6e1819d615
This patch introduces a user space interface for swsusp. The interface is based on a special character device, called the snapshot device, that allows user space processes to perform suspend and resume-related operations with the help of some ioctls and the read()/write() functions. Additionally it allows these processes to allocate free swap pages from a selected swap partition, called the resume partition, so that they know which sectors of the resume partition are available to them. The interface uses the same low-level system memory snapshot-handling functions that are used by the built-it swap-writing/reading code of swsusp. The interface documentation is included in the patch. The patch assumes that the major and minor numbers of the snapshot device will be 10 (ie. misc device) and 231, the registration of which has already been requested. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
125 lines
3.1 KiB
C
125 lines
3.1 KiB
C
#define __KERNEL_SYSCALLS__
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#include <linux/unistd.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/minix_fs.h>
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#include <linux/ext2_fs.h>
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#include <linux/romfs_fs.h>
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#include <linux/initrd.h>
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#include <linux/sched.h>
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#include "do_mounts.h"
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unsigned long initrd_start, initrd_end;
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int initrd_below_start_ok;
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unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
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static int __initdata old_fd, root_fd;
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static int __initdata mount_initrd = 1;
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static int __init no_initrd(char *str)
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{
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mount_initrd = 0;
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return 1;
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}
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__setup("noinitrd", no_initrd);
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static int __init do_linuxrc(void * shell)
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{
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static char *argv[] = { "linuxrc", NULL, };
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extern char * envp_init[];
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sys_close(old_fd);sys_close(root_fd);
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sys_close(0);sys_close(1);sys_close(2);
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sys_setsid();
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(void) sys_open("/dev/console",O_RDWR,0);
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(void) sys_dup(0);
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(void) sys_dup(0);
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return execve(shell, argv, envp_init);
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}
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static void __init handle_initrd(void)
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{
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int error;
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int pid;
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real_root_dev = new_encode_dev(ROOT_DEV);
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create_dev("/dev/root.old", Root_RAM0, NULL);
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/* mount initrd on rootfs' /root */
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mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
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sys_mkdir("/old", 0700);
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root_fd = sys_open("/", 0, 0);
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old_fd = sys_open("/old", 0, 0);
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/* move initrd over / and chdir/chroot in initrd root */
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sys_chdir("/root");
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sys_mount(".", "/", NULL, MS_MOVE, NULL);
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sys_chroot(".");
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mount_devfs_fs ();
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current->flags |= PF_NOFREEZE;
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pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
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if (pid > 0) {
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while (pid != sys_wait4(-1, NULL, 0, NULL))
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yield();
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}
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/* move initrd to rootfs' /old */
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sys_fchdir(old_fd);
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sys_mount("/", ".", NULL, MS_MOVE, NULL);
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/* switch root and cwd back to / of rootfs */
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sys_fchdir(root_fd);
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sys_chroot(".");
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sys_close(old_fd);
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sys_close(root_fd);
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umount_devfs("/old/dev");
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if (new_decode_dev(real_root_dev) == Root_RAM0) {
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sys_chdir("/old");
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return;
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}
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ROOT_DEV = new_decode_dev(real_root_dev);
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mount_root();
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printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
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error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
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if (!error)
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printk("okay\n");
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else {
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int fd = sys_open("/dev/root.old", O_RDWR, 0);
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if (error == -ENOENT)
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printk("/initrd does not exist. Ignored.\n");
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else
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printk("failed\n");
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printk(KERN_NOTICE "Unmounting old root\n");
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sys_umount("/old", MNT_DETACH);
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printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
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if (fd < 0) {
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error = fd;
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} else {
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error = sys_ioctl(fd, BLKFLSBUF, 0);
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sys_close(fd);
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}
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printk(!error ? "okay\n" : "failed\n");
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}
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}
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int __init initrd_load(void)
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{
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if (mount_initrd) {
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create_dev("/dev/ram", Root_RAM0, NULL);
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/*
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* Load the initrd data into /dev/ram0. Execute it as initrd
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* unless /dev/ram0 is supposed to be our actual root device,
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* in that case the ram disk is just set up here, and gets
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* mounted in the normal path.
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*/
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if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
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sys_unlink("/initrd.image");
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handle_initrd();
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return 1;
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}
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}
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sys_unlink("/initrd.image");
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return 0;
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}
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