diff options
author | Andrey Vagin <avagin@openvz.org> | 2013-07-03 15:08:12 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-03 16:08:01 -0700 |
commit | 29000caecbe87b6b66f144f72111f0d02fbbf0c1 (patch) | |
tree | 91d178abd9543a49c087af857a3cfabececfd71e | |
parent | 37f07655522042399db7a4b54aee830bdb52ce2c (diff) |
ptrace: add ability to get/set signal-blocked mask
crtools uses a parasite code for dumping processes. The parasite code is
injected into a process with help PTRACE_SEIZE.
Currently crtools blocks signals from a parasite code. If a process has
pending signals, crtools wait while a process handles these signals.
This method is not suitable for stopped tasks. A stopped task can have a
few pending signals, when we will try to execute a parasite code, we will
need to drop SIGSTOP, but all other signals must remain pending, because a
state of processes must not be changed during checkpointing.
This patch adds two ptrace commands to set/get signal-blocked mask.
I think gdb can use this commands too.
[akpm@linux-foundation.org: be consistent with brace layout]
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/uapi/linux/ptrace.h | 3 | ||||
-rw-r--r-- | kernel/ptrace.c | 44 |
2 files changed, 45 insertions, 2 deletions
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h index 52ebcc89f306..cf1019e15f5b 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -61,6 +61,9 @@ struct ptrace_peeksiginfo_args { __s32 nr; /* how may siginfos to take */ }; +#define PTRACE_GETSIGMASK 0x420a +#define PTRACE_SETSIGMASK 0x420b + /* Read signals from a shared (process wide) queue */ #define PTRACE_PEEKSIGINFO_SHARED (1 << 0) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 335a7ae697f5..ba5e6cea181a 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -844,6 +844,47 @@ int ptrace_request(struct task_struct *child, long request, ret = ptrace_setsiginfo(child, &siginfo); break; + case PTRACE_GETSIGMASK: + if (addr != sizeof(sigset_t)) { + ret = -EINVAL; + break; + } + + if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) + ret = -EFAULT; + else + ret = 0; + + break; + + case PTRACE_SETSIGMASK: { + sigset_t new_set; + + if (addr != sizeof(sigset_t)) { + ret = -EINVAL; + break; + } + + if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { + ret = -EFAULT; + break; + } + + sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); + + /* + * Every thread does recalc_sigpending() after resume, so + * retarget_shared_pending() and recalc_sigpending() are not + * called here. + */ + spin_lock_irq(&child->sighand->siglock); + child->blocked = new_set; + spin_unlock_irq(&child->sighand->siglock); + + ret = 0; + break; + } + case PTRACE_INTERRUPT: /* * Stop tracee without any side-effect on signal or job @@ -948,8 +989,7 @@ int ptrace_request(struct task_struct *child, long request, #ifdef CONFIG_HAVE_ARCH_TRACEHOOK case PTRACE_GETREGSET: - case PTRACE_SETREGSET: - { + case PTRACE_SETREGSET: { struct iovec kiov; struct iovec __user *uiov = datavp; |