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>

1 files changed, 2 insertions, 386 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b6c84cbdb73..b55c3bb298e3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -90,6 +90,7 @@
 #endif
 #include <trace/events/oom.h>
 #include "internal.h"
+#include "fd.h"
 
 /* NOTE:
  *      Implementing inode permission operations in /proc is almost
@@ -136,8 +137,6 @@ struct pid_entry {
                 NULL, &proc_single_file_operations,     \
                 { .proc_show = show } )
 
-static int proc_fd_permission(struct inode *inode, int mask);
-
 /*
  * Count the number of hardlinks for the pid_entry table, excluding the .
  * and .. links.
@@ -1492,7 +1491,7 @@ out:
         return error;
 }
 
-static const struct inode_operations proc_pid_link_inode_operations = {
+const struct inode_operations proc_pid_link_inode_operations = {
         .readlink       = proc_pid_readlink,
         .follow_link    = proc_pid_follow_link,
         .setattr        = proc_setattr,
@@ -1501,21 +1500,6 @@ static const struct inode_operations proc_pid_link_inode_operations = {
 
 /* building an inode */
 
-static int task_dumpable(struct task_struct *task)
-{
-        int dumpable = 0;
-        struct mm_struct *mm;
-
-        task_lock(task);
-        mm = task->mm;
-        if (mm)
-                dumpable = get_dumpable(mm);
-        task_unlock(task);
-        if(dumpable == 1)
-                return 1;
-        return 0;
-}
-
 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
 {
         struct inode * inode;
@@ -1641,15 +1625,6 @@ int pid_revalidate(struct dentry *dentry, unsigned int flags)
         return 0;
 }
 
-static int pid_delete_dentry(const struct dentry * dentry)
-{
-        /* Is the task we represent dead?
-         * If so, then don't put the dentry on the lru list,
-         * kill it immediately.
-         */
-        return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
-}
-
 const struct dentry_operations pid_dentry_operations =
 {
         .d_revalidate   = pid_revalidate,
@@ -1712,289 +1687,6 @@ end_instantiate:
         return filldir(dirent, name, len, filp->f_pos, ino, type);
 }
 
-static unsigned name_to_int(struct dentry *dentry)
-{
-        const char *name = dentry->d_name.name;
-        int len = dentry->d_name.len;
-        unsigned n = 0;
-
-        if (len > 1 && *name == '0')
-                goto out;
-        while (len-- > 0) {
-                unsigned c = *name++ - '0';
-                if (c > 9)
-                        goto out;
-                if (n >= (~0U-9)/10)
-                        goto out;
-                n *= 10;
-                n += c;
-        }
-        return n;
-out:
-        return ~0U;
-}
-
-#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;
-        struct file *file;
-        int fd = proc_fd(inode);
-
-        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 proc_fd_link(struct dentry *dentry, struct path *path)
-{
-        return proc_fd_info(dentry->d_inode, path, NULL);
-}
-
-static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
-{
-        struct inode *inode;
-        struct task_struct *task;
-        int fd;
-        struct files_struct *files;
-        const struct cred *cred;
-
-        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 struct dentry *proc_fd_instantiate(struct inode *dir,
-        struct dentry *dentry, struct task_struct *task, const void *ptr)
-{
-        unsigned fd = (unsigned long)ptr;
-        struct inode *inode;
-        struct proc_inode *ei;
-        struct dentry *error = ERR_PTR(-ENOENT);
-
-        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);
-        unsigned fd = name_to_int(dentry);
-        struct dentry *result = ERR_PTR(-ENOENT);
-
-        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);
-        unsigned int fd, ino;
-        int retval;
-        struct files_struct * files;
-
-        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 struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
-                                    unsigned int flags)
-{
-        return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
-}
-
-static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
-{
-        return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
-}
-
-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 const struct file_operations proc_fd_operations = {
-        .read           = generic_read_dir,
-        .readdir        = proc_readfd,
-        .llseek         = default_llseek,
-};
-
 #ifdef CONFIG_CHECKPOINT_RESTORE
 
 /*
@@ -2337,82 +2029,6 @@ static const struct file_operations proc_map_files_operations = {
 
 #endif /* CONFIG_CHECKPOINT_RESTORE */
 
-/*
- * /proc/pid/fd needs a special permission handler so that a process can still
- * access /proc/self/fd after it has executed a setuid().
- */
-static 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;
-}
-
-/*
- * proc directories can do almost nothing..
- */
-static 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)
-{
-        unsigned fd = (unsigned long)ptr;
-        struct inode *inode;
-        struct proc_inode *ei;
-        struct dentry *error = ERR_PTR(-ENOENT);
-
-        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);
-}
-
-static const struct file_operations proc_fdinfo_operations = {
-        .read           = generic_read_dir,
-        .readdir        = proc_readfdinfo,
-        .llseek         = default_llseek,
-};
-
-/*
- * proc directories can do almost nothing..
- */
-static const struct inode_operations proc_fdinfo_inode_operations = {
-        .lookup         = proc_lookupfdinfo,
-        .setattr        = proc_setattr,
-};
-
-
 static struct dentry *proc_pident_instantiate(struct inode *dir,
         struct dentry *dentry, struct task_struct *task, const void *ptr)
 {