Rewrite of last_siginfo_read() and eventmessage_read()

Author: igorcanadi

fs/proc/base.c

@@ -52,7 +52,6 @@
 #include <linux/errno.h>
 #include <linux/time.h>
 #include <linux/proc_fs.h>
-#include <linux/signal.h>
 #include <linux/stat.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/init.h>
@@ -1069,12 +1068,18 @@ static const struct file_operations proc_ctl_operations = {
 
 static ssize_t eventmessage_read(struct file *file, char __user *buf,
 size_t count, loff_t *ppos) {
+int length;
 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 
-if (count < sizeof(task->ptrace_message))
-return -EIO;
+length = -ESRCH;
+if (!task)
+goto out_no_task;
 
-return put_user(task->ptrace_message, buf);
+length = simple_read_from_buffer(buf, count, ppos,
+(char *)&task->ptrace_message, sizeof(task->ptrace_message));
+
+out_no_task:
+return length;
 }
 
 static const struct file_operations proc_eventmessage_operations = {
@@ -1086,27 +1091,30 @@ static ssize_t last_siginfo_read(struct file *file, char __user *buf,
 size_t count, loff_t *ppos) {
 unsigned long flags;
 siginfo_t info;
-int error = -ESRCH;
+int length;
 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 
-if (count < sizeof(siginfo_t) && lock_task_sighand(task, &flags)) {
-error = -EINVAL;
+length = -ESRCH;
+if (!task)
+goto out_no_task;
+length = -EINVAL;
+
+if (lock_task_sighand(task, &flags)) {
+length = 0;
 if (likely(task->last_siginfo != NULL)) {
 info = *task->last_siginfo;
-error = 0;
+length = sizeof(info);
 }
 
 unlock_task_sighand(task, &flags);
 }
 
-if (!error) {
-error = copy_siginfo_to_user((siginfo_t __user *) buf, &info);
-}
-
-if (!error)
-error = sizeof(siginfo_t);
+if (length >= 0)
+length = simple_read_from_buffer(buf, count,
+ppos, (char *)&info, length);
 
-return error;
+out_no_task:
+return length;
 }
 
 static const struct file_operations proc_last_siginfo_operations = {

kernel/signal.c

@@ -2144,6 +2144,7 @@ static int proctrace_signal(int signr, siginfo_t *info) {
 set_current_state(TASK_RUNNING);
 spin_lock_irq(&current->sighand->siglock);
 current->last_siginfo = NULL;
+printk("PROCTRACE Ubijam last_siginfo\n");
 }
 
 return retval;