syscall_user.c

来自「底层驱动开发」· C语言 代码 · 共 62 行

/* 
 * Copyright (C) 2000, 2001, 2002 Jeff Dike ([e-mail])
 * Licensed under the GPL
 */

#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <asm/unistd.h>
#include "sysdep/ptrace.h"
#include "sigcontext.h"
#include "ptrace_user.h"
#include "task.h"
#include "user_util.h"
#include "kern_util.h"
#include "syscall.h"
#include "tt.h"

void do_sigtrap(void *task)
{
	UPT_SYSCALL_NR(TASK_REGS(task)) = -1;
}

void do_syscall(void *task, int pid, int local_using_sysemu)
{
	unsigned long proc_regs[FRAME_SIZE];

	if(ptrace_getregs(pid, proc_regs) < 0)
		tracer_panic("Couldn't read registers");

	UPT_SYSCALL_NR(TASK_REGS(task)) = PT_SYSCALL_NR(proc_regs);

#ifdef UPT_ORIGGPR2
        UPT_ORIGGPR2(TASK_REGS(task)) = REGS_ORIGGPR2(proc_regs);
#endif

	if(((unsigned long *) PT_IP(proc_regs) >= &_stext) &&
	   ((unsigned long *) PT_IP(proc_regs) <= &_etext))
		tracer_panic("I'm tracing myself and I can't get out");

	/* advanced sysemu mode set syscall number to -1 automatically */
	if (local_using_sysemu==2)
		return;

	/* syscall number -1 in sysemu skips syscall restarting in host */
	if(ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
		  local_using_sysemu ? -1 : __NR_getpid) < 0)
		tracer_panic("do_syscall : Nullifying syscall failed, "
			     "errno = %d", errno);
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */