cregit-Linux how code gets into the kernel

Release 4.10 init/do_mounts_rd.c

Directory: init
/*
 * 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/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/ext2_fs.h>
#include <linux/romfs_fs.h>
#include <uapi/linux/cramfs_fs.h>
#include <linux/initrd.h>
#include <linux/string.h>
#include <linux/slab.h>

#include "do_mounts.h"
#include "../fs/squashfs/squashfs_fs.h"

#include <linux/decompress/generic.h>



int __initdata rd_prompt = 1;
/* 1 = prompt for RAM disk, 0 = don't prompt */


static int __init prompt_ramdisk(char *str) { rd_prompt = simple_strtol(str,NULL,0) & 1; return 1; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski27100.00%1100.00%
Total27100.00%1100.00%

__setup("prompt_ramdisk=", prompt_ramdisk); int __initdata rd_image_start; /* starting block # of image */
static int __init ramdisk_start_setup(char *str) { rd_image_start = simple_strtol(str,NULL,0); return 1; }

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PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski25100.00%1100.00%
Total25100.00%1100.00%

__setup("ramdisk_start=", ramdisk_start_setup); static int __init crd_load(int in_fd, int out_fd, decompress_fn deco); /* * This routine tries to find a RAM disk image to load, and returns the * number of blocks to read for a non-compressed image, 0 if the image * is a compressed image, and -1 if an image with the right magic * numbers could not be found. * * We currently check for the following magic numbers: * minix * ext2 * romfs * cramfs * squashfs * gzip * bzip2 * lzma * xz * lzo * lz4 */
static int __init identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) { const int size = 512; struct minix_super_block *minixsb; struct romfs_super_block *romfsb; struct cramfs_super *cramfsb; struct squashfs_super_block *squashfsb; int nblocks = -1; unsigned char *buf; const char *compress_name; unsigned long n; buf = kmalloc(size, GFP_KERNEL); if (!buf) return -ENOMEM; minixsb = (struct minix_super_block *) buf; romfsb = (struct romfs_super_block *) buf; cramfsb = (struct cramfs_super *) buf; squashfsb = (struct squashfs_super_block *) buf; memset(buf, 0xe5, size); /* * Read block 0 to test for compressed kernel */ sys_lseek(fd, start_block * BLOCK_SIZE, 0); sys_read(fd, buf, size); *decompressor = decompress_method(buf, size, &compress_name); if (compress_name) { printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n", compress_name, start_block); if (!*decompressor) printk(KERN_EMERG "RAMDISK: %s decompressor not configured!\n", compress_name); nblocks = 0; goto done; } /* romfs is at block zero too */ if (romfsb->word0 == ROMSB_WORD0 && romfsb->word1 == ROMSB_WORD1) { printk(KERN_NOTICE "RAMDISK: romfs filesystem found at block %d\n", start_block); nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; goto done; } if (cramfsb->magic == CRAMFS_MAGIC) { printk(KERN_NOTICE "RAMDISK: cramfs filesystem found at block %d\n", start_block); nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; goto done; } /* squashfs is at block zero too */ if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { printk(KERN_NOTICE "RAMDISK: squashfs filesystem found at block %d\n", start_block); nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; goto done; } /* * Read 512 bytes further to check if cramfs is padded */ sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0); sys_read(fd, buf, size); if (cramfsb->magic == CRAMFS_MAGIC) { printk(KERN_NOTICE "RAMDISK: cramfs filesystem found at block %d\n", start_block); nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; goto done; } /* * Read block 1 to test for minix and ext2 superblock */ sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0); sys_read(fd, buf, size); /* Try minix */ if (minixsb->s_magic == MINIX_SUPER_MAGIC || minixsb->s_magic == MINIX_SUPER_MAGIC2) { printk(KERN_NOTICE "RAMDISK: Minix filesystem found at block %d\n", start_block); nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; goto done; } /* Try ext2 */ n = ext2_image_size(buf); if (n) { printk(KERN_NOTICE "RAMDISK: ext2 filesystem found at block %d\n", start_block); nblocks = n; goto done; } printk(KERN_NOTICE "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", start_block); done: sys_lseek(fd, start_block * BLOCK_SIZE, 0); kfree(buf); return nblocks; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski26553.21%17.69%
neil armstrongneil armstrong5811.65%17.69%
phillip lougherphillip lougher5511.04%17.69%
james bottomleyjames bottomley5010.04%17.69%
h. peter anvinh. peter anvin377.43%430.77%
al viroal viro132.61%17.69%
alain knaffalain knaff132.61%17.69%
andrew mortonandrew morton51.00%17.69%
stephen hemmingerstephen hemminger10.20%17.69%
davidlohr buesodavidlohr bueso10.20%17.69%
Total498100.00%13100.00%


int __init rd_load_image(char *from) { int res = 0; int in_fd, out_fd; unsigned long rd_blocks, devblocks; int nblocks, i, disk; char *buf = NULL; unsigned short rotate = 0; decompress_fn decompressor = NULL; #if !defined(CONFIG_S390) char rotator[4] = { '|' , '/' , '-' , '\\' }; #endif out_fd = sys_open("/dev/ram", O_RDWR, 0); if (out_fd < 0) goto out; in_fd = sys_open(from, O_RDONLY, 0); if (in_fd < 0) goto noclose_input; nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor); if (nblocks < 0) goto done; if (nblocks == 0) { if (crd_load(in_fd, out_fd, decompressor) == 0) goto successful_load; goto done; } /* * NOTE NOTE: nblocks is not actually blocks but * the number of kibibytes of data to load into a ramdisk. */ if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0) rd_blocks = 0; else rd_blocks >>= 1; if (nblocks > rd_blocks) { printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n", nblocks, rd_blocks); goto done; } /* * OK, time to copy in the data */ if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0) devblocks = 0; else devblocks >>= 1; if (strcmp(from, "/initrd.image") == 0) devblocks = nblocks; if (devblocks == 0) { printk(KERN_ERR "RAMDISK: could not determine device size\n"); goto done; } buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); if (!buf) { printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); goto done; } printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ", nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : ""); for (i = 0, disk = 1; i < nblocks; i++) { if (i && (i % devblocks == 0)) { printk("done disk #%d.\n", disk++); rotate = 0; if (sys_close(in_fd)) { printk("Error closing the disk.\n"); goto noclose_input; } change_floppy("disk #%d", disk); in_fd = sys_open(from, O_RDONLY, 0); if (in_fd < 0) { printk("Error opening disk.\n"); goto noclose_input; } printk("Loading disk #%d... ", disk); } sys_read(in_fd, buf, BLOCK_SIZE); sys_write(out_fd, buf, BLOCK_SIZE); #if !defined(CONFIG_S390) if (!(i % 16)) { pr_cont("%c\b", rotator[rotate & 0x3]); rotate++; } #endif } printk("done.\n"); successful_load: res = 1; done: sys_close(in_fd); noclose_input: sys_close(out_fd); out: kfree(buf); sys_unlink("/dev/ram"); return res; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski48793.65%110.00%
andrew mortonandrew morton152.88%220.00%
alain knaffalain knaff101.92%110.00%
martin schwidefskymartin schwidefsky20.38%110.00%
eric w. biedermaneric w. biederman20.38%110.00%
nicolas schichannicolas schichan10.19%110.00%
robert elliottrobert elliott10.19%110.00%
al viroal viro10.19%110.00%
harvey harrisonharvey harrison10.19%110.00%
Total520100.00%10100.00%


int __init rd_load_disk(int n) { if (rd_prompt) change_floppy("root floppy disk to be loaded into RAM disk"); create_dev("/dev/root", ROOT_DEV); create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n)); return rd_load_image("/dev/root"); }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski43100.00%2100.00%
Total43100.00%2100.00%

static int exit_code; static int decompress_error; static int crd_infd, crd_outfd;
static long __init compr_fill(void *buf, unsigned long len) { long r = sys_read(crd_infd, buf, len); if (r < 0) printk(KERN_ERR "RAMDISK: error while reading compressed data"); else if (r == 0) printk(KERN_ERR "RAMDISK: EOF while reading compressed data"); return r; }

Contributors

PersonTokensPropCommitsCommitProp
alain knaffalain knaff2749.09%120.00%
kai germaschewskikai germaschewski2341.82%120.00%
yinghai luyinghai lu35.45%120.00%
andries brouwerandries brouwer11.82%120.00%
andrew mortonandrew morton11.82%120.00%
Total55100.00%5100.00%


static long __init compr_flush(void *window, unsigned long outcnt) { long written = sys_write(crd_outfd, window, outcnt); if (written != outcnt) { if (decompress_error == 0) printk(KERN_ERR "RAMDISK: incomplete write (%ld != %ld)\n", written, outcnt); decompress_error = 1; return -1; } return outcnt; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski3759.68%125.00%
alain knaffalain knaff2032.26%125.00%
yinghai luyinghai lu46.45%125.00%
andrew mortonandrew morton11.61%125.00%
Total62100.00%4100.00%


static void __init error(char *x) { printk(KERN_ERR "%s\n", x); exit_code = 1; decompress_error = 1; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski2592.59%133.33%
andrew mortonandrew morton13.70%133.33%
alain knaffalain knaff13.70%133.33%
Total27100.00%3100.00%


static int __init crd_load(int in_fd, int out_fd, decompress_fn deco) { int result; crd_infd = in_fd; crd_outfd = out_fd; if (!deco) { pr_emerg("Invalid ramdisk decompression routine. " "Select appropriate config option.\n"); panic("Could not decompress initial ramdisk image."); } result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error); if (decompress_error) result = 1; return result; }

Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski4053.33%133.33%
p j pp j p1824.00%133.33%
alain knaffalain knaff1722.67%133.33%
Total75100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
kai germaschewskikai germaschewski104172.49%26.25%
alain knaffalain knaff956.62%13.12%
neil armstrongneil armstrong584.04%13.12%
phillip lougherphillip lougher563.90%13.12%
james bottomleyjames bottomley523.62%13.12%
h. peter anvinh. peter anvin372.58%412.50%
andrew mortonandrew morton231.60%39.38%
p j pp j p191.32%26.25%
al viroal viro151.04%39.38%
h hartley sweetenh hartley sweeten120.84%13.12%
yinghai luyinghai lu70.49%13.12%
adrian bunkadrian bunk30.21%13.12%
christoph hellwigchristoph hellwig30.21%13.12%
tejun heotejun heo30.21%13.12%
eric w. biedermaneric w. biederman20.14%13.12%
ingo molnaringo molnar20.14%13.12%
martin schwidefskymartin schwidefsky20.14%13.12%
stephen hemmingerstephen hemminger10.07%13.12%
davidlohr buesodavidlohr bueso10.07%13.12%
robert elliottrobert elliott10.07%13.12%
nicolas schichannicolas schichan10.07%13.12%
andries brouwerandries brouwer10.07%13.12%
harvey harrisonharvey harrison10.07%13.12%
Total1436100.00%32100.00%
Directory: init
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