Renaming perf_evsel__disable() to evsel__disable(), so we don't have a
name clash when we add perf_evsel__disable() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-17-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evsel__enable() to evsel__enable(), so we don't have a name
clash when we add perf_evsel__enable() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-16-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evsel__open() to evsel__open(), so we don't have a name
clash when we add perf_evsel__open() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-15-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evlist__remove() to evlist__remove(), so we don't have a
name clash when we add perf_evlist__remove() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-14-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evlist__add() to evlist__add(), so we don't have a name
clash when we add perf_evlist__add() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-13-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evsel__new() to evsel__new(), so we don't have a name clash
when we add perf_evsel__new() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-12-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Remame perf_evsel__delete() to evsel__delete(), so we don't have a name
clash when we add perf_evsel__delete() in libperf.

Also renaming perf_evsel__delete_priv() to evsel__delete_priv().
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-11-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evlist__delete() to evlist__delete(), so we don't have a
name clash when we add perf_evlist__delete() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-10-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evlist__new() to evlist__new(), so we don't have a name
clash when we add perf_evlist__new() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-9-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evlist__init() to evlist__init(), so we don't have a name
clash when we add perf_evlist__init() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-8-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename perf_evsel__init() to evsel__init(), so we don't have a name
clash when we add perf_evsel__init() in libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-7-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename struct perf_evlist to struct evlist, so we don't have a name
clash when we add struct perf_evlist in libperf.

Committer notes:

Added fixes to build on arm64, from Jiri and from me
(tools/perf/util/cs-etm.c)
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-6-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename struct perf_evsel to struct evsel, so we don't have a name clash
when we add struct perf_evsel in libperf.

Committer notes:

Added fixes for arm64, provided by Jiri.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-5-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename struct thread_map to struct perf_thread_map, so it could be part
of libperf.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-4-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Rename struct cpu_map to struct perf_cpu_map, so it could be part of
libperf.

Committer notes:

Added fixes for arm64, provided by Jiri.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-3-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Because we will make struct perf_counts_values public in following
patches and 'loaded' is implementation related.

No functional change is expected.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-2-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We were looking in tracefs for:

  /sys/kernel/debug/tracing/events/syscalls/sys_enter_sendfile/format when

what is there is just

  /sys/kernel/debug/tracing/events/syscalls/sys_enter_sendfile/format

Its the same id, 40 in x86_64, so just add an alias and let the existing
logic take care of that.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-km2hmg7hru6u4pawi5fi903q@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We have an augmenter for the "open" syscall, which has just one pointer,
in the first argument, a "const char *", so any other syscall that has
just one pointer and that is the first can reuse the "open" BPF
augmenter program.

Even more, syscalls that get two pointers with the first being a string
can reuse "open"'s BPF augmenter till we have an augmenter that better
matches that syscall with two pointers.

With this the few augmenters we have, for open (first arg is a string),
openat (2nd arg is a string), renameat (2nd and 4th are strings) can be
reused by a lot of syscalls, ditto for "bind" reusing "connect" because
both have the 2nd argument as a sockaddr and the 3rd as its len.

Lets see how this makes the "bind" syscall reuse the "connect" BPF prog
augmenter found in tools/perf/examples/bpf/augmented_raw_syscalls.c:

  # perf trace -e bind,connect systemctl restart sshd
  connect(3, { .family: PF_LOCAL, path: /run/systemd/private }, 23) = 0
  #

Oh, it just connects to some daemon, so we better do it system wide and then
stop/start sshd:

  # perf trace -e bind,connect
  systemctl/10124 connect(3, { .family: PF_LOCAL, path: /run/systemd/private }, 23) = 0
  sshd/10102 connect(7, { .family: PF_LOCAL, path: /dev/log }, 110) = 0
  systemctl/10126 connect(3, { .family: PF_LOCAL, path: /run/systemd/private }, 23) = 0
  systemd/10128  ... [continued]: connect())            = 0
  (sshd)/10128 connect(3, { .family: PF_LOCAL, path: /run/systemd/journal/stdout }, 30) ...
  sshd/10128 bind(3, { .family: PF_NETLINK }, 12)    = 0
  sshd/10128 connect(4, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  sshd/10128 connect(3, { .family: PF_INET6, port: 22, addr: :: }, 28) = 0
  sshd/10128 connect(3, { .family: PF_UNSPEC }, 16)  = 0
  sshd/10128 connect(3, { .family: PF_INET, port: 22, addr: 0.0.0.0 }, 16) = 0
  sshd/10128 connect(3, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  sshd/10128 connect(3, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  sshd/10128 connect(5, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  sshd/10128 connect(5, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  sshd/10128 bind(4, { .family: PF_INET, port: 22, addr: 0.0.0.0 }, 16) = 0
  sshd/10128 connect(6, { .family: PF_LOCAL, path: /dev/log }, 110) = 0
  sshd/10128 bind(6, { .family: PF_INET6, port: 22, addr: :: }, 28) = 0
  sshd/10128 connect(7, { .family: PF_LOCAL, path: /dev/log }, 110) = 0
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-zfley2ghs4nim1uq4nu6ed3l@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We'll continue reading its details from tracefs as we need it, but
preallocate the whole thing otherwise we may realloc and end up with
pointers to the previous buffer.

I.e. in an upcoming algorithm we'll look for syscalls that have function
signatures that are similar to a given syscall to see if we can reuse
its BPF augmenter, so we may be at syscall 42, having a 'struct syscall'
pointing to that slot in trace->syscalls.table[] and try to read the
slot for an yet unread syscall, which would realloc that table to read
the info for syscall 43, say, which would trigger a realoc of
trace->syscalls.table[], and then the pointer we had for syscall 42
would be pointing to the previous block of memory. b00m.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-m3cjzzifibs13imafhkk77a0@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

There are holes in syscall tables with IDs not associated with any
syscall, mark those when trying to read information for syscalls, which
could happen when iterating thru all syscalls from 0 to the highest
numbered syscall id.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-cku9mpcrcsqaiq0jepu86r68@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We iterate thru the syscall table produced from the kernel syscall
tables reading info, propagate the error and add to the debug message.

This helps in fixing further bugs, such as failing to read the
"sendfile" syscall info when it really should try the aliasm
"sendfile64".

  Problems reading syscall 40: 2 (No such file or directory)(sendfile) information

  # grep sendfile /tmp/build/perf/arch/x86/include/generated/asm/syscalls_64.c
	[40] = "sendfile",
  #

I.e. in the tracefs format file for the syscall tracepoints we have it
as sendfile64:

  # find /sys -type f -name format | grep sendfile
  /sys/kernel/debug/tracing/events/syscalls/sys_enter_sendfile64/format
  /sys/kernel/debug/tracing/events/syscalls/sys_exit_sendfile64/format
  #

But as "sendfile" in the file used to build the syscall table used in
perf:

  $ grep sendfile arch/x86/entry/syscalls/syscall_64.tbl
  40	common	sendfile		__x64_sys_sendfile64
  $

So we need to add, in followup patches, aliases in 'perf trace' syscall
data structures to cope with thie.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-w3eluap63x9je0bb8o3t79tz@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

I.e. two strings:

  # perf trace -e rename
  systemd/1 rename("/run/systemd/units/.#invocation:dnf-makecache.service970761b7f2840dcc", "/run/systemd/units/invocation:dnf-makecache.service") = 0
  systemd-journa/715 rename("/run/systemd/journal/streams/.#9:17539785BJDblc", "/run/systemd/journal/streams/9:17539785") = 0
  mv/1936 rename("/tmp/build/perf/fd/.array.o.tmp", "/tmp/build/perf/fd/.array.o.cmd") = 0
  sh/1949 rename("/tmp/build/perf/.cpu.o.tmp", "/tmp/build/perf/.cpu.o.cmd") = 0
  mv/1954 rename("/tmp/build/perf/fs/.tracing_path.o.tmp", "/tmp/build/perf/fs/.tracing_path.o.cmd") = 0
  mv/1963 rename("/tmp/build/perf/common-cmds.h+", "/tmp/build/perf/common-cmds.h") = 0
  :1975/1975 rename("/tmp/build/perf/.exec-cmd.o.tmp", "/tmp/build/perf/.exec-cmd.o.cmd") = 0
  mv/1979 rename("/tmp/build/perf/fs/.fs.o.tmp", "/tmp/build/perf/fs/.fs.o.cmd") = 0
  mv/2005 rename("/tmp/build/perf/.debug.o.tmp", "/tmp/build/perf/.debug.o.cmd") = 0
  mv/2012 rename("/tmp/build/perf/.str_error_r.o.tmp", "/tmp/build/perf/.str_error_r.o.cmd") = 0
  mv/2019 rename("/tmp/build/perf/.help.o.tmp", "/tmp/build/perf/.help.o.cmd") = 0
  mv/2031 rename("/tmp/build/perf/.trace-seq.o.tmp", "/tmp/build/perf/.trace-seq.o.cmd") = 0
  make/2038  ... [continued]: rename())             = 0
  :2038/2038 rename("/tmp/build/perf/.event-plugin.o.tmp", "/tmp/build/perf/.event-plugin.o.cmd") ...
  ar/2035 rename("/tmp/build/perf/stzwBX3a", "/tmp/build/perf/libapi.a") = 0
  mv/2051 rename("/tmp/build/perf/.parse-utils.o.tmp", "/tmp/build/perf/.parse-utils.o.cmd") = 0
  mv/2069 rename("/tmp/build/perf/.subcmd-config.o.tmp", "/tmp/build/perf/.subcmd-config.o.cmd") = 0
  make/2080 rename("/tmp/build/perf/.parse-filter.o.tmp", "/tmp/build/perf/.parse-filter.o.cmd") = 0
  mv/2099 rename("/tmp/build/perf/.pager.o.tmp", "/tmp/build/perf/.pager.o.cmd") = 0
  :2124/2124 rename("/tmp/build/perf/.sigchain.o.tmp", "/tmp/build/perf/.sigchain.o.cmd") = 0
  make/2140 rename("/tmp/build/perf/.event-parse.o.tmp", "/tmp/build/perf/.event-parse.o.cmd") = 0
  mv/2164 rename("/tmp/build/perf/.kbuffer-parse.o.tmp", "/tmp/build/perf/.kbuffer-parse.o.cmd") = 0
  sh/2174 rename("/tmp/build/perf/.run-command.o.tmp", "/tmp/build/perf/.run-command.o.cmd") = 0
  mv/2190 rename("/tmp/build/perf/.tep_strerror.o.tmp", "/tmp/build/perf/.tep_strerror.o.cmd") = 0
  :2261/2261 rename("/tmp/build/perf/.event-parse-api.o.tmp", "/tmp/build/perf/.event-parse-api.o.cmd") = 0
  :2480/2480 rename("/tmp/build/perf/stLv3kG2", "/tmp/build/perf/libtraceevent.a") = 0
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-6hh2rl27uri6gsxhmk6q3hx5@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

By reusing the "connect" BPF collector.

Testing it system wide and stopping/starting sshd:

  # perf trace -e bind
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  DNS Res~er #18/15132 bind(243, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #19/4833 bind(247, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #19/4833 bind(238, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #18/15132 bind(243, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #18/10327 bind(258, { .family: PF_NETLINK }, 12)  = 0
  :6507/6507 bind(24, { .family: PF_NETLINK }, 12)   = 0
  DNS Res~er #19/4833 bind(238, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #18/15132 bind(242, { .family: PF_NETLINK }, 12)  = 0
  sshd/6514 bind(3, { .family: PF_NETLINK }, 12)    = 0
  sshd/6514 bind(5, { .family: PF_INET, port: 22, addr: 0.0.0.0 }, 16) = 0
  sshd/6514 bind(7, { .family: PF_INET6, port: 22, addr: :: }, 28) = 0
  DNS Res~er #18/10327 bind(229, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #18/15132 bind(231, { .family: PF_NETLINK }, 12)  = 0
  DNS Res~er #19/4833 bind(229, { .family: PF_NETLINK }, 12)  = 0
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-m2hmxqrckxxw2ciki0tu889u@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

By just writing the collector in the augmented_raw_syscalls.c BPF
program:

  # perf trace -e sendto
  <SNIP>
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  Socket Thread/3573 sendto(247, 0x7fb32d49c000, 120, NONE, { .family: PF_UNSPEC }, NULL) = 120
  DNS Res~er #18/11374 sendto(242, 0x7fb342cfe420, 20, NONE, { .family: PF_NETLINK }, 0xc) = 20
  DNS Res~er #18/11374 sendto(242, 0x7fb342cfcca0, 42, MSG_NOSIGNAL, { .family: PF_UNSPEC }, NULL) = 42
  DNS Res~er #18/11374 sendto(242, 0x7fb342cfcccc, 42, MSG_NOSIGNAL, { .family: PF_UNSPEC }, NULL) = 42
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  Socket Thread/3573 sendto(242, 0x7fb308bb1c08, 296, NONE, { .family: PF_UNSPEC }, NULL) = 296
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
  ^C
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-p0l0rlvq19v5zf8qc2x2itow@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Doesn't make sense and also we now beautify the sockaddr, which provides
enough info:

  # trace -e close,socket,connec* ssh www.bla.com
  <SNIP>
  close(5)                                = 0
  socket(PF_INET, SOCK_DGRAM|CLOEXEC|NONBLOCK, IPPROTO_IP) = 5
  connect(5, { .family: PF_INET, port: 53, addr: 192.168.44.1 }, 16) = 0
  close(5)                                = 0
  socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 5
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-h9drpb7ail808d2mh4n7tla4@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

As we invalidate the fd->pathname table in the SCA_CLOSE_FD beautifier,
if we don't have it we may end up keeping an fd->pathname association
that then gets misprinted.

The previous behaviour continues when the close() syscall is enabled,
which may still be a a problem if we lose records (i.e. we may lose a
'close' record and then get that fd reused by socket()) but then the
tool will notify that records are being lost and the user will be warned
that some of the heuristics will fall apart.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-b7t6h8sq9lebemvfy2zh3qq1@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

  # perf trace -e connec* ssh www.bla.com
  connect(3</var/lib/sss/mc/passwd>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(3</var/lib/sss/mc/passwd>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(4<socket:[16610959]>, { .family: PF_LOCAL, path: /var/lib/sss/pipes/nss }, 110) = 0
  connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(5, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(5</usr/lib64/libnss_mdns4_minimal.so.2>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  connect(5</usr/lib64/libnss_mdns4_minimal.so.2>, { .family: PF_INET, port: 53, addr: 192.168.44.1 }, 16) = 0
  connect(5</usr/lib64/libnss_mdns4_minimal.so.2>, { .family: PF_INET, port: 22, addr: 146.112.61.108 }, 16) = 0
  connect(5</usr/lib64/libnss_mdns4_minimal.so.2>, { .family: PF_INET6, port: 22, addr: ::ffff:146.112.61.108 }, 28) = 0
  ^Cconnect(5</usr/lib64/libnss_mdns4_minimal.so.2>, { .family: PF_INET, port: 22, addr: 146.112.61.108 }, 16) = -1 (unknown) (INTERNAL ERROR: strerror_r(512, [buf], 128)=22)
  #

Argh, the SCA_FD needs to invalidate its cache when close is done...

It works if the 'close' syscall is not filtered out ;-\

  # perf trace -e close,connec* ssh www.bla.com
  close(3)                                = 0
  close(3</usr/lib64/libpcre2-8.so.0.8.0>) = 0
  close(3)                                = 0
  close(3</usr/lib64/libkrb5.so.3.3>)     = 0
  close(3</usr/lib64/libkrb5.so.3.3>)     = 0
  close(3)                                = 0
  close(3</usr/lib64/libk5crypto.so.3.1>) = 0
  close(3</usr/lib64/libk5crypto.so.3.1>) = 0
  close(3</usr/lib64/libcom_err.so.2.1>)  = 0
  close(3</usr/lib64/libcom_err.so.2.1>)  = 0
  close(3)                                = 0
  close(3</usr/lib64/libkrb5support.so.0.1>) = 0
  close(3</usr/lib64/libkrb5support.so.0.1>) = 0
  close(3</usr/lib64/libkeyutils.so.1.8>) = 0
  close(3</usr/lib64/libkeyutils.so.1.8>) = 0
  close(3)                                = 0
  close(3)                                = 0
  close(3)                                = 0
  close(3)                                = 0
  close(4)                                = 0
  close(3)                                = 0
  close(3)                                = 0
  connect(3</etc/nsswitch.conf>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  close(3</etc/nsswitch.conf>)            = 0
  connect(3</usr/lib64/libnss_sss.so.2>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 110) = -1 ENOENT (No such file or directory)
  close(3</usr/lib64/libnss_sss.so.2>)    = 0
  close(3</usr/lib64/libnss_sss.so.2>)    = 0
  close(3)                                = 0
  close(3)                                = 0
  connect(4<socket:[16616519]>, { .family: PF_LOCAL, path: /var/lib/sss/pipes/nss }, 110) = 0
  ^C
  #

Will disable this beautifier when 'close' is filtered out...

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-ekuiciyx4znchvy95c8p1yyi@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We already had a beautifier for an augmented sockaddr payload, but that
was when we were hooking on each syscalls:sys_enter_foo tracepoints,
since now we're almost doing that by doing a tail call from
raw_syscalls:sys_enter, its almost the same, we can reuse it straight
away.

  # perf trace -e connec* ssh www.bla.com
  connect(3</var/lib/sss/mc/passwd>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(3</var/lib/sss/mc/passwd>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(4<socket:[16604782]>, { .family: PF_LOCAL, path: /var/lib/sss/pipes/nss }, 0x6e) = 0
  connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(7, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(5</etc/hosts>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(5</etc/hosts>, { .family: PF_LOCAL, path: /var/run/nscd/socket }, 0x6e) = -1 ENOENT (No such file or directory)
  connect(5</etc/hosts>, { .family: PF_INET, port: 53, addr: 192.168.44.1 }, 0x10) = 0
  connect(5</etc/hosts>, { .family: PF_INET, port: 22, addr: 146.112.61.108 }, 0x10) = 0
  connect(5</etc/hosts>, { .family: PF_INET6, port: 22, addr: ::ffff:146.112.61.108 }, 0x1c) = 0
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-5xkrbcpjsgnr3zt1aqdd7nvc@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It'll get other stuff in there than just filenames, starting with
sockaddr for 'connect' and 'bind'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-bsexidtsn91ehdpzcd6n5fm9@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

I.e. just look for "!syscalls:sys_enter_" or "exit_" plus the syscall
name, that way we need just to add entries to the
augmented_raw_syscalls.c BPF source to add handlers.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-6xavwddruokp6ohs7tf4qilb@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Starting with the renameat and renameat2 syscall, that both receive as
second and fourth parameters a pathname:

  # perf trace -e rename* mv one ANOTHER
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  mv: cannot stat 'one': No such file or directory
  renameat2(AT_FDCWD, "one", AT_FDCWD, "ANOTHER", RENAME_NOREPLACE) = -1 ENOENT (No such file or directory)
  #

Since the per CPU scratch buffer map has space for two maximum sized
pathnames, the verifier is satisfied that there will be no overrun.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-x2uboyg5kx2wqeru288209b6@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Trying to control what arguments to copy, which ones were strings, etc
all from userspace via maps went nowhere, lots of difficulties to get
the verifier satisfied, so use what the fine BPF guys designed for such
a syscall handling mechanism: bpf_tail_call + BPF_MAP_TYPE_PROG_ARRAY.

The series leading to this should have explained it thoroughly, but the
end result, explained via gdb should help understand this:

  Breakpoint 1, syscall_arg__scnprintf_filename (bf=0xc002b1 "", size=2031, arg=0x7fffffff7970) at builtin-trace.c:1268
  1268	{
  (gdb) n
  1269		unsigned long ptr = arg->val;
  (gdb) n
  1271		if (arg->augmented.args)
  (gdb) n
  1272			return syscall_arg__scnprintf_augmented_string(arg, bf, size);
  (gdb) s
  syscall_arg__scnprintf_augmented_string (arg=0x7fffffff7970, bf=0xc002b1 "", size=2031) at builtin-trace.c:1251
  1251	{
  (gdb) n
  1252		struct augmented_arg *augmented_arg = arg->augmented.args;
  (gdb) n
  1253		size_t printed = scnprintf(bf, size, "\"%.*s\"", augmented_arg->size, augmented_arg->value);
  (gdb) n
  1258		int consumed = sizeof(*augmented_arg) + augmented_arg->size;
  (gdb) p bf
  $1 = 0xc002b1 "\"/etc/ld.so.cache\""
  (gdb) bt
  #0  syscall_arg__scnprintf_augmented_string (arg=0x7fffffff7970, bf=0xc002b1 "\"/etc/ld.so.cache\"", size=2031) at builtin-trace.c:1258
  #1  0x0000000000492634 in syscall_arg__scnprintf_filename (bf=0xc002b1 "\"/etc/ld.so.cache\"", size=2031, arg=0x7fffffff7970) at builtin-trace.c:1272
  #2  0x0000000000493cd7 in syscall__scnprintf_val (sc=0xc0de68, bf=0xc002b1 "\"/etc/ld.so.cache\"", size=2031, arg=0x7fffffff7970, val=140737354091036) at builtin-trace.c:1689
  #3  0x000000000049404f in syscall__scnprintf_args (sc=0xc0de68, bf=0xc002a7 "AT_FDCWD, \"/etc/ld.so.cache\"", size=2041, args=0x7ffff6cbf1ec "\234\377\377\377", augmented_args=0x7ffff6cbf21c, augmented_args_size=28, trace=0x7fffffffa170,
      thread=0xbff940) at builtin-trace.c:1756
  #4  0x0000000000494a97 in trace__sys_enter (trace=0x7fffffffa170, evsel=0xbe1900, event=0x7ffff6cbf1a0, sample=0x7fffffff7b00) at builtin-trace.c:1975
  #5  0x0000000000496ff1 in trace__handle_event (trace=0x7fffffffa170, event=0x7ffff6cbf1a0, sample=0x7fffffff7b00) at builtin-trace.c:2685
  #6  0x0000000000497edb in __trace__deliver_event (trace=0x7fffffffa170, event=0x7ffff6cbf1a0) at builtin-trace.c:3029
  #7  0x000000000049801e in trace__deliver_event (trace=0x7fffffffa170, event=0x7ffff6cbf1a0) at builtin-trace.c:3056
  #8  0x00000000004988de in trace__run (trace=0x7fffffffa170, argc=2, argv=0x7fffffffd660) at builtin-trace.c:3258
  #9  0x000000000049c2d3 in cmd_trace (argc=2, argv=0x7fffffffd660) at builtin-trace.c:4220
  #10 0x00000000004dcb6c in run_builtin (p=0xa18e00 <commands+576>, argc=5, argv=0x7fffffffd660) at perf.c:304
  #11 0x00000000004dcdd9 in handle_internal_command (argc=5, argv=0x7fffffffd660) at perf.c:356
  #12 0x00000000004dcf20 in run_argv (argcp=0x7fffffffd4bc, argv=0x7fffffffd4b0) at perf.c:400
  #13 0x00000000004dd28c in main (argc=5, argv=0x7fffffffd660) at perf.c:522
  (gdb)
  (gdb) continue
  Continuing.
  openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3

Now its a matter of automagically assigning the BPF programs copying
syscall arg pointers to functions that are "open"-like (i.e. that need
only the first syscall arg copied as a string), or "openat"-like (2nd
arg, etc).

End result in tool output:

  # perf trace -e open* ls /tmp/notthere
  LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
  openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libcap.so.2", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libpcre2-8.so.0", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/lib64/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
  openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = ls: cannot access '/tmp/notthere'-1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo", O_RDONLY: No such file or directory) =
  -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-snc7ry99cl6r0pqaspjim98x@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

I.e. for a syscall that has its second argument being a string, its
difficult these days to find 'open' being used in the wild :-)

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-yf3kbzirqrukd3fb2sp5qx4p@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So, we use a PERF_COUNT_SW_BPF_OUTPUT to output the augmented sys_enter
payload, i.e. to output more than just the raw syscall args, and if
something goes wrong when handling an unfiltered syscall, we bail out
and just return 1 in the bpf program associated with
raw_syscalls:sys_enter, meaning, don't filter that tracepoint, in which
case what will appear in the perf ring buffer isn't the BPF_OUTPUT
event, but the original raw_syscalls:sys_enter event with its normal
payload.

Now that we're switching to using a bpf_tail_call +
BPF_MAP_TYPE_PROG_ARRAY we're going to use this in the common case, so a
bug where raw_syscalls:sys_enter wasn't being handled by
trace__sys_enter() surfaced and for  that case, instead of using the
strace-like augmenter (trace__sys_enter()), we continued to use the
normal generic tracepoint handler:

  (gdb) p evsel
  $2 = (struct perf_evsel *) 0xc03e40
  (gdb) p evsel->name
  $3 = 0xbc56c0 "raw_syscalls:sys_enter"
  (gdb) p ((struct perf_evsel *) 0xc03e40)->name
  $4 = 0xbc56c0 "raw_syscalls:sys_enter"
  (gdb) p ((struct perf_evsel *) 0xc03e40)->handler
  $5 = (void *) 0x495eb3 <trace__event_handler>

This resulted in this:

     0.027 raw_syscalls:sys_enter:NR 12 (0, 7fcfcac64c9b, 4d, 7fcfcac64c9b, 7fcfcac6ce00, 19)
     ... [continued]: brk())                = 0x563b88677000

I.e. only the sys_exit tracepoint was being properly handled, but since
the sys_enter went to the generic trace__event_handler() we printed it
using libtraceevent's formatter instead of 'perf trace's strace-like
one.

Fix it by setting trace__sys_enter() as the handler for
raw_syscalls:sys_enter and setup the tp_field tracepoint field
accessors.

Now, to test it we just make raw_syscalls:sys_enter return 1 right after
checking if the pid is filtered, making it not use
bpf_perf_output_event() but rather ask for the tracepoint not to be
filtered and the result is the expected one:

  brk(NULL)                               = 0x556f42d6e000

I.e. raw_syscalls:sys_enter returns 1, gets handled by
trace__sys_enter() and gets it combined with the raw_syscalls:sys_exit
in a strace-like way.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-0mkocgk31nmy0odknegcby4z@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

I.e. look for "syscalls_sys_enter" and "syscalls_sys_exit" BPF maps of
type PROG_ARRAY and populate it with the handlers as specified per
syscall, for now only 'open' is wiring it to something, in time all
syscalls that need to copy arguments entering a syscall or returning
from one will set these to the right handlers, reusing when possible
pre-existing ones.

Next step is to use bpf_tail_call() into that.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-t0p4u43i9vbpzs1xtowna3gb@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This is a step in the direction of being able to use a
BPF_MAP_TYPE_PROG_ARRAY to handle syscalls that need to copy pointer
payloads in addition to the raw tracepoint syscall args.

There is a first example in
tools/perf/examples/bpf/augmented_raw_syscalls.c for the 'open' syscall.

Next step is to introduce the prog array map and use this 'open'
augmenter, then use that augmenter in other syscalls that also only copy
the first arg as a string, and then show how to use with a syscall that
reads more than one filename, like 'rename', etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-pys4v57x5qqrybb4cery2mc8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Will be used to assign to syscalls that don't need augmentation, i.e.
those with just integer args.

All syscalls will be in a BPF_MAP_TYPE_PROG_ARRAY, and the
bpf_tail_call() keyed by the syscall id will either find nothing in
place, which means the syscall is being filtered, or a function that
will either add things like filenames to the ring buffer, right after
the raw syscall args, or be this unaugmented handler that will just
return 1, meaning don't filter the original
raw_syscalls:sys_{enter,exit} tracepoint.

For now it is not really being used, this is just leg work to break the
patch into smaller pieces.

It introduces a trace__find_bpf_program_by_title() helper that in turn
uses libbpf's bpf_object__find_program_by_title() on the BPF object with
the __augmented_syscalls__ map. "title" is how libbpf calls the SEC()
argument for functions, i.e. the ELF section that follows a convention
to specify what BPF program (a function with this SEC() marking) should
be connected to which tracepoint, kprobes, etc.

In perf anything that is of the form SEC("sys:event_name") will be
connected to that tracepoint by perf's BPF loader.

In this case its something that will be bpf_tail_call()ed from either
the "raw_syscalls:sys_enter" or "raw_syscall:sys_exit" tracepoints, so
its named "!raw_syscalls:unaugmented" to convey that idea, i.e. its not
going to be directly attached to a tracepoint, thus it starts with a
"!".

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-meucpjx2u0slpkayx56lxqq6@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The ev_qualifier is an array with the syscall ids passed via -e on the
command line, sort it as we'll search it when setting up the
BPF_MAP_TYPE_PROG_ARRAY.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-c8hprylp3ai6e0z9burn2r3s@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We can conceivably have multiple BPF object files for other purposes, so
better look just on the BPF object containing the __augmented_syscalls__
map for all things augmented_syscalls related.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-3jt8knkuae9lt705r1lns202@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

So that we can use it when looking for other components of that object
file, such as other programs to add to the BPF_MAP_TYPE_PROG_ARRAY and
use with bpf_tail_call().

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-1ibmz7ouv6llqxajy7m8igtd@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>