lib/xz/xz_dec_test.c

File Facts

System

Linux kernel

Corpus path

lib/xz/xz_dec_test.c

Extension

.c

Size

5072 bytes

Lines

215

Domain

Kernel Services

Bucket

lib

Inferred role

Kernel Services: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

• Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.
• 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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/kernel.h
• linux/module.h
• linux/fs.h
• linux/uaccess.h
• linux/crc32.h
• linux/xz.h

Detected Declarations

• function xz_dec_test_open
• function xz_dec_test_release
• function xz_dec_test_write
• function xz_dec_test_init
• function xz_dec_test_exit
• module init xz_dec_test_init

Annotated Snippet

static const struct file_operations fileops = {
		.owner = THIS_MODULE,
		.open = &xz_dec_test_open,
		.release = &xz_dec_test_release,
		.write = &xz_dec_test_write
	};

	state = xz_dec_init(XZ_PREALLOC, DICT_MAX);
	if (state == NULL)
		return -ENOMEM;

	device_major = register_chrdev(0, DEVICE_NAME, &fileops);
	if (device_major < 0) {
		xz_dec_end(state);
		return device_major;
	}

	printk(KERN_INFO DEVICE_NAME ": module loaded\n");
	printk(KERN_INFO DEVICE_NAME ": Create a device node with "
			"'mknod " DEVICE_NAME " c %d 0' and write .xz files "
			"to it.\n", device_major);
	return 0;
}

static void __exit xz_dec_test_exit(void)
{
	unregister_chrdev(device_major, DEVICE_NAME);
	xz_dec_end(state);
	printk(KERN_INFO DEVICE_NAME ": module unloaded\n");
}

module_init(xz_dec_test_init);
module_exit(xz_dec_test_exit);

MODULE_DESCRIPTION("XZ decompressor tester");
MODULE_VERSION("1.0");
MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org>");
MODULE_LICENSE("Dual BSD/GPL");

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/module.h`, `linux/fs.h`, `linux/uaccess.h`, `linux/crc32.h`, `linux/xz.h`.
• Detected declarations: `function xz_dec_test_open`, `function xz_dec_test_release`, `function xz_dec_test_write`, `function xz_dec_test_init`, `function xz_dec_test_exit`, `module init xz_dec_test_init`.
• Atlas domain: Kernel Services / lib.
• 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.