bbc26c693
Denys Vlasenko
2017-08-22
Subject
run-init: implement -n "dry run"
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No binary (build failed)
Architecture & Compiler Flags
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Build Log
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Commit Diff GitHub →
selinux/setfiles.c+1 -1
| @@ -679,7 +679,7 @@ int setfiles_main(int argc UNUSED_PARAM, char **argv) | |
| bb_show_usage(); | |
| xstat(argv[0], &sb); | |
| if (!S_ISREG(sb.st_mode)) { | |
| - | bb_error_msg_and_die("spec file %s is not a regular file", argv[0]); |
| + | bb_error_msg_and_die("'%s' is not a regular file", argv[0]); |
| } | |
| /* Load the file contexts configuration and check it. */ | |
| rc = matchpathcon_init(argv[0]); | |
util-linux/switch_root.c+43 -34
| @@ -24,6 +24,8 @@ | |
| //config: * Because the Linux kernel uses rootfs internally as the starting | |
| //config: and ending point for searching through the kernel's doubly linked | |
| //config: list of active mount points. That's why. | |
| + | //config: |
| + | // RUN_INIT config item is in klibc-utils |
| //applet:IF_SWITCH_ROOT(APPLET(switch_root, BB_DIR_SBIN, BB_SUID_DROP)) | |
| // APPLET_ODDNAME:name main location suid_type help | |
| @@ -32,23 +34,6 @@ | |
| //kbuild:lib-$(CONFIG_SWITCH_ROOT) += switch_root.o | |
| //kbuild:lib-$(CONFIG_RUN_INIT) += switch_root.o | |
| - | //usage:#define switch_root_trivial_usage |
| - | //usage: "[-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]" |
| - | //usage:#define switch_root_full_usage "\n\n" |
| - | //usage: "Free initramfs and switch to another root fs:\n" |
| - | //usage: "chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,\n" |
| - | //usage: "execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.\n" |
| - | //usage: "\n -c DEV Reopen stdio to DEV after switch" |
| - | |
| - | //usage:#define run_init_trivial_usage |
| - | //usage: "[-d CAP,CAP...] [-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]" |
| - | //usage:#define run_init_full_usage "\n\n" |
| - | //usage: "Free initramfs and switch to another root fs:\n" |
| - | //usage: "chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,\n" |
| - | //usage: "execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.\n" |
| - | //usage: "\n -c DEV Reopen stdio to DEV after switch" |
| - | //usage: "\n -d CAPS Drop capabilities" |
| - | |
| #include <sys/vfs.h> | |
| #include <sys/mount.h> | |
| #if ENABLE_RUN_INIT | |
| @@ -122,13 +107,8 @@ static void drop_capset(int cap_idx) | |
| { | |
| struct caps caps; | |
| - | /* Get the current capability mask */ |
| getcaps(&caps); | |
| - | |
| - | /* Drop the bit */ |
| caps.data[CAP_TO_INDEX(cap_idx)].inheritable &= ~CAP_TO_MASK(cap_idx); | |
| - | |
| - | /* And drop the capability. */ |
| if (capset(&caps.header, caps.data) != 0) | |
| bb_perror_msg_and_die("capset"); | |
| } | |
| @@ -199,10 +179,18 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) | |
| char *newroot, *console = NULL; | |
| struct stat st; | |
| struct statfs stfs; | |
| + | unsigned dry_run = 0; |
| dev_t rootdev; | |
| - | // Parse args (-c console). '+': stop at first non-option |
| + | // Parse args. '+': stop at first non-option |
| if (ENABLE_SWITCH_ROOT && (!ENABLE_RUN_INIT || applet_name[0] == 's')) { | |
| + | //usage:#define switch_root_trivial_usage |
| + | //usage: "[-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]" |
| + | //usage:#define switch_root_full_usage "\n\n" |
| + | //usage: "Free initramfs and switch to another root fs:\n" |
| + | //usage: "chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,\n" |
| + | //usage: "execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.\n" |
| + | //usage: "\n -c DEV Reopen stdio to DEV after switch" |
| getopt32(argv, "^+" | |
| "c:" | |
| "\0" "-2" /* minimum 2 args */, | |
| @@ -210,13 +198,23 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) | |
| ); | |
| } else { | |
| #if ENABLE_RUN_INIT | |
| + | //usage:#define run_init_trivial_usage |
| + | //usage: "[-d CAP,CAP...] [-n] [-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]" |
| + | //usage:#define run_init_full_usage "\n\n" |
| + | //usage: "Free initramfs and switch to another root fs:\n" |
| + | //usage: "chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,\n" |
| + | //usage: "execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.\n" |
| + | //usage: "\n -c DEV Reopen stdio to DEV after switch" |
| + | //usage: "\n -d CAPS Drop capabilities" |
| + | //usage: "\n -n Dry run" |
| char *cap_list = NULL; | |
| - | getopt32(argv, "^+" |
| - | "c:d:" |
| + | dry_run = getopt32(argv, "^+" |
| + | "c:d:n" |
| "\0" "-2" /* minimum 2 args */, | |
| &console, | |
| &cap_list | |
| ); | |
| + | dry_run >>= 2; // -n |
| if (cap_list) | |
| drop_capabilities(cap_list); | |
| #endif | |
| @@ -239,7 +237,7 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) | |
| // we mean it. I could make this a CONFIG option, but I would get email | |
| // from all the people who WILL destroy their filesystems. | |
| if (stat("/init", &st) != 0 || !S_ISREG(st.st_mode)) { | |
| - | bb_error_msg_and_die("/init is not a regular file"); |
| + | bb_error_msg_and_die("'%s' is not a regular file", "/init"); |
| } | |
| statfs("/", &stfs); // this never fails | |
| if ((unsigned)stfs.f_type != RAMFS_MAGIC | |
| @@ -248,13 +246,15 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) | |
| bb_error_msg_and_die("root filesystem is not ramfs/tmpfs"); | |
| } | |
| - | // Zap everything out of rootdev |
| - | delete_contents("/", rootdev); |
| + | if (!dry_run) { |
| + | // Zap everything out of rootdev |
| + | delete_contents("/", rootdev); |
| - | // 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"); |
| + | // 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"); |
| + | } |
| } | |
| xchroot("."); | |
| // The chdir is needed to recalculate "." and ".." links | |
| @@ -270,8 +270,17 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv) | |
| } | |
| } | |
| - | // Exec real init |
| - | execv(argv[0], argv); |
| + | if (dry_run) { |
| + | // Does NEW_INIT look like it can be executed? |
| + | //xstat(argv[0], &st); |
| + | //if (!S_ISREG(st.st_mode)) |
| + | // bb_perror_msg_and_die("'%s' is not a regular file", argv[0]); |
| + | if (access(argv[0], X_OK) == 0) |
| + | return 0; |
| + | } else { |
| + | // Exec NEW_INIT |
| + | execv(argv[0], argv); |
| + | } |
| bb_perror_msg_and_die("can't execute '%s'", argv[0]); | |
| } | |