Brice Goglin <brice.gog...@inria.fr> writes:
> Le 10/04/2020 à 14:33, Alex Bennée a écrit : >> That was by inspection on my system which seems to truncate a lot >> earlier. It would be nice to find where in the Linux kernel it is >> output but I failed to grep the relevant function last night. > > > It's in proc/array.c, do_task_stat() calls proc_task_name(). In the end, > it seems to use task->tcomm or task->comm which is limited by > > #define TASK_COMM_LEN 16 Thanks. I'll amend the commit message. Are you happy with the fix on your end? > > Brice > > > >> >> On Fri, 10 Apr 2020, 12:11 Philippe Mathieu-Daudé, <phi...@redhat.com >> <mailto:phi...@redhat.com>> wrote: >> >> Cc'ing Ludovic in case he can test with Guix-HPC. >> >> On 4/9/20 11:15 PM, Alex Bennée wrote: >> > In the original bug report long files names in Guix caused >> > /proc/self/stat be truncated without the trailing ") " as >> specified in >> > proc manpage which says: >> > (2) comm %s >> > The filename of the executable, in parentheses. This >> > is visible whether or not the executable is swapped >> > out. >> > >> > Additionally it should only be reporting the executable name rather >> > than the full path. Fix both these failings while cleaning up >> the code >> > to use GString to build up the reported values. As the whole >> function >> > is cleaned up also adjust the white space to the current coding >> style. >> > >> > Message-ID: <fb4c55fa-d539-67ee-c6c9-de8fb63c8...@inria.fr >> <mailto:fb4c55fa-d539-67ee-c6c9-de8fb63c8...@inria.fr>> >> > Reported-by: Brice Goglin <brice.gog...@inria.fr >> <mailto:brice.gog...@inria.fr>> >> > Cc: Philippe_Mathieu-Daudé <phi...@redhat.com >> <mailto:phi...@redhat.com>> >> > Signed-off-by: Alex Bennée <alex.ben...@linaro.org >> <mailto:alex.ben...@linaro.org>> >> > --- >> > linux-user/syscall.c | 43 >> +++++++++++++++++++------------------------ >> > 1 file changed, 19 insertions(+), 24 deletions(-) >> > >> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c >> > index 6495ddc4cda..674f70e70a5 100644 >> > --- a/linux-user/syscall.c >> > +++ b/linux-user/syscall.c >> > @@ -7295,34 +7295,29 @@ static int open_self_stat(void *cpu_env, >> int fd) >> > { >> > CPUState *cpu = env_cpu((CPUArchState *)cpu_env); >> > TaskState *ts = cpu->opaque; >> > - abi_ulong start_stack = ts->info->start_stack; >> > + g_autoptr(GString) buf = g_string_new(NULL); >> > int i; >> > >> > for (i = 0; i < 44; i++) { >> > - char buf[128]; >> > - int len; >> > - uint64_t val = 0; >> > - >> > - if (i == 0) { >> > - /* pid */ >> > - val = getpid(); >> > - snprintf(buf, sizeof(buf), "%"PRId64 " ", val); >> > - } else if (i == 1) { >> > - /* app name */ >> > - snprintf(buf, sizeof(buf), "(%s) ", ts->bprm->argv[0]); >> > - } else if (i == 27) { >> > - /* stack bottom */ >> > - val = start_stack; >> > - snprintf(buf, sizeof(buf), "%"PRId64 " ", val); >> > - } else { >> > - /* for the rest, there is MasterCard */ >> > - snprintf(buf, sizeof(buf), "0%c", i == 43 ? '\n' : ' '); >> > - } >> > + if (i == 0) { >> > + /* pid */ >> > + g_string_printf(buf, FMT_pid " ", getpid()); >> > + } else if (i == 1) { >> > + /* app name */ >> > + gchar *bin = g_strrstr(ts->bprm->argv[0], "/"); >> > + bin = bin ? bin + 1 : ts->bprm->argv[0]; >> > + g_string_printf(buf, "(%.15s) ", bin); >> >> 15 or 125? 15 seems short. From your previous test I understood it >> was >> 124, for >> >> sizeof("cat_with9_12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890___40"). >> >> > + } else if (i == 27) { >> > + /* stack bottom */ >> > + g_string_printf(buf, TARGET_ABI_FMT_ld " ", >> ts->info->start_stack); >> > + } else { >> > + /* for the rest, there is MasterCard */ >> > + g_string_printf(buf, "0%c", i == 43 ? '\n' : ' '); >> > + } >> > >> > - len = strlen(buf); >> > - if (write(fd, buf, len) != len) { >> > - return -1; >> > - } >> > + if (write(fd, buf->str, buf->len) != buf->len) { >> > + return -1; >> > + } >> > } >> > >> > return 0; >> > >> -- Alex Bennée
