From 2c804457879c2dd76823d1b47f1a1eba5073727c Mon Sep 17 00:00:00 2001 From: Stefan Liebler Date: Tue, 11 Jul 2017 10:37:03 +0200 Subject: S390: Fix tst-ptrace-singleblock if kernel does not support PTRACE_SINGLEBLOCK. The request PTRACE_SINGLEBLOCK was introduced in Linux 3.15. Thus the ptrace call will fail on older kernels. Thus the test is now testing PTRACE_SINGLEBLOCK with data argument pointing to a buffer on stack which is assumed to fail. If the request would be interpreted as PTRACE_GETREGS, then the ptrace call will not fail and the regs are written to buf. If we run with a kernel with support for PTRACE_SINGLEBLOCK a ptrace call with data=NULL, returns zero with no error. If we run with a kernel without support for PTRACE_SINGLEBLOCK a ptrace call with data=NULL reports an error. In the latter case, the test is just continuing with PTRACE_CONT. ChangeLog: * sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c: Support running on kernels without PTRACE_SINGLEBLOCK. --- .../unix/sysv/linux/s390/tst-ptrace-singleblock.c | 54 +++++++++++++++++++++- 1 file changed, 52 insertions(+), 2 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c b/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c index 95a2f55612..c8eea0ad65 100644 --- a/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c +++ b/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include /* Ensure that we use the PTRACE_SINGLEBLOCK definition from glibc ptrace.h in tracer_func. We need the kernel ptrace.h for structs ptrace_area @@ -63,6 +65,10 @@ tracer_func (int pid) gregset_t regs2; int status; + int ret; +#define MAX_CHARS_IN_BUF 4096 + char buf[MAX_CHARS_IN_BUF + 1]; + size_t buf_count; while (1) { @@ -104,11 +110,55 @@ tracer_func (int pid) The s390 kernel has no support for PTRACE_GETREGS! Thus glibc ptrace.h is adjusted to match kernel ptrace.h. + The glibc sys/ptrace.h header contains the identifier + PTRACE_SINGLEBLOCK in enum __ptrace_request. In contrast, the kernel + asm/ptrace.h header defines PTRACE_SINGLEBLOCK. + This test ensures, that PTRACE_SINGLEBLOCK defined in glibc works as expected. If the kernel would interpret it as PTRACE_GETREGS, then the tracee will not make any progress - and this testcase will time out. */ - TEST_VERIFY_EXIT (ptrace (req_singleblock, pid, NULL, NULL) == 0); + and this testcase will time out or the ptrace call will fail with + different errors. */ + + /* Ptrace request 12 is first done with data argument pointing to + a buffer: + -If request 12 is interpreted as PTRACE_GETREGS, it will store the regs + to buffer without an error. + + -If request 12 is interpreted as PTRACE_SINGLEBLOCK, it will fail + as data argument is used as signal-number and the address of + buf is no valid signal. + + -If request 12 is not implemented, it will also fail. + + Here the test expects that the buffer is untouched and an error is + returned. */ + memset (buf, 'a', MAX_CHARS_IN_BUF); + ret = ptrace (req_singleblock, pid, NULL, buf); + buf [MAX_CHARS_IN_BUF] = '\0'; + buf_count = strspn (buf, "a"); + TEST_VERIFY_EXIT (buf_count == MAX_CHARS_IN_BUF); + TEST_VERIFY_EXIT (ret == -1); + + /* If request 12 is interpreted as PTRACE_GETREGS, the first ptrace + call will touch the buffer which is detected by this test. */ + errno = 0; + ret = ptrace (req_singleblock, pid, NULL, NULL); + if (ret == 0) + { + /* The kernel has support for PTRACE_SINGLEBLOCK ptrace request. */ + TEST_VERIFY_EXIT (errno == 0); + } + else + { + /* The kernel (< 3.15) has no support for PTRACE_SINGLEBLOCK ptrace + request. */ + TEST_VERIFY_EXIT (errno == EIO); + TEST_VERIFY_EXIT (ret == -1); + + /* Just continue tracee until it exits normally. */ + TEST_VERIFY_EXIT (ptrace (PTRACE_CONT, pid, NULL, NULL) == 0); + } } } -- cgit v1.2.1