liminix/pkgs/preinit/preinit.c

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1.8 KiB
C
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#ifdef PREINIT_USE_LIBC
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <sys/wait.h>
#include <string.h>
#else
#include <nolibc.h>
#endif
#include <asm/setup.h>
#define ERR(x) write(2, x, strlen(x))
#define AVER(c) do { if(c < 0) ERR("failed: " #c); } while(0)
static int begins_with(char * str, char * prefix)
{
while(*prefix) {
if(*str == '\0') return 0;
if(*str != *prefix) return 0;
str++;
prefix++;
}
return 1;
}
static void fork_exec(char * command, char *args[])
{
int fork_pid = fork();
AVER(fork_pid);
if(fork_pid > 0)
wait(NULL);
else
AVER(execve(command, args, NULL));
}
char banner[] = "Running pre-init...\n";
char buf[COMMAND_LINE_SIZE];
int main(int argc, char *argv[], char *envp[])
{
char *rootdevice = 0;
char *p = buf;
write(1, banner, strlen(banner));
mount("none", "/proc", "proc", 0, NULL);
int cmdline = open("/proc/cmdline", O_RDONLY, 0);
if(cmdline>=0) {
int len = read(cmdline, buf, sizeof buf - 1);
buf[len]='\0';
write(1, "cmdline ", 8);
write(1, buf, len);
};
while(*p) {
if(begins_with(p, "root=")) {
rootdevice = p + 5;
while(*p && (*p != ' ')) p++;
*p= '\0';
}
while(*p && (*p != ' ')) p++;
p++;
}
if(rootdevice) {
write(1, "rootdevice ", 11);
write(1, rootdevice, strlen(rootdevice));
write(1, "\n", 1);
AVER(mount(rootdevice, "/target/persist", "jffs2", 0, NULL));
AVER(mount("/target/persist/nix", "/target/nix",
"bind", MS_BIND, NULL));
char *exec_args[] = { "activate", "/target", NULL };
fork_exec("/target/persist/activate", exec_args);
AVER(chdir("/target"));
AVER(mount("/target", "/", "bind", MS_BIND | MS_REC, NULL));
AVER(chroot("."));
argv[0] = "init";
argv[1] = NULL;
AVER(execve("/persist/init", argv, envp));
}
}