As we'll also hook into the syscalls:sys_exit_SYSCALL for which there
are enter hooks.
This way we'll be able to iterate the ELF file for the eBPF program,
find the syscalls that have hooks and filter them out from the general
raw_syscalls:sys_{enter,exit} tracepoint for not-yet-augmented (the ones
with pointer arguments not yet being attached to the usual syscalls
tracepoint payload) and non augmentable syscalls (syscalls without
pointer arguments).
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-cl1xyghwb1usp500354mv37h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Create auxiliary trace data log files when invoked with option
--itrace=d as in:
[root@s35lp76 perf] perf report -i perf.data.aux1 --stdio --itrace=d
perf report creates several data files in the current directory named
aux.smp.## where ## is a 2 digit hex number with leading zeros
representing the CPU number this trace data was recorded from. The file
contents is binary and contains the CPU-Measurement Sampling Data Blocks
(SDBs).
The directory to save the auxiliary trace buffer can be changed using
the perf config file and command. Specify section 'auxtrace' keyword
'dumpdir' and assign it a valid directory name. If the directory does
not exist or has the wrong file type, the current directory is used.
[root@p23lp27 perf]# perf config auxtrace.dumpdir=/tmp
[root@p23lp27 perf]# perf config --user -l auxtrace.dumpdir=/tmp
[root@p23lp27 perf]# perf report ...
[root@p23lp27 perf]# ll /tmp/aux.smp.00
-rw-r--r-- 1 root root 204800 Aug 2 13:48 /tmp/aux.smp.00
[root@p23lp27 perf]#
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180809045650.89197-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
One more, to reuse the augmented_sockaddr_syscall_enter() macro
introduced from the augmentation of connect's sockaddr arg, also to get
a subset of the struct arg augmentations done using the manual method,
before switching to something automatic, using tracefs's format file or,
even better, BTF containing the syscall args structs.
# perf trace -e tools/perf/examples/bpf/augmented_syscalls.c
0.000 sshd/11479 bind(fd: 3<socket:[170336]>, umyaddr: { .family: NETLINK }, addrlen: 12)
1.752 sshd/11479 bind(fd: 3<socket:[170336]>, umyaddr: { .family: INET, port: 22, addr: 0.0.0.0 }, addrlen: 16)
1.924 sshd/11479 bind(fd: 4<socket:[170338]>, umyaddr: { .family: INET6, port: 22, addr: :: }, addrlen: 28)
^C#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-a2drqpahpmc7uwb3n3gj2plu@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This is the final touch in showing how a syscall argument beautifier can
access the augmented args put in place by the
tools/perf/examples/bpf/augmented_syscalls.c eBPF script, right after
the regular raw syscall args, i.e. the up to 6 long integer values in
the syscall interface.
With this we are able to show the 'openat' syscall arg, now with up to
64 bytes, but in time this will be configurable, just like with the
'strace -s strsize' argument, from 'strace''s man page:
-s strsize Specify the maximum string size to print (the default is 32).
This actually is the maximum string to _collect_ and store in the ring
buffer, not just print.
Before:
# perf trace -e tools/perf/examples/bpf/augmented_syscalls.c,openat cat /etc/passwd > /dev/null
0.000 ( ): cat/9658 openat(dfd: CWD, filename: 0x6626eda8, flags: CLOEXEC)
0.017 ( 0.007 ms): cat/9658 openat(dfd: CWD, filename: 0x6626eda8, flags: CLOEXEC) = 3
0.049 ( ): cat/9658 openat(dfd: CWD, filename: 0x66476ce0, flags: CLOEXEC)
0.051 ( 0.007 ms): cat/9658 openat(dfd: CWD, filename: 0x66476ce0, flags: CLOEXEC) = 3
0.377 ( ): cat/9658 openat(dfd: CWD, filename: 0x1e8f806b)
0.379 ( 0.005 ms): cat/9658 openat(dfd: CWD, filename: 0x1e8f806b) = 3
#
After:
# perf trace -e tools/perf/examples/bpf/augmented_syscalls.c,openat cat /etc/passwd > /dev/null
0.000 ( ): cat/11966 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC)
0.006 ( 0.006 ms): cat/11966 openat(dfd: CWD, filename: 0x4bfdcda8, flags: CLOEXEC) = 3
0.034 ( ): cat/11966 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC)
0.036 ( 0.008 ms): cat/11966 openat(dfd: CWD, filename: 0x4c1e4ce0, flags: CLOEXEC) = 3
0.375 ( ): cat/11966 openat(dfd: CWD, filename: /etc/passwd)
0.377 ( 0.005 ms): cat/11966 openat(dfd: CWD, filename: 0xe87906b) = 3
#
This cset should show all the aspects of establishing a protocol between
an eBPF syscall arg augmenter program, tools/perf/examples/bpf/augmented_syscalls.c and
a 'perf trace' beautifier, the one associated with all 'char *' point
syscall args with names that can heuristically be associated with
filenames.
Now to wire up 'open' to show a second syscall using this scheme, all we
have to do now is to change tools/perf/examples/bpf/augmented_syscalls.c,
as 'perf trace' will notice that the perf_sample.raw_size is more than
what is expected for a particular syscall payload as defined by its
tracefs format file and will then use the augmented payload in the
'filename' syscall arg beautifier.
The same protocol will be used for structs such as 'struct sockaddr *',
'struct pollfd', etc, with additions for handling arrays.
This will all be done under the hood when 'perf trace' realizes the
system has the necessary components, and also can be done by providing
a precompiled augmented_syscalls.c eBPF ELF object.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-gj9kqb61wo7m3shtpzercbcr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
