| Message ID | 20210121202203.9346-2-jolsa@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | dwarves,libbpf: Add support to use optional extended section index table | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Thu, Jan 21, 2021 at 12:24 PM Jiri Olsa <jolsa@kernel.org> wrote: > > In case the elf's header e_shstrndx contains SHN_XINDEX, > we need to call elf_getshdrstrndx to get the proper > string table index. > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > --- > dutil.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/dutil.c b/dutil.c > index 7b667647420f..9e0fdca3ae04 100644 > --- a/dutil.c > +++ b/dutil.c > @@ -179,13 +179,17 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, > { > Elf_Scn *sec = NULL; > size_t cnt = 1; > + size_t str_idx; > + > + if (elf_getshdrstrndx(elf, &str_idx)) > + return NULL; > > while ((sec = elf_nextscn(elf, sec)) != NULL) { > char *str; > > gelf_getshdr(sec, shp); > - str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); > - if (!strcmp(name, str)) { > + str = elf_strptr(elf, str_idx, shp->sh_name); > + if (str && !strcmp(name, str)) { if (!str) would be an error? should we bail out here? > if (index) > *index = cnt; > break; > -- > 2.27.0 >
On Thu, Jan 21, 2021 at 03:10:25PM -0800, Andrii Nakryiko wrote: > On Thu, Jan 21, 2021 at 12:24 PM Jiri Olsa <jolsa@kernel.org> wrote: > > > > In case the elf's header e_shstrndx contains SHN_XINDEX, > > we need to call elf_getshdrstrndx to get the proper > > string table index. > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > --- > > dutil.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > diff --git a/dutil.c b/dutil.c > > index 7b667647420f..9e0fdca3ae04 100644 > > --- a/dutil.c > > +++ b/dutil.c > > @@ -179,13 +179,17 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, > > { > > Elf_Scn *sec = NULL; > > size_t cnt = 1; > > + size_t str_idx; > > + > > + if (elf_getshdrstrndx(elf, &str_idx)) > > + return NULL; > > > > while ((sec = elf_nextscn(elf, sec)) != NULL) { > > char *str; > > > > gelf_getshdr(sec, shp); > > - str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); > > - if (!strcmp(name, str)) { > > + str = elf_strptr(elf, str_idx, shp->sh_name); > > + if (str && !strcmp(name, str)) { > > if (!str) would be an error? should we bail out here? seems like if elf_nextscn returns NULL, it will be the case for all the sections in here.. but bailing out on (!str) is more direct and safer I'll send an update thanks, jirka > > > if (index) > > *index = cnt; > > break; > > -- > > 2.27.0 > > >
diff --git a/dutil.c b/dutil.c index 7b667647420f..9e0fdca3ae04 100644 --- a/dutil.c +++ b/dutil.c @@ -179,13 +179,17 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, { Elf_Scn *sec = NULL; size_t cnt = 1; + size_t str_idx; + + if (elf_getshdrstrndx(elf, &str_idx)) + return NULL; while ((sec = elf_nextscn(elf, sec)) != NULL) { char *str; gelf_getshdr(sec, shp); - str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); - if (!strcmp(name, str)) { + str = elf_strptr(elf, str_idx, shp->sh_name); + if (str && !strcmp(name, str)) { if (index) *index = cnt; break;
In case the elf's header e_shstrndx contains SHN_XINDEX, we need to call elf_getshdrstrndx to get the proper string table index. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- dutil.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)