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No longer needed

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This commit is contained in:
Bruce Leidl 2017-10-18 19:14:05 +00:00
parent 42070f7532
commit 0713cbce69
2 changed files with 0 additions and 138 deletions
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2
kernel/init/Makefile
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@ -1,2 +0,0 @@
init: init.c
gcc -o init init.c

136
kernel/init/init.c
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#include <sys/mount.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/reboot.h>
#include <sys/syscall.h>
char *splash[] = {
"",
" ------------------------------||-------------------------------",
" [##]",
" /~~~~~~\\",
" |~~\\ /~~|",
" ==][===|___||___|===][==",
" [::] ( () ) [::]",
" ~/~~~~\\~",
" O' `o", "",NULL
};
static int run_shell()
{
char *new_argv[] = { "/bin/bash", NULL };
char *new_env[] = { "TERM=xterm-256color", "HOME=/home/user", NULL };
char **p;
for(p = splash; *p; p++) {
printf("%s\n", *p);
}
return execve("/bin/bash", new_argv, new_env);
}
static void do_mkdir(const char* path) {
if(mkdir(path, 0755) < 0) {
printf("mkdir %s failed: %s\n", path, strerror(errno));
}
}
static void mount_tmpfs(const char *path) {
if(mount("tmpfs", path, "tmpfs", 0, "mode=755") < 0) {
printf("mount tmpfs to %s failed: %s\n", path, strerror(errno));
}
}
static void pivot_root(const char *new_root, const char *put_old) {
if(syscall(SYS_pivot_root, new_root, put_old) < 0) {
printf("pivot_root failed (%s : %s) : %s\n", new_root, put_old, strerror(errno));
}
}
static void move_mount(const char *source, const char *target) {
if(mount(source, target, "", MS_MOVE, NULL) < 0) {
printf("move mount of %s to %s failed: %s\n", source, target, strerror(errno));
}
}
static void setup_overlay(void) {
mount_tmpfs("/tmp");
do_mkdir("/tmp/ro");
do_mkdir("/tmp/rw");
mount_tmpfs("/tmp/rw");
do_mkdir("/tmp/rw/upper");
do_mkdir("/tmp/rw/work");
do_mkdir("/tmp/overlay");
pivot_root("/tmp", "/tmp/ro");
/*
* /ro real root mounted here
* /rw tmpfs mounted here
* /rw/upper empty directory
* /rw/work empty directory
* /overlay empty directory
*
*/
if(mount("overlay", "/overlay", "overlay", 0, "lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work") < 0) {
printf("mount overlay failed: %s\n", strerror(errno));
}
do_mkdir("/overlay/ro");
do_mkdir("/overlay/rw");
do_mkdir("/overlay/old-root");
move_mount("/ro", "/overlay/ro");
move_mount("/rw", "/overlay/rw");
pivot_root("/overlay", "/overlay/old-root");
umount("/old-root");
umount("/ro/tmp");
}
static void do_mounts(void)
{
mount("sysfs", "/sys", "sysfs", 0, NULL);
mount("proc", "/proc", "proc", 0, NULL);
mount("devtmpfs", "/dev", "devtmpfs", 0, NULL);
mkdir("/dev/pts", 0755);
mount("devpts", "/dev/pts", "devpts", 0, NULL);
}
int main(int argc, char *argv[])
{
pid_t child;
int status;
setup_overlay();
do_mounts();
sethostname("airwolf", 7);
/* get session leader */
setsid();
/* set controlling terminal */
ioctl(0, TIOCSCTTY, 1);
child = fork();
if (child < 0) {
printf("Fatal: fork() failed with %d\n", child);
return 0;
} else if (child == 0) {
run_shell();
} else {
pid_t corpse;
do {
corpse = waitpid(-1, &status, 0);
} while (corpse != child);
}
reboot(RB_AUTOBOOT);
printf("Init failed: %s\n", strerror(errno));
return 0;
}