forked from DGNum/liminix
132 lines
3.5 KiB
C
132 lines
3.5 KiB
C
#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/mount.h>
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#include <sys/wait.h>
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#include <string.h>
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#include <stdint.h>
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#include <errno.h>
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#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
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#include "opts.h"
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#define ERR(x) write(2, x, strlen(x))
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#define AVER(c) do { if(c < 0) { ERR("failed: " #c ": error=0x" ); pr_u32(errno); ERR ( " - "); ERR(strerror(errno)); ERR("\n"); } } while(0)
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char * pr_u32(int32_t input);
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static void die() {
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/* if init exits, it causes a kernel panic. On the Turris
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* Omnia (and maybe other hardware, I don't know), the kernel
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* panics _before_ any of the messages from AVER are printed,
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* which makes it really hard to tell what went wrong. So
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* let's wait a little here to give the console a chance to
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* catch up.
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*
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* Yes, I know that file descriptor IO is supposedly
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* non-buffered. Empirical observation suggests that there
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* must be a buffer of some kind somewhere though.
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*/
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sleep(10);
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exit(1);
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}
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static int fork_exec(char * command, char *args[])
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{
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int fork_pid = fork();
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AVER(fork_pid);
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if(fork_pid > 0)
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return wait(NULL);
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else
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return execve(command, args, NULL);
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}
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char banner[] = "Running pre-init...\n";
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char buf[COMMAND_LINE_SIZE];
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int main(int argc, char *argv[], char *envp[])
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{
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struct root_opts opts = {
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.device = NULL,
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.fstype = NULL,
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.mount_opts = NULL
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};
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write(1, banner, strlen(banner));
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AVER(mount("none", "/proc", "proc", 0, NULL));
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AVER(mount("none", "/dev", "devtmpfs", 0, NULL));
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int cmdline = open("/proc/cmdline", O_RDONLY, 0);
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if(cmdline>=0) {
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int len = read(cmdline, buf, sizeof buf - 1);
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buf[len]='\0';
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while(buf[len-1]=='\n') {
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buf[len-1]='\0';
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len--;
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}
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write(1, "cmdline: \"", 10);
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write(1, buf, len);
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write(1, "\"\n", 2);
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} else {
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ERR("failed: open(\"/proc/cmdline\")\n");
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die();
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}
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parseopts(buf, &opts);
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if(opts.device) {
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if(!opts.fstype) opts.fstype = "jffs2"; /* backward compatibility */
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write(1, "rootdevice ", 11);
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write(1, opts.device, strlen(opts.device));
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write(1, " (", 2);
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write(1, opts.fstype, strlen(opts.fstype));
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if(opts.mount_opts) {
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write(1, ", opts=", 7);
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write(1, opts.mount_opts, strlen(opts.mount_opts));
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}
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if(opts.altdevice) {
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write(1, ", altdevice=", 12);
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write(1, opts.altdevice, strlen(opts.altdevice));
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}
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write(1, ")\n", 2);
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if(!opts.altdevice) {
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AVER(mount(opts.device, "/target/persist", opts.fstype, 0, opts.mount_opts));
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} else {
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if(mount(opts.device, "/target/persist", opts.fstype, 0, opts.mount_opts) < 0) {
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ERR("failed to mount primary device, mount the alternative device\n");
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AVER(mount(opts.altdevice, "/target/persist", opts.fstype, 0, opts.mount_opts));
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}
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}
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// FUTUREWORK: any failure using `opts.device` should force us to consider rerunning this with the alternative rootfs.
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AVER(mount("/target/persist/nix", "/target/nix",
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"bind", MS_BIND, NULL));
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char *exec_args[] = { "activate", "/target", NULL };
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AVER(fork_exec("/target/persist/activate", exec_args));
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AVER(chdir("/target"));
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AVER(mount("/target", "/", "bind", MS_BIND | MS_REC, NULL));
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AVER(chroot("."));
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argv[0] = "init";
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argv[1] = NULL;
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AVER(execve("/persist/init", argv, envp));
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}
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ERR("failed to mount the rootfs\n");
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ERR("final stand using the failsafe initialization method\n");
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ERR("the boot process is manual from now on\n");
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argv[0] = "init";
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argv[1] = NULL;
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AVER(execve("/failsafe-init", argv, envp));
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die();
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}
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