Fixed MTP to work with TWRP

init/initramfs.c

@@ -0,0 +1,675 @@
+/*
+ * Many of the syscalls used in this file expect some of the arguments
+ * to be __user pointers not __kernel pointers.  To limit the sparse
+ * noise, turn off sparse checking for this file.
+ */
+#ifdef __CHECKER__
+#undef __CHECKER__
+#warning "Sparse checking disabled for this file"
+#endif
+
+#include <linux/init.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/initramfs.h>
+
+static ssize_t __init xwrite(int fd, const char *p, size_t count)
+{
+	ssize_t out = 0;
+
+	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
+	while (count) {
+		ssize_t rv = sys_write(fd, p, count);
+
+		if (rv < 0) {
+			if (rv == -EINTR || rv == -EAGAIN)
+				continue;
+			return out ? out : rv;
+		} else if (rv == 0)
+			break;
+
+		p += rv;
+		out += rv;
+		count -= rv;
+	}
+
+	return out;
+}
+
+static __initdata char *message;
+static void __init error(char *x)
+{
+	if (!message)
+		message = x;
+}
+
+/* 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 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("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;
+	return NULL;
+}
+
+static void __init free_hash(void)
+{
+	struct hash **p, *q;
+	for (p = head; p < head + 32; p++) {
+		while (*p) {
+			q = *p;
+			*p = q->next;
+			kfree(q);
+		}
+	}
+}
+
+static long __init do_utime(char *filename, time_t mtime)
+{
+	struct timespec t[2];
+
+	t[0].tv_sec = mtime;
+	t[0].tv_nsec = 0;
+	t[1].tv_sec = mtime;
+	t[1].tv_nsec = 0;
+
+	return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
+}
+
+static __initdata LIST_HEAD(dir_list);
+struct dir_entry {
+	struct list_head list;
+	char *name;
+	time_t mtime;
+};
+
+static void __init dir_add(const char *name, time_t mtime)
+{
+	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
+	if (!de)
+		panic("can't allocate dir_entry buffer");
+	INIT_LIST_HEAD(&de->list);
+	de->name = kstrdup(name, GFP_KERNEL);
+	de->mtime = mtime;
+	list_add(&de->list, &dir_list);
+}
+
+static void __init dir_utime(void)
+{
+	struct dir_entry *de, *tmp;
+	list_for_each_entry_safe(de, tmp, &dir_list, list) {
+		list_del(&de->list);
+		do_utime(de->name, de->mtime);
+		kfree(de->name);
+		kfree(de);
+	}
+}
+
+static __initdata time_t mtime;
+
+/* cpio header parsing */
+
+static __initdata unsigned long ino, major, minor, nlink;
+static __initdata umode_t mode;
+static __initdata unsigned long body_len, name_len;
+static __initdata uid_t uid;
+static __initdata gid_t gid;
+static __initdata unsigned rdev;
+
+static void __init parse_header(char *s)
+{
+	unsigned long parsed[12];
+	char buf[9];
+	int i;
+
+	buf[8] = '\0';
+	for (i = 0, s += 6; i < 12; i++, s += 8) {
+		memcpy(buf, s, 8);
+		parsed[i] = simple_strtoul(buf, NULL, 16);
+	}
+	ino = parsed[0];
+	mode = parsed[1];
+	uid = parsed[2];
+	gid = parsed[3];
+	nlink = parsed[4];
+	mtime = parsed[5];
+	body_len = parsed[6];
+	major = parsed[7];
+	minor = parsed[8];
+	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
+	name_len = parsed[11];
+}
+
+/* FSM */
+
+static __initdata enum state {
+	Start,
+	Collect,
+	GotHeader,
+	SkipIt,
+	GotName,
+	CopyFile,
+	GotSymlink,
+	Reset
+} state, next_state;
+
+static __initdata char *victim;
+static unsigned long byte_count __initdata;
+static __initdata loff_t this_header, next_header;
+
+static inline void __init eat(unsigned n)
+{
+	victim += n;
+	this_header += n;
+	byte_count -= n;
+}
+
+static __initdata char *vcollected;
+static __initdata char *collected;
+static long remains __initdata;
+static __initdata char *collect;
+
+static void __init read_into(char *buf, unsigned size, enum state next)
+{
+	if (byte_count >= size) {
+		collected = victim;
+		eat(size);
+		state = next;
+	} else {
+		collect = collected = buf;
+		remains = size;
+		next_state = next;
+		state = Collect;
+	}
+}
+
+static __initdata char *header_buf, *symlink_buf, *name_buf;
+
+static int __init do_start(void)
+{
+	read_into(header_buf, 110, GotHeader);
+	return 0;
+}
+
+static int __init do_collect(void)
+{
+	unsigned long n = remains;
+	if (byte_count < n)
+		n = byte_count;
+	memcpy(collect, victim, n);
+	eat(n);
+	collect += n;
+	if ((remains -= n) != 0)
+		return 1;
+	state = next_state;
+	return 0;
+}
+
+static int __init do_header(void)
+{
+	if (memcmp(collected, "070707", 6)==0) {
+		error("incorrect cpio method used: use -H newc option");
+		return 1;
+	}
+	if (memcmp(collected, "070701", 6)) {
+		error("no cpio magic");
+		return 1;
+	}
+	parse_header(collected);
+	next_header = this_header + N_ALIGN(name_len) + body_len;
+	next_header = (next_header + 3) & ~3;
+	state = SkipIt;
+	if (name_len <= 0 || name_len > PATH_MAX)
+		return 0;
+	if (S_ISLNK(mode)) {
+		if (body_len > PATH_MAX)
+			return 0;
+		collect = collected = symlink_buf;
+		remains = N_ALIGN(name_len) + body_len;
+		next_state = GotSymlink;
+		state = Collect;
+		return 0;
+	}
+	if (S_ISREG(mode) || !body_len)
+		read_into(name_buf, N_ALIGN(name_len), GotName);
+	return 0;
+}
+
+static int __init do_skip(void)
+{
+	if (this_header + byte_count < next_header) {
+		eat(byte_count);
+		return 1;
+	} else {
+		eat(next_header - this_header);
+		state = next_state;
+		return 0;
+	}
+}
+
+static int __init do_reset(void)
+{
+	while (byte_count && *victim == '\0')
+		eat(1);
+	if (byte_count && (this_header & 3))
+		error("broken padding");
+	return 1;
+}
+
+static int __init maybe_link(void)
+{
+	if (nlink >= 2) {
+		char *old = find_link(major, minor, ino, mode, collected);
+		if (old)
+			return (sys_link(old, collected) < 0) ? -1 : 1;
+	}
+	return 0;
+}
+
+static void __init clean_path(char *path, umode_t fmode)
+{
+	struct stat st;
+
+	if (!sys_newlstat(path, &st) && (st.st_mode ^ fmode) & S_IFMT) {
+		if (S_ISDIR(st.st_mode))
+			sys_rmdir(path);
+		else
+			sys_unlink(path);
+	}
+}
+
+static __initdata int wfd;
+
+static int __init do_name(void)
+{
+	state = SkipIt;
+	next_state = Reset;
+	if (strcmp(collected, "TRAILER!!!") == 0) {
+		free_hash();
+		return 0;
+	}
+	clean_path(collected, mode);
+	if (S_ISREG(mode)) {
+		int ml = maybe_link();
+		if (ml >= 0) {
+			int openflags = O_WRONLY|O_CREAT;
+			if (ml != 1)
+				openflags |= O_TRUNC;
+			wfd = sys_open(collected, openflags, mode);
+
+			if (wfd >= 0) {
+				sys_fchown(wfd, uid, gid);
+				sys_fchmod(wfd, mode);
+				if (body_len)
+					sys_ftruncate(wfd, body_len);
+				vcollected = kstrdup(collected, GFP_KERNEL);
+				state = CopyFile;
+			}
+		}
+	} else if (S_ISDIR(mode)) {
+		sys_mkdir(collected, mode);
+		sys_chown(collected, uid, gid);
+		sys_chmod(collected, mode);
+		dir_add(collected, mtime);
+	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
+		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
+		if (maybe_link() == 0) {
+			sys_mknod(collected, mode, rdev);
+			sys_chown(collected, uid, gid);
+			sys_chmod(collected, mode);
+			do_utime(collected, mtime);
+		}
+	}
+	return 0;
+}
+
+static int __init do_copy(void)
+{
+	if (byte_count >= body_len) {
+		if (xwrite(wfd, victim, body_len) != body_len)
+			error("write error");
+		sys_close(wfd);
+		do_utime(vcollected, mtime);
+		kfree(vcollected);
+		eat(body_len);
+		state = SkipIt;
+		return 0;
+	} else {
+		if (xwrite(wfd, victim, byte_count) != byte_count)
+			error("write error");
+		body_len -= byte_count;
+		eat(byte_count);
+		return 1;
+	}
+}
+
+static int __init do_symlink(void)
+{
+	collected[N_ALIGN(name_len) + body_len] = '\0';
+	clean_path(collected, 0);
+	sys_symlink(collected + N_ALIGN(name_len), collected);
+	sys_lchown(collected, uid, gid);
+	do_utime(collected, mtime);
+	state = SkipIt;
+	next_state = Reset;
+	return 0;
+}
+
+static __initdata int (*actions[])(void) = {
+	[Start]		= do_start,
+	[Collect]	= do_collect,
+	[GotHeader]	= do_header,
+	[SkipIt]	= do_skip,
+	[GotName]	= do_name,
+	[CopyFile]	= do_copy,
+	[GotSymlink]	= do_symlink,
+	[Reset]		= do_reset,
+};
+
+static long __init write_buffer(char *buf, unsigned long len)
+{
+	byte_count = len;
+	victim = buf;
+
+	while (!actions[state]())
+		;
+	return len - byte_count;
+}
+
+static long __init flush_buffer(void *bufv, unsigned long len)
+{
+	char *buf = (char *) bufv;
+	long written;
+	long origLen = len;
+	if (message)
+		return -1;
+	while ((written = write_buffer(buf, len)) < len && !message) {
+		char c = buf[written];
+		if (c == '0') {
+			buf += written;
+			len -= written;
+			state = Start;
+		} else if (c == 0) {
+			buf += written;
+			len -= written;
+			state = Reset;
+		} else
+			error("junk in compressed archive");
+	}
+	return origLen;
+}
+
+static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
+
+#include <linux/decompress/generic.h>
+
+static char * __init unpack_to_rootfs(char *buf, unsigned long len)
+{
+	long written;
+	decompress_fn decompress;
+	const char *compress_name;
+	static __initdata char msg_buf[64];
+
+	header_buf = kmalloc(110, GFP_KERNEL);
+	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
+	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
+
+	if (!header_buf || !symlink_buf || !name_buf)
+		panic("can't allocate buffers");
+
+	state = Start;
+	this_header = 0;
+	message = NULL;
+	while (!message && len) {
+		loff_t saved_offset = this_header;
+		if (*buf == '0' && !(this_header & 3)) {
+			state = Start;
+			written = write_buffer(buf, len);
+			buf += written;
+			len -= written;
+			continue;
+		}
+		if (!*buf) {
+			buf++;
+			len--;
+			this_header++;
+			continue;
+		}
+		this_header = 0;
+		decompress = decompress_method(buf, len, &compress_name);
+		pr_debug("Detected %s compressed data\n", compress_name);
+		if (decompress) {
+			int res = decompress(buf, len, NULL, flush_buffer, NULL,
+				   &my_inptr, error);
+			if (res)
+				error("decompressor failed");
+		} else if (compress_name) {
+			if (!message) {
+				snprintf(msg_buf, sizeof msg_buf,
+					 "compression method %s not configured",
+					 compress_name);
+				message = msg_buf;
+			}
+		} else
+			error("junk in compressed archive");
+		if (state != Reset)
+			error("junk in compressed archive");
+		this_header = saved_offset + my_inptr;
+		buf += my_inptr;
+		len -= my_inptr;
+	}
+	dir_utime();
+	kfree(name_buf);
+	kfree(symlink_buf);
+	kfree(header_buf);
+	return message;
+}
+
+static int __initdata do_retain_initrd;
+
+static int __init retain_initrd_param(char *str)
+{
+	if (*str)
+		return 0;
+	do_retain_initrd = 1;
+	return 1;
+}
+__setup("retain_initrd", retain_initrd_param);
+
+extern char __initramfs_start[];
+extern unsigned long __initramfs_size;
+#include <linux/initrd.h>
+#include <linux/kexec.h>
+
+static void __init free_initrd(void)
+{
+#ifdef CONFIG_KEXEC
+	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
+	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
+#endif
+	if (do_retain_initrd)
+		goto skip;
+
+#ifdef CONFIG_KEXEC
+	/*
+	 * If the initrd region is overlapped with crashkernel reserved region,
+	 * free only memory that is not part of crashkernel region.
+	 */
+	if (initrd_start < crashk_end && initrd_end > crashk_start) {
+		/*
+		 * Initialize initrd memory region since the kexec boot does
+		 * not do.
+		 */
+		memset((void *)initrd_start, 0, initrd_end - initrd_start);
+		if (initrd_start < crashk_start)
+			free_initrd_mem(initrd_start, crashk_start);
+		if (initrd_end > crashk_end)
+			free_initrd_mem(crashk_end, initrd_end);
+	} else
+#endif
+		free_initrd_mem(initrd_start, initrd_end);
+skip:
+	initrd_start = 0;
+	initrd_end = 0;
+}
+
+#ifdef CONFIG_BLK_DEV_RAM
+#define BUF_SIZE 1024
+static void __init clean_rootfs(void)
+{
+	int fd;
+	void *buf;
+	struct linux_dirent64 *dirp;
+	int num;
+
+	fd = sys_open("/", O_RDONLY, 0);
+	WARN_ON(fd < 0);
+	if (fd < 0)
+		return;
+	buf = kzalloc(BUF_SIZE, GFP_KERNEL);
+	WARN_ON(!buf);
+	if (!buf) {
+		sys_close(fd);
+		return;
+	}
+
+	dirp = buf;
+	num = sys_getdents64(fd, dirp, BUF_SIZE);
+	while (num > 0) {
+		while (num > 0) {
+			struct stat st;
+			int ret;
+
+			ret = sys_newlstat(dirp->d_name, &st);
+			WARN_ON_ONCE(ret);
+			if (!ret) {
+				if (S_ISDIR(st.st_mode))
+					sys_rmdir(dirp->d_name);
+				else
+					sys_unlink(dirp->d_name);
+			}
+
+			num -= dirp->d_reclen;
+			dirp = (void *)dirp + dirp->d_reclen;
+		}
+		dirp = buf;
+		memset(buf, 0, BUF_SIZE);
+		num = sys_getdents64(fd, dirp, BUF_SIZE);
+	}
+
+	sys_close(fd);
+	kfree(buf);
+}
+#endif
+
+static int __initdata do_skip_initramfs;
+
+static int __init skip_initramfs_param(char *str)
+{
+	if (*str)
+		return 0;
+	do_skip_initramfs = 1;
+	return 1;
+}
+__setup("skip_initramfs", skip_initramfs_param);
+
+static int __init populate_rootfs(void)
+{
+	char *err;
+
+	if (do_skip_initramfs)
+		return default_rootfs();
+
+	err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
+	if (err)
+		panic("%s", err); /* Failed to decompress INTERNAL initramfs */
+	if (initrd_start) {
+#ifdef CONFIG_BLK_DEV_RAM
+		int fd;
+		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
+		err = unpack_to_rootfs((char *)initrd_start,
+			initrd_end - initrd_start);
+		if (!err) {
+			free_initrd();
+			goto done;
+		} else {
+			clean_rootfs();
+			unpack_to_rootfs(__initramfs_start, __initramfs_size);
+		}
+		printk(KERN_INFO "rootfs image is not initramfs (%s)"
+				"; looks like an initrd\n", err);
+		fd = sys_open("/initrd.image",
+			      O_WRONLY|O_CREAT, 0700);
+		if (fd >= 0) {
+			ssize_t written = xwrite(fd, (char *)initrd_start,
+						initrd_end - initrd_start);
+
+			if (written != initrd_end - initrd_start)
+				pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
+				       written, initrd_end - initrd_start);
+
+			sys_close(fd);
+			free_initrd();
+		}
+	done:
+#else
+		printk(KERN_INFO "Unpacking initramfs...\n");
+		err = unpack_to_rootfs((char *)initrd_start,
+			initrd_end - initrd_start);
+		if (err)
+			printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
+		free_initrd();
+#endif
+		/*
+		 * Try loading default modules from initramfs.  This gives
+		 * us a chance to load before device_initcalls.
+		 */
+		load_default_modules();
+	}
+	return 0;
+}
+rootfs_initcall(populate_rootfs);