wind_cheng <wind_ch...@asustek.com.cn> writes:
> I want to know system call number, after your method, I print
> regs.ARM_ORIG_r0. it's 0
On ARM the syscall number is not in register r0.
> and i find out none of them is the right one.
> i make a system call execve, it's system call number is 11, but none of the
> regs is 11.
> Please tell me how should i do to get system call number .
apt-get source strace
shows
/*
* Get the ARM-mode system call number
*/
errno = 0;
scno = ptrace(PTRACE_PEEKTEXT, pid, (void *)(regs.ARM_pc - 4), NULL);
if (errno)
return -1;
if (scno == 0 && (tcp->flags & TCB_WAITEXECVE)) {
tcp->flags &= ~TCB_WAITEXECVE;
return 0;
}
/* Handle the EABI syscall convention. We do not
bother converting structures between the two
ABIs, but basic functionality should work even
if strace and the traced program have different
ABIs. */
if (scno == 0xef000000) {
scno = regs.ARM_r7;
} else {
if ((scno & 0x0ff00000) != 0x0f900000) {
fprintf(stderr, "syscall: unknown syscall trap 0x%08lx\n",
scno);
return -1;
}
/*
* Fixup the syscall number
*/
scno &= 0x000fffff;
}
Just curious, why are you trying to reimplement this?
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