| Message ID | 1477447172-19677-1-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 10/25/2016 08:59 PM, Fam Zheng wrote: > Currently, the generated function body will do "strlen(arg)" but the > argument could be 'char **'. Avoid that by exclusding such cases in s/exclusding/excluding/ > is_string check. > > Reported by patchew's "make docker-test-mingw@fedora". > > Signed-off-by: Fam Zheng <famz@redhat.com> > --- > scripts/tracetool/backend/simple.py | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py > index 9885e83..2538795 100644 > --- a/scripts/tracetool/backend/simple.py > +++ b/scripts/tracetool/backend/simple.py > @@ -21,7 +21,9 @@ PUBLIC = True > > def is_string(arg): > strtype = ('const char*', 'char*', 'const char *', 'char *') > - if arg.lstrip().startswith(strtype): > + non_strtype = ('const char**', 'char**', 'const char **', 'char **') > + arg_strip = arg.lstrip() > + if arg_strip.startswith(strtype) and not arg_strip.startswith(non_strtype): There may be a more compact way to write it, but I'm not enough of a python expert to know offhand what else to suggest (it's not as simple as string concatenation of strtype + '*', since strtype is a tuple rather than a string). What you have will fail to detect 'const char *const *' as a non-string (possible if we have some argv-like function that takes a constant array of constant strings), but I guess we can worry about that if we actually try to trace something with that signature. In the meantime, what you have solves the immediate failure, so: Reviewed-by: Eric Blake <eblake@redhat.com>
On Tue, 10/25 21:29, Eric Blake wrote: > On 10/25/2016 08:59 PM, Fam Zheng wrote: > > Currently, the generated function body will do "strlen(arg)" but the > > argument could be 'char **'. Avoid that by exclusding such cases in > > s/exclusding/excluding/ Yes, I blame the insomnia last night. @.@ I assume this can be fixed when applying. > > > is_string check. > > > > Reported by patchew's "make docker-test-mingw@fedora". > > > > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > > scripts/tracetool/backend/simple.py | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py > > index 9885e83..2538795 100644 > > --- a/scripts/tracetool/backend/simple.py > > +++ b/scripts/tracetool/backend/simple.py > > @@ -21,7 +21,9 @@ PUBLIC = True > > > > def is_string(arg): > > strtype = ('const char*', 'char*', 'const char *', 'char *') > > - if arg.lstrip().startswith(strtype): > > + non_strtype = ('const char**', 'char**', 'const char **', 'char **') > > + arg_strip = arg.lstrip() > > + if arg_strip.startswith(strtype) and not arg_strip.startswith(non_strtype): > > There may be a more compact way to write it, but I'm not enough of a > python expert to know offhand what else to suggest (it's not as simple > as string concatenation of strtype + '*', since strtype is a tuple > rather than a string). Did you mean non_strtype = tuple(x + '*' for x in strtype) ? But personally I'd stick to the flatten version in this specific case for a bit more readability. Thanks! Fam
On 10/25/2016 09:46 PM, Fam Zheng wrote: > On Tue, 10/25 21:29, Eric Blake wrote: >> On 10/25/2016 08:59 PM, Fam Zheng wrote: >>> Currently, the generated function body will do "strlen(arg)" but the >>> argument could be 'char **'. Avoid that by exclusding such cases in >> >>> def is_string(arg): >>> strtype = ('const char*', 'char*', 'const char *', 'char *') >>> - if arg.lstrip().startswith(strtype): >>> + non_strtype = ('const char**', 'char**', 'const char **', 'char **') >>> + arg_strip = arg.lstrip() >>> + if arg_strip.startswith(strtype) and not arg_strip.startswith(non_strtype): >> >> There may be a more compact way to write it, but I'm not enough of a >> python expert to know offhand what else to suggest (it's not as simple >> as string concatenation of strtype + '*', since strtype is a tuple >> rather than a string). > > Did you mean > > non_strtype = tuple(x + '*' for x in strtype) Hmm, I guess that would work. Or, what about a different approach, something like: if arg_strip.startswith(strtype) and no_multiple_star(arg_strip): for some sane definition of no_multiple_star() that checks that there is exactly one '*' in a string. In C, I'd check roughly: p = strchr(str, '*'); if (p && !strchr(p + 1, '*')) { // treat str as string } but again, I'm not enough of an expert to pop that out late at night, even if python has an easy one-liner way to express that. > But personally I'd stick to the flatten version in this specific case for > a bit more readability. Indeed, and that's why I gave R-b as-is, even if it fails when there are multiple 'const' qualifiers in a string with multiple '*' :)
On Tue, 10/25 21:56, Eric Blake wrote: > On 10/25/2016 09:46 PM, Fam Zheng wrote: > > On Tue, 10/25 21:29, Eric Blake wrote: > >> On 10/25/2016 08:59 PM, Fam Zheng wrote: > >>> Currently, the generated function body will do "strlen(arg)" but the > >>> argument could be 'char **'. Avoid that by exclusding such cases in > >> > > >>> def is_string(arg): > >>> strtype = ('const char*', 'char*', 'const char *', 'char *') > >>> - if arg.lstrip().startswith(strtype): > >>> + non_strtype = ('const char**', 'char**', 'const char **', 'char **') > >>> + arg_strip = arg.lstrip() > >>> + if arg_strip.startswith(strtype) and not arg_strip.startswith(non_strtype): > >> > >> There may be a more compact way to write it, but I'm not enough of a > >> python expert to know offhand what else to suggest (it's not as simple > >> as string concatenation of strtype + '*', since strtype is a tuple > >> rather than a string). > > > > Did you mean > > > > non_strtype = tuple(x + '*' for x in strtype) > > Hmm, I guess that would work. > > Or, what about a different approach, something like: > if arg_strip.startswith(strtype) and no_multiple_star(arg_strip): > for some sane definition of no_multiple_star() that checks that there is > exactly one '*' in a string. In C, I'd check roughly: > p = strchr(str, '*'); > if (p && !strchr(p + 1, '*')) { > // treat str as string > } > but again, I'm not enough of an expert to pop that out late at night, > even if python has an easy one-liner way to express that. That's indeed a nicer approach: if arg_strip.startswith(strtype) and arg_strip.count("*") == 1: Do you want a respin with your suggested-by? :-) Fam > > > > But personally I'd stick to the flatten version in this specific case for > > a bit more readability. > > Indeed, and that's why I gave R-b as-is, even if it fails when there are > multiple 'const' qualifiers in a string with multiple '*' :) > > -- > Eric Blake eblake redhat com +1-919-301-3266 > Libvirt virtualization library http://libvirt.org >
diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py index 9885e83..2538795 100644 --- a/scripts/tracetool/backend/simple.py +++ b/scripts/tracetool/backend/simple.py @@ -21,7 +21,9 @@ PUBLIC = True def is_string(arg): strtype = ('const char*', 'char*', 'const char *', 'char *') - if arg.lstrip().startswith(strtype): + non_strtype = ('const char**', 'char**', 'const char **', 'char **') + arg_strip = arg.lstrip() + if arg_strip.startswith(strtype) and not arg_strip.startswith(non_strtype): return True else: return False
Currently, the generated function body will do "strlen(arg)" but the argument could be 'char **'. Avoid that by exclusding such cases in is_string check. Reported by patchew's "make docker-test-mingw@fedora". Signed-off-by: Fam Zheng <famz@redhat.com> --- scripts/tracetool/backend/simple.py | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)