cregit-Linux how code gets into the kernel

Release 4.18 fs/anon_inodes.c

Directory: fs
/*
 *  fs/anon_inodes.c
 *
 *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>
 *
 *  Thanks to Arnd Bergmann for code review and suggestions.
 *  More changes for Thomas Gleixner suggestions.
 *
 */

#include <linux/cred.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/magic.h>
#include <linux/anon_inodes.h>

#include <linux/uaccess.h>


static struct vfsmount *anon_inode_mnt __read_mostly;

static struct inode *anon_inode_inode;

/*
 * anon_inodefs_dname() is called from d_path().
 */

static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen) { return dynamic_dname(dentry, buffer, buflen, "anon_inode:%s", dentry->d_name.name); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro1951.35%266.67%
Davide Libenzi1848.65%133.33%
Total37100.00%3100.00%

static const struct dentry_operations anon_inodefs_dentry_operations = { .d_dname = anon_inodefs_dname, };
static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { return mount_pseudo(fs_type, "anon_inode:", NULL, &anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2050.00%133.33%
Nicholas Piggin1947.50%133.33%
Jan Kara12.50%133.33%
Total40100.00%3100.00%

static struct file_system_type anon_inode_fs_type = { .name = "anon_inodefs", .mount = anon_inodefs_mount, .kill_sb = kill_anon_super, }; /** * anon_inode_getfile - creates a new file instance by hooking it up to an * anonymous inode, and a dentry that describe the "class" * of the file * * @name: [in] name of the "class" of the new file * @fops: [in] file operations for the new file * @priv: [in] private data for the new file (will be file's private_data) * @flags: [in] flags * * Creates a new file by hooking it on a single inode. This is useful for files * that do not need to have a full-fledged inode in order to operate correctly. * All the files created with anon_inode_getfile() will share a single inode, * hence saving memory and avoiding code duplication for the file/inode/dentry * setup. Returns the newly created file* or an error pointer. */
struct file *anon_inode_getfile(const char *name, const struct file_operations *fops, void *priv, int flags) { struct qstr this; struct path path; struct file *file; if (IS_ERR(anon_inode_inode)) return ERR_PTR(-ENODEV); if (fops->owner && !try_module_get(fops->owner)) return ERR_PTR(-ENOENT); /* * Link the inode to a directory entry by creating a unique name * using the inode sequence number. */ file = ERR_PTR(-ENOMEM); this.name = name; this.len = strlen(name); this.hash = 0; path.dentry = d_alloc_pseudo(anon_inode_mnt->mnt_sb, &this); if (!path.dentry) goto err_module; path.mnt = mntget(anon_inode_mnt); /* * We know the anon_inode inode count is always greater than zero, * so ihold() is safe. */ ihold(anon_inode_inode); d_instantiate(path.dentry, anon_inode_inode); file = alloc_file(&path, OPEN_FMODE(flags), fops); if (IS_ERR(file)) goto err_dput; file->f_mapping = anon_inode_inode->i_mapping; file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); file->private_data = priv; return file; err_dput: path_put(&path); err_module: module_put(fops->owner); return file; }

Contributors

PersonTokensPropCommitsCommitProp
Davide Libenzi15066.67%323.08%
Al Viro2812.44%323.08%
Christian Bornträger177.56%17.69%
Dave Hansen104.44%17.69%
Ulrich Drepper83.56%215.38%
Anatol Pomozov83.56%17.69%
Roland Dreier31.33%17.69%
Nicholas Piggin10.44%17.69%
Total225100.00%13100.00%

EXPORT_SYMBOL_GPL(anon_inode_getfile); /** * anon_inode_getfd - creates a new file instance by hooking it up to an * anonymous inode, and a dentry that describe the "class" * of the file * * @name: [in] name of the "class" of the new file * @fops: [in] file operations for the new file * @priv: [in] private data for the new file (will be file's private_data) * @flags: [in] flags * * Creates a new file by hooking it on a single inode. This is useful for files * that do not need to have a full-fledged inode in order to operate correctly. * All the files created with anon_inode_getfd() will share a single inode, * hence saving memory and avoiding code duplication for the file/inode/dentry * setup. Returns new descriptor or an error code. */
int anon_inode_getfd(const char *name, const struct file_operations *fops, void *priv, int flags) { int error, fd; struct file *file; error = get_unused_fd_flags(flags); if (error < 0) return error; fd = error; file = anon_inode_getfile(name, fops, priv, flags); if (IS_ERR(file)) { error = PTR_ERR(file); goto err_put_unused_fd; } fd_install(fd, file); return fd; err_put_unused_fd: put_unused_fd(fd); return error; }

Contributors

PersonTokensPropCommitsCommitProp
Davide Libenzi9994.29%250.00%
Christian Bornträger43.81%125.00%
Dave Hansen21.90%125.00%
Total105100.00%4100.00%

EXPORT_SYMBOL_GPL(anon_inode_getfd);
static int __init anon_inode_init(void) { anon_inode_mnt = kern_mount(&anon_inode_fs_type); if (IS_ERR(anon_inode_mnt)) panic("anon_inode_init() kernel mount failed (%ld)\n", PTR_ERR(anon_inode_mnt)); anon_inode_inode = alloc_anon_inode(anon_inode_mnt->mnt_sb); if (IS_ERR(anon_inode_inode)) panic("anon_inode_init() inode allocation failed (%ld)\n", PTR_ERR(anon_inode_inode)); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Davide Libenzi3758.73%150.00%
Jan Kara2641.27%150.00%
Total63100.00%2100.00%

fs_initcall(anon_inode_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
Davide Libenzi37865.97%314.29%
Al Viro8314.49%523.81%
Jan Kara274.71%14.76%
Christian Bornträger213.66%14.76%
Nicholas Piggin203.49%29.52%
Dave Hansen122.09%14.76%
Ulrich Drepper81.40%29.52%
Anatol Pomozov81.40%14.76%
Alexey Dobriyan61.05%14.76%
Avi Kivity50.87%14.76%
Roland Dreier30.52%14.76%
Linus Torvalds10.17%14.76%
Namhyung Kim10.17%14.76%
Total573100.00%21100.00%
Directory: fs
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