linux-kernel - [PATCH] timerfd: show procfs fdinfo helper, and now accepts write()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1391443273-2031-1-git-send-email-shawn@churchofgit.com>
Date:	Mon,  3 Feb 2014 08:01:13 -0800
From:	Shawn Landden <shawn@...rchofgit.com>
To:	unlisted-recipients:; (no To-header on input)
Cc:	criu@...nvz.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, avagin@...il.com,
	Shawn Landden <shawn@...rchofgit.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Alexander Viro <viro@...iv.linux.org.uk>
Subject: [PATCH] timerfd: show procfs fdinfo helper, and now accepts write()

| pos:	0
| flags:	02004002
| clockid:	0
| ticks:        6

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Signed-off-by: Shawn Landden <shawn@...rchofgit.com>
---
 fs/timerfd.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 9293121..2e81bdb 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -25,6 +25,7 @@
 #include <linux/syscalls.h>
 #include <linux/compat.h>
 #include <linux/rcupdate.h>
+#include <linux/seq_file.h>
 
 struct timerfd_ctx {
 	union {
@@ -284,10 +285,73 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
 	return res;
 }
 
+#ifdef CONFIG_PROC_FS
+static int timerfd_show_fdinfo(struct seq_file *m, struct file *f)
+{
+	struct timerfd_ctx *ctx = f->private_data;
+
+	seq_printf(m, "clockid:\t%d\n"
+		      "ticks:\t%llu\n", ctx->clockid, ctx->ticks);
+
+	return 0;
+}
+#endif
+
+static ssize_t timerfd_write(struct file *file, const char __user *buf, size_t count,
+			 loff_t *ppos)
+{
+	struct timerfd_ctx *ctx = file->private_data;
+	ssize_t res;
+	__u64 ucnt;
+	DECLARE_WAITQUEUE(wait, current);
+
+	if (count < sizeof(ucnt))
+		return -EINVAL;
+	if (copy_from_user(&ucnt, buf, sizeof(ucnt)))
+		return -EFAULT;
+	if (ucnt == ULLONG_MAX)
+		return -EINVAL;
+	spin_lock_irq(&ctx->wqh.lock);
+	res = -EAGAIN;
+	if (ULLONG_MAX - ctx->ticks > ucnt)
+		res = sizeof(ucnt);
+	else if (!(file->f_flags & O_NONBLOCK)) {
+		__add_wait_queue(&ctx->wqh, &wait);
+		for (res = 0;;) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (ULLONG_MAX - ctx->ticks > ucnt) {
+				res = sizeof(ucnt);
+				break;
+			}
+			if (signal_pending(current)) {
+				res = -ERESTARTSYS;
+				break;
+			}
+			spin_unlock_irq(&ctx->wqh.lock);
+			schedule();
+			spin_lock_irq(&ctx->wqh.lock);
+		}
+		__remove_wait_queue(&ctx->wqh, &wait);
+		__set_current_state(TASK_RUNNING);
+	}
+	if (likely(res > 0)) {
+		ctx->ticks += ucnt;
+		if (waitqueue_active(&ctx->wqh))
+			wake_up_locked_poll(&ctx->wqh, POLLIN);
+	}
+	spin_unlock_irq(&ctx->wqh.lock);
+
+	return res;
+}
+
 static const struct file_operations timerfd_fops = {
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= timerfd_show_fdinfo,
+#endif
 	.release	= timerfd_release,
 	.poll		= timerfd_poll,
 	.read		= timerfd_read,
+	.write		= timerfd_write,
 	.llseek		= noop_llseek,
 };
 
-- 
1.8.5.2.297.g3e57c29

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/