diff options
| -rw-r--r-- | util-linux/switch_root.c | 32 |
1 files changed, 11 insertions, 21 deletions
diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c index 1f6ec2dc7..21cc99229 100644 --- a/util-linux/switch_root.c +++ b/util-linux/switch_root.c @@ -9,9 +9,7 @@ #include "libbb.h" #include <sys/vfs.h> - // Make up for header deficiencies. - #ifndef RAMFS_MAGIC #define RAMFS_MAGIC ((unsigned)0x858458f6) #endif @@ -24,18 +22,16 @@ #define MS_MOVE 8192 #endif -static dev_t rootdev; - // Recursively delete contents of rootfs. - -static void delete_contents(const char *directory) +static void delete_contents(const char *directory, dev_t rootdev) { DIR *dir; struct dirent *d; struct stat st; // Don't descend into other filesystems - if (lstat(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)) { @@ -45,13 +41,13 @@ static void delete_contents(const char *directory) char *newdir = d->d_name; // Skip . and .. - if (*newdir=='.' && (!newdir[1] || (newdir[1]=='.' && !newdir[2]))) + if (DOT_OR_DOTDOT(newdir)) 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); + newdir = concat_path_file(directory, newdir); + delete_contents(newdir, rootdev); + free(newdir); } closedir(dir); @@ -60,7 +56,6 @@ static void delete_contents(const char *directory) } // It wasn't a directory. Zap it. - } else unlink(directory); } @@ -70,15 +65,14 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) char *newroot, *console = NULL; struct stat st1, st2; struct statfs stfs; + dev_t rootdev; // Parse args (-c console) - opt_complementary = "-2"; // minimum 2 params getopt32(argv, "+c:", &console); // '+': stop parsing at first non-option argv += optind; // Change to new root directory and verify it's a different fs. - newroot = *argv++; xchdir(newroot); @@ -90,7 +84,6 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) // 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 filesystems.) - if (lstat("/init", &st1) || !S_ISREG(st1.st_mode) || statfs("/", &stfs) || (((unsigned)stfs.f_type != RAMFS_MAGIC) && ((unsigned)stfs.f_type != TMPFS_MAGIC)) || (getpid() != 1) @@ -99,24 +92,21 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) } // Zap everything out of rootdev - - delete_contents("/"); + delete_contents("/", rootdev); // Overmount / with newdir and chroot into it. The chdir is needed to // recalculate "." and ".." links. - if (mount(".", "/", NULL, MS_MOVE, NULL)) bb_error_msg_and_die("error moving root"); xchroot("."); xchdir("/"); // If a new console specified, redirect stdin/stdout/stderr to that. - if (console) { close(0); xopen(console, O_RDWR); - dup2(0, 1); - dup2(0, 2); + xdup2(0, 1); + xdup2(0, 2); } // Exec real init. (This is why we must be pid 1.) |