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331 lines (266 loc) · 6.2 KB
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Copy pathkinit.c
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331 lines (266 loc) · 6.2 KB
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#include <sys/mount.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <alloca.h>
#include <limits.h>
#include <ctype.h>
#include <termios.h>
#include "kinit.h"
#include "ipconfig.h"
#include "run-init.h"
#include "resume.h"
const char *progname = "kinit";
int mnt_procfs;
int mnt_sysfs;
#ifdef DEBUG
void dump_args(int argc, char *argv[])
{
int i;
printf(" argc == %d\n", argc);
for (i = 0; i < argc; i++)
printf(" argv[%d]: \"%s\"\n", i, argv[i]);
if (argv[argc] != NULL)
printf(" argv[%d]: \"%s\" (SHOULD BE NULL)\n",
argc, argv[argc]);
}
#endif /* DEBUG */
static int do_ipconfig(int argc, char *argv[])
{
int i, a = 0;
char **args = alloca((argc + 3) * sizeof(char *));
if (!args)
return -1;
args[a++] = (char *)"IP-Config";
args[a++] = (char *)"-i";
args[a++] = (char *)"Linux kinit";
dprintf("Running ipconfig\n");
for (i = 1; i < argc; i++) {
if (strncmp(argv[i], "ip=", 3) == 0 ||
strncmp(argv[i], "nfsaddrs=", 9) == 0) {
args[a++] = argv[i];
}
}
if (a > 1) {
args[a] = NULL;
dump_args(a, args);
return ipconfig_main(a, args);
}
return 0;
}
static int split_cmdline(int cmdcmax, char *cmdv[], char *argv0,
char *cmdlines[], char *args[])
{
int was_space;
char c, *p;
int vmax = cmdcmax;
int v = 1;
int space;
if (cmdv)
cmdv[0] = argv0;
/* First, add the parsable command lines */
while (*cmdlines) {
p = *cmdlines++;
was_space = 1;
while (v < vmax) {
c = *p;
space = isspace(c);
if ((space || !c) && !was_space) {
if (cmdv)
*p = '\0';
v++;
} else if (was_space) {
if (cmdv)
cmdv[v] = p;
}
if (!c)
break;
was_space = space;
p++;
}
}
/* Second, add the explicit command line arguments */
while (*args && v < vmax) {
if (cmdv)
cmdv[v] = *args;
v++;
args++;
}
if (cmdv)
cmdv[v] = NULL;
return v;
}
static int mount_sys_fs(const char *check, const char *fsname,
const char *fstype)
{
struct stat st;
if (stat(check, &st) == 0)
return 0;
mkdir(fsname, 0555);
if (mount("none", fsname, fstype, 0, NULL) == -1) {
fprintf(stderr, "%s: could not mount %s as %s\n",
progname, fsname, fstype);
return -1;
}
return 1;
}
static void check_path(const char *path)
{
struct stat st;
if (stat(path, &st) == -1) {
if (errno != ENOENT) {
perror("stat");
exit(1);
}
if (mkdir(path, 0755) == -1) {
perror("mkdir");
exit(1);
}
} else if (!S_ISDIR(st.st_mode)) {
fprintf(stderr, "%s: '%s' not a directory\n", progname, path);
exit(1);
}
}
static const char *find_init(const char *root, const char *user)
{
const char *init_paths[] = {
"/sbin/init", "/bin/init", "/etc/init", "/bin/sh", NULL
};
const char **p;
const char *path;
if (chdir(root)) {
perror("chdir");
exit(1);
}
if (user)
dprintf("Checking for init: %s\n", user);
if (user && user[0] == '/' && !access(user+1, X_OK)) {
path = user;
} else {
for (p = init_paths; *p; p++) {
dprintf("Checking for init: %s\n", *p);
if (!access(*p+1, X_OK))
break;
}
path = *p;
}
chdir("/");
return path;
}
/* This is the argc and argv we pass to init */
const char *init_path;
int init_argc;
char **init_argv;
extern ssize_t readfile(const char *, char **);
int main(int argc, char *argv[])
{
char **cmdv, **args;
char *cmdlines[3];
int i;
const char *errmsg;
int ret = 0;
int cmdc;
int fd;
struct timeval now;
gettimeofday(&now, NULL);
srand48(now.tv_usec ^ (now.tv_sec << 24));
/* Default parameters for anything init-like we execute */
init_argc = argc;
init_argv = alloca((argc+1)*sizeof(char *));
memcpy(init_argv, argv, (argc+1)*sizeof(char *));
if ((fd = open("/dev/console", O_RDWR)) != -1) {
dup2(fd, STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO)
close(fd);
}
mnt_procfs = mount_sys_fs("/proc/cmdline", "/proc", "proc") >= 0;
if (!mnt_procfs) {
ret = 1;
goto bail;
}
mnt_sysfs = mount_sys_fs("/sys/bus", "/sys", "sysfs") >= 0;
if (!mnt_sysfs) {
ret = 1;
goto bail;
}
/* Construct the effective kernel command line. The
effective kernel command line consists of /arch.cmd, if
it exists, /proc/cmdline, plus any arguments after an --
argument on the proper command line, in that order. */
ret = readfile("/arch.cmd", &cmdlines[0]);
if (ret < 0)
cmdlines[0] = "";
ret = readfile("/proc/cmdline", &cmdlines[1]);
if (ret < 0) {
fprintf(stderr, "%s: cannot read /proc/cmdline\n", progname);
ret = 1;
goto bail;
}
cmdlines[2] = NULL;
/* Find an -- argument, and if so append to the command line */
for (i = 1; i < argc; i++) {
if (!strcmp(argv[i], "--")) {
i++;
break;
}
}
args = &argv[i]; /* Points either to first argument past -- or
to the final NULL */
/* Count the number of arguments */
cmdc = split_cmdline(INT_MAX, NULL, argv[0], cmdlines, args);
/* Actually generate the cmdline array */
cmdv = (char **)alloca((cmdc+1)*sizeof(char *));
if (split_cmdline(cmdc, cmdv, argv[0], cmdlines, args) != cmdc) {
ret = 1;
goto bail;
}
/* Debugging... */
dump_args(cmdc, cmdv);
/* Resume from suspend-to-disk, if appropriate */
/* If successful, does not return */
do_resume(cmdc, cmdv);
/* Initialize networking, if applicable */
do_ipconfig(cmdc, cmdv);
check_path("/root");
do_mounts(cmdc, cmdv);
if (mnt_procfs) {
umount2("/proc", 0);
mnt_procfs = 0;
}
if (mnt_sysfs) {
umount2("/sys", 0);
mnt_sysfs = 0;
}
init_path = find_init("/root", get_arg(cmdc, cmdv, "init="));
if (!init_path) {
fprintf(stderr, "%s: init not found!\n", progname);
ret = 2;
goto bail;
}
init_argv[0] = strrchr(init_path, '/') + 1;
errmsg = run_init("/root", "/dev/console",
get_arg(cmdc, cmdv, "drop_capabilities="), false,
false, init_path, init_argv);
/* If run_init returned, something went bad */
fprintf(stderr, "%s: %s: %s\n", progname, errmsg, strerror(errno));
ret = 2;
goto bail;
bail:
if (mnt_procfs)
umount2("/proc", 0);
if (mnt_sysfs)
umount2("/sys", 0);
/*
* If we get here, something bad probably happened, and the kernel
* will most likely panic. Drain console output so the user can
* figure out what happened.
*/
tcdrain(2);
tcdrain(1);
return ret;
}