Re: [PATCH man] kcmp: Add KCMP_EPOLL_TFD description
From: Michael Kerrisk (man-pages) <hidden>
Date: 2017-08-15 19:49:47
Hello Cyril, On 08/06/2017 09:38 AM, Cyrill Gorcunov wrote:
KCMP_EPOLL_TFD
Check whether the file descriptor idx1 of process pid1 present in epoll(7)
instance described by idx2 of process pid2. The argument idx2 is an
address of structure where the target file is described.
struct kcmp_epoll_slot {
__u32 efd;
__u32 tfd;
__u64 toff;
};
where efd is epoll file descriptor from epoll_create(2) call, tfd is a
target file number, toff is a target file offset counted from zero. Sev‐
eral different targets may be registered with the same file descriptor
number and setting specific offset helps to investigate each of them.Thanks. I've applied this patch. Is there some example program that demonstrates the use of this feature? Cheers, Michael
quoted hunk
Signed-off-by: Cyrill Gorcunov <redacted> --- man2/kcmp.2 | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) Index: man-pages/man2/kcmp.2 ===================================================================--- man-pages.orig/man2/kcmp.2 +++ man-pages/man2/kcmp.2@@ -156,6 +156,44 @@ See the discussion of the .BR CLONE_VM flag in .BR clone (2). +.TP +.BR KCMP_EPOLL_TFD +Check whether the file descriptor +.I idx1 +of the process +.I pid1 +present in +.BR epoll (7) +instance described by +.I idx2 +of the process +.IR pid2 . +The argument +.I idx2 +is an address of a structure where the target file is described. +.in +4n +.nf +.sp +struct kcmp_epoll_slot { + __u32 efd; + __u32 tfd; + __u64 toff; +}; +.fi +.in +.sp +where +.I efd +is epoll file descriptor from +.BR epoll_create (2) +call, +.I tfd +is a target file number, +.I toff +is a target file offset counted from zero. +Several different targets may be registered with +the same file descriptor number and setting specific +offset helps to investigate each of them. .PP Note the .BR kcmp ()@@ -246,6 +284,16 @@ Process or .I pid2 does not exist. +.TP +.B EFAULT +The epoll slot addressed by +.I idx2 +is outside of the user's address space. +.TP +.B ENOENT +The target file is not present in +.BR epoll () +instance. .SH VERSIONS The .BR kcmp ()
-- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/