procfs: Move /proc/pid/fd[info] handling code to fd.[ch]
This patch prepares the ground for further extension of
/proc/pid/fd[info] handling code by moving fdinfo handling
code into fs/proc/fd.c.
I think such move makes both fs/proc/base.c and fs/proc/fd.c
easier to read.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
CC: Al Viro <viro@ZenIV.linux.org.uk>
CC: Alexey Dobriyan <adobriyan@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: James Bottomley <jbottomley@parallels.com>
CC: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
CC: Alexey Dobriyan <adobriyan@gmail.com>
CC: Matthew Helsley <matt.helsley@gmail.com>
CC: "J. Bruce Fields" <bfields@fieldses.org>
CC: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
new file mode 100644
index 0000000..1b0f932b
--- /dev/null
+++ b/fs/proc/fd.c
@@ -0,0 +1,351 @@
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/dcache.h>
+#include <linux/path.h>
+#include <linux/fdtable.h>
+#include <linux/namei.h>
+#include <linux/pid.h>
+#include <linux/security.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)
+{
+ struct task_struct *task = get_proc_task(inode);
+ struct files_struct *files = NULL;
+ int fd = proc_fd(inode);
+ struct file *file;
+
+ 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.
+ */
+ spin_lock(&files->file_lock);
+ file = fcheck_files(files, fd);
+ if (file) {
+ unsigned int f_flags;
+ struct fdtable *fdt;
+
+ 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;
+ }
+ spin_unlock(&files->file_lock);
+ put_files_struct(files);
+ }
+ return -ENOENT;
+}
+
+static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct files_struct *files;
+ struct task_struct *task;
+ const struct cred *cred;
+ struct inode *inode;
+ int fd;
+
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ inode = dentry->d_inode;
+ task = get_proc_task(inode);
+ fd = proc_fd(inode);
+
+ if (task) {
+ files = get_files_struct(task);
+ if (files) {
+ struct file *file;
+
+ rcu_read_lock();
+ file = fcheck_files(files, fd);
+ if (file) {
+ unsigned f_mode = file->f_mode;
+
+ rcu_read_unlock();
+ put_files_struct(files);
+
+ if (task_dumpable(task)) {
+ rcu_read_lock();
+ cred = __task_cred(task);
+ inode->i_uid = cred->euid;
+ inode->i_gid = cred->egid;
+ rcu_read_unlock();
+ } else {
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
+ }
+
+ if (S_ISLNK(inode->i_mode)) {
+ unsigned i_mode = S_IFLNK;
+ if (f_mode & FMODE_READ)
+ i_mode |= S_IRUSR | S_IXUSR;
+ if (f_mode & FMODE_WRITE)
+ i_mode |= S_IWUSR | S_IXUSR;
+ inode->i_mode = i_mode;
+ }
+
+ security_task_to_inode(task, inode);
+ put_task_struct(task);
+ return 1;
+ }
+ rcu_read_unlock();
+ put_files_struct(files);
+ }
+ put_task_struct(task);
+ }
+
+ d_drop(dentry);
+ return 0;
+}
+
+static const struct dentry_operations tid_fd_dentry_operations = {
+ .d_revalidate = tid_fd_revalidate,
+ .d_delete = pid_delete_dentry,
+};
+
+static int proc_fd_link(struct dentry *dentry, struct path *path)
+{
+ return proc_fd_info(dentry->d_inode, path, NULL);
+}
+
+static struct dentry *
+proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
+ struct task_struct *task, const void *ptr)
+{
+ struct dentry *error = ERR_PTR(-ENOENT);
+ unsigned fd = (unsigned long)ptr;
+ struct proc_inode *ei;
+ struct inode *inode;
+
+ inode = proc_pid_make_inode(dir->i_sb, task);
+ if (!inode)
+ goto out;
+
+ ei = PROC_I(inode);
+ ei->fd = fd;
+
+ inode->i_mode = S_IFLNK;
+ inode->i_op = &proc_pid_link_inode_operations;
+ inode->i_size = 64;
+
+ ei->op.proc_get_link = proc_fd_link;
+
+ d_set_d_op(dentry, &tid_fd_dentry_operations);
+ d_add(dentry, inode);
+
+ /* Close the race of the process dying before we return the dentry */
+ if (tid_fd_revalidate(dentry, 0))
+ error = NULL;
+ out:
+ return error;
+}
+
+static struct dentry *proc_lookupfd_common(struct inode *dir,
+ struct dentry *dentry,
+ instantiate_t instantiate)
+{
+ struct task_struct *task = get_proc_task(dir);
+ struct dentry *result = ERR_PTR(-ENOENT);
+ unsigned fd = name_to_int(dentry);
+
+ if (!task)
+ goto out_no_task;
+ if (fd == ~0U)
+ goto out;
+
+ result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
+out:
+ put_task_struct(task);
+out_no_task:
+ return result;
+}
+
+static int proc_readfd_common(struct file * filp, void * dirent,
+ filldir_t filldir, instantiate_t instantiate)
+{
+ struct dentry *dentry = filp->f_path.dentry;
+ struct inode *inode = dentry->d_inode;
+ struct task_struct *p = get_proc_task(inode);
+ struct files_struct *files;
+ unsigned int fd, ino;
+ int retval;
+
+ retval = -ENOENT;
+ if (!p)
+ goto out_no_task;
+ retval = 0;
+
+ fd = filp->f_pos;
+ switch (fd) {
+ case 0:
+ if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
+ goto out;
+ filp->f_pos++;
+ case 1:
+ ino = parent_ino(dentry);
+ if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
+ goto out;
+ filp->f_pos++;
+ default:
+ files = get_files_struct(p);
+ if (!files)
+ goto out;
+ rcu_read_lock();
+ for (fd = filp->f_pos - 2;
+ fd < files_fdtable(files)->max_fds;
+ fd++, filp->f_pos++) {
+ char name[PROC_NUMBUF];
+ int len;
+ int rv;
+
+ if (!fcheck_files(files, fd))
+ continue;
+ rcu_read_unlock();
+
+ len = snprintf(name, sizeof(name), "%d", fd);
+ rv = proc_fill_cache(filp, dirent, filldir,
+ name, len, instantiate, p,
+ (void *)(unsigned long)fd);
+ if (rv < 0)
+ goto out_fd_loop;
+ rcu_read_lock();
+ }
+ rcu_read_unlock();
+out_fd_loop:
+ put_files_struct(files);
+ }
+out:
+ put_task_struct(p);
+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);
+}
+
+const struct file_operations proc_fd_operations = {
+ .read = generic_read_dir,
+ .readdir = proc_readfd,
+ .llseek = default_llseek,
+};
+
+static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
+}
+
+/*
+ * /proc/pid/fd needs a special permission handler so that a process can still
+ * access /proc/self/fd after it has executed a setuid().
+ */
+int proc_fd_permission(struct inode *inode, int mask)
+{
+ int rv = generic_permission(inode, mask);
+ if (rv == 0)
+ return 0;
+ if (task_pid(current) == proc_pid(inode))
+ rv = 0;
+ return rv;
+}
+
+const struct inode_operations proc_fd_inode_operations = {
+ .lookup = proc_lookupfd,
+ .permission = proc_fd_permission,
+ .setattr = proc_setattr,
+};
+
+static struct dentry *
+proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
+ struct task_struct *task, const void *ptr)
+{
+ struct dentry *error = ERR_PTR(-ENOENT);
+ unsigned fd = (unsigned long)ptr;
+ struct proc_inode *ei;
+ struct inode *inode;
+
+ inode = proc_pid_make_inode(dir->i_sb, task);
+ if (!inode)
+ goto out;
+
+ ei = PROC_I(inode);
+ ei->fd = fd;
+
+ inode->i_mode = S_IFREG | S_IRUSR;
+ inode->i_fop = &proc_fdinfo_file_operations;
+
+ d_set_d_op(dentry, &tid_fd_dentry_operations);
+ d_add(dentry, inode);
+
+ /* Close the race of the process dying before we return the dentry */
+ if (tid_fd_revalidate(dentry, 0))
+ error = NULL;
+ out:
+ return error;
+}
+
+static struct dentry *
+proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+ return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
+}
+
+static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
+{
+ return proc_readfd_common(filp, dirent, filldir,
+ proc_fdinfo_instantiate);
+}
+
+const struct inode_operations proc_fdinfo_inode_operations = {
+ .lookup = proc_lookupfdinfo,
+ .setattr = proc_setattr,
+};
+
+const struct file_operations proc_fdinfo_operations = {
+ .read = generic_read_dir,
+ .readdir = proc_readfdinfo,
+ .llseek = default_llseek,
+};