diff options
author | Andy Lutomirski <luto@amacapital.net> | 2014-11-20 11:33:59 +1100 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-11-20 11:33:59 +1100 |
commit | 1160d4a951a74c55435112509ff3d1a6927367f4 (patch) | |
tree | 1344c1ccd9c61df898a63dfa801d9227d9d73743 | |
parent | 25ed378135eccff8b6802fa95704d66567153e1b (diff) |
init: allow CONFIG_INIT_FALLBACK=n to disable defaults if init= fails
If a user puts init=/whatever on the command line and /whatever can't be
run, then the kernel will try a few default options before giving up. If
init=/whatever came from a bootloader prompt, then this is unexpected but
probably harmless. On the other hand, if it comes from a script (e.g. a
tool like virtme or perhaps a future kselftest script), then the fallbacks
are likely to exist, but they'll do the wrong thing. For example, they
might unexpectedly invoke systemd.
This adds a config option CONFIG_INIT_FALLBACK. If unset, then a failure
to run the specified init= process be fatal.
The tentative plan is to remove CONFIG_INIT_FALLBACK for 3.20.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Rob Landley <rob@landley.net>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shuah Khan <shuah.kh@samsung.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | init/Kconfig | 16 | ||||
-rw-r--r-- | init/main.c | 7 |
2 files changed, 22 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig index b74a3ca9b8b7..f7852be9421a 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1287,6 +1287,22 @@ source "usr/Kconfig" endif +config INIT_FALLBACK + bool "Fall back to defaults if init= parameter is bad" + default y + help + If enabled, the kernel will try the default init binaries if an + explicit request from the init= parameter fails. + + This can have unexpected effects. For example, booting + with init=/sbin/kiosk_app will run /sbin/init or even /bin/sh + if /sbin/kiosk_app cannot be executed. + + The default value of Y is consistent with historical behavior. + Selecting N is likely to be more appropriate for most uses, + especially on kiosks and on kernels that are indended to be + run under the control of a script. + config CC_OPTIMIZE_FOR_SIZE bool "Optimize for size" help diff --git a/init/main.c b/init/main.c index d2e4ead4891f..ca380ec685de 100644 --- a/init/main.c +++ b/init/main.c @@ -952,8 +952,13 @@ static int __ref kernel_init(void *unused) ret = run_init_process(execute_command); if (!ret) return 0; +#ifndef CONFIG_INIT_FALLBACK + panic("Requested init %s failed (error %d).", + execute_command, ret); +#else pr_err("Failed to execute %s (error %d). Attempting defaults...\n", - execute_command, ret); + execute_command, ret); +#endif } if (!try_to_run_init_process("/sbin/init") || !try_to_run_init_process("/etc/init") || |