cregit-Linux how code gets into the kernel

Release 4.17 init/do_mounts_initrd.c

Directory: init
// SPDX-License-Identifier: GPL-2.0
 * 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"

#include <linux/unistd.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/romfs_fs.h>
#include <linux/initrd.h>
#include <linux/sched.h>
#include <linux/freezer.h>
#include <linux/kmod.h>

#include "do_mounts.h"

unsigned long initrd_start, initrd_end;

int initrd_below_start_ok;

unsigned int real_root_dev;	
/* do_proc_dointvec cannot handle kdev_t */

static int __initdata mount_initrd = 1;

static int __init no_initrd(char *str) { mount_initrd = 0; return 1; }


Linus Torvalds18100.00%1100.00%

__setup("noinitrd", no_initrd);
static int init_linuxrc(struct subprocess_info *info, struct cred *new) { ksys_unshare(CLONE_FS | CLONE_FILES); /* stdin/stdout/stderr for /linuxrc */ ksys_open("/dev/console", O_RDWR, 0); ksys_dup(0); ksys_dup(0); /* move initrd over / and chdir/chroot in initrd root */ ksys_chdir("/root"); ksys_mount(".", "/", NULL, MS_MOVE, NULL); ksys_chroot("."); ksys_setsid(); return 0; }


Al Viro4764.38%220.00%
Linus Torvalds1824.66%110.00%
Dominik Brodowski810.96%770.00%

static void __init handle_initrd(void) { struct subprocess_info *info; static char *argv[] = { "linuxrc", NULL, }; extern char *envp_init[]; int error; real_root_dev = new_encode_dev(ROOT_DEV); create_dev("/dev/root.old", Root_RAM0); /* mount initrd on rootfs' /root */ mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); ksys_mkdir("/old", 0700); ksys_chdir("/old"); /* try loading default modules from initrd */ load_default_modules(); /* * In case that a resume from disk is carried out by linuxrc or one of * its children, we need to tell the freezer not to wait for us. */ current->flags |= PF_FREEZER_SKIP; info = call_usermodehelper_setup("/linuxrc", argv, envp_init, GFP_KERNEL, init_linuxrc, NULL, NULL); if (!info) return; call_usermodehelper_exec(info, UMH_WAIT_PROC); current->flags &= ~PF_FREEZER_SKIP; /* move initrd to rootfs' /old */ ksys_mount("..", ".", NULL, MS_MOVE, NULL); /* switch root and cwd back to / of rootfs */ ksys_chroot(".."); if (new_decode_dev(real_root_dev) == Root_RAM0) { ksys_chdir("/old"); return; } ksys_chdir("/"); ROOT_DEV = new_decode_dev(real_root_dev); mount_root(); printk(KERN_NOTICE "Trying to move old root to /initrd ... "); error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL); if (!error) printk("okay\n"); else { int fd = ksys_open("/dev/root.old", O_RDWR, 0); if (error == -ENOENT) printk("/initrd does not exist. Ignored.\n"); else printk("failed\n"); printk(KERN_NOTICE "Unmounting old root\n"); ksys_umount("/old", MNT_DETACH); printk(KERN_NOTICE "Trying to free ramdisk memory ... "); if (fd < 0) { error = fd; } else { error = ksys_ioctl(fd, BLKFLSBUF, 0); ksys_close(fd); } printk(!error ? "okay\n" : "failed\n"); } }


Linus Torvalds19364.77%211.11%
Al Viro4013.42%316.67%
Lucas De Marchi227.38%15.56%
Rafael J. Wysocki144.70%15.56%
Jay Lan134.36%15.56%
Dominik Brodowski113.69%844.44%
Tejun Heo41.34%15.56%
Andrew Morton10.34%15.56%

bool __init initrd_load(void) { if (mount_initrd) { create_dev("/dev/ram", Root_RAM0); /* * Load the initrd data into /dev/ram0. Execute it as initrd * unless /dev/ram0 is supposed to be our actual root device, * in that case the ram disk is just set up here, and gets * mounted in the normal path. */ if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) { ksys_unlink("/initrd.image"); handle_initrd(); return true; } } ksys_unlink("/initrd.image"); return false; }


Linus Torvalds3666.67%120.00%
Andrew Morton1018.52%120.00%
Yaowei Bai35.56%120.00%
Al Viro35.56%120.00%
Dominik Brodowski23.70%120.00%

Overall Contributors

Linus Torvalds30258.75%26.67%
Al Viro9318.09%516.67%
Andrew Morton234.47%26.67%
Lucas De Marchi224.28%13.33%
Dominik Brodowski214.09%1240.00%
Rafael J. Wysocki142.72%13.33%
Jay Lan132.53%13.33%
H Hartley Sweeten122.33%13.33%
Tejun Heo40.78%13.33%
Adrian Bunk30.58%13.33%
Yaowei Bai30.58%13.33%
Nigel Cunningham30.58%13.33%
Greg Kroah-Hartman10.19%13.33%
Directory: init
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