[CRIU] [PATCH 1/2] criu: Dump and restore pdeath_sig value
Serge Hallyn
serge.hallyn at ubuntu.com
Fri Jun 27 10:06:56 PDT 2014
Quoting Pavel Emelyanov (xemul at parallels.com):
> The implementation is pretty straightforward. When dumping per-thread
> misc data with parasite, collect one, then write in thread_core_info.
>
> On restore wait for creds restore and put the value back (some creds
> changes drop it to zero).
>
> Signed-off-by: Pavel Emelyanov <xemul at parallels.com>
Thanks - simple containers actually probably won't need this (because
the deathsig is used between the lxc monitor and init, not inside the
container) but eventually for nested containers it will.
Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>
> ---
> cr-dump.c | 4 ++++
> cr-restore.c | 5 +++++
> include/parasite.h | 1 +
> include/restorer.h | 1 +
> pie/parasite.c | 14 ++++++++++++--
> pie/restorer.c | 20 ++++++++++++++++++++
> protobuf/core.proto | 1 +
> 7 files changed, 44 insertions(+), 2 deletions(-)
>
> diff --git a/cr-dump.c b/cr-dump.c
> index c4c9777..45f1f5f 100644
> --- a/cr-dump.c
> +++ b/cr-dump.c
> @@ -689,6 +689,10 @@ int dump_thread_core(int pid, CoreEntry *core, const struct parasite_dump_thread
> CORE_THREAD_ARCH_INFO(core)->clear_tid_addr = encode_pointer(ti->tid_addr);
> BUG_ON(!tc->sas);
> copy_sas(tc->sas, &ti->sas);
> + if (ti->pdeath_sig) {
> + tc->has_pdeath_sig = true;
> + tc->pdeath_sig = ti->pdeath_sig;
> + }
> }
>
> return ret;
> diff --git a/cr-restore.c b/cr-restore.c
> index 573b989..270d1d1 100644
> --- a/cr-restore.c
> +++ b/cr-restore.c
> @@ -2557,6 +2557,11 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core)
> thread_args[i].has_futex = true;
> thread_args[i].futex_rla = tcore->thread_core->futex_rla;
> thread_args[i].futex_rla_len = tcore->thread_core->futex_rla_len;
> + thread_args[i].pdeath_sig = tcore->thread_core->pdeath_sig;
> + if (tcore->thread_core->pdeath_sig > _KNSIG) {
> + pr_err("Pdeath signal is too big\n");
> + goto err;
> + }
>
> ret = prep_sched_info(&thread_args[i].sp, tcore->thread_core);
> if (ret)
> diff --git a/include/parasite.h b/include/parasite.h
> index ddfe975..eaabc01 100644
> --- a/include/parasite.h
> +++ b/include/parasite.h
> @@ -141,6 +141,7 @@ struct parasite_dump_thread {
> pid_t tid;
> tls_t tls;
> stack_t sas;
> + int pdeath_sig;
> };
>
> /*
> diff --git a/include/restorer.h b/include/restorer.h
> index bdb2adc..842cc32 100644
> --- a/include/restorer.h
> +++ b/include/restorer.h
> @@ -90,6 +90,7 @@ struct thread_restore_args {
>
> siginfo_t *siginfo;
> unsigned int siginfo_nr;
> + int pdeath_sig;
> } __aligned(64);
>
> struct task_restore_args {
> diff --git a/pie/parasite.c b/pie/parasite.c
> index be46bfc..92e7708 100644
> --- a/pie/parasite.c
> +++ b/pie/parasite.c
> @@ -35,6 +35,10 @@ static struct parasite_dump_pages_args *mprotect_args = NULL;
> #define SPLICE_F_GIFT 0x08
> #endif
>
> +#ifndef PR_GET_PDEATHSIG
> +#define PR_GET_PDEATHSIG 2
> +#endif
> +
> static int mprotect_vmas(struct parasite_dump_pages_args *args)
> {
> struct parasite_vma_entry *vmas, *vma;
> @@ -145,9 +149,15 @@ static int dump_thread_common(struct parasite_dump_thread *ti)
>
> arch_get_tls(&ti->tls);
> ret = sys_prctl(PR_GET_TID_ADDRESS, (unsigned long) &ti->tid_addr, 0, 0, 0);
> - if (ret == 0)
> - ret = sys_sigaltstack(NULL, &ti->sas);
> + if (ret)
> + goto out;
>
> + ret = sys_sigaltstack(NULL, &ti->sas);
> + if (ret)
> + goto out;
> +
> + ret = sys_prctl(PR_GET_PDEATHSIG, (unsigned long)&ti->pdeath_sig, 0, 0, 0);
> +out:
> return ret;
> }
>
> diff --git a/pie/restorer.c b/pie/restorer.c
> index 27e6929..1ba14e7 100644
> --- a/pie/restorer.c
> +++ b/pie/restorer.c
> @@ -35,6 +35,10 @@
>
> #include "asm/restorer.h"
>
> +#ifndef PR_SET_PDEATHSIG
> +#define PR_SET_PDEATHSIG 1
> +#endif
> +
> #define sys_prctl_safe(opcode, val1, val2, val3) \
> ({ \
> long __ret = sys_prctl(opcode, val1, val2, val3, 0); \
> @@ -189,6 +193,20 @@ static int restore_creds(CredsEntry *ce)
> return 0;
> }
>
> +/*
> + * This should be done after creds restore, as
> + * some creds changes might drop the value back
> + * to zero.
> + */
> +
> +static inline int restore_pdeath_sig(struct thread_restore_args *ta)
> +{
> + if (ta->pdeath_sig)
> + return sys_prctl(PR_SET_PDEATHSIG, ta->pdeath_sig, 0, 0, 0);
> + else
> + return 0;
> +}
> +
> static int restore_dumpable_flag(MmEntry *mme)
> {
> int current_dumpable;
> @@ -349,6 +367,7 @@ long __export_restore_thread(struct thread_restore_args *args)
> goto core_restore_end;
>
> restore_finish_stage(CR_STATE_RESTORE_SIGCHLD);
> + restore_pdeath_sig(args);
> restore_finish_stage(CR_STATE_RESTORE_CREDS);
> futex_dec_and_wake(&thread_inprogress);
>
> @@ -1004,6 +1023,7 @@ long __export_restore_task(struct task_restore_args *args)
>
> ret = restore_creds(&args->creds);
> ret = ret || restore_dumpable_flag(&args->mm);
> + ret = ret || restore_pdeath_sig(args->t);
>
> futex_set_and_wake(&thread_inprogress, args->nr_threads);
>
> diff --git a/protobuf/core.proto b/protobuf/core.proto
> index 21218ec..d850e2e 100644
> --- a/protobuf/core.proto
> +++ b/protobuf/core.proto
> @@ -48,6 +48,7 @@ message thread_core_entry {
> optional uint32 sched_prio = 5;
> optional uint64 blk_sigset = 6;
> optional thread_sas_entry sas = 7;
> + optional uint32 pdeath_sig = 8;
> }
>
> message task_rlimits_entry {
> --
> 1.8.4.2
>
>
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