1 /* Return codes: 1 - ok, 0 - ignore, other - error. */
2 static int
arch_get_scno(struct tcb * tcp)3 arch_get_scno(struct tcb *tcp)
4 {
5 long scno = 0;
6
7 /*
8 * In the new syscall ABI, the system call number is in R3.
9 */
10 if (upeek(tcp->pid, 4*(REG_REG0+3), &scno) < 0)
11 return -1;
12
13 if (scno < 0) {
14 /* Odd as it may seem, a glibc bug has been known to cause
15 glibc to issue bogus negative syscall numbers. So for
16 our purposes, make strace print what it *should* have been */
17 long correct_scno = (scno & 0xff);
18 if (debug_flag)
19 error_msg("Detected glibc bug: bogus system call"
20 " number = %ld, correcting to %ld",
21 scno, correct_scno);
22 scno = correct_scno;
23 }
24
25 tcp->scno = scno;
26 return 1;
27 }
28