[v6,2/2] tr2: log parent process name

Message ID	20210722012707.205776-3-emilyshaffer@google.com (mailing list archive)
State	Accepted
Commit	2f732bf15e6dc9c2caf210784f180c6c059c570a
Headers	show Return-Path: <git-owner@kernel.org> Date: Wed, 21 Jul 2021 18:27:07 -0700 In-Reply-To: <20210722012707.205776-1-emilyshaffer@google.com> Message-Id: <20210722012707.205776-3-emilyshaffer@google.com> Mime-Version: 1.0 References: <20210722012707.205776-1-emilyshaffer@google.com> Subject: [PATCH v6 2/2] tr2: log parent process name From: Emily Shaffer <emilyshaffer@google.com> To: git@vger.kernel.org Cc: Emily Shaffer <emilyshaffer@google.com> Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	tr2: log parent process name \| expand [v6,0/2] tr2: log parent process name [v6,1/2] tr2: make process info collection platform-generic [v6,2/2] tr2: log parent process name

diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt index 3f52f981a2..8a0b360a0e 100644 --- a/Documentation/technical/api-trace2.txt +++ b/Documentation/technical/api-trace2.txt @@ -493,6 +493,20 @@ about specific error arguments. } ------------ +`"cmd_ancestry"`:: + This event contains the text command name for the parent (and earlier + generations of parents) of the current process, in an array ordered from + nearest parent to furthest great-grandparent. It may not be implemented + on all platforms. ++ +------------ +{ + "event":"cmd_ancestry", + ... + "ancestry":["bash","tmux: server","systemd"] +} +------------ + `"cmd_name"`:: This event contains the command name for this git process and the hierarchy of commands from parent git processes. diff --git a/compat/linux/procinfo.c b/compat/linux/procinfo.c new file mode 100644 index 0000000000..578fed4cd3 --- /dev/null +++ b/compat/linux/procinfo.c @@ -0,0 +1,55 @@ +#include "cache.h" + +#include "strbuf.h" +#include "strvec.h" +#include "trace2.h" + +static void get_ancestry_names(struct strvec *names) +{ + /* + * NEEDSWORK: We could gather the entire pstree into an array to match + * functionality with compat/win32/trace2_win32_process_info.c. + * To do so, we may want to examine /proc/<pid>/stat. For now, just + * gather the immediate parent name which is readily accessible from + * /proc/$(getppid())/comm. + */ + struct strbuf procfs_path = STRBUF_INIT; + struct strbuf name = STRBUF_INIT; + + /* try to use procfs if it's present. */ + strbuf_addf(&procfs_path, "/proc/%d/comm", getppid()); + if (strbuf_read_file(&name, procfs_path.buf, 0)) { + strbuf_release(&procfs_path); + strbuf_trim_trailing_newline(&name); + strvec_push(names, strbuf_detach(&name, NULL)); + } + + return; + /* NEEDSWORK: add non-procfs-linux implementations here */ +} + +void trace2_collect_process_info(enum trace2_process_info_reason reason) +{ + if (!trace2_is_enabled()) + return; + + /* someday we may want to write something extra here, but not today */ + if (reason == TRACE2_PROCESS_INFO_EXIT) + return; + + if (reason == TRACE2_PROCESS_INFO_STARTUP) { + /* + * NEEDSWORK: we could do the entire ptree in an array instead, + * see compat/win32/trace2_win32_process_info.c. + */ + struct strvec names = STRVEC_INIT; + + get_ancestry_names(&names); + + if (names.nr) + trace2_cmd_ancestry(names.v); + strvec_clear(&names); + } + + return; +} diff --git a/config.mak.uname b/config.mak.uname index 185ff79b14..d3bd4c6843 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -58,6 +58,8 @@ ifeq ($(uname_S),Linux) FREAD_READS_DIRECTORIES = UnfortunatelyYes BASIC_CFLAGS += -DHAVE_SYSINFO PROCFS_EXECUTABLE_PATH = /proc/self/exe + HAVE_PLATFORM_PROCINFO = YesPlease + COMPAT_OBJS += compat/linux/procinfo.o endif ifeq ($(uname_S),GNU/kFreeBSD) HAVE_ALLOCA_H = YesPlease diff --git a/t/t0210/scrub_normal.perl b/t/t0210/scrub_normal.perl index c65d1a815e..7cc4de392a 100644 --- a/t/t0210/scrub_normal.perl +++ b/t/t0210/scrub_normal.perl @@ -42,6 +42,12 @@ # so just omit it for testing purposes. # print "cmd_path _EXE_\n"; } + elsif ($line =~ m/^cmd_ancestry/) { + # 'cmd_ancestry' is not implemented everywhere, so for portability's + # sake, skip it when parsing normal. + # + # print "$line"; + } else { print "$line"; } diff --git a/t/t0211/scrub_perf.perl b/t/t0211/scrub_perf.perl index 351af7844e..d164b750ff 100644 --- a/t/t0211/scrub_perf.perl +++ b/t/t0211/scrub_perf.perl @@ -44,6 +44,11 @@ # $tokens[$col_rest] = "_EXE_"; goto SKIP_LINE; } + elsif ($tokens[$col_event] =~ m/cmd_ancestry/) { + # 'cmd_ancestry' is platform-specific and not implemented everywhere, + # so skip it. + goto SKIP_LINE; + } elsif ($tokens[$col_event] =~ m/child_exit/) { $tokens[$col_rest] =~ s/ pid:\d* / pid:_PID_ /; } diff --git a/t/t0212/parse_events.perl b/t/t0212/parse_events.perl index 6584bb5634..b6408560c0 100644 --- a/t/t0212/parse_events.perl +++ b/t/t0212/parse_events.perl @@ -132,7 +132,10 @@ # just omit it for testing purposes. # $processes->{$sid}->{'path'} = "_EXE_"; } - + elsif ($event eq 'cmd_ancestry') { + # 'cmd_ancestry' is platform-specific and not implemented everywhere, so + # just skip it for testing purposes. + } elsif ($event eq 'cmd_name') { $processes->{$sid}->{'name'} = $line->{'name'}; $processes->{$sid}->{'hierarchy'} = $line->{'hierarchy'}; diff --git a/trace2.c b/trace2.c index 256120c7fd..b9b154ac44 100644 --- a/trace2.c +++ b/trace2.c @@ -260,6 +260,19 @@ void trace2_cmd_path_fl(const char *file, int line, const char *pathname) tgt_j->pfn_command_path_fl(file, line, pathname); } +void trace2_cmd_ancestry_fl(const char *file, int line, const char **parent_names) +{ + struct tr2_tgt *tgt_j; + int j; + + if (!trace2_enabled) + return; + + for_each_wanted_builtin (j, tgt_j) + if (tgt_j->pfn_command_ancestry_fl) + tgt_j->pfn_command_ancestry_fl(file, line, parent_names); +} + void trace2_cmd_name_fl(const char *file, int line, const char *name) { struct tr2_tgt *tgt_j; diff --git a/trace2.h b/trace2.h index 0d990db817..9b7286c572 100644 --- a/trace2.h +++ b/trace2.h @@ -133,6 +133,16 @@ void trace2_cmd_path_fl(const char *file, int line, const char *pathname); #define trace2_cmd_path(p) trace2_cmd_path_fl(__FILE__, __LINE__, (p)) +/* + * Emit an 'ancestry' event with the process name of the current process's + * parent process. + * This gives post-processors a way to determine what invoked the command and + * learn more about usage patterns. + */ +void trace2_cmd_ancestry_fl(const char *file, int line, const char **parent_names); + +#define trace2_cmd_ancestry(v) trace2_cmd_ancestry_fl(__FILE__, __LINE__, (v)) + /* * Emit a 'cmd_name' event with the canonical name of the command. * This gives post-processors a simple field to identify the command diff --git a/trace2/tr2_tgt.h b/trace2/tr2_tgt.h index 7b90469212..1f66fd6573 100644 --- a/trace2/tr2_tgt.h +++ b/trace2/tr2_tgt.h @@ -27,6 +27,8 @@ typedef void(tr2_tgt_evt_error_va_fl_t)(const char *file, int line, typedef void(tr2_tgt_evt_command_path_fl_t)(const char *file, int line, const char *command_path); +typedef void(tr2_tgt_evt_command_ancestry_fl_t)(const char *file, int line, + const char **parent_names); typedef void(tr2_tgt_evt_command_name_fl_t)(const char *file, int line, const char *name, const char *hierarchy); @@ -108,6 +110,7 @@ struct tr2_tgt { tr2_tgt_evt_atexit_t *pfn_atexit; tr2_tgt_evt_error_va_fl_t *pfn_error_va_fl; tr2_tgt_evt_command_path_fl_t *pfn_command_path_fl; + tr2_tgt_evt_command_ancestry_fl_t *pfn_command_ancestry_fl; tr2_tgt_evt_command_name_fl_t *pfn_command_name_fl; tr2_tgt_evt_command_mode_fl_t *pfn_command_mode_fl; tr2_tgt_evt_alias_fl_t *pfn_alias_fl; diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c index 6353e8ad91..578a9a5287 100644 --- a/trace2/tr2_tgt_event.c +++ b/trace2/tr2_tgt_event.c @@ -261,6 +261,26 @@ static void fn_command_path_fl(const char *file, int line, const char *pathname) jw_release(&jw); } +static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names) +{ + const char *event_name = "cmd_ancestry"; + const char *parent_name = NULL; + struct json_writer jw = JSON_WRITER_INIT; + + jw_object_begin(&jw, 0); + event_fmt_prepare(event_name, file, line, NULL, &jw); + jw_object_inline_begin_array(&jw, "ancestry"); + + while ((parent_name = *parent_names++)) + jw_array_string(&jw, parent_name); + + jw_end(&jw); /* 'ancestry' array */ + jw_end(&jw); /* event object */ + + tr2_dst_write_line(&tr2dst_event, &jw.json); + jw_release(&jw); +} + static void fn_command_name_fl(const char *file, int line, const char *name, const char *hierarchy) { @@ -584,6 +604,7 @@ struct tr2_tgt tr2_tgt_event = { fn_atexit, fn_error_va_fl, fn_command_path_fl, + fn_command_ancestry_fl, fn_command_name_fl, fn_command_mode_fl, fn_alias_fl, diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c index 31b602c171..a5751c8864 100644 --- a/trace2/tr2_tgt_normal.c +++ b/trace2/tr2_tgt_normal.c @@ -160,6 +160,24 @@ static void fn_command_path_fl(const char *file, int line, const char *pathname) strbuf_release(&buf_payload); } +static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names) +{ + const char *parent_name = NULL; + struct strbuf buf_payload = STRBUF_INIT; + + /* cmd_ancestry parent <- grandparent <- great-grandparent */ + strbuf_addstr(&buf_payload, "cmd_ancestry "); + while ((parent_name = *parent_names++)) { + strbuf_addstr(&buf_payload, parent_name); + /* if we'll write another one after this, add a delimiter */ + if (parent_names && *parent_names) + strbuf_addstr(&buf_payload, " <- "); + } + + normal_io_write_fl(file, line, &buf_payload); + strbuf_release(&buf_payload); +} + static void fn_command_name_fl(const char *file, int line, const char *name, const char *hierarchy) { @@ -306,6 +324,7 @@ struct tr2_tgt tr2_tgt_normal = { fn_atexit, fn_error_va_fl, fn_command_path_fl, + fn_command_ancestry_fl, fn_command_name_fl, fn_command_mode_fl, fn_alias_fl, diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c index a8018f18cc..af4d65a0a5 100644 --- a/trace2/tr2_tgt_perf.c +++ b/trace2/tr2_tgt_perf.c @@ -253,6 +253,21 @@ static void fn_command_path_fl(const char *file, int line, const char *pathname) strbuf_release(&buf_payload); } +static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names) +{ + const char *event_name = "cmd_ancestry"; + struct strbuf buf_payload = STRBUF_INIT; + + strbuf_addstr(&buf_payload, "ancestry:["); + /* It's not an argv but the rules are basically the same. */ + sq_append_quote_argv_pretty(&buf_payload, parent_names); + strbuf_addch(&buf_payload, ']'); + + perf_io_write_fl(file, line, event_name, NULL, NULL, NULL, NULL, + &buf_payload); + strbuf_release(&buf_payload); +} + static void fn_command_name_fl(const char *file, int line, const char *name, const char *hierarchy) { @@ -532,6 +547,7 @@ struct tr2_tgt tr2_tgt_perf = { fn_atexit, fn_error_va_fl, fn_command_path_fl, + fn_command_ancestry_fl, fn_command_name_fl, fn_command_mode_fl, fn_alias_fl,

[v6,2/2] tr2: log parent process name

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