From: Cong Wu <congwu@alauda.io>
To: "systemtap@sourceware.org" <systemtap@sourceware.org>
Subject: a idea about probe proc path like /proc/pid/root/xxx
Date: Wed, 13 Jul 2022 05:18:52 +0000 [thread overview]
Message-ID: <HK0PR01MB34916D6B6B1BD921A62CCA64C9899@HK0PR01MB3491.apcprd01.prod.exchangelabs.com> (raw)
hi all. currently, I'm use stap to probe user process like `probe process("/proc/xx/root/xxx").function("a")`, what I really want is to probe a process running in docker, I make a small patch.
here is what i did. https://github.com/woodgear/systemtap-wg/commit/0872dc3f5594be520afd83fc5075fff8c6bec955.
basically if solib_pathname start with /proc/$(task->tgid)/root then i just compare the rest part of it.
```
--- a/runtime/linux/uprobes-inode.c
+++ b/runtime/linux/uprobes-inode.c
@@ -813,6 +813,8 @@ stapiu_mmap_found(struct stap_task_finder_target *tf_target,
struct stapiu_process* p;
int known_mapping_p;
unsigned long flags;
+ char proc_path_buff[100];
+ char *proc_path="/proc/";
dbug_uprobes("wg: in mmap_found pid %d inode %ld\n",task->tgid,dentry->d_inode->i_ino);
@@ -876,18 +878,33 @@ stapiu_mmap_found(struct stap_task_finder_target *tf_target,
if (! known_mapping_p) {
/* The file path or build-id must match. The build-id address
* is calculated using start address of this vma, the file
* offset of the vma start address and the file offset of
* the build-id. */
- if (c->solib_pathname && path && strcmp (path, c->solib_pathname))
- return 0;
+ if (c->solib_pathname && path) {
+ if (strncmp(proc_path, c->solib_pathname, strlen(proc_path)) == 0) {
+ sprintf(proc_path_buff,"/proc/%d/root%s",task->tgid,path);
+ if (strcmp (proc_path_buff, c->solib_pathname)) {
+ return 0;
+ }
+ }else {
+ // not proc path just compare
+ if (strcmp (path, c->solib_pathname)) {
+ return 0;
+ }
+ }
+ }
if (c->solib_build_id_len > 0 && !__verify_build_id(task,
addr - offset + c->solib_build_id_vaddr,
c->solib_build_id,
- c->solib_build_id_len))
+ c->solib_build_id_len)) {
+
return 0;
+ }
}
// If we made it this far, we have an interesting solib.
@@ -923,7 +940,7 @@ stapiu_mmap_found(struct stap_task_finder_target *tf_target,
spin_lock_irqsave (&c->process_list_lock, flags);
list_add(&p->process_list, &c->process_list_head);
spin_unlock_irqrestore (&c->process_list_lock, flags);
} else
_stp_warn("out of memory tracking solib %s in process %ld\n",
path, (long) task->tgid);
```
this is just a draft code to show what I want to change.
is this way work?
A further idea is that we can add an option like --use-proc-path to find the uprobe file path at a given pid.
next reply other threads:[~2022-07-13 5:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 5:18 Cong Wu [this message]
2022-08-18 17:35 ` Frank Ch. Eigler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=HK0PR01MB34916D6B6B1BD921A62CCA64C9899@HK0PR01MB3491.apcprd01.prod.exchangelabs.com \
--to=congwu@alauda.io \
--cc=systemtap@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).