On 2025/09/17 16:20, lijiang wrote:
> On Wed, Sep 17, 2025 at 2:17 PM HAGIO KAZUHITO(萩尾　一仁)
> <k-hagio-ab@nec.com <mailto:k-hagio-ab@nec.com>> wrote:
>
>     Hi Lianbo,
>
>     Thank you for fixing it quickly.
>
>     btw, seeing 99bb57ac98af, I had a couple of questions, is there a
>     way to
>     print the original (not mangled) log buffer?
>
>
> Good questions, Kazu.
> Add an option(E.g -R) to the log command that can help solve it. For
> example:
> The log will print original messages.
> crash> log
> The log -R will print demangled Rust symbol names if there are any
> mangled Rust symbol names.
> crash> log -R
>
>     also, if the log buffer has lines like "_R ... +" which are not rust
>     symbols unexpectedly, how are they printed?
>
>
>   For this case, the rust_demangle() will fail, and still print the
> original messages.
>
>                  res = rust_demangle(mangled, DMGL_RUST);
>                  if (res) {
>                         snprintf(demangled+slen, BUFSIZE-slen, "%s%s",
> res, p2);
>                         fprintf(fp, "%s",demangled);
>                         free(res);
>                   }  else
>                        fprintf(fp, "%s", buf);
> How about the above solutions? Kazu.

Thank you for considering, these look good to me.

also, if text_len is limited to BUFSIZE for this function, maybe it
should be only when "log -R" ?

>
> BWT: Originally I tried the following code, but it looks ugly. So
> simplify this one.
>
>          char *p1 = strstr(buf, "_R");
>          if (!p1)
>                  p1 = strstr(buf, "_ZN");
>          char *p2 = strrchr(buf, '+');
>          if (p1 && p2) {
>                  char mangled[BUFSIZE] = {0};
>                  char demangled[BUFSIZE] = {0};
>                  char *res;
>                  size_t slen = p1 - buf;
>
>                  if (slen)
>                          memcpy(demangled, buf, slen);
>
>                  memcpy(mangled, p1, p2-p1);
>                  res = rust_demangle(mangled, DMGL_RUST);
>                  if (res) {
>                          snprintf(demangled+slen, BUFSIZE-slen, "%s%s",
> res, p2);
>                          if (CRASHDEBUG(1))
>                                  fprintf(fp, "%s", buf);
>                          else
>                                  fprintf(fp, "%s",demangled);
>                          free(res);
>                  } else
>                          fprintf(fp, "%s", buf);
>          } else
>                  fprintf(fp, "%s", buf);
>
> I did not realize that the original messages(mangled Rust symbols names)
> are still helpful to you.

It's just confusing that we see different logs in crash "log" and
vmcore-dmesg.txt etc, and like this time, if there is a bug in the
demangling process, then we would like to check the original messages.

Thanks,
Kazu

>
> Thanks
> Lianbo
>
>     (nice function, but maybe such function should be an option imho..)
>
>     Thanks,
>     Kazu