X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=include%2Flinux%2Ftracehook.h;h=1eb44a924e5643066677f7d3edef90d6ef9cce0d;hb=f653398c86a1c104f0992bd788dd4bb065449be4;hp=8b4c15e208feb4e7a651787efb488a666611191c;hpb=445a91d2fe3667fb8fc251433645f686933cf56a;p=safe%2Fjmp%2Flinux-2.6 diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 8b4c15e..1eb44a9 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -1,7 +1,7 @@ /* * Tracing hooks * - * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions @@ -66,13 +66,84 @@ static inline int tracehook_expect_breakpoints(struct task_struct *task) return (task_ptrace(task) & PT_PTRACED) != 0; } +/* + * ptrace report for syscall entry and exit looks identical. + */ +static inline void ptrace_report_syscall(struct pt_regs *regs) +{ + int ptrace = task_ptrace(current); + + if (!(ptrace & PT_PTRACED)) + return; + + ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); + + /* + * this isn't the same as continuing with a signal, but it will do + * for normal use. strace only continues with a signal if the + * stopping signal is not SIGTRAP. -brl + */ + if (current->exit_code) { + send_sig(current->exit_code, current, 1); + current->exit_code = 0; + } +} + +/** + * tracehook_report_syscall_entry - task is about to attempt a system call + * @regs: user register state of current task + * + * This will be called if %TIF_SYSCALL_TRACE has been set, when the + * current task has just entered the kernel for a system call. + * Full user register state is available here. Changing the values + * in @regs can affect the system call number and arguments to be tried. + * It is safe to block here, preventing the system call from beginning. + * + * Returns zero normally, or nonzero if the calling arch code should abort + * the system call. That must prevent normal entry so no system call is + * made. If @task ever returns to user mode after this, its register state + * is unspecified, but should be something harmless like an %ENOSYS error + * return. It should preserve enough information so that syscall_rollback() + * can work (see asm-generic/syscall.h). + * + * Called without locks, just after entering kernel mode. + */ +static inline __must_check int tracehook_report_syscall_entry( + struct pt_regs *regs) +{ + ptrace_report_syscall(regs); + return 0; +} + +/** + * tracehook_report_syscall_exit - task has just finished a system call + * @regs: user register state of current task + * @step: nonzero if simulating single-step or block-step + * + * This will be called if %TIF_SYSCALL_TRACE has been set, when the + * current task has just finished an attempted system call. Full + * user register state is available here. It is safe to block here, + * preventing signals from being processed. + * + * If @step is nonzero, this report is also in lieu of the normal + * trap that would follow the system call instruction because + * user_enable_block_step() or user_enable_single_step() was used. + * In this case, %TIF_SYSCALL_TRACE might not be set. + * + * Called without locks, just before checking for pending signals. + */ +static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) +{ + ptrace_report_syscall(regs); +} + /** * tracehook_unsafe_exec - check for exec declared unsafe due to tracing * @task: current task doing exec * * Return %LSM_UNSAFE_* bits applied to an exec because of tracing. * - * Called with task_lock() held on @task. + * @task->cred_guard_mutex is held by the caller through the do_execve(). */ static inline int tracehook_unsafe_exec(struct task_struct *task) { @@ -173,7 +244,7 @@ static inline int tracehook_prepare_clone(unsigned clone_flags) * tracehook_finish_clone - new child created and being attached * @child: new child task * @clone_flags: %CLONE_* flags from clone/fork/vfork system call - * @trace: return value from tracehook_clone_prepare() + * @trace: return value from tracehook_prepare_clone() * * This is called immediately after adding @child to its parent's children list. * The @trace value is that returned by tracehook_prepare_clone(). @@ -188,29 +259,29 @@ static inline void tracehook_finish_clone(struct task_struct *child, /** * tracehook_report_clone - in parent, new child is about to start running - * @trace: return value from tracehook_clone_prepare() * @regs: parent's user register state * @clone_flags: flags from parent's system call * @pid: new child's PID in the parent's namespace * @child: new child task * * Called after a child is set up, but before it has been started running. - * The @trace value is that returned by tracehook_clone_prepare(). - * This is not a good place to block, because the child has not started yet. - * Suspend the child here if desired, and block in tracehook_clone_complete(). - * This must prevent the child from self-reaping if tracehook_clone_complete() - * uses the @child pointer; otherwise it might have died and been released by - * the time tracehook_report_clone_complete() is called. + * This is not a good place to block, because the child has not started + * yet. Suspend the child here if desired, and then block in + * tracehook_report_clone_complete(). This must prevent the child from + * self-reaping if tracehook_report_clone_complete() uses the @child + * pointer; otherwise it might have died and been released by the time + * tracehook_report_clone_complete() is called. * * Called with no locks held, but the child cannot run until this returns. */ -static inline void tracehook_report_clone(int trace, struct pt_regs *regs, +static inline void tracehook_report_clone(struct pt_regs *regs, unsigned long clone_flags, pid_t pid, struct task_struct *child) { - if (unlikely(trace)) { + if (unlikely(task_ptrace(child))) { /* - * The child starts up with an immediate SIGSTOP. + * It doesn't matter who attached/attaching to this + * task, the pending SIGSTOP is right in any case. */ sigaddset(&child->pending.signal, SIGSTOP); set_tsk_thread_flag(child, TIF_SIGPENDING); @@ -219,7 +290,7 @@ static inline void tracehook_report_clone(int trace, struct pt_regs *regs, /** * tracehook_report_clone_complete - new child is running - * @trace: return value from tracehook_clone_prepare() + * @trace: return value from tracehook_prepare_clone() * @regs: parent's user register state * @clone_flags: flags from parent's system call * @pid: new child's PID in the parent's namespace @@ -276,7 +347,7 @@ static inline void tracehook_prepare_release_task(struct task_struct *task) } /** - * tracehook_finish_release_task - task is being reaped, clean up tracing + * tracehook_finish_release_task - final tracing clean-up * @task: task in %EXIT_DEAD state * * This is called in release_task() when @task is being in the middle of @@ -316,17 +387,14 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info, * tracehook_consider_ignored_signal - suppress short-circuit of ignored signal * @task: task receiving the signal * @sig: signal number being sent - * @handler: %SIG_IGN or %SIG_DFL * * Return zero iff tracing doesn't care to examine this ignored signal, * so it can short-circuit normal delivery and never even get queued. - * Either @handler is %SIG_DFL and @sig's default is ignore, or it's %SIG_IGN. * * Called with @task->sighand->siglock held. */ static inline int tracehook_consider_ignored_signal(struct task_struct *task, - int sig, - void __user *handler) + int sig) { return (task_ptrace(task) & PT_PTRACED) != 0; } @@ -335,21 +403,190 @@ static inline int tracehook_consider_ignored_signal(struct task_struct *task, * tracehook_consider_fatal_signal - suppress special handling of fatal signal * @task: task receiving the signal * @sig: signal number being sent - * @handler: %SIG_DFL or %SIG_IGN * * Return nonzero to prevent special handling of this termination signal. - * Normally @handler is %SIG_DFL. It can be %SIG_IGN if @sig is ignored, - * in which case force_sig() is about to reset it to %SIG_DFL. + * Normally handler for signal is %SIG_DFL. It can be %SIG_IGN if @sig is + * ignored, in which case force_sig() is about to reset it to %SIG_DFL. * When this returns zero, this signal might cause a quick termination * that does not give the debugger a chance to intercept the signal. * * Called with or without @task->sighand->siglock held. */ static inline int tracehook_consider_fatal_signal(struct task_struct *task, - int sig, - void __user *handler) + int sig) { return (task_ptrace(task) & PT_PTRACED) != 0; } +/** + * tracehook_force_sigpending - let tracing force signal_pending(current) on + * + * Called when recomputing our signal_pending() flag. Return nonzero + * to force the signal_pending() flag on, so that tracehook_get_signal() + * will be called before the next return to user mode. + * + * Called with @current->sighand->siglock held. + */ +static inline int tracehook_force_sigpending(void) +{ + return 0; +} + +/** + * tracehook_get_signal - deliver synthetic signal to traced task + * @task: @current + * @regs: task_pt_regs(@current) + * @info: details of synthetic signal + * @return_ka: sigaction for synthetic signal + * + * Return zero to check for a real pending signal normally. + * Return -1 after releasing the siglock to repeat the check. + * Return a signal number to induce an artifical signal delivery, + * setting *@info and *@return_ka to specify its details and behavior. + * + * The @return_ka->sa_handler value controls the disposition of the + * signal, no matter the signal number. For %SIG_DFL, the return value + * is a representative signal to indicate the behavior (e.g. %SIGTERM + * for death, %SIGQUIT for core dump, %SIGSTOP for job control stop, + * %SIGTSTP for stop unless in an orphaned pgrp), but the signal number + * reported will be @info->si_signo instead. + * + * Called with @task->sighand->siglock held, before dequeuing pending signals. + */ +static inline int tracehook_get_signal(struct task_struct *task, + struct pt_regs *regs, + siginfo_t *info, + struct k_sigaction *return_ka) +{ + return 0; +} + +/** + * tracehook_notify_jctl - report about job control stop/continue + * @notify: zero, %CLD_STOPPED or %CLD_CONTINUED + * @why: %CLD_STOPPED or %CLD_CONTINUED + * + * This is called when we might call do_notify_parent_cldstop(). + * + * @notify is zero if we would not ordinarily send a %SIGCHLD, + * or is the %CLD_STOPPED or %CLD_CONTINUED .si_code for %SIGCHLD. + * + * @why is %CLD_STOPPED when about to stop for job control; + * we are already in %TASK_STOPPED state, about to call schedule(). + * It might also be that we have just exited (check %PF_EXITING), + * but need to report that a group-wide stop is complete. + * + * @why is %CLD_CONTINUED when waking up after job control stop and + * ready to make a delayed @notify report. + * + * Return the %CLD_* value for %SIGCHLD, or zero to generate no signal. + * + * Called with the siglock held. + */ +static inline int tracehook_notify_jctl(int notify, int why) +{ + return notify ?: (current->ptrace & PT_PTRACED) ? why : 0; +} + +/** + * tracehook_finish_jctl - report about return from job control stop + * + * This is called by do_signal_stop() after wakeup. + */ +static inline void tracehook_finish_jctl(void) +{ +} + +#define DEATH_REAP -1 +#define DEATH_DELAYED_GROUP_LEADER -2 + +/** + * tracehook_notify_death - task is dead, ready to notify parent + * @task: @current task now exiting + * @death_cookie: value to pass to tracehook_report_death() + * @group_dead: nonzero if this was the last thread in the group to die + * + * A return value >= 0 means call do_notify_parent() with that signal + * number. Negative return value can be %DEATH_REAP to self-reap right + * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our + * parent. Note that a return value of 0 means a do_notify_parent() call + * that sends no signal, but still wakes up a parent blocked in wait*(). + * + * Called with write_lock_irq(&tasklist_lock) held. + */ +static inline int tracehook_notify_death(struct task_struct *task, + void **death_cookie, int group_dead) +{ + if (task_detached(task)) + return task->ptrace ? SIGCHLD : DEATH_REAP; + + /* + * If something other than our normal parent is ptracing us, then + * send it a SIGCHLD instead of honoring exit_signal. exit_signal + * only has special meaning to our real parent. + */ + if (thread_group_empty(task) && !ptrace_reparented(task)) + return task->exit_signal; + + return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; +} + +/** + * tracehook_report_death - task is dead and ready to be reaped + * @task: @current task now exiting + * @signal: return value from tracheook_notify_death() + * @death_cookie: value passed back from tracehook_notify_death() + * @group_dead: nonzero if this was the last thread in the group to die + * + * Thread has just become a zombie or is about to self-reap. If positive, + * @signal is the signal number just sent to the parent (usually %SIGCHLD). + * If @signal is %DEATH_REAP, this thread will self-reap. If @signal is + * %DEATH_DELAYED_GROUP_LEADER, this is a delayed_group_leader() zombie. + * The @death_cookie was passed back by tracehook_notify_death(). + * + * If normal reaping is not inhibited, @task->exit_state might be changing + * in parallel. + * + * Called without locks. + */ +static inline void tracehook_report_death(struct task_struct *task, + int signal, void *death_cookie, + int group_dead) +{ +} + +#ifdef TIF_NOTIFY_RESUME +/** + * set_notify_resume - cause tracehook_notify_resume() to be called + * @task: task that will call tracehook_notify_resume() + * + * Calling this arranges that @task will call tracehook_notify_resume() + * before returning to user mode. If it's already running in user mode, + * it will enter the kernel and call tracehook_notify_resume() soon. + * If it's blocked, it will not be woken. + */ +static inline void set_notify_resume(struct task_struct *task) +{ + if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME)) + kick_process(task); +} + +/** + * tracehook_notify_resume - report when about to return to user mode + * @regs: user-mode registers of @current task + * + * This is called when %TIF_NOTIFY_RESUME has been set. Now we are + * about to return to user mode, and the user state in @regs can be + * inspected or adjusted. The caller in arch code has cleared + * %TIF_NOTIFY_RESUME before the call. If the flag gets set again + * asynchronously, this will be called again before we return to + * user mode. + * + * Called without locks. + */ +static inline void tracehook_notify_resume(struct pt_regs *regs) +{ +} +#endif /* TIF_NOTIFY_RESUME */ + #endif /* */