As part of my previous sys_ptrace consolidation I introduce a
ptrace_get_task_struct helper, that gets a reference to the taskstruct
for a given pid, after doing all the ptrace attach checks.
This pathces makes all but a few ptrace and compat_ptrace
implementations use it.  The implementations not covered are:

  - m68k: has some large ptrace changes pending, should be converted to
    the common sys_ptrace later
  - ia64 (native ptrace only): does some wierd stuff about finding a
    different thread in the same threadgroup


Signed-off-by: Christoph Hellwig <[EMAIL PROTECTED]>

Index: linux-2.6/arch/alpha/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/alpha/kernel/ptrace.c   2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/alpha/kernel/ptrace.c        2005-08-13 18:14:22.000000000 
+0200
@@ -265,28 +265,7 @@
        lock_kernel();
        DBG(DBG_MEM, ("request=%ld pid=%ld addr=0x%lx data=0x%lx\n",
                      request, pid, addr, data));
-       ret = -EPERM;
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
-                       goto out_notsk;
-               ret = security_ptrace(current->parent, current);
-               if (ret)
-                       goto out_notsk;
-               /* set the ptrace bit in the process ptrace flags. */
-               current->ptrace |= PT_PTRACED;
-               ret = 0;
-               goto out_notsk;
-       }
-       if (pid == 1)           /* you may not mess with init */
-               goto out_notsk;
-
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out_notsk;
 
Index: linux-2.6/arch/ia64/ia32/sys_ia32.c
===================================================================
--- linux-2.6.orig/arch/ia64/ia32/sys_ia32.c    2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/ia64/ia32/sys_ia32.c 2005-08-13 18:14:22.000000000 +0200
@@ -1759,22 +1759,9 @@
        long i, ret;
 
        lock_kernel();
-       if (request == PTRACE_TRACEME) {
-               ret = sys_ptrace(request, pid, addr, data);
-               goto out;
-       }
-
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out;
-       ret = -EPERM;
-       if (pid == 1)           /* no messing around with init! */
-               goto out_tsk;
 
        if (request == PTRACE_ATTACH) {
                ret = sys_ptrace(request, pid, addr, data);
Index: linux-2.6/arch/m32r/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/m32r/kernel/ptrace.c    2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/m32r/kernel/ptrace.c 2005-08-13 18:14:22.000000000 +0200
@@ -762,29 +762,10 @@
        int ret;
 
        lock_kernel();
-       ret = -EPERM;
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
-                       goto out;
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               ret = 0;
-               goto out;
-       }
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out;
 
-       ret = -EPERM;
-       if (pid == 1)           /* you may not mess with init */
-               goto out;
-
        if (request == PTRACE_ATTACH) {
                ret = ptrace_attach(child);
                if (ret == 0)
Index: linux-2.6/arch/mips/kernel/ptrace32.c
===================================================================
--- linux-2.6.orig/arch/mips/kernel/ptrace32.c  2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/mips/kernel/ptrace32.c       2005-08-13 18:14:22.000000000 
+0200
@@ -50,31 +50,10 @@
               (unsigned long) data);
 #endif
        lock_kernel();
-       ret = -EPERM;
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
-                       goto out;
-               if ((ret = security_ptrace(current->parent, current)))
-                       goto out;
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               ret = 0;
-               goto out;
-       }
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out;
 
-       ret = -EPERM;
-       if (pid == 1)           /* you may not mess with init */
-               goto out_tsk;
-
        if (request == PTRACE_ATTACH) {
                ret = ptrace_attach(child);
                goto out_tsk;
Index: linux-2.6/arch/parisc/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/parisc/kernel/ptrace.c  2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/parisc/kernel/ptrace.c       2005-08-13 18:14:22.000000000 
+0200
@@ -87,33 +87,9 @@
 #endif
 
        lock_kernel();
-       ret = -EPERM;
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
-                       goto out;
-
-               ret = security_ptrace(current->parent, current);
-               if (ret) 
-                       goto out;
-
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               ret = 0;
-               goto out;
-       }
-
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out;
-       ret = -EPERM;
-       if (pid == 1)           /* no messing around with init! */
-               goto out_tsk;
 
        if (request == PTRACE_ATTACH) {
                ret = ptrace_attach(child);
Index: linux-2.6/arch/ppc64/kernel/ptrace32.c
===================================================================
--- linux-2.6.orig/arch/ppc64/kernel/ptrace32.c 2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/ppc64/kernel/ptrace32.c      2005-08-13 18:14:22.000000000 
+0200
@@ -45,31 +45,10 @@
        int ret = -EPERM;
 
        lock_kernel();
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED)
-                       goto out;
-               ret = security_ptrace(current->parent, current);
-               if (ret)
-                       goto out;
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               ret = 0;
-               goto out;
-       }
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                goto out;
 
-       ret = -EPERM;
-       if (pid == 1)           /* you may not mess with init */
-               goto out_tsk;
-
        if (request == PTRACE_ATTACH) {
                ret = ptrace_attach(child);
                goto out_tsk;
Index: linux-2.6/arch/s390/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/ptrace.c    2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/s390/kernel/ptrace.c 2005-08-13 18:14:22.000000000 +0200
@@ -712,36 +712,11 @@
        int ret;
 
        lock_kernel();
-
-       if (request == PTRACE_TRACEME) {
-               /* are we already being traced? */
-               ret = -EPERM;
-               if (current->ptrace & PT_PTRACED)
-                       goto out;
-               ret = security_ptrace(current->parent, current);
-               if (ret)
-                       goto out;
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               goto out;
+       ret = ptrace_get_task_struct(request, pid, &child);
+       if (child) {
+               ret = do_ptrace(child, request, addr, data);
+               put_task_struct(child);
        }
-
-       ret = -EPERM;
-       if (pid == 1)           /* you may not mess with init */
-               goto out;
-
-       ret = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
-       if (!child)
-               goto out;
-
-       ret = do_ptrace(child, request, addr, data);
-
-       put_task_struct(child);
 out:
        unlock_kernel();
        return ret;
Index: linux-2.6/arch/sparc/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/ptrace.c   2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/sparc/kernel/ptrace.c        2005-08-13 18:14:22.000000000 
+0200
@@ -286,40 +286,13 @@
                               s, (int) request, (int) pid, addr, data, addr2);
        }
 #endif
-       if (request == PTRACE_TRACEME) {
-               int my_ret;
-
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED) {
-                       pt_error_return(regs, EPERM);
-                       goto out;
-               }
-               my_ret = security_ptrace(current->parent, current);
-               if (my_ret) {
-                       pt_error_return(regs, -my_ret);
-                       goto out;
-               }
-
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               pt_succ_return(regs, 0);
-               goto out;
-       }
-#ifndef ALLOW_INIT_TRACING
-       if (pid == 1) {
-               /* Can't dork with init. */
-               pt_error_return(regs, EPERM);
-               goto out;
-       }
-#endif
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
 
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child) {
-               pt_error_return(regs, ESRCH);
+               if (ret)
+                       pt_error_return(regs, -ret);
+               else
+                       pt_succ_return(regs, 0);
                goto out;
        }
 
Index: linux-2.6/arch/sparc64/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/sparc64/kernel/ptrace.c 2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/sparc64/kernel/ptrace.c      2005-08-13 18:14:22.000000000 
+0200
@@ -188,40 +188,12 @@
                               s, request, pid, addr, data, addr2);
        }
 #endif
-       if (request == PTRACE_TRACEME) {
-               int ret;
-
-               /* are we already being traced? */
-               if (current->ptrace & PT_PTRACED) {
-                       pt_error_return(regs, EPERM);
-                       goto out;
-               }
-               ret = security_ptrace(current->parent, current);
-               if (ret) {
-                       pt_error_return(regs, -ret);
-                       goto out;
-               }
-
-               /* set the ptrace bit in the process flags. */
-               current->ptrace |= PT_PTRACED;
-               pt_succ_return(regs, 0);
-               goto out;
-       }
-#ifndef ALLOW_INIT_TRACING
-       if (pid == 1) {
-               /* Can't dork with init. */
-               pt_error_return(regs, EPERM);
-               goto out;
-       }
-#endif
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
-
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child) {
-               pt_error_return(regs, ESRCH);
+               if (ret)
+                       pt_error_return(regs, -ret);
+               else
+                       pt_succ_return(regs, 0);
                goto out;
        }
 
Index: linux-2.6/arch/x86_64/ia32/ptrace32.c
===================================================================
--- linux-2.6.orig/arch/x86_64/ia32/ptrace32.c  2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/arch/x86_64/ia32/ptrace32.c       2005-08-13 18:14:22.000000000 
+0200
@@ -196,36 +196,6 @@
 
 #undef R32
 
-static struct task_struct *find_target(int request, int pid, int *err)
-{ 
-       struct task_struct *child;
-
-       *err = -EPERM; 
-       if (pid == 1)
-               return NULL; 
-
-       *err = -ESRCH;
-       read_lock(&tasklist_lock);
-       child = find_task_by_pid(pid);
-       if (child)
-               get_task_struct(child);
-       read_unlock(&tasklist_lock);
-       if (child) { 
-               *err = -EPERM;
-               if (child->pid == 1) 
-                       goto out;
-               *err = ptrace_check_attach(child, request == PTRACE_KILL); 
-               if (*err < 0) 
-                       goto out;
-               return child; 
-       } 
- out:
-       if (child)
-       put_task_struct(child);
-       return NULL; 
-       
-} 
-
 asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
 {
        struct task_struct *child;
@@ -254,10 +224,14 @@
                break;
        } 
 
-       child = find_target(request, pid, &ret);
+       ret = ptrace_get_task_struct(request, pid, &child);
        if (!child)
                return ret;
 
+       ret = ptrace_check_attach(child, request == PTRACE_KILL);
+       if (ret < 0)
+               goto out;
+
        childregs = (struct pt_regs *)(child->thread.rsp0 - sizeof(struct 
pt_regs)); 
 
        switch (request) {
@@ -373,6 +347,7 @@
                break;
        }
 
+ out:
        put_task_struct(child);
        return ret;
 }
Index: linux-2.6/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/kernel/ptrace.c      2005-08-13 18:14:17.000000000 +0200
+++ linux-2.6/kernel/ptrace.c   2005-08-13 18:14:22.000000000 +0200
@@ -389,9 +389,7 @@
        return ret;
 }
 
-#ifndef __ARCH_SYS_PTRACE
-static int ptrace_get_task_struct(long request, long pid,
-               struct task_struct **childp)
+int ptrace_get_task_struct(long request, long pid, struct task_struct **childp)
 {
        struct task_struct *child;
        int ret;
@@ -437,6 +435,7 @@
        return 0;
 }
 
+#ifndef __ARCH_SYS_PTRACE
 asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 {
        struct task_struct *child;
Index: linux-2.6/include/linux/ptrace.h
===================================================================
--- linux-2.6.orig/include/linux/ptrace.h       2005-08-13 18:13:26.000000000 
+0200
+++ linux-2.6/include/linux/ptrace.h    2005-08-13 18:14:22.000000000 +0200
@@ -78,6 +78,7 @@
 
 
 extern long arch_ptrace(struct task_struct *child, long request, long addr, 
long data);
+extern int ptrace_get_task_struct(long request, long pid, struct task_struct 
**childp);
 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char 
__user *dst, int len);
 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, 
unsigned long dst, int len);
 extern int ptrace_attach(struct task_struct *tsk);
-
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