From f9d4fc3cf8ca91dbebfa305c5c08f8781caa1a0f Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Tue, 21 Apr 2009 20:40:51 +0000 Subject: [PATCH] switch_root: improve behavior on error; improve help text *: make "can't execute '%s'" message uniform --- archival/libunarchive/open_transformer.c | 2 +- archival/tar.c | 2 +- coreutils/chroot.c | 2 +- debianutils/run_parts.c | 2 +- include/usage.h | 11 +++-- loginutils/adduser.c | 2 +- selinux/runcon.c | 4 +- shell/cttyhack.c | 2 +- shell/hush.c | 2 +- util-linux/switch_root.c | 60 +++++++++++++----------- 10 files changed, 48 insertions(+), 41 deletions(-) diff --git a/archival/libunarchive/open_transformer.c b/archival/libunarchive/open_transformer.c index fae589ee0..47c13e6f4 100644 --- a/archival/libunarchive/open_transformer.c +++ b/archival/libunarchive/open_transformer.c @@ -52,7 +52,7 @@ void FAST_FUNC open_transformer(int fd, argv[2] = (char*)"-"; argv[3] = NULL; BB_EXECVP(transform_prog, argv); - bb_perror_msg_and_die("can't exec %s", transform_prog); + bb_perror_msg_and_die("can't execute '%s'", transform_prog); } #endif /* notreached */ diff --git a/archival/tar.c b/archival/tar.c index 379028bd9..9b7a42a18 100644 --- a/archival/tar.c +++ b/archival/tar.c @@ -577,7 +577,7 @@ static void NOINLINE vfork_compressor(int tar_fd, int gzip) #endif if (vfork_exec_errno) { errno = vfork_exec_errno; - bb_perror_msg_and_die("cannot exec %s", zip_exec); + bb_perror_msg_and_die("can't execute '%s'", zip_exec); } } #endif /* ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2 */ diff --git a/coreutils/chroot.c b/coreutils/chroot.c index 1198a415a..9b3d70044 100644 --- a/coreutils/chroot.c +++ b/coreutils/chroot.c @@ -33,5 +33,5 @@ int chroot_main(int argc, char **argv) } BB_EXECVP(*argv, argv); - bb_perror_msg_and_die("cannot execute %s", *argv); + bb_perror_msg_and_die("can't execute '%s'", *argv); } diff --git a/debianutils/run_parts.c b/debianutils/run_parts.c index 77fdcccb0..ea019c27c 100644 --- a/debianutils/run_parts.c +++ b/debianutils/run_parts.c @@ -164,7 +164,7 @@ int run_parts_main(int argc UNUSED_PARAM, char **argv) continue; n = 1; if (ret < 0) - bb_perror_msg("can't exec %s", name); + bb_perror_msg("can't execute '%s'", name); else /* ret > 0 */ bb_error_msg("%s exited with code %d", name, ret); } diff --git a/include/usage.h b/include/usage.h index bfb07a4cf..84da445f2 100644 --- a/include/usage.h +++ b/include/usage.h @@ -4125,12 +4125,13 @@ ) \ #define switch_root_trivial_usage \ - "[-c /dev/console] NEW_ROOT NEW_INIT [ARGUMENTS_TO_INIT]" + "[-c /dev/console] NEW_ROOT NEW_INIT [ARG...]" #define switch_root_full_usage "\n\n" \ - "Use from PID 1 under initramfs to free initramfs, chroot to NEW_ROOT,\n" \ - "and exec NEW_INIT\n" \ + "Free initramfs and switch to another root fs:\n" \ + "chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,\n" \ + "execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.\n" \ "\nOptions:" \ - "\n -c Redirect console to device on new root" \ + "\n -c DEV Reopen stdio to DEV after switch" \ #define sync_trivial_usage \ "" @@ -4142,7 +4143,7 @@ #define sysctl_full_usage "\n\n" \ "Configure kernel parameters at runtime\n" \ "\nOptions:" \ - "\n -n Disable printing of key names" \ + "\n -n Don't print key names" \ "\n -e Don't warn about unknown keys" \ "\n -w Change sysctl setting" \ "\n -p FILE Load sysctl settings from FILE (default /etc/sysctl.conf)" \ diff --git a/loginutils/adduser.c b/loginutils/adduser.c index 8a5d902e6..df4fad694 100644 --- a/loginutils/adduser.c +++ b/loginutils/adduser.c @@ -60,7 +60,7 @@ static void passwd_wrapper(const char *login) static const char prog[] ALIGN1 = "passwd"; BB_EXECLP(prog, prog, login, NULL); - bb_error_msg_and_die("cannot execute %s, you must set password manually", prog); + bb_error_msg_and_die("can't execute %s, you must set password manually", prog); } #if ENABLE_FEATURE_ADDUSER_LONG_OPTIONS diff --git a/selinux/runcon.c b/selinux/runcon.c index e94ff1454..6ecd7899d 100644 --- a/selinux/runcon.c +++ b/selinux/runcon.c @@ -129,10 +129,10 @@ int runcon_main(int argc UNUSED_PARAM, char **argv) context_str(con)); if (setexeccon(context_str(con))) - bb_error_msg_and_die("cannot set up security context '%s'", + bb_error_msg_and_die("can't set up security context '%s'", context_str(con)); execvp(argv[0], argv); - bb_perror_msg_and_die("cannot execute '%s'", argv[0]); + bb_perror_msg_and_die("can't execute '%s'", argv[0]); } diff --git a/shell/cttyhack.c b/shell/cttyhack.c index 0aa4b8a2c..572a3af03 100644 --- a/shell/cttyhack.c +++ b/shell/cttyhack.c @@ -73,5 +73,5 @@ int cttyhack_main(int argc UNUSED_PARAM, char **argv) } BB_EXECVP(argv[0], argv); - bb_perror_msg_and_die("cannot exec '%s'", argv[0]); + bb_perror_msg_and_die("can't execute '%s'", argv[0]); } diff --git a/shell/hush.c b/shell/hush.c index 53b1f3f8b..56b12cebc 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -3048,7 +3048,7 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save, debug_printf_exec("execing '%s'\n", argv[0]); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execvp(argv[0], argv); - bb_perror_msg("can't exec '%s'", argv[0]); + bb_perror_msg("can't execute '%s'", argv[0]); _exit(EXIT_FAILURE); } diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c index 08aa72597..f9e3444d5 100644 --- a/util-linux/switch_root.c +++ b/util-linux/switch_root.c @@ -5,11 +5,10 @@ * * Licensed under GPL version 2, see file LICENSE in this tarball for details. */ - #include "libbb.h" #include -// Make up for header deficiencies. +// Make up for header deficiencies #ifndef RAMFS_MAGIC #define RAMFS_MAGIC ((unsigned)0x858458f6) #endif @@ -22,7 +21,7 @@ #define MS_MOVE 8192 #endif -// Recursively delete contents of rootfs. +// Recursively delete contents of rootfs static void delete_contents(const char *directory, dev_t rootdev) { DIR *dir; @@ -33,7 +32,7 @@ static void delete_contents(const char *directory, dev_t rootdev) if (lstat(directory, &st) || st.st_dev != rootdev) return; - // Recursively delete the contents of directories. + // Recursively delete the contents of directories if (S_ISDIR(st.st_mode)) { dir = opendir(directory); if (dir) { @@ -51,42 +50,47 @@ static void delete_contents(const char *directory, dev_t rootdev) } closedir(dir); - // Directory should now be empty. Zap it. + // Directory should now be empty, zap it rmdir(directory); } - - // It wasn't a directory. Zap it. - } else unlink(directory); + } else { + // It wasn't a directory, zap it + unlink(directory); + } } int switch_root_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int switch_root_main(int argc UNUSED_PARAM, char **argv) { char *newroot, *console = NULL; - struct stat st1, st2; + struct stat st; 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 + getopt32(argv, "+c:", &console); // '+': stop at first non-option argv += optind; - - // Change to new root directory and verify it's a different fs. newroot = *argv++; + // Change to new root directory and verify it's a different fs xchdir(newroot); - if (lstat(".", &st1) || lstat("/", &st2) || st1.st_dev == st2.st_dev) { - bb_error_msg_and_die("bad newroot %s", newroot); + xstat("/", &st); + rootdev = st.st_dev; + xstat(".", &st); + if (st.st_dev == rootdev || getpid() != 1) { + // Show usage, it says new root must be a mountpoint + // and we must be PID 1 + bb_show_usage(); } - 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 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) + // 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 destroy their filesystems. + statfs("/", &stfs); // this never fails + if (lstat("/init", &st) != 0 || !S_ISREG(st.st_mode) + || ((unsigned)stfs.f_type != RAMFS_MAGIC + && (unsigned)stfs.f_type != TMPFS_MAGIC) ) { bb_error_msg_and_die("not rootfs"); } @@ -94,14 +98,16 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) // Zap everything out of rootdev delete_contents("/", rootdev); - // Overmount / with newdir and chroot into it. The chdir is needed to - // recalculate "." and ".." links. - if (mount(".", "/", NULL, MS_MOVE, NULL)) + // Overmount / with newdir and chroot into it + if (mount(".", "/", NULL, MS_MOVE, NULL)) { + // For example, fails when newroot is not a mountpoint bb_perror_msg_and_die("error moving root"); + } + // The chdir is needed to recalculate "." and ".." links xchroot("."); xchdir("/"); - // If a new console specified, redirect stdin/stdout/stderr to that. + // If a new console specified, redirect stdin/stdout/stderr to it if (console) { close(0); xopen(console, O_RDWR); @@ -109,7 +115,7 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) xdup2(0, 2); } - // Exec real init. (This is why we must be pid 1.) + // Exec real init execv(argv[0], argv); - bb_perror_msg_and_die("bad init %s", argv[0]); + bb_perror_msg_and_die("can't execute '%s'", argv[0]); }