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[PATCH] use ptrace_get_task_struct in various places

Browse source 
The ptrace_get_task_struct() helper that I added as part of the ptrace
consolidation is useful in variety of places that currently opencode it.
Switch them to the common helpers.

Add a ptrace_traceme() helper that needs to be explicitly called, and simplify
the ptrace_get_task_struct() interface.  We don't need the request argument
now, and we return the task_struct directly, using ERR_PTR() for error
returns.  It's a bit more code in the callers, but we have two sane routines
that do one thing well now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Christoph Hellwig 2006-01-08 01:02:33 -08:00 committed by Linus Torvalds
parent 6b34350f49
commit 6b9c7ed848
12 changed files with 106 additions and 242 deletions
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24
arch/alpha/kernel/ptrace.c
View file

@ -265,30 +265,16 @@ do_sys_ptrace(long request, long pid, long addr, long data,
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;
ret = ptrace_traceme();
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);
if (!child)
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out_notsk;
}
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);

16
arch/ia64/ia32/sys_ia32.c
View file

@ -1761,21 +1761,15 @@ sys32_ptrace (int request, pid_t pid, unsigned int addr, unsigned int data)
lock_kernel();
if (request == PTRACE_TRACEME) {
ret = sys_ptrace(request, pid, addr, data);
ret = ptrace_traceme();
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)
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(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);

9
arch/ia64/kernel/ptrace.c
View file

@ -1422,14 +1422,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
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;
current->ptrace |= PT_PTRACED;
ret = 0;
ret = ptrace_traceme();
goto out;
}

22
arch/m32r/kernel/ptrace.c
View file

@ -762,28 +762,16 @@ asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
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;
ret = ptrace_traceme();
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 = -EPERM;
if (pid == 1) /* you may not mess with init */
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out;
}
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);

26
arch/mips/kernel/ptrace32.c
View file

@ -57,30 +57,16 @@ asmlinkage int sys32_ptrace(int request, int pid, int addr, int data)
(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;
ret = ptrace_traceme();
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 = -EPERM;
if (pid == 1) /* you may not mess with init */
goto out_tsk;
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out;
}
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);

28
arch/powerpc/kernel/ptrace32.c
View file

@ -45,33 +45,19 @@ long compat_sys_ptrace(int request, int pid, unsigned long addr,
unsigned long data)
{
struct task_struct *child;
int ret = -EPERM;
int ret;
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;
ret = ptrace_traceme();
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 = -EPERM;
if (pid == 1) /* you may not mess with init */
goto out_tsk;
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out;
}
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);

31
arch/s390/kernel/ptrace.c
View file

@ -712,35 +712,18 @@ sys_ptrace(long request, long pid, long addr, long data)
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;
ret = ptrace_traceme();
goto out;
}
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out;
}
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();

35
arch/sparc/kernel/ptrace.c
View file

@ -286,40 +286,17 @@ asmlinkage void do_ptrace(struct pt_regs *regs)
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;
ret = ptrace_traceme();
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);
if (!child) {
pt_error_return(regs, ESRCH);
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
pt_error_return(regs, -ret);
goto out;
}

34
arch/sparc64/kernel/ptrace.c
View file

@ -198,39 +198,15 @@ asmlinkage void do_ptrace(struct pt_regs *regs)
}
#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;
ret = ptrace_traceme();
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);
if (!child) {
pt_error_return(regs, ESRCH);
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
pt_error_return(regs, -ret);
goto out;
}

44
arch/x86_64/ia32/ptrace32.c
View file

@ -196,36 +196,6 @@ static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
#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;
@ -254,9 +224,16 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
break;
}
child = find_target(request, pid, &ret);
if (!child)
return ret;
if (request == PTRACE_TRACEME)
return ptrace_traceme();
child = ptrace_get_task_struct(pid);
if (IS_ERR(child))
return PTR_ERR(child);
ret = ptrace_check_attach(child, request == PTRACE_KILL);
if (ret < 0)
goto out;
childregs = (struct pt_regs *)(child->thread.rsp0 - sizeof(struct pt_regs));
@ -373,6 +350,7 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
break;
}
out:
put_task_struct(child);
return ret;
}

2
include/linux/ptrace.h
View file

@ -80,6 +80,8 @@
extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
extern struct task_struct *ptrace_get_task_struct(pid_t pid);
extern int ptrace_traceme(void);
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);

77
kernel/ptrace.c
View file

@ -408,54 +408,62 @@ int ptrace_request(struct task_struct *child, long request,
return ret;
}
#ifndef __ARCH_SYS_PTRACE
static int ptrace_get_task_struct(long request, long pid,
struct task_struct **childp)
/**
* ptrace_traceme -- helper for PTRACE_TRACEME
*
* Performs checks and sets PT_PTRACED.
* Should be used by all ptrace implementations for PTRACE_TRACEME.
*/
int ptrace_traceme(void)
{
struct task_struct *child;
int ret;
/*
* Callers use child == NULL as an indication to exit early even
* when the return value is 0, so make sure it is non-NULL here.
* Are we already being traced?
*/
*childp = NULL;
if (current->ptrace & PT_PTRACED)
return -EPERM;
ret = security_ptrace(current->parent, current);
if (ret)
return -EPERM;
/*
* Set the ptrace bit in the process ptrace flags.
*/
current->ptrace |= PT_PTRACED;
return 0;
}
if (request == PTRACE_TRACEME) {
/*
* Are we already being traced?
*/
if (current->ptrace & PT_PTRACED)
return -EPERM;
ret = security_ptrace(current->parent, current);
if (ret)
return -EPERM;
/*
* Set the ptrace bit in the process ptrace flags.
*/
current->ptrace |= PT_PTRACED;
return 0;
}
/**
* ptrace_get_task_struct -- grab a task struct reference for ptrace
* @pid: process id to grab a task_struct reference of
*
* This function is a helper for ptrace implementations. It checks
* permissions and then grabs a task struct for use of the actual
* ptrace implementation.
*
* Returns the task_struct for @pid or an ERR_PTR() on failure.
*/
struct task_struct *ptrace_get_task_struct(pid_t pid)
{
struct task_struct *child;
/*
* You may not mess with init
* Tracing init is not allowed.
*/
if (pid == 1)
return -EPERM;
return ERR_PTR(-EPERM);
ret = -ESRCH;
read_lock(&tasklist_lock);
child = find_task_by_pid(pid);
if (child)
get_task_struct(child);
read_unlock(&tasklist_lock);
if (!child)
return -ESRCH;
*childp = child;
return 0;
return ERR_PTR(-ESRCH);
return child;
}
#ifndef __ARCH_SYS_PTRACE
asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
@ -465,9 +473,16 @@ asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
* This lock_kernel fixes a subtle race with suid exec
*/
lock_kernel();
ret = ptrace_get_task_struct(request, pid, &child);
if (!child)
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);