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procfs: Convert /proc/pid/fdinfo/ handling routines to seq-file v2 

This patch converts /proc/pid/fdinfo/ handling routines to seq-file which
is needed to extend seq operations and plug in auxiliary fdinfo provides
from subsystems like eventfd/eventpoll/fsnotify.

Note the proc_fd_link no longer call for proc_fd_info, simply because
the guts of proc_fd_info() got merged into ->show() of that seq_file

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Cyrill Gorcunov 2012-08-26 18:28:20 +04:00 committed by Al Viro
parent faf60af17f
commit ddd3e0771b
1 changed files with 64 additions and 48 deletions
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112
fs/proc/fd.c
View File

@ -6,61 +6,68 @@
#include <linux/namei.h>
#include <linux/pid.h>
#include <linux/security.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include "internal.h"
#include "fd.h"
#define PROC_FDINFO_MAX 64
static int proc_fd_info(struct inode *inode, struct path *path, char *info)
static int seq_show(struct seq_file *m, void *v)
{
struct task_struct *task = get_proc_task(inode);
struct files_struct *files = NULL;
int fd = proc_fd(inode);
struct file *file;
int f_flags = 0, ret = -ENOENT;
struct file *file = NULL;
struct task_struct *task;
task = get_proc_task(m->private);
if (!task)
return -ENOENT;
files = get_files_struct(task);
put_task_struct(task);
if (task) {
files = get_files_struct(task);
put_task_struct(task);
}
if (files) {
/*
* We are not taking a ref to the file structure, so we must
* hold ->file_lock.
*/
int fd = proc_fd(m->private);
spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (file) {
unsigned int f_flags;
struct fdtable *fdt;
struct fdtable *fdt = files_fdtable(files);
fdt = files_fdtable(files);
f_flags = file->f_flags & ~O_CLOEXEC;
if (close_on_exec(fd, fdt))
f_flags |= O_CLOEXEC;
if (path) {
*path = file->f_path;
path_get(&file->f_path);
}
if (info)
snprintf(info, PROC_FDINFO_MAX,
"pos:\t%lli\n"
"flags:\t0%o\n",
(long long) file->f_pos,
f_flags);
spin_unlock(&files->file_lock);
put_files_struct(files);
return 0;
get_file(file);
ret = 0;
}
spin_unlock(&files->file_lock);
put_files_struct(files);
}
return -ENOENT;
if (!ret) {
seq_printf(m, "pos:\t%lli\nflags:\t0%o\n",
(long long)file->f_pos, f_flags);
fput(file);
}
return ret;
}
static int seq_fdinfo_open(struct inode *inode, struct file *file)
{
return single_open(file, seq_show, inode);
}
static const struct file_operations proc_fdinfo_file_operations = {
.open = seq_fdinfo_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
{
struct files_struct *files;
@ -130,7 +137,32 @@ static const struct dentry_operations tid_fd_dentry_operations = {
static int proc_fd_link(struct dentry *dentry, struct path *path)
{
return proc_fd_info(dentry->d_inode, path, NULL);
struct files_struct *files = NULL;
struct task_struct *task;
int ret = -ENOENT;
task = get_proc_task(dentry->d_inode);
if (task) {
files = get_files_struct(task);
put_task_struct(task);
}
if (files) {
int fd = proc_fd(dentry->d_inode);
struct file *fd_file;
spin_lock(&files->file_lock);
fd_file = fcheck_files(files, fd);
if (fd_file) {
*path = fd_file->f_path;
path_get(&fd_file->f_path);
ret = 0;
}
spin_unlock(&files->file_lock);
put_files_struct(files);
}
return ret;
}
static struct dentry *
@ -245,22 +277,6 @@ out_no_task:
return retval;
}
static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
char tmp[PROC_FDINFO_MAX];
int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
if (!err)
err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
return err;
}
static const struct file_operations proc_fdinfo_file_operations = {
.open = nonseekable_open,
.read = proc_fdinfo_read,
.llseek = no_llseek,
};
static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
{
return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);