On 9/13/19 5:40 PM, Dmitry V. Levin wrote:
> On Thu, Sep 12, 2019 at 11:17:52AM +0200, Michael Kerrisk (man-pages) wrote:
>> Hello Dmitry,
>>
>> On 9/11/19 7:38 PM, Dmitry V. Levin wrote:
>>> Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx>
>>> ---
>>> man2/ptrace.2 | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 50 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/man2/ptrace.2 b/man2/ptrace.2
>>> index ff897bb19..b030247e6 100644
>>> --- a/man2/ptrace.2
>>> +++ b/man2/ptrace.2
>>> @@ -1026,7 +1026,56 @@ If the size of the data to be written by the kernel exceeds the size
>>> specified by the
>>> .I addr
>>> argument, the output data is truncated.
>>> -.\" FIXME Document 'struct ptrace_syscall_info'
>>> +.IP
>>> +The
>>> +.I ptrace_syscall_info
>>> +structure contains the following fields:
>>> +.IP
>>> +.in
>>> +.EX
>>> +struct ptrace_syscall_info {
>>> + __u8 op; /* PTRACE_SYSCALL_INFO_* value
>>> + describing the kind
>>> + of system call stop,
>>> + see <linux/ptrace.h> */
>>> + __u32 arch; /* AUDIT_ARCH_* value,
>>> + see seccomp(2) */
>>> + __u64 instruction_pointer; /* CPU instruction pointer */
>>> + __u64 stack_pointer; /* CPU stack pointer */
>>> + union {
>>> + struct {
>>> + __u64 nr; /* System call number */
>>> + __u64 args[6]; /* System call arguments */
>>> + } entry; /* Information specific to
>>> + system call entry stops */
>>> + struct {
>>> + __s64 rval; /* System call return value */
>>> + __u8 is_error; /* System call error flag */
>>> + } exit; /* Information specific to
>>> + system call exit stops */
>>> + struct {
>>> + __u64 nr; /* System call number */
>>> + __u64 args[6]; /* System call arguments */
>>> + __u32 ret_data; /* The SECCOMP_RET_DATA portion
>>> + of SECCOMP_RET_TRACE return
>>> + value */
>>> + } seccomp; /* Information specific to
>>> + PTRACE_EVENT_SECCOMP stops */
>>> + };
>>> +};
>>> +.EE
>>> +.in
>>> +.IP
>>> +.IR op ,
>>> +.IR arch ,
>>> +.IR instruction_pointer ,
>>> +and
>>> +.I stack_pointer
>>> +fields are defined for all kinds of ptrace system call stops.
>>> +The rest of the structure is a union, one should read only those fields
>>> +that are meaningful for the kind of system call stop specified by the
>>> +.IR op
>>> +field.
>>> .\"
>>> .SS Death under ptrace
>>> When a (possibly multithreaded) process receives a killing signal
>>
>> Thanks. I've applied, and done some light editing.
>>
>> I also added some pieces. Could you please take a look at commits
>> f04534d22c69 [1] and 227a3682312 [2] let me know if they are okay.
>
> Thanks. The only thing that needs correction is
> "Boolean: is rval != 0?" comment about is_error field.
>
> In fact, is_error is a boolean that tells whether rval field
> contains a non-error return value (e.g. file descriptor) or
> an error value (e.g. -ERRORCODE).
Thanks for checking this Dmitry. I see what I missed before.
I've now changed the text here to be:
__u8 is_error; /* System call error flag;
Boolean: does rval contain
an error value (\-ERRCODE) or
a nonerror return value? */
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
