From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Emily Shaffer <emilyshaffer@google.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v6 2/2] tr2: log parent process name
Date: Mon, 02 Aug 2021 12:22:07 +0200 [thread overview]
Message-ID: <87o8agp29o.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <20210722012707.205776-3-emilyshaffer@google.com>
On Wed, Jul 21 2021, Emily Shaffer wrote:
> Git for Windows also gathers information about more than one generation
> of parent. In Linux further ancestry info can be gathered with procfs,
> but it's unwieldy to do so.
Having read the win32 get_processes() implementation and read proc(5) I
don't get how it's unweildy to do so on Linux? Perhaps I'm missing some
special-case but this rather simple patch-on-top seems to do the job for
me. This includes the unrelated enum/switch/case change I suggested.
I can submit it as a patch-on-top with SOB etc, but maybe there's some
subtle reason it won't work properly. It works for me, I get e.g.:
{
"event": "cmd_ancestry",
"sid": "20210802T102731.879424Z-Hc2f5b994-P00001acc",
"thread": "main",
"time": "2021-08-02T10:27:31.879618Z",
"file": "compat/linux/procinfo.c",
"line": 66,
"ancestry": [
"bash",
"screen",
"systemd"
]
}
If anything the existing Windows version seems a bit unweildy, having to
apparently deal with cycles etc., I don't think that happens under
procfs, but maybe I'm missing some special-case.
diff --git a/compat/linux/procinfo.c b/compat/linux/procinfo.c
index 578fed4cd31..671fe2395fd 100644
--- a/compat/linux/procinfo.c
+++ b/compat/linux/procinfo.c
@@ -4,51 +4,65 @@
#include "strvec.h"
#include "trace2.h"
-static void get_ancestry_names(struct strvec *names)
+static int stat_parent_pid(FILE *fp, char *statcomm, int *statppid)
+{
+ char statstate;
+ int statpid;
+
+ int ret = fscanf(fp, "%d %s %c %d", &statpid, statcomm, &statstate,
+ statppid);
+ if (ret != 4)
+ return -1;
+ return 0;
+}
+
+static void push_ancestry_name(struct strvec *names, pid_t pid)
{
- /*
- * 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;
+ char statcomm[PATH_MAX];
+ FILE *fp;
+ int ppid;
/* 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));
- }
+ strbuf_addf(&procfs_path, "/proc/%d/stat", pid);
+ fp = fopen(procfs_path.buf, "r");
+ if (!fp)
+ return;
- return;
- /* NEEDSWORK: add non-procfs-linux implementations here */
+ if (stat_parent_pid(fp, statcomm, &ppid) < 0)
+ return;
+
+ /*
+ * The comm field is in parenthesis, use printf + offset as a
+ * poor man's trimming of both ends.
+ */
+ strvec_pushf(names, "%.*s", (int)strlen(statcomm) - 2, statcomm + 1);
+
+ /*
+ * Both errors and reaching the end of the process chain are
+ * reported as fields of 0 by proc(5)
+ */
+ if (ppid != 0)
+ push_ancestry_name(names, ppid);
}
void trace2_collect_process_info(enum trace2_process_info_reason reason)
{
- if (!trace2_is_enabled())
- return;
+ struct strvec names = STRVEC_INIT;
- /* someday we may want to write something extra here, but not today */
- if (reason == TRACE2_PROCESS_INFO_EXIT)
+ if (!trace2_is_enabled())
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);
+ switch (reason) {
+ case TRACE2_PROCESS_INFO_EXIT:
+ break;
+ case TRACE2_PROCESS_INFO_STARTUP:
+ push_ancestry_name(&names, getppid());
if (names.nr)
trace2_cmd_ancestry(names.v);
strvec_clear(&names);
+ break;
}
return;
next prev parent reply other threads:[~2021-08-02 10:30 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 0:29 [PATCH] tr2: log parent process name Emily Shaffer
2021-05-07 3:25 ` Bagas Sanjaya
2021-05-07 17:09 ` Emily Shaffer
2021-05-10 12:29 ` Ævar Arnfjörð Bjarmason
2021-05-11 21:31 ` Junio C Hamano
2021-05-14 22:06 ` Emily Shaffer
2021-05-16 3:48 ` Junio C Hamano
2021-05-17 20:17 ` Emily Shaffer
2021-05-11 17:28 ` Jeff Hostetler
2021-05-14 22:07 ` Emily Shaffer
2021-05-20 21:05 ` [PATCH v2] " Emily Shaffer
2021-05-20 21:36 ` Randall S. Becker
2021-05-20 23:23 ` Emily Shaffer
2021-05-21 13:20 ` Randall S. Becker
2021-05-21 16:24 ` Randall S. Becker
2021-05-21 2:09 ` Junio C Hamano
2021-05-21 19:02 ` Emily Shaffer
2021-05-21 23:22 ` Junio C Hamano
2021-05-24 18:37 ` Emily Shaffer
2021-05-21 19:15 ` Jeff Hostetler
2021-05-21 20:05 ` Emily Shaffer
2021-05-21 20:23 ` Randall S. Becker
2021-05-22 11:18 ` Jeff Hostetler
2021-05-24 23:33 ` Ævar Arnfjörð Bjarmason
2021-05-24 20:10 ` [PATCH v3] " Emily Shaffer
2021-05-24 20:49 ` Emily Shaffer
2021-05-25 3:54 ` Junio C Hamano
2021-05-25 13:33 ` Randall S. Becker
2021-06-08 18:58 ` [PATCH v4] " Emily Shaffer
2021-06-08 20:56 ` Emily Shaffer
2021-06-08 22:10 ` [PATCH v5] " Emily Shaffer
2021-06-08 22:16 ` Randall S. Becker
2021-06-08 22:24 ` Emily Shaffer
2021-06-08 22:39 ` Randall S. Becker
2021-06-09 20:17 ` Emily Shaffer
2021-06-16 8:42 ` Junio C Hamano
2021-06-28 16:45 ` Jeff Hostetler
2021-06-29 23:51 ` Emily Shaffer
2021-06-30 6:10 ` Ævar Arnfjörð Bjarmason
2021-07-22 0:21 ` Emily Shaffer
2021-07-22 1:27 ` [PATCH v6 0/2] " Emily Shaffer
2021-07-22 1:27 ` [PATCH v6 1/2] tr2: make process info collection platform-generic Emily Shaffer
2021-08-02 9:34 ` Ævar Arnfjörð Bjarmason
2021-07-22 1:27 ` [PATCH v6 2/2] tr2: log parent process name Emily Shaffer
2021-07-22 21:02 ` Junio C Hamano
2021-08-02 9:38 ` Ævar Arnfjörð Bjarmason
2021-08-02 12:45 ` Ævar Arnfjörð Bjarmason
2021-08-02 10:22 ` Ævar Arnfjörð Bjarmason [this message]
2021-08-02 12:47 ` Ævar Arnfjörð Bjarmason
2021-08-02 15:23 ` Jeff Hostetler
2021-08-02 16:10 ` Randall S. Becker
2021-08-02 18:41 ` Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-26 3:09 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 4/6] tr2: fix memory leak & logic error in 2f732bf15e6 Ævar Arnfjörð Bjarmason
2021-08-26 3:21 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-26 3:23 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-25 23:49 ` Eric Sunshine
2021-08-26 4:07 ` Taylor Blau
2021-08-26 12:24 ` "I don't know what the author meant by that..." (was "Re: [PATCH 6/6] tr2: log N parent process names on Linux") Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 4/6] tr2: fix memory leak & logic error in 2f732bf15e6 Ævar Arnfjörð Bjarmason
2021-08-26 15:58 ` Eric Sunshine
2021-08-26 16:42 ` Junio C Hamano
2021-08-26 12:22 ` [PATCH v2 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-26 22:38 ` [PATCH v2 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Taylor Blau
2021-08-27 8:02 ` [PATCH v3 " Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 4/6] tr2: leave the parent list empty upon failure & don't leak memory Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-31 0:17 ` [PATCH v3 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Taylor Blau
2021-08-02 10:30 ` [PATCH v6 2/2] tr2: log parent process name Ævar Arnfjörð Bjarmason
2021-08-02 16:24 ` Junio C Hamano
2021-08-02 18:42 ` Ævar Arnfjörð Bjarmason
2021-07-22 16:59 ` [PATCH v6 0/2] " Jeff Hostetler
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