88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/* SPDX-FileCopyrightText: 2023 Richard Masters <grick23@gmail.com> */
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/* SPDX-License-Identifier: MIT */
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <sys/reboot.h>
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#include <sys/stat.h>
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#include <time.h>
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int append_file(FILE *dst_file, char *src_file_name);
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int main(int argc, char **argv) {
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char *ramdrive_file_name, *kernel_file_name, *initramfs_file_name;
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FILE *ramdrive_file;
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struct stat stats;
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uint32_t size;
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if (argc < 3) {
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puts("Usage: fiwix-kexec-linux <ram-drive-name> <kernel-file-name> <initramfs-file-name>");
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exit(1);
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}
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ramdrive_file_name = argv[1];
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kernel_file_name = argv[2];
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initramfs_file_name = argv[3];
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ramdrive_file = fopen(ramdrive_file_name, "wb");
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/* Move past where lengths go */
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int length_offset = 2 * sizeof(uint32_t);
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fseek(ramdrive_file, length_offset, SEEK_SET);
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uint32_t last_pos = ftell(ramdrive_file);
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/* Write the kernel and initramfs */
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if (append_file(ramdrive_file, kernel_file_name)) {
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fprintf(stderr, "Cannot append kernel '%s'\n", kernel_file_name);
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exit(1);
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}
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uint32_t kernel_size = ftell(ramdrive_file) - last_pos;
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last_pos = ftell(ramdrive_file);
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if (append_file(ramdrive_file, initramfs_file_name)) {
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fprintf(stderr, "Cannot append initramfs '%s'\n", initramfs_file_name);
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exit(1);
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}
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uint32_t initramfs_size = ftell(ramdrive_file) - last_pos;
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/* Now write the lengths */
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fseek(ramdrive_file, 0, SEEK_SET);
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fwrite(&kernel_size, sizeof(kernel_size), 1, ramdrive_file);
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fwrite(&initramfs_size, sizeof(initramfs_size), 1, ramdrive_file);
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fclose(ramdrive_file);
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/* Flush ram drive writes to device */
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sync();
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/* Perform syscall reboot to initiate kexec */
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reboot(RB_HALT_SYSTEM);
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}
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int append_file(FILE *dst_file, char *src_file_name) {
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FILE *src_file;
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char buff[BUFSIZ];
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size_t n;
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if (*src_file_name == '!') {
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src_file_name++;
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src_file = popen(src_file_name, "r");
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} else {
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src_file = fopen(src_file_name, "rb");
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}
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if (src_file) {
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while ((n = fread(buff, 1, BUFSIZ, src_file)) != 0) {
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fwrite(buff, 1, n, dst_file);
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}
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fclose(src_file);
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return 0;
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} else {
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printf("Cannot open file '%s'\n", src_file_name);
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return 1;
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}
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}
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