Add more checks, add handling of console
diff --git a/utils/run-init.c b/utils/run-init.c
index 5e95962..8ac953b 100644
--- a/utils/run-init.c
+++ b/utils/run-init.c
@@ -1,4 +1,4 @@
-#ident "$Id: run-init.c,v 1.2 2004/06/08 06:40:33 hpa Exp $"
+#ident "$Id: run-init.c,v 1.3 2004/06/08 20:24:42 hpa Exp $"
/* ----------------------------------------------------------------------- *
*
* Copyright 2004 H. Peter Anvin - All Rights Reserved
@@ -29,7 +29,7 @@
/*
* run-init.c
*
- * Usage: exec run-init /real-root /sbin/init "$@"
+ * Usage: exec run-init [-c /dev/console] /real-root /sbin/init "$@"
*
* This program should be called as the last thing in a shell script
* acting as /init in an initramfs; it does the following:
@@ -37,6 +37,7 @@
* - Delete all files in the initramfs;
* - Remounts /real-root onto the root filesystem;
* - Chroots;
+ * - Opens /dev/console;
* - Spawns the specified init program (with arguments.)
*/
@@ -44,6 +45,7 @@
#include <assert.h>
#include <dirent.h>
#include <errno.h>
+#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
@@ -146,42 +148,93 @@
}
}
+
+static void __attribute__((noreturn)) usage(void)
+{
+ fprintf(stderr, "Usage: exec %s [-c consoledev] /real-root /sbin/init [args]\n", program);
+ exit(1);
+}
+
+
int main(int argc, char *argv[])
{
+ struct stat rst, cst, ist;
struct statfs sfs;
+ int o;
+ int confd;
+ /* Command-line options and defaults */
+ const char *console = "/dev/console";
+ const char *realroot;
+ const char *init;
+ char **initargs;
+
+ /* First, parse the command line */
program = argv[0];
- if ( argc < 3 ) {
- fprintf(stderr, "Usage: exec %s /real-root /sbin/init [args]\n", program);
- exit(1);
+ while ( (o = getopt(argc, argv, "c:")) != -1 ) {
+ if ( o == 'c' ) {
+ console = optarg;
+ } else {
+ usage();
+ }
}
- /* Make sure we're in the root directory */
- if ( chdir("/") )
- die("cd /");
-
- /* Make sure we're on a ramfs - this avoids accidents */
- if ( statfs(".", &sfs) )
+ if ( argc-optind < 2 )
+ usage();
+
+ realroot = argv[optind];
+ init = argv[optind+1];
+ initargs = argv+optind+1;
+
+ /* First, change to the new root directory */
+ if ( chdir(argv[1]) )
+ die("chdir to new root");
+
+ /* This is a potentially highly destructive program. Take some
+ extra precautions. */
+
+ /* Make sure the current directory is not on the same filesystem
+ as the root directory */
+ if ( stat("/", &rst) || stat(".", &cst) )
+ die("stat");
+
+ if ( rst.st_dev == cst.st_dev )
+ die("current directory on the same filesystem as the root");
+
+ /* The initramfs should have /init */
+ if ( stat("/init", &ist) || !S_ISREG(ist.st_mode) )
+ die("can't find /init on initramfs");
+
+ /* Make sure we're on a ramfs */
+ if ( statfs("/", &sfs) )
die("statfs /");
if ( sfs.f_type != RAMFS_MAGIC && sfs.f_type != TMPFS_MAGIC )
die("rootfs not a ramfs or tmpfs");
+ /* Okay, I think we should be safe... */
+
/* Delete rootfs contents */
- if ( nuke_dir(".") )
+ if ( nuke_dir("/") )
die("nuking initramfs contents");
/* Overmount the root */
- if ( mount(argv[2], "/", NULL, MS_BIND, NULL) )
+ if ( mount(".", "/", NULL, MS_BIND, NULL) )
die("overmounting root");
- /* Chroot */
- if ( chroot(".") )
+ /* chroot, chdir */
+ if ( chroot(".") || chdir("/") )
die("chroot");
+ /* Open /dev/console */
+ if ( (confd = open(console, O_RDWR)) < 0 )
+ die("opening console");
+ dup2(confd, 0);
+ dup2(confd, 1);
+ dup2(confd, 2);
+ close(confd);
+
/* Spawn init */
- execv(argv[3], argv+3);
-
- die(argv[3]); /* Failed to spawn init */
+ execv(init, initargs);
+ die(init); /* Failed to spawn init */
}
-
