prove that man-db and tar works(which used to segfault). hope builtin argp could be updated soon. i will report if i met another NULL pointer case. thanks for your work! :) Bruno Haible 于2019年1月6日周日 上午12:17写道： > He X wrote: > > > The msgid argument is a null-terminated string. > > > > problem is that msgid is a empty pointer, not a pointer to a > > NULL-terminated string. > > > > full backtrace: > > > > ``` > > #0 0x00007ffff7fab65d in strcmp (l=0x0, r=0x7ffff7eff7df "Packaged by > > %s\n") at src/string/strcmp.c:5 > > #1 0x00007ffff7f51351 in __mo_lookup (p=0x7ffff7efa000, size=55838, > s=0x0) > > at src/locale/__mo_lookup.c:25 > > #2 0x00007ffff7f51e14 in dcngettext (domainname=0x7ffff7ffe320 "tar", > > msgid1=0x0, msgid2=0x0, n=1, category=5) at src/locale/dcngettext.c:211 > > #3 0x00007ffff7f52204 in dgettext (domainname=0x0, msgid=0x0) at > > src/locale/dcngettext.c:271 > > #4 0x000055555558a63c in argp_args_usage (argp=argp@entry > =0x7fffffffe740, > > state=state@entry=0x7fffffffe8f0, levels=levels@entry=0x7fffffffe690, > > advance=advance@entry=1, stream=stream@entry=0x5555555c5e20) at > > argp-help.c:1415 > > #5 0x000055555558bcdd in _help (argp=0x7fffffffe740, > > state=state@entry=0x7fffffffe8f0, > > stream=0x7ffff7ffb2a0 , flags=flags@entry=634, > > name=0x7fffffffed94 "tar") at argp-help.c:1640 > > #6 0x000055555558ca08 in argp_state_help (state=state@entry > =0x7fffffffe8f0, > > stream=, flags=flags@entry=634) at argp-help.c:1741 > > #7 0x000055555558d088 in argp_default_parser (key=, > > arg=, state=0x7fffffffe8f0) at argp-parse.c:96 > > #8 0x000055555558df89 in group_parse (arg=, key=63, > > state=0x7fffffffe8f0, group=0x5555555c40b0) at argp-parse.c:234 > > #9 parser_parse_opt (val=, opt=50331711, > > parser=0x7fffffffe880) at argp-parse.c:749 > > #10 parser_parse_next (arg_ebadkey=, > > parser=0x7fffffffe880) at argp-parse.c:860 > > #11 argp_parse (argp=, argc=2, argv=, > > flags=, end_index=0x7fffffffe9f0, input=0x5555555c3500 > > ) > > at argp-parse.c:928 > > #12 0x000055555555d3b7 in decode_options (argv=0x7fffffffeb58, argc=2) at > > tar.c:2312 > > #13 main (argc=, argv=) at tar.c:2698 > > ``` > > Thank you! With this stack trace, I'm fixing the issue as follows: > > > 2019-01-05 Bruno Haible > > argp: Don't pass an invalid argument to dgettext(). > Reported by He X . > * lib/argp.h (struct argp): Clarify that the args_doc field may be > NULL. > * lib/argp-help.c (argp_args_usage): Don't pass a NULL args_doc to > dgettext(). > > diff --git a/lib/argp.h b/lib/argp.h > index 317ac03..7aba887 100644 > --- a/lib/argp.h > +++ b/lib/argp.h > @@ -69,6 +69,9 @@ typedef int error_t; > extern "C" { > #endif > > +/* Glibc documentation: > + https://www.gnu.org/software/libc/manual/html_node/Argp.html */ > + > /* A description of a particular option. A pointer to an array of > these is passed in the OPTIONS field of an argp structure. Each option > entry can correspond to one long option and/or one short option; more > @@ -236,9 +239,9 @@ struct argp > ARGP_KEY_ definitions below. */ > argp_parser_t parser; > > - /* A string describing what other arguments are wanted by this > program. It > - is only used by argp_usage to print the "Usage:" message. If it > - contains newlines, the strings separated by them are considered > + /* If non-NULL, a string describing what other arguments are wanted by > this > + program. It is only used by argp_usage to print the "Usage:" > message. > + If it contains newlines, the strings separated by them are considered > alternative usage patterns, and printed on separate lines (lines > after > the first are prefix by " or: " instead of "Usage:"). */ > const char *args_doc; > diff --git a/lib/argp-help.c b/lib/argp-help.c > index e5375a0..e5e97ec 100644 > --- a/lib/argp-help.c > +++ b/lib/argp-help.c > @@ -1412,8 +1412,10 @@ argp_args_usage (const struct argp *argp, const > struct argp_state *state, > char *our_level = *levels; > int multiple = 0; > const struct argp_child *child = argp->children; > - const char *tdoc = dgettext (argp->argp_domain, argp->args_doc), *nl = > 0; > + const char *tdoc = > + argp->args_doc ? dgettext (argp->argp_domain, argp->args_doc) : NULL; > const char *fdoc = filter_doc (tdoc, ARGP_KEY_HELP_ARGS_DOC, argp, > state); > + const char *nl = NULL; > > if (fdoc) > { > > > > you could see that from #3, msgid is 0x0. > > > > > I don't see which dgettext invocation in argp-help.c is the one that > > needs the > > NULL check. > > > > it's not one but multiple. argp->doc[argp_doc()], and > > argp->args_doc[argp_args_usage[]) are what i have found . i am not sure > if > > there's any other, but i'll give the fix a test and see. > > Ah right. The 'doc' field of a 'struct argp' can be NULL as well, this is > documented in > https://www.gnu.org/software/libc/manual/html_node/Argp-Parsers.html. > The 'doc' field in a 'struct argp_option' looks like it can be NULL as > well, > see argp-help.c line 1178. > > > 2019-01-05 Bruno Haible > > argp: Don't pass an invalid argument to dgettext(). > Reported by He X . > * lib/argp-help.c (print_header, argp_doc): Don't pass a NULL doc > to > dgettext(). > > diff --git a/lib/argp-help.c b/lib/argp-help.c > index e5e97ec..75abe84 100644 > --- a/lib/argp-help.c > +++ b/lib/argp-help.c > @@ -1021,7 +1021,7 @@ static void > print_header (const char *str, const struct argp *argp, > struct pentry_state *pest) > { > - const char *tstr = dgettext (argp->argp_domain, str); > + const char *tstr = str ? dgettext (argp->argp_domain, str) : NULL; > const char *fstr = filter_doc (tstr, ARGP_KEY_HELP_HEADER, argp, > pest->state); > > if (fstr) > @@ -1479,7 +1479,7 @@ argp_doc (const struct argp *argp, const struct > argp_state *state, > void *input = 0; > int anything = 0; > size_t inp_text_limit = 0; > - const char *doc = dgettext (argp->argp_domain, argp->doc); > + const char *doc = argp->doc ? dgettext (argp->argp_domain, argp->doc) : > NULL; > const struct argp_child *child = argp->children; > > if (doc) > > -- Best regards, xhe