114 lines
2.1 KiB
C
114 lines
2.1 KiB
C
![]() |
#include <linux/ftrace.h>
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#include <linux/kernel.h>
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#include <asm/syscall.h>
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#include "trace_output.h"
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#include "trace.h"
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static atomic_t refcount;
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void start_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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if (atomic_inc_return(&refcount) != 1)
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goto out;
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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out:
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atomic_dec(&refcount);
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}
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void stop_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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if (atomic_dec_return(&refcount))
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goto out;
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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out:
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atomic_inc(&refcount);
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}
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void ftrace_syscall_enter(struct pt_regs *regs)
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{
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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trace_printk("syscall %d enter\n", syscall_nr);
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}
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void ftrace_syscall_exit(struct pt_regs *regs)
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{
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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trace_printk("syscall %d exit\n", syscall_nr);
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}
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static int init_syscall_tracer(struct trace_array *tr)
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{
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start_ftrace_syscalls();
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return 0;
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}
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static void reset_syscall_tracer(struct trace_array *tr)
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{
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stop_ftrace_syscalls();
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}
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static struct trace_event syscall_enter_event = {
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.type = TRACE_SYSCALL_ENTER,
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};
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static struct trace_event syscall_exit_event = {
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.type = TRACE_SYSCALL_EXIT,
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};
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static struct tracer syscall_tracer __read_mostly = {
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.name = "syscall",
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.init = init_syscall_tracer,
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.reset = reset_syscall_tracer
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};
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__init int register_ftrace_syscalls(void)
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{
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int ret;
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ret = register_ftrace_event(&syscall_enter_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_enter_event.type);
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WARN_ON_ONCE(1);
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}
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ret = register_ftrace_event(&syscall_exit_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_exit_event.type);
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WARN_ON_ONCE(1);
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}
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return register_tracer(&syscall_tracer);
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}
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device_initcall(register_ftrace_syscalls);
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