applets: fix compile-time warning

[oweals/busybox.git] / util-linux / switch_root.c

diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
index 0c86eec080074b29e7542f9b521af68970ed3cb6..88bb9db2a67e92ff9c36028ee2c36209fc6cefa6 100644 (file)
--- a/util-linux/switch_root.c
+++ b/util-linux/switch_root.c
@@ -1,15 +1,14 @@
-/* vi:set ts=4:*/
-
-#include <dirent.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <sys/mount.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <sys/vfs.h>
-#include <unistd.h>
+/* vi: set sw=4 ts=4: */
+/* Copyright 2005 Rob Landley <rob@landley.net>
+ *
+ * Switch from rootfs to another filesystem as the root of the mount tree.
+ *
+ * Licensed under GPL version 2, see file LICENSE in this tarball for details.
+ */
 
 #include "busybox.h"
+#include <sys/vfs.h>
+
 
 // Make up for header deficiencies.
 
@@ -25,72 +24,74 @@
 #define MS_MOVE                        8192
 #endif
 
-dev_t rootdev;
+static dev_t rootdev;
 
 // Recursively delete contents of rootfs.
 
-static void delete_contents(char *directory)
+static void delete_contents(const char *directory)
 {
        DIR *dir;
        struct dirent *d;
        struct stat st;
 
        // Don't descend into other filesystems
-       if (stat(directory,&st) || st.st_dev != rootdev) return;
+       if (lstat(directory, &st) || st.st_dev != rootdev) return;
 
        // Recursively delete the contents of directories.
        if (S_ISDIR(st.st_mode)) {
-               if((dir = opendir(directory))) {
+               dir = opendir(directory);
+               if (dir) {
                        while ((d = readdir(dir))) {
-                               char *newdir=d->d_name;
+                               char *newdir = d->d_name;
 
                                // Skip . and ..
-                               if(*newdir=='.' && (!newdir[1] || (newdir[1]=='.' && !newdir[2])))
+                               if (*newdir=='.' && (!newdir[1] || (newdir[1]=='.' && !newdir[2])))
                                        continue;
-                               
+
                                // Recurse to delete contents
                                newdir = alloca(strlen(directory) + strlen(d->d_name) + 2);
                                sprintf(newdir, "%s/%s", directory, d->d_name);
                                delete_contents(newdir);
                        }
                        closedir(dir);
-                       
+
                        // Directory should now be empty.  Zap it.
                        rmdir(directory);
                }
-               
+
        // It wasn't a directory.  Zap it.
-               
+
        } else unlink(directory);
 }
 
-int switch_root_main(int argc, char *argv[])
+int switch_root_main(int argc, char **argv);
+int switch_root_main(int argc, char **argv)
 {
-       char *newroot, *console=NULL;
+       char *newroot, *console = NULL;
        struct stat st1, st2;
        struct statfs stfs;
 
        // Parse args (-c console)
 
-       bb_opt_complementally="-2";
-       bb_getopt_ulflags(argc,argv,"c:",&console);
-       
+       opt_complementary = "-2";
+       getopt32(argc, argv, "c:", &console);
+       argv += optind;
+
        // Change to new root directory and verify it's a different fs.
 
-       newroot=argv[optind++];
-       
-       if (chdir(newroot) || stat(".", &st1) || stat("/", &st2) ||
-               st1.st_dev == st2.st_dev)
-       {
-               bb_error_msg_and_die("bad newroot %s",newroot);
+       newroot = *argv++;
+
+       xchdir(newroot);
+       if (lstat(".", &st1) || lstat("/", &st2) || st1.st_dev == st2.st_dev) {
+               bb_error_msg_and_die("bad newroot %s", newroot);
        }
-       rootdev=st2.st_dev;
-       
+       rootdev = st2.st_dev;
+
        // Additional sanity checks: we're about to rm -rf /,  so be REALLY SURE
        // we mean it.  (I could make this a CONFIG option, but I would get email
-       // from all the people who WILL eat their filesystemss.)
+       // from all the people who WILL eat their filesystems.)
 
-       if (stat("/init", &st1) || !S_ISREG(st1.st_mode) || statfs("/", &stfs) ||
+       if (lstat("/init", &st1) || !S_ISREG(st1.st_mode) || statfs("/", &stfs) ||
                (stfs.f_type != RAMFS_MAGIC && stfs.f_type != TMPFS_MAGIC) ||
                getpid() != 1)
        {
@@ -100,24 +101,24 @@ int switch_root_main(int argc, char *argv[])
        // Zap everything out of rootdev
 
        delete_contents("/");
-       
+
        // Overmount / with newdir and chroot into it.  The chdir is needed to
        // recalculate "." and ".." links.
 
-       if (mount(".", "/", NULL, MS_MOVE, NULL) || chroot(".") || chdir("/"))
-               bb_error_msg_and_die("moving root");
-       
+       if (mount(".", "/", NULL, MS_MOVE, NULL) || chroot("."))
+               bb_error_msg_and_die("error moving root");
+       xchdir("/");
+
        // If a new console specified, redirect stdin/stdout/stderr to that.
 
        if (console) {
                close(0);
-               if(open(console, O_RDWR) < 0)
-                       bb_error_msg_and_die("Bad console '%s'",console);
+               xopen(console, O_RDWR);
                dup2(0, 1);
                dup2(0, 2);
        }
 
        // Exec real init.  (This is why we must be pid 1.)
-       execv(argv[optind],argv+optind+1);
-       bb_error_msg_and_die("Bad init '%s'",argv[optind]);
+       execv(argv[0], argv);
+       bb_perror_msg_and_die("bad init %s", argv[0]);
 }