39acf4533
Denis Vlasenko
2008-07-11
Subject
switch_root: shrink
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util-linux/switch_root.c+11 -21
| @@ -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.) | |