsigned long tmp;
+ int copied;
+
+ copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
+ if (copied != sizeof(tmp))
+ return -EIO;
+ return put_user(tmp, (unsigned long __user *)data);
+}
+
+int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
+{
+ int copied;
+
+ copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
+ return (copied == sizeof(data)) ? 0 : -EIO;
+}
+
+#if defined CONFIG_COMPAT
+#include <linux/compat.h>
+
+asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
+ compat_long_t addr, compat_long_t data)
+{
+ struct task_struct *child;
+ long ret;
+
+ /*
+ * This lock_kernel fixes a subtle race with suid exec
+ */
+ lock_kernel();
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH) {
+ ret = ptrace_attach(child);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (!ret)
+ ret = compat_arch_ptrace(child, request, addr, data);
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ unlock_kernel();
+ return ret;
+}
+#endif /* CONFIG_COMPAT */
/*
* ptrace a task: make the debugger its new parent and
@@ -117,53 +395,6 @@ int ptrace_check_attach(struct task_stru
return ret;
}
-int __ptrace_may_access(struct task_struct *task, unsigned int mode)
-{
- const struct cred *cred = current_cred(), *tcred;
-
- /* May we inspect the given task?
- * This check is used both for attaching with ptrace
- * and for allowing access to sensitive information in /proc.
- *
- * ptrace_attach denies several cases that /proc allows
- * because setting up the necessary parent/child relationship
- * or halting the specified task is impossible.
- */
- int dumpable = 0;
- /* Don't let security modules deny introspection */
- if (task == current)
- return 0;
- rcu_read_lock();
- tcred = __task_cred(task);
- if ((cred->uid != tcred->euid ||
- cred->uid != tcred->suid ||
- cred->uid != tcred->uid ||
- cred->gid != tcred->egid ||
- cred->gid != tcred->sgid ||
- cred->gid != tcred->gid) &&
- !capable(CAP_SYS_PTRACE)) {
- rcu_read_unlock();
- return -EPERM;
- }
- rcu_read_unlock();
- smp_rmb();
- if (task->mm)
- dumpable = get_dumpable(task->mm);
- if (!dumpable && !capable(CAP_SYS_PTRACE))
- return -EPERM;
-
- return security_ptrace_access_check(task, mode);
-}
-
-bool ptrace_may_access(struct task_struct *task, unsigned int mode)
-{
- int err;
- task_lock(task);
- err = __ptrace_may_access(task, mode);
- task_unlock(task);
- return !err;
-}
-
int ptrace_attach(struct task_struct *task)
{
int retval;
@@ -243,57 +474,6 @@ int ptrace_traceme(void)
return ret;
}
-/*
- * Called with irqs disabled, returns true if childs should reap themselves.
- */
-static int ignoring_children(struct sighand_struct *sigh)
-{
- int ret;
- spin_lock(&sigh->siglock);
- ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
- (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
- spin_unlock(&sigh->siglock);
- return ret;
-}
-
-/*
- * Called with tasklist_lock held for writing.
- * Unlink a traced task, and clean it up if it was a traced zombie.
- * Return true if it needs to be reaped with release_task().
- * (We can't call release_task() here because we already hold tasklist_lock.)
- *
- * If it's a zombie, our attachedness prevented normal parent notification
- * or self-reaping. Do notification now if it would have happened earlier.
- * If it should reap itself, return true.
- *
- * If it's our own child, there is no notification to do. But if our normal
- * children self-reap, then this child was prevented by ptrace and we must
- * reap it now, in that case we must also wake up sub-threads sleeping in
- * do_wait().
- */
-bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
-{
- __ptrace_unlink(p);
-
- if (p->exit_state == EXIT_ZOMBIE) {
- if (!task_detached(p) && thread_group_empty(p)) {
- if (!same_thread_group(p->real_parent, tracer))
- do_notify_parent(p, p->exit_signal);
- else if (ignoring_children(tracer->sighand)) {
- __wake_up_parent(p, tracer);
- p->exit_signal = -1;
- }
- }
- if (task_detached(p)) {
- /* Mark it as in the process of being reaped. */
- p->exit_state = EXIT_DEAD;
- return true;
- }
- }
-
- return false;
-}
-
int ptrace_detach(struct task_struct *child, unsigned int data)
{
bool dead = false;
@@ -347,56 +527,6 @@ void exit_ptrace(struct task_struct *tra
}
}
-int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
-{
- int copied = 0;
-
- while (len > 0) {
- char buf[128];
- int this_len, retval;
-
- this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
- retval = access_process_vm(tsk, src, buf, this_len, 0);
- if (!retval) {
- if (copied)
- break;
- return -EIO;
- }
- if (copy_to_user(dst, buf, retval))
- return -EFAULT;
- copied += retval;
- src += retval;
- dst += retval;
- len -= retval;
- }
- return copied;
-}
-
-int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
-{
- int copied = 0;
-
- while (len > 0) {
- char buf[128];
- int this_len, retval;
-
- this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
- if (copy_from_user(buf, src, this_len))
- return -EFAULT;
- retval = access_process_vm(tsk, dst, buf, this_len, 1);
- if (!retval) {
- if (copied)
- break;
- return -EIO;
- }
- copied += retval;
- src += retval;
- dst += retval;
- len -= retval;
- }
- return copied;
-}
-
static int ptrace_setoptions(struct task_struct *child, long data)
{
child->ptrace &= ~PT_TRACE_MASK;
@@ -457,7 +587,6 @@ static int ptrace_setsiginfo(struct task
return error;
}
-
#ifdef PTRACE_SINGLESTEP
#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
#else
@@ -580,93 +709,7 @@ int ptrace_request(struct task_struct *c
return ret;
}
-static struct task_struct *ptrace_get_task_struct(pid_t pid)
-{
- struct task_struct *child;
-
- rcu_read_lock();
- child = find_task_by_vpid(pid);
- if (child)
- get_task_struct(child);
- rcu_read_unlock();
-
- if (!child)
- return ERR_PTR(-ESRCH);
- return child;
-}
-
-#ifndef arch_ptrace_attach
-#define arch_ptrace_attach(child) do { } while (0)
-#endif
-
-SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
-{
- struct task_struct *child;
- long ret;
-
- /*
- * This lock_kernel fixes a subtle race with suid exec
- */
- lock_kernel();
- if (request == PTRACE_TRACEME) {
- ret = ptrace_traceme();
- if (!ret)
- arch_ptrace_attach(current);
- goto out;
- }
-
- child = ptrace_get_task_struct(pid);
- if (IS_ERR(child)) {
- ret = PTR_ERR(child);
- goto out;
- }
-
- if (request == PTRACE_ATTACH) {
- ret = ptrace_attach(child);
- /*
- * Some architectures need to do book-keeping after
- * a ptrace attach.
- */
- if (!ret)
- arch_ptrace_attach(child);
- goto out_put_task_struct;
- }
-
- ret = ptrace_check_attach(child, request == PTRACE_KILL);
- if (ret < 0)
- goto out_put_task_struct;
-
- ret = arch_ptrace(child, request, addr, data);
-
- out_put_task_struct:
- put_task_struct(child);
- out:
- unlock_kernel();
- return ret;
-}
-
-int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
-{
- unsigned long tmp;
- int copied;
-
- copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
- if (copied != sizeof(tmp))
- return -EIO;
- return put_user(tmp, (unsigned long __user *)data);
-}
-
-int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
-{
- int copied;
-
- copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
- return (copied == sizeof(data)) ? 0 : -EIO;
-}
-
#if defined CONFIG_COMPAT
-#include <linux/compat.h>
-
int compat_ptrace_request(struct task_struct *child, compat_long_t request,
compat_ulong_t addr, compat_ulong_t data)
{
@@ -718,47 +761,4 @@ int compat_ptrace_request(struct task_st
return ret;
}
-
-asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
- compat_long_t addr, compat_long_t data)
-{
- struct task_struct *child;
- long ret;
-
- /*
- * This lock_kernel fixes a subtle race with suid exec
- */
- lock_kernel();
- if (request == PTRACE_TRACEME) {
- ret = ptrace_traceme();
- goto out;
- }
-
- child = ptrace_get_task_struct(pid);
- if (IS_ERR(child)) {
- ret = PTR_ERR(child);
- goto out;
- }
-
- if (request == PTRACE_ATTACH) {
- ret = ptrace_attach(child);
- /*
- * Some architectures need to do book-keeping after
- * a ptrace attach.
- */
- if (!ret)
- arch_ptrace_attach(child);
- goto out_put_task_struct;
- }
-
- ret = ptrace_check_attach(child, request == PTRACE_KILL);
- if (!ret)
- ret = compat_arch_ptrace(child, request, addr, data);
-
- out_put_task_struct:
- put_task_struct(child);
- out:
- unlock_kernel();
- return ret;
-}
#endif /* CONFIG_COMPAT */
--
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