linux - linux

diff options

Diffstat (limited to 'fs/read_write.c')

-rw-r--r--

1 files changed, 11 insertions, 27 deletions

#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/syscalls.h> static __initdata char *message; static void __init error(char *x) { if (!message) message = x; } static void __init *malloc(size_t size) { return kmalloc(size, GFP_KERNEL); } static void __init free(void *where) { kfree(where); } /* link hash */ #define N_ALIGN(len) ((((len) + 1) & ~3) + 2) static __initdata struct hash { int ino, minor, major; mode_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, mode_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 = (struct hash *)malloc(sizeof(struct hash)); 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; free(q); } } } /* cpio header parsing */ static __initdata unsigned long ino, major, minor, nlink; static __initdata mode_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]; 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 __initdata unsigned count; static __initdata loff_t this_header, next_header; static __initdata int dry_run; static inline void __init eat(unsigned n) { victim += n; this_header += n; count -= n; } static __initdata char *collected; static __initdata int remains; static __initdata char *collect; static void __init read_into(char *buf, unsigned size, enum state next) { if (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 n = remains; if (count < n) n = 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; if (dry_run) { read_into(name_buf, N_ALIGN(name_len), GotName); return 0; } 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 + count < next_header) { eat(count); return 1; } else { eat(next_header - this_header); state = next_state; return 0; } } static int __init do_reset(void) { while(count && *victim == '\0') eat(1); if (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, mode_t mode) { struct stat st; if (!sys_newlstat(path, &st) && (st.st_mode^mode) & 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; } if (dry_run) 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); state = CopyFile; } } } else if (S_ISDIR(mode)) { sys_mkdir(collected, mode); sys_chown(collected, uid, gid); sys_chmod(collected, mode); } 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); } } return 0; } static int __init do_copy(void) { if (count >= body_len) { sys_write(wfd, victim, body_len); sys_close(wfd); eat(body_len); state = SkipIt; return 0; } else { sys_write(wfd, victim, count); body_len -= count; eat(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); 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 int __init write_buffer(char *buf, unsigned len) { count = len; victim = buf; while (!actions[state]()) ; return len - count; } static void __init flush_buffer(char *buf, unsigned len) { int written; if (message) return; 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"); } } /* * gzip declarations */ #define OF(args) args #ifndef memzero #define memzero(s, n) memset ((s), 0, (n)) #endif typedef unsigned char uch; typedef unsigned short ush; typedef unsigned long ulg; #define WSIZE 0x8000 /* window size--must be a power of two, and */ /* at least 32K for zip's deflate method */ static uch *inbuf; static uch *window; static unsigned insize; /* valid bytes in inbuf */ static unsigned inptr; /* index of next byte to be processed in inbuf */ static unsigned outcnt; /* bytes in output buffer */ static long bytes_out; #define get_byte() (inptr < insize ? inbuf[inptr++] : -1) /* Diagnostic functions (stubbed out) */ #define Assert(cond,msg) #define Trace(x) #define Tracev(x) #define Tracevv(x) #define Tracec(c,x) #define Tracecv(c,x) #define STATIC static #define INIT __init static void __init flush_window(void); static void __init error(char *m); static void __init gzip_mark(void **); static void __init gzip_release(void **); #include "../lib/inflate.c" static void __init gzip_mark(void **ptr) { } static void __init gzip_release(void **ptr) { } /* =========================================================================== * Write the output window window[0..outcnt-1] and update crc and bytes_out. * (Used for the decompressed data only.) */ static void __init flush_window(void) { ulg c = crc; /* temporary variable */ unsigned n; uch *in, ch; flush_buffer(window, outcnt); in = window; for (n = 0; n < outcnt; n++) { ch = *in++; c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8); } crc = c; bytes_out += (ulg)outcnt; outcnt = 0; } static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only) { int written; dry_run = check_only; header_buf = malloc(110); symlink_buf = malloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1); name_buf = malloc(N_ALIGN(PATH_MAX)); window = malloc(WSIZE); if (!window || !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; insize = len; inbuf = buf; inptr = 0; outcnt = 0; /* bytes in output buffer */ bytes_out = 0; crc = (ulg)0xffffffffL; /* shift register contents */ makecrc(); gunzip(); if (state != Reset) error("junk in gzipped archive"); this_header = saved_offset + inptr; buf += inptr; len -= inptr; } free(window); free(name_buf); free(symlink_buf); free(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[], __initramfs_end[]; #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; } static int __init populate_rootfs(void) { char *err = unpack_to_rootfs(__initramfs_start, __initramfs_end - __initramfs_start, 0); if (err) panic(err); if (initrd_start) { #ifdef CONFIG_BLK_DEV_RAM int fd; printk(KERN_INFO "checking if image is initramfs..."); err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start, 1); if (!err) { printk(" it is\n"); unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start, 0); free_initrd(); return 0; } printk("it isn't (%s); looks like an initrd\n", err); fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 0700); if (fd >= 0) { sys_write(fd, (char *)initrd_start, initrd_end - initrd_start); sys_close(fd); free_initrd(); } #else printk(KERN_INFO "Unpacking initramfs..."); err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start, 0); if (err) panic(err); printk(" done\n"); free_initrd(); #endif } return 0; } rootfs_initcall(populate_rootfs);


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