From: Cong Wang <xiyou.wangcong@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
WANG Cong <xiyou.wangcong@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Vasiliy Kulikov <segoon@openwall.com>,
Stephen Wilson <wilsons@start.ca>,
David Rientjes <rientjes@google.com>
Subject: [PATCH] proc: clean up /proc/<pid>/environ handling
Date: Tue, 31 Jan 2012 20:50:44 +0800 [thread overview]
Message-ID: <1328014247-16461-1-git-send-email-xiyou.wangcong@gmail.com> (raw)
Similar to commit e268337dfe26dfc7efd422a804dbb27977a3cccc
(proc: clean up and fix /proc/<pid>/mem handling), move the
check of permission to open(), this will simplify read() code.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
---
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9cde9edf..3d30eb4 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -835,28 +835,38 @@ static const struct file_operations proc_mem_operations = {
.release = mem_release,
};
+static int environ_open(struct inode *inode, struct file *file)
+{
+ struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
+ struct mm_struct *mm;
+
+ if (!task)
+ return -ESRCH;
+
+ mm = mm_for_maps(task);
+ put_task_struct(task);
+
+ if (!mm)
+ return -ENOENT;
+ if (IS_ERR(mm))
+ return PTR_ERR(mm);
+
+ file->private_data = mm;
+
+ return 0;
+}
+
static ssize_t environ_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
- struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
char *page;
unsigned long src = *ppos;
- int ret = -ESRCH;
- struct mm_struct *mm;
-
- if (!task)
- goto out_no_task;
+ int ret = 0;
+ struct mm_struct *mm = file->private_data;
- ret = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
- goto out;
-
-
- mm = mm_for_maps(task);
- ret = PTR_ERR(mm);
- if (!mm || IS_ERR(mm))
- goto out_free;
+ return -ENOMEM;
ret = 0;
while (count > 0) {
@@ -870,7 +880,7 @@ static ssize_t environ_read(struct file *file, char __user *buf,
max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
this_len = (this_len > max_len) ? max_len : this_len;
- retval = access_process_vm(task, (mm->env_start + src),
+ retval = access_remote_vm(mm, (mm->env_start + src),
page, this_len, 0);
if (retval <= 0) {
@@ -890,18 +900,23 @@ static ssize_t environ_read(struct file *file, char __user *buf,
}
*ppos = src;
- mmput(mm);
-out_free:
free_page((unsigned long) page);
-out:
- put_task_struct(task);
-out_no_task:
return ret;
}
+static int environ_release(struct inode *inode, struct file *file)
+{
+ struct mm_struct *mm = file->private_data;
+
+ mmput(mm);
+ return 0;
+}
+
static const struct file_operations proc_environ_operations = {
+ .open = environ_open,
.read = environ_read,
.llseek = generic_file_llseek,
+ .release = environ_release,
};
static ssize_t oom_adjust_read(struct file *file, char __user *buf,
reply other threads:[~2012-01-31 12:59 UTC|newest]
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