| 1 | |
| 2 |
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| 3 | #include <stdio.h>
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| 4 | #include <unistd.h>
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| 5 | #include <fcntl.h>
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| 6 | #include <sys/syscall.h>
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| 7 | #include <sys/mount.h>
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| 8 | #include <sys/reboot.h>
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| 9 | #include <linux/kexec.h>
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| 10 |
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| 11 |
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| 12 | #define COMMAND_LINE_SIZE 2048
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| 13 |
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| 14 | #define KERNEL_IMAGE "/kernel"
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| 15 |
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| 16 | static int mount_filesystems(void)
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| 17 | {
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| 18 | if (mount("debugfs", "/debugfs", "debugfs", 0, NULL) < 0)
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| 19 | return -1;
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| 20 |
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| 21 | return mount("proc", "/proc", "proc", 0, NULL);
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| 22 | }
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| 23 |
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| 24 | static long kexec_file_load(int kernel_fd, int initrd_fd,
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| 25 | unsigned long cmdline_len, const char *cmdline,
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| 26 | unsigned long flags)
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| 27 | {
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| 28 | return syscall(__NR_kexec_file_load, kernel_fd, initrd_fd, cmdline_len,
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| 29 | cmdline, flags);
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| 30 | }
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| 31 |
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| 32 | static int kexec_load(void)
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| 33 | {
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| 34 | char cmdline[COMMAND_LINE_SIZE];
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| 35 | ssize_t len;
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| 36 | int fd, err;
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| 37 |
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| 38 | fd = open("/proc/cmdline", O_RDONLY);
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| 39 | if (fd < 0)
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| 40 | return -1;
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| 41 |
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| 42 | len = read(fd, cmdline, sizeof(cmdline));
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| 43 | close(fd);
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| 44 | if (len < 0)
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| 45 | return -1;
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| 46 |
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| 47 |
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| 48 | cmdline[len - 1] = 0;
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| 49 | fd = open(KERNEL_IMAGE, O_RDONLY);
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| 50 | if (fd < 0)
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| 51 | return -1;
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| 52 |
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| 53 | err = kexec_file_load(fd, -1, len, cmdline, KEXEC_FILE_NO_INITRAMFS);
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| 54 | close(fd);
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| 55 |
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| 56 | return err ? : 0;
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| 57 | }
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| 58 |
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| 59 | int main(int argc, char *argv[])
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| 60 | {
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| 61 | if (mount_filesystems())
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| 62 | goto err_reboot;
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| 63 |
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| 64 | if (kexec_load())
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| 65 | goto err_reboot;
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| 66 |
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| 67 | if (reboot(RB_KEXEC))
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| 68 | goto err_reboot;
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| 69 |
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| 70 | return 0;
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| 71 |
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| 72 | err_reboot:
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| 73 | reboot(RB_AUTOBOOT);
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| 74 | return -1;
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| 75 | }
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