On Fri, 26 Sep 2014 12:13:57 -0700 Andy Lutomirski <[email protected]> wrote:
> 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 probably makes sense. 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 new option called strictinit. If init= and strictinit > are both set, and the init= binary is not executable, then the > kernel will panic immediately. If strictinit is set but init= is > not set, then strictinit will have no effect, because the only real > alternative would be to panic regardless of the contents of the root > fs. > > Signed-off-by: Andy Lutomirski <[email protected]> > --- > Documentation/kernel-parameters.txt | 8 ++++++++ > init/main.c | 16 ++++++++++++++-- > 2 files changed, 22 insertions(+), 2 deletions(-) > > diff --git a/Documentation/kernel-parameters.txt > b/Documentation/kernel-parameters.txt > index 10d51c2f10d7..1576273edce6 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -3236,6 +3236,14 @@ bytes respectively. Such letter suffixes can also be > entirely omitted. > stifb= [HW] > Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] > > + strictinit [KNL,BOOT] > + Normally, if the kernel can't find the init binary > + specified by rdinit= and/or init=, then it will > + try several fallbacks. If strictinit is set > + and the value specified by init= does not work, > + then the kernel will panic instead. > + This option makes no sense if init= is not specified. > + > sunrpc.min_resvport= > sunrpc.max_resvport= > [NFS,SUNRPC] > diff --git a/init/main.c b/init/main.c > index bb1aed928f21..2ae0f2776155 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -131,6 +131,7 @@ static char *initcall_command_line; > > static char *execute_command; > static char *ramdisk_execute_command; > +static bool strictinit; > > /* > * Used to generate warnings if static_key manipulation functions are used > @@ -347,6 +348,13 @@ static int __init rdinit_setup(char *str) > } > __setup("rdinit=", rdinit_setup); > > +static int __init strictinit_setup(char *str) > +{ > + strictinit = true; > + return 1; > +} > +__setup("strictinit", strictinit_setup); > + > #ifndef CONFIG_SMP > static const unsigned int setup_max_cpus = NR_CPUS; > #ifdef CONFIG_X86_LOCAL_APIC > @@ -960,8 +968,12 @@ static int __ref kernel_init(void *unused) > ret = run_init_process(execute_command); > if (!ret) > return 0; > - pr_err("Failed to execute %s (error %d). Attempting > defaults...\n", > - execute_command, ret); > + if (strictinit) > + panic("Requested init %s failed (error %d) and > strictinit was set.", > + execute_command, ret); > + else > + pr_err("Failed to execute %s (error %d). Attempting > defaults...\n", > + execute_command, ret); > } > if (!try_to_run_init_process("/sbin/init") || > !try_to_run_init_process("/etc/init") || Can't you just make it use "init=foo,strict" instead? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
