Messages in this thread Patch in this message | | | Date | Thu, 20 Apr 2006 17:21:16 +0200 | From | "Claudio Scordino" <> | Subject | [PATCH] Extending getrusage |
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For the people who missed the beginning of the discussion, the following patch is an extension of the existing getrusage syscall() and it applies to the 2.6.16.9 kernel.
It allows a task to read usage information about another task. The argument who can be equal to RUSAGE_SELF, to RUSAGE_CHILDREN or to a valid pid.
The permissions are checked through security_ptrace() as suggested by Andy.
Any other comment ?
Thanks,
Claudio
Signed-off-by: Claudio Scordino <cloud.of.andor@gmail.com> --- sys.old.c 2006-04-19 02:10:14.000000000 -0400 +++ sys.c 2006-04-20 10:53:16.000000000 -0400 @@ -1765,11 +1765,30 @@ int getrusage(struct task_struct *p, int return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; }
+/* who can be RUSAGE_SELF, RUSAGE_CHILDREN or a valid pid */ asmlinkage long sys_getrusage(int who, struct rusage __user *ru) { - if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN) - return -EINVAL; - return getrusage(current, who, ru); + struct rusage r; + struct task_struct* tsk = current; + read_lock(&tasklist_lock); + if ((who != RUSAGE_SELF) && (who != RUSAGE_CHILDREN)) { + if (who <= 0) + goto bad; + tsk = find_task_by_pid(who); + if (tsk == NULL) + goto bad; + if ((tsk != current) && security_ptrace(current, tsk)) + goto bad; + /* current can get info about tsk */ + who = RUSAGE_SELF; + } + k_getrusage(tsk, who, &r); + read_unlock(&tasklist_lock); + return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; + +bad: + read_unlock(&tasklist_lock); + return tsk ? -EPERM : -EINVAL; }
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