diff options
Diffstat (limited to 'init/initramfs.c')
| -rw-r--r-- | init/initramfs.c | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/init/initramfs.c b/init/initramfs.c new file mode 100644 index 000000000..55b74d7e5 --- /dev/null +++ b/init/initramfs.c @@ -0,0 +1,642 @@ +// SPDX-License-Identifier: GPL-2.0 +#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/file.h> +#include <linux/memblock.h> +#include <linux/namei.h> +#include <linux/init_syscalls.h> + +static ssize_t __init xwrite(struct file *file, const 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; + + 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, time64_t mtime) +{ + struct timespec64 t[2]; + + t[0].tv_sec = mtime; + t[0].tv_nsec = 0; + t[1].tv_sec = mtime; + t[1].tv_nsec = 0; + return init_utimes(filename, t); +} + +static __initdata LIST_HEAD(dir_list); +struct dir_entry { + struct list_head list; + char *name; + time64_t mtime; +}; + +static void __init dir_add(const char *name, time64_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 time64_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]; /* breaks in y2106 */ + 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 *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 void __init clean_path(char *path, umode_t fmode) +{ + struct kstat st; + + if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) && + (st.mode ^ fmode) & S_IFMT) { + if (S_ISDIR(st.mode)) + init_rmdir(path); + else + init_unlink(path); + } +} + +static int __init maybe_link(void) +{ + if (nlink >= 2) { + char *old = find_link(major, minor, ino, mode, collected); + if (old) { + clean_path(collected, 0); + return (init_link(old, collected) < 0) ? -1 : 1; + } + } + return 0; +} + +static __initdata struct file *wfile; +static __initdata loff_t wfile_pos; + +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; + wfile = filp_open(collected, openflags, mode); + if (IS_ERR(wfile)) + return 0; + wfile_pos = 0; + + vfs_fchown(wfile, uid, gid); + vfs_fchmod(wfile, mode); + if (body_len) + vfs_truncate(&wfile->f_path, body_len); + state = CopyFile; + } + } else if (S_ISDIR(mode)) { + init_mkdir(collected, mode); + init_chown(collected, uid, gid, 0); + init_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) { + init_mknod(collected, mode, rdev); + init_chown(collected, uid, gid, 0); + init_chmod(collected, mode); + do_utime(collected, mtime); + } + } + return 0; +} + +static int __init do_copy(void) +{ + if (byte_count >= body_len) { + struct timespec64 t[2] = { }; + if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len) + error("write error"); + + t[0].tv_sec = mtime; + t[1].tv_sec = mtime; + vfs_utimes(&wfile->f_path, t); + + fput(wfile); + eat(body_len); + state = SkipIt; + return 0; + } else { + if (xwrite(wfile, victim, byte_count, &wfile_pos) != 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); + init_symlink(collected + N_ALIGN(name_len), collected); + init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW); + 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 within 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("invalid magic at start of compressed archive"); + if (state != Reset) + error("junk at the end of 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); + +#ifdef CONFIG_ARCH_HAS_KEEPINITRD +static int __init keepinitrd_setup(char *__unused) +{ + do_retain_initrd = 1; + return 1; +} +__setup("keepinitrd", keepinitrd_setup); +#endif + +extern char __initramfs_start[]; +extern unsigned long __initramfs_size; +#include <linux/initrd.h> +#include <linux/kexec.h> + +void __weak __init free_initrd_mem(unsigned long start, unsigned long end) +{ +#ifdef CONFIG_ARCH_KEEP_MEMBLOCK + unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE); + unsigned long aligned_end = ALIGN(end, PAGE_SIZE); + + memblock_free(__pa(aligned_start), aligned_end - aligned_start); +#endif + + free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM, + "initrd"); +} + +#ifdef CONFIG_KEXEC_CORE +static bool __init kexec_free_initrd(void) +{ + unsigned long crashk_start = (unsigned long)__va(crashk_res.start); + unsigned long crashk_end = (unsigned long)__va(crashk_res.end); + + /* + * 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) + return false; + + /* + * 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); + return true; +} +#else +static inline bool kexec_free_initrd(void) +{ + return false; +} +#endif /* CONFIG_KEXEC_CORE */ + +#ifdef CONFIG_BLK_DEV_RAM +static void __init populate_initrd_image(char *err) +{ + ssize_t written; + struct file *file; + loff_t pos = 0; + + unpack_to_rootfs(__initramfs_start, __initramfs_size); + + printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n", + err); + file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700); + if (IS_ERR(file)) + return; + + written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start, + &pos); + if (written != initrd_end - initrd_start) + pr_err("/initrd.image: incomplete write (%zd != %ld)\n", + written, initrd_end - initrd_start); + fput(file); +} +#endif /* CONFIG_BLK_DEV_RAM */ + +static int __init populate_rootfs(void) +{ + /* Load the built in initramfs */ + char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size); + if (err) + panic("%s", err); /* Failed to decompress INTERNAL initramfs */ + + if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE)) + goto done; + + if (IS_ENABLED(CONFIG_BLK_DEV_RAM)) + printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n"); + else + printk(KERN_INFO "Unpacking initramfs...\n"); + + err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start); + if (err) { +#ifdef CONFIG_BLK_DEV_RAM + populate_initrd_image(err); +#else + printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err); +#endif + } + +done: + /* + * If the initrd region is overlapped with crashkernel reserved region, + * free only memory that is not part of crashkernel region. + */ + if (!do_retain_initrd && initrd_start && !kexec_free_initrd()) + free_initrd_mem(initrd_start, initrd_end); + initrd_start = 0; + initrd_end = 0; + + flush_delayed_fput(); + return 0; +} +rootfs_initcall(populate_rootfs); |