* Chris Wright ([EMAIL PROTECTED]) wrote:
> * Ulrich Drepper ([EMAIL PROTECTED]) wrote:
> > And is another thing to consider. There is at least one other event
> > which should be pollable: process (maybe threads) deaths. I was
> > hoping that we get support for this, perhaps in the form of polling
> > the /proc/PID directory. For poll(), a POLLERR value could mean the
> > process/thread died. For select(), once again a bit in the except
> > array could be set.
>
> I have a simple patch that does just that. It worked after brief testing,
> then I never went back to look at it any more. I'll see if I can't dig
> it up, maybe it's useful.
Yeah, here it is. I refreshed it against a current kernel. It passes my
same old test, where I select on /proc/<pid>/status fd in exceptfds.
===== fs/proc/base.c 1.86 vs edited =====
--- 1.86/fs/proc/base.c 2005-01-10 17:29:31 -08:00
+++ edited/fs/proc/base.c 2005-01-21 22:51:00 -08:00
@@ -32,6 +32,7 @@
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/ptrace.h>
+#include <linux/poll.h>
#include "internal.h"
/*
@@ -519,8 +520,21 @@ static ssize_t proc_info_read(struct fil
return length;
}
+static unsigned int proc_info_poll(struct file *file, poll_table *wait)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct task_struct *task = proc_task(inode);
+ wait_queue_head_t *pid_wait = &PROC_I(task->proc_dentry->d_inode)->wait;
+
+ poll_wait(file, pid_wait, wait);
+ if (!pid_alive(task))
+ return POLLPRI;
+ return 0;
+}
+
static struct file_operations proc_info_file_operations = {
.read = proc_info_read,
+ .poll = proc_info_poll,
};
static int mem_open(struct inode* inode, struct file* file)
@@ -1489,6 +1503,8 @@ void proc_pid_flush(struct dentry *proc_
{
might_sleep();
if(proc_dentry != NULL) {
+ wait_queue_head_t *pid_wait=&PROC_I(proc_dentry->d_inode)->wait;
+ wake_up_interruptible(pid_wait);
shrink_dcache_parent(proc_dentry);
dput(proc_dentry);
}
===== fs/proc/inode.c 1.31 vs edited =====
--- 1.31/fs/proc/inode.c 2005-01-04 18:48:14 -08:00
+++ edited/fs/proc/inode.c 2005-01-21 22:48:06 -08:00
@@ -97,6 +97,7 @@ static struct inode *proc_alloc_inode(st
ei->type = 0;
ei->op.proc_get_link = NULL;
ei->pde = NULL;
+ init_waitqueue_head(&ei->wait);
inode = &ei->vfs_inode;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
return inode;
===== include/linux/proc_fs.h 1.41 vs edited =====
--- 1.41/include/linux/proc_fs.h 2005-01-07 21:44:33 -08:00
+++ edited/include/linux/proc_fs.h 2005-01-21 22:48:06 -08:00
@@ -243,6 +243,7 @@ struct proc_inode {
int (*proc_read)(struct task_struct *task, char *page);
} op;
struct proc_dir_entry *pde;
+ wait_queue_head_t wait;
struct inode vfs_inode;
};
-
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