fs/proc/root.c

File Facts

System

Linux kernel

Corpus path

fs/proc/root.c

Extension

.c

Size

11899 bytes

Lines

469

Domain

Core OS

Bucket

VFS And Filesystem Core

Inferred role

Core OS: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/errno.h
• linux/time.h
• linux/proc_fs.h
• linux/stat.h
• linux/init.h
• linux/sched.h
• linux/sched/stat.h
• linux/module.h
• linux/bitops.h
• linux/user_namespace.h
• linux/fs_context.h
• linux/mount.h
• linux/pid_namespace.h
• linux/fs_parser.h
• linux/cred.h
• linux/magic.h
• linux/slab.h
• internal.h

Detected Declarations

• struct proc_fs_context
• enum proc_param
• function valid_hidepid
• function proc_parse_hidepid_param
• function proc_parse_subset_param
• function proc_parse_pidns_param
• function pidns_install
• function proc_parse_param
• function proc_sb_info
• function proc_apply_options
• function proc_fill_super
• function proc_reconfigure
• function proc_get_tree
• function proc_fs_context_free
• function proc_init_fs_context
• function proc_kill_sb
• function proc_root_init
• function proc_root_getattr
• function proc_root_readdir

Annotated Snippet

static const struct file_operations proc_root_operations = {
	.read		 = generic_read_dir,
	.iterate_shared	 = proc_root_readdir,
	.llseek		= generic_file_llseek,
};

/*
 * proc root can do almost nothing..
 */
static const struct inode_operations proc_root_inode_operations = {
	.lookup		= proc_root_lookup,
	.getattr	= proc_root_getattr,
};

/*
 * This is the root "inode" in the /proc tree..
 */
struct proc_dir_entry proc_root = {
	.low_ino	= PROCFS_ROOT_INO,
	.namelen	= 5,
	.mode		= S_IFDIR | S_IRUGO | S_IXUGO,
	.nlink		= 2,
	.refcnt		= REFCOUNT_INIT(1),
	.proc_iops	= &proc_root_inode_operations,
	.proc_dir_ops	= &proc_root_operations,
	.parent		= &proc_root,
	.subdir		= RB_ROOT,
	.name		= "/proc",
};

Annotation

• Immediate include surface: `linux/errno.h`, `linux/time.h`, `linux/proc_fs.h`, `linux/stat.h`, `linux/init.h`, `linux/sched.h`, `linux/sched/stat.h`, `linux/module.h`.
• Detected declarations: `struct proc_fs_context`, `enum proc_param`, `function valid_hidepid`, `function proc_parse_hidepid_param`, `function proc_parse_subset_param`, `function proc_parse_pidns_param`, `function pidns_install`, `function proc_parse_param`, `function proc_sb_info`, `function proc_apply_options`.
• Atlas domain: Core OS / VFS And Filesystem Core.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.