path: root/init/initramfs.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/async.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/dirent.h>
#include <linux/syscalls.h>
#include <linux/utime.h>
#include <linux/file.h>
#include <linux/kstrtox.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/namei.h>
#include <linux/init_syscalls.h>
#include <linux/umh.h>
#include <linux/security.h>

#include "do_mounts.h"
#include "initramfs_internal.h"

static __initdata bool csum_present;
static __initdata u32 io_csum;

static ssize_t __init xwrite(struct file *file, const unsigned char *p,
		size_t count, loff_t *pos)
{
	ssize_t out = 0;

	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
	while (count) {
		ssize_t rv = kernel_write(file, p, count, pos);

		if (rv < 0) {
			if (rv == -EINTR || rv == -EAGAIN)
				continue;
			return out ? out : rv;
		} else if (rv == 0)
			break;

		if (csum_present) {
			ssize_t i;

			for (i = 0; i < rv; i++)
				io_csum += p[i];
		}

		p += rv;
		out += rv;
		count -= rv;
	}

	return out;
}

static __initdata char *message;
static void __init error(char *x)
{
	if (!message)
		message = x;
}

#define panic_show_mem(fmt, ...) \
	({ show_mem(); panic(fmt, ##__VA_ARGS__); })

/* link hash */

#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)

static __initdata struct hash {
	int ino, minor, major;
	umode_t mode;
	struct hash *next;
	char name[N_ALIGN(PATH_MAX)];
} *head[32];
static __initdata bool hardlink_seen;

static inline int hash(int major, int minor, int ino)
{
	unsigned long tmp = ino + minor + (major << 3);
	tmp += tmp >> 5;
	return tmp & 31;
}

static char __init *find_link(int major, int minor, int ino,
			      umode_t mode, char *name)
{
	struct hash **p, *q;
	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
		if ((*p)->ino != ino)
			continue;
		if ((*p)->minor != minor)
			continue;
		if ((*p)->major != major)
			continue;
		if (((*p)->mode ^ mode) & S_IFMT)
			continue;
		return (*p)->name;
	}
	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
	if (!q)
		panic_show_mem("can't allocate link hash entry");
	q->major = major;
	q->minor = minor;
	q->ino = ino;
	q->mode = mode;
	strcpy(q->name, name);
	q->next = NULL;
	*p = q;
	hardlink_seen = true;
	return NULL;
}

static void __init free_hash(void)
{
	struct hash **p, *q;
	for (p = head; hardlink_seen && p < head + 32; p++) {
		while (*p) {
			q = *p;
			*p = q->next;
			kfree(q);
		}
	}
	hardlink_seen = false;
}

#ifdef CONFIG_INITRAMFS_PRESERVE_MTIME
static void __init do_utime(char *filename, time64_t mtime)
{
	struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
	init_utimes(filename, t);
}

static void __init do_utime_path(const struct path *path, time64_t mtime)
{
	struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
	vfs_utimes(path, t);
}

static __initdata LIST_HEAD(dir_list);
struct dir_entry {
	struct list_head list;
	time64_t mtime;
	char name[];
};

static void __init dir_add(const char *name, size_t nlen, time64_t mtime)
{
	struct dir_entry *de;

	de = kmalloc(sizeof(struct dir_entry) + nlen, GFP_KERNEL);
	if (!de)
		panic_show_mem("can't allocate dir_entry buffer");
	INIT_LIST_HEAD(&de->list);
	strscpy(de->name, name, nlen);
	de->mtime = mtime;
	list_add(&</