| Message ID | 20240424154806.3417662-5-alan.maguire@oracle.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: support resilient split BTF | expand |
On Wed, Apr 24, 2024 at 8:48 AM Alan Maguire <alan.maguire@oracle.com> wrote: > > Options cover existing parsing scenarios (ELF, raw, retrieving > .BTF.ext) and also allow specification of the ELF section name > containing BTF. This will allow consumers to retrieve BTF from > .BTF.base sections (BTF_BASE_ELF_SEC) also. > > Signed-off-by: Alan Maguire <alan.maguire@oracle.com> > --- > tools/lib/bpf/btf.c | 50 ++++++++++++++++++++++++++++------------ > tools/lib/bpf/btf.h | 32 +++++++++++++++++++++++++ > tools/lib/bpf/libbpf.map | 1 + > 3 files changed, 68 insertions(+), 15 deletions(-) > > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c > index 419cc4fa2e86..9036c1dc45d0 100644 > --- a/tools/lib/bpf/btf.c > +++ b/tools/lib/bpf/btf.c > @@ -1084,7 +1084,7 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) > return libbpf_ptr(btf_new(data, size, base_btf)); > } > > -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > +static struct btf *btf_parse_elf(const char *path, const char *btf_sec, struct btf *base_btf, > struct btf_ext **btf_ext) > { > Elf_Data *btf_data = NULL, *btf_ext_data = NULL; > @@ -1146,7 +1146,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > idx, path); > goto done; > } > - if (strcmp(name, BTF_ELF_SEC) == 0) { > + if (strcmp(name, btf_sec) == 0) { > btf_data = elf_getdata(scn, 0); > if (!btf_data) { > pr_warn("failed to get section(%d, %s) data from %s\n", > @@ -1166,7 +1166,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > } > > if (!btf_data) { > - pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); > + pr_warn("failed to find '%s' ELF section in %s\n", btf_sec, path); > err = -ENODATA; > goto done; > } > @@ -1212,12 +1212,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > > struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) > { > - return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext)); > + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, NULL, btf_ext)); > } > > struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) > { > - return libbpf_ptr(btf_parse_elf(path, base_btf, NULL)); > + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, base_btf, NULL)); > } > > static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) > @@ -1293,7 +1293,8 @@ struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) > return libbpf_ptr(btf_parse_raw(path, base_btf)); > } > > -static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) > +static struct btf *btf_parse(const char *path, const char *btf_elf_sec, struct btf *base_btf, > + struct btf_ext **btf_ext) > { > struct btf *btf; > int err; > @@ -1301,23 +1302,42 @@ static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ > if (btf_ext) > *btf_ext = NULL; > > - btf = btf_parse_raw(path, base_btf); > - err = libbpf_get_error(btf); > - if (!err) > - return btf; > - if (err != -EPROTO) > - return ERR_PTR(err); > - return btf_parse_elf(path, base_btf, btf_ext); > + if (!btf_elf_sec) { > + btf = btf_parse_raw(path, base_btf); > + err = libbpf_get_error(btf); > + if (!err) > + return btf; > + if (err != -EPROTO) > + return ERR_PTR(err); > + } > + if (!btf_elf_sec) > + btf_elf_sec = BTF_ELF_SEC; > + > + return btf_parse_elf(path, btf_elf_sec, base_btf, btf_ext); nit: btf_elf_sec ?: BTF_ELF_SEC > +} > + > +struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts) > +{ > + struct btf *base_btf; > + const char *btf_sec; > + struct btf_ext **btf_ext; > + > + if (!OPTS_VALID(opts, btf_parse_opts)) > + return libbpf_err_ptr(-EINVAL); > + base_btf = OPTS_GET(opts, base_btf, NULL); > + btf_sec = OPTS_GET(opts, btf_sec, NULL); > + btf_ext = OPTS_GET(opts, btf_ext, NULL); > + return libbpf_ptr(btf_parse(path, btf_sec, base_btf, btf_ext)); > } > > struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) > { > - return libbpf_ptr(btf_parse(path, NULL, btf_ext)); > + return libbpf_ptr(btf_parse(path, NULL, NULL, btf_ext)); > } > > struct btf *btf__parse_split(const char *path, struct btf *base_btf) > { > - return libbpf_ptr(btf_parse(path, base_btf, NULL)); > + return libbpf_ptr(btf_parse(path, NULL, base_btf, NULL)); > } > > static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); > diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h > index 025ed28b7fe8..94dfdfdef617 100644 > --- a/tools/lib/bpf/btf.h > +++ b/tools/lib/bpf/btf.h > @@ -18,6 +18,7 @@ extern "C" { > > #define BTF_ELF_SEC ".BTF" > #define BTF_EXT_ELF_SEC ".BTF.ext" > +#define BTF_BASE_ELF_SEC ".BTF.base" Does libbpf code itself use this? If not, let's get rid of it. > #define MAPS_ELF_SEC ".maps" > > struct btf; > @@ -134,6 +135,37 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b > LIBBPF_API struct btf *btf__parse_raw(const char *path); > LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf); > > +struct btf_parse_opts { > + size_t sz; > + /* use base BTF to parse split BTF */ > + struct btf *base_btf; > + /* retrieve optional .BTF.ext info */ > + struct btf_ext **btf_ext; > + /* BTF section name */ let's mention that if not set, libbpf will default to trying to parse data as raw BTF, and then will fallback to .BTF in ELF. If it is set to non-NULL, we'll assume ELF and use that section to fetch BTF data. > + const char *btf_sec; > + size_t:0; nit: size_t :0; (consistency) > +}; > + > +#define btf_parse_opts__last_field btf_sec > + > +/* @brief **btf__parse_opts()** parses BTF information from either a > + * raw BTF file (*btf_sec* is NULL) or from the specified BTF section, > + * also retrieving .BTF.ext info if *btf_ext* is non-NULL. If > + * *base_btf* is specified, use it to parse split BTF from the > + * specified location. > + * > + * @return new BTF object instance which has to be eventually freed with > + * **btf__free()** > + * > + * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract this is false, we don't encode error as pointer anymore. starting from v1.0 it's always NULL + errno. > + * error code from such a pointer `libbpf_get_error()` should be used. If > + * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is > + * returned on error instead. In both cases thread-local `errno` variable is > + * always set to error code as well. > + */ > + > +LIBBPF_API struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts); > + > LIBBPF_API struct btf *btf__load_vmlinux_btf(void); > LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf); > > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map > index c4d9bd7d3220..a9151e31dfa9 100644 > --- a/tools/lib/bpf/libbpf.map > +++ b/tools/lib/bpf/libbpf.map > @@ -421,6 +421,7 @@ LIBBPF_1.5.0 { > global: > bpf_program__attach_sockmap; > btf__distill_base; > + btf__parse_opts; > ring__consume_n; > ring_buffer__consume_n; > } LIBBPF_1.4.0; > -- > 2.31.1 >
On Wed, 2024-04-24 at 16:47 +0100, Alan Maguire wrote: [...] > @@ -1301,23 +1302,42 @@ static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ > if (btf_ext) > *btf_ext = NULL; > > - btf = btf_parse_raw(path, base_btf); > - err = libbpf_get_error(btf); > - if (!err) > - return btf; > - if (err != -EPROTO) > - return ERR_PTR(err); > - return btf_parse_elf(path, base_btf, btf_ext); > + if (!btf_elf_sec) { > + btf = btf_parse_raw(path, base_btf); > + err = libbpf_get_error(btf); > + if (!err) > + return btf; > + if (err != -EPROTO) > + return ERR_PTR(err); > + } > + if (!btf_elf_sec) > + btf_elf_sec = BTF_ELF_SEC; > + > + return btf_parse_elf(path, btf_elf_sec, base_btf, btf_ext); > +} > + > +struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts) > +{ > + struct btf *base_btf; > + const char *btf_sec; > + struct btf_ext **btf_ext; > + > + if (!OPTS_VALID(opts, btf_parse_opts)) > + return libbpf_err_ptr(-EINVAL); > + base_btf = OPTS_GET(opts, base_btf, NULL); > + btf_sec = OPTS_GET(opts, btf_sec, NULL); > + btf_ext = OPTS_GET(opts, btf_ext, NULL); > + return libbpf_ptr(btf_parse(path, btf_sec, base_btf, btf_ext)); > } > I think that btf_parse() should be inlined into btf__parse_opts() and removed. As a proxy for passing btf_parse_opts fields as parameters it does not make much sense. [...]
On 30/04/2024 00:40, Andrii Nakryiko wrote: > On Wed, Apr 24, 2024 at 8:48 AM Alan Maguire <alan.maguire@oracle.com> wrote: >> >> Options cover existing parsing scenarios (ELF, raw, retrieving >> .BTF.ext) and also allow specification of the ELF section name >> containing BTF. This will allow consumers to retrieve BTF from >> .BTF.base sections (BTF_BASE_ELF_SEC) also. >> >> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> >> --- >> tools/lib/bpf/btf.c | 50 ++++++++++++++++++++++++++++------------ >> tools/lib/bpf/btf.h | 32 +++++++++++++++++++++++++ >> tools/lib/bpf/libbpf.map | 1 + >> 3 files changed, 68 insertions(+), 15 deletions(-) >> >> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c >> index 419cc4fa2e86..9036c1dc45d0 100644 >> --- a/tools/lib/bpf/btf.c >> +++ b/tools/lib/bpf/btf.c >> @@ -1084,7 +1084,7 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) >> return libbpf_ptr(btf_new(data, size, base_btf)); >> } >> >> -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, >> +static struct btf *btf_parse_elf(const char *path, const char *btf_sec, struct btf *base_btf, >> struct btf_ext **btf_ext) >> { >> Elf_Data *btf_data = NULL, *btf_ext_data = NULL; >> @@ -1146,7 +1146,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, >> idx, path); >> goto done; >> } >> - if (strcmp(name, BTF_ELF_SEC) == 0) { >> + if (strcmp(name, btf_sec) == 0) { >> btf_data = elf_getdata(scn, 0); >> if (!btf_data) { >> pr_warn("failed to get section(%d, %s) data from %s\n", >> @@ -1166,7 +1166,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, >> } >> >> if (!btf_data) { >> - pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); >> + pr_warn("failed to find '%s' ELF section in %s\n", btf_sec, path); >> err = -ENODATA; >> goto done; >> } >> @@ -1212,12 +1212,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, >> >> struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) >> { >> - return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext)); >> + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, NULL, btf_ext)); >> } >> >> struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) >> { >> - return libbpf_ptr(btf_parse_elf(path, base_btf, NULL)); >> + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, base_btf, NULL)); >> } >> >> static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) >> @@ -1293,7 +1293,8 @@ struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) >> return libbpf_ptr(btf_parse_raw(path, base_btf)); >> } >> >> -static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) >> +static struct btf *btf_parse(const char *path, const char *btf_elf_sec, struct btf *base_btf, >> + struct btf_ext **btf_ext) >> { >> struct btf *btf; >> int err; >> @@ -1301,23 +1302,42 @@ static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ >> if (btf_ext) >> *btf_ext = NULL; >> >> - btf = btf_parse_raw(path, base_btf); >> - err = libbpf_get_error(btf); >> - if (!err) >> - return btf; >> - if (err != -EPROTO) >> - return ERR_PTR(err); >> - return btf_parse_elf(path, base_btf, btf_ext); >> + if (!btf_elf_sec) { >> + btf = btf_parse_raw(path, base_btf); >> + err = libbpf_get_error(btf); >> + if (!err) >> + return btf; >> + if (err != -EPROTO) >> + return ERR_PTR(err); >> + } >> + if (!btf_elf_sec) >> + btf_elf_sec = BTF_ELF_SEC; >> + >> + return btf_parse_elf(path, btf_elf_sec, base_btf, btf_ext); > > nit: btf_elf_sec ?: BTF_ELF_SEC > sure, will fix. > >> +} >> + >> +struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts) >> +{ >> + struct btf *base_btf; >> + const char *btf_sec; >> + struct btf_ext **btf_ext; >> + >> + if (!OPTS_VALID(opts, btf_parse_opts)) >> + return libbpf_err_ptr(-EINVAL); >> + base_btf = OPTS_GET(opts, base_btf, NULL); >> + btf_sec = OPTS_GET(opts, btf_sec, NULL); >> + btf_ext = OPTS_GET(opts, btf_ext, NULL); >> + return libbpf_ptr(btf_parse(path, btf_sec, base_btf, btf_ext)); >> } >> >> struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) >> { >> - return libbpf_ptr(btf_parse(path, NULL, btf_ext)); >> + return libbpf_ptr(btf_parse(path, NULL, NULL, btf_ext)); >> } >> >> struct btf *btf__parse_split(const char *path, struct btf *base_btf) >> { >> - return libbpf_ptr(btf_parse(path, base_btf, NULL)); >> + return libbpf_ptr(btf_parse(path, NULL, base_btf, NULL)); >> } >> >> static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); >> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h >> index 025ed28b7fe8..94dfdfdef617 100644 >> --- a/tools/lib/bpf/btf.h >> +++ b/tools/lib/bpf/btf.h >> @@ -18,6 +18,7 @@ extern "C" { >> >> #define BTF_ELF_SEC ".BTF" >> #define BTF_EXT_ELF_SEC ".BTF.ext" >> +#define BTF_BASE_ELF_SEC ".BTF.base" > > Does libbpf code itself use this? If not, let's get rid of it. > We could, but I wonder would there be value to keeping it around as multiple consumers need to agree on this name (pahole, resolve_btfids, bpftool)? >> #define MAPS_ELF_SEC ".maps" >> >> struct btf; >> @@ -134,6 +135,37 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b >> LIBBPF_API struct btf *btf__parse_raw(const char *path); >> LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf); >> >> +struct btf_parse_opts { >> + size_t sz; >> + /* use base BTF to parse split BTF */ >> + struct btf *base_btf; >> + /* retrieve optional .BTF.ext info */ >> + struct btf_ext **btf_ext; >> + /* BTF section name */ > > let's mention that if not set, libbpf will default to trying to parse > data as raw BTF, and then will fallback to .BTF in ELF. If it is set > to non-NULL, we'll assume ELF and use that section to fetch BTF data. > sure, will do. >> + const char *btf_sec; >> + size_t:0; > > nit: size_t :0; (consistency) > >> +}; >> + >> +#define btf_parse_opts__last_field btf_sec >> + >> +/* @brief **btf__parse_opts()** parses BTF information from either a >> + * raw BTF file (*btf_sec* is NULL) or from the specified BTF section, >> + * also retrieving .BTF.ext info if *btf_ext* is non-NULL. If >> + * *base_btf* is specified, use it to parse split BTF from the >> + * specified location. >> + * >> + * @return new BTF object instance which has to be eventually freed with >> + * **btf__free()** >> + * >> + * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract > > this is false, we don't encode error as pointer anymore. starting from > v1.0 it's always NULL + errno. > ah good catch, I must have cut-and-pasted this.. Thanks again for all the review help! Alan >> + * error code from such a pointer `libbpf_get_error()` should be used. If >> + * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is >> + * returned on error instead. In both cases thread-local `errno` variable is >> + * always set to error code as well. >> + */ >> + >> +LIBBPF_API struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts); >> + >> LIBBPF_API struct btf *btf__load_vmlinux_btf(void); >> LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf); >> >> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map >> index c4d9bd7d3220..a9151e31dfa9 100644 >> --- a/tools/lib/bpf/libbpf.map >> +++ b/tools/lib/bpf/libbpf.map >> @@ -421,6 +421,7 @@ LIBBPF_1.5.0 { >> global: >> bpf_program__attach_sockmap; >> btf__distill_base; >> + btf__parse_opts; >> ring__consume_n; >> ring_buffer__consume_n; >> } LIBBPF_1.4.0; >> -- >> 2.31.1 >>
On Wed, May 1, 2024 at 10:43 AM Alan Maguire <alan.maguire@oracle.com> wrote: > > On 30/04/2024 00:40, Andrii Nakryiko wrote: > > On Wed, Apr 24, 2024 at 8:48 AM Alan Maguire <alan.maguire@oracle.com> wrote: > >> > >> Options cover existing parsing scenarios (ELF, raw, retrieving > >> .BTF.ext) and also allow specification of the ELF section name > >> containing BTF. This will allow consumers to retrieve BTF from > >> .BTF.base sections (BTF_BASE_ELF_SEC) also. > >> > >> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> > >> --- > >> tools/lib/bpf/btf.c | 50 ++++++++++++++++++++++++++++------------ > >> tools/lib/bpf/btf.h | 32 +++++++++++++++++++++++++ > >> tools/lib/bpf/libbpf.map | 1 + > >> 3 files changed, 68 insertions(+), 15 deletions(-) > >> > >> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c > >> index 419cc4fa2e86..9036c1dc45d0 100644 > >> --- a/tools/lib/bpf/btf.c > >> +++ b/tools/lib/bpf/btf.c > >> @@ -1084,7 +1084,7 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) > >> return libbpf_ptr(btf_new(data, size, base_btf)); > >> } > >> > >> -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > >> +static struct btf *btf_parse_elf(const char *path, const char *btf_sec, struct btf *base_btf, > >> struct btf_ext **btf_ext) > >> { > >> Elf_Data *btf_data = NULL, *btf_ext_data = NULL; > >> @@ -1146,7 +1146,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > >> idx, path); > >> goto done; > >> } > >> - if (strcmp(name, BTF_ELF_SEC) == 0) { > >> + if (strcmp(name, btf_sec) == 0) { > >> btf_data = elf_getdata(scn, 0); > >> if (!btf_data) { > >> pr_warn("failed to get section(%d, %s) data from %s\n", > >> @@ -1166,7 +1166,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > >> } > >> > >> if (!btf_data) { > >> - pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); > >> + pr_warn("failed to find '%s' ELF section in %s\n", btf_sec, path); > >> err = -ENODATA; > >> goto done; > >> } > >> @@ -1212,12 +1212,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > >> > >> struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) > >> { > >> - return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext)); > >> + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, NULL, btf_ext)); > >> } > >> > >> struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) > >> { > >> - return libbpf_ptr(btf_parse_elf(path, base_btf, NULL)); > >> + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, base_btf, NULL)); > >> } > >> > >> static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) > >> @@ -1293,7 +1293,8 @@ struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) > >> return libbpf_ptr(btf_parse_raw(path, base_btf)); > >> } > >> > >> -static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) > >> +static struct btf *btf_parse(const char *path, const char *btf_elf_sec, struct btf *base_btf, > >> + struct btf_ext **btf_ext) > >> { > >> struct btf *btf; > >> int err; > >> @@ -1301,23 +1302,42 @@ static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ > >> if (btf_ext) > >> *btf_ext = NULL; > >> > >> - btf = btf_parse_raw(path, base_btf); > >> - err = libbpf_get_error(btf); > >> - if (!err) > >> - return btf; > >> - if (err != -EPROTO) > >> - return ERR_PTR(err); > >> - return btf_parse_elf(path, base_btf, btf_ext); > >> + if (!btf_elf_sec) { > >> + btf = btf_parse_raw(path, base_btf); > >> + err = libbpf_get_error(btf); > >> + if (!err) > >> + return btf; > >> + if (err != -EPROTO) > >> + return ERR_PTR(err); > >> + } > >> + if (!btf_elf_sec) > >> + btf_elf_sec = BTF_ELF_SEC; > >> + > >> + return btf_parse_elf(path, btf_elf_sec, base_btf, btf_ext); > > > > nit: btf_elf_sec ?: BTF_ELF_SEC > > > > sure, will fix. > > > > >> +} > >> + > >> +struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts) > >> +{ > >> + struct btf *base_btf; > >> + const char *btf_sec; > >> + struct btf_ext **btf_ext; > >> + > >> + if (!OPTS_VALID(opts, btf_parse_opts)) > >> + return libbpf_err_ptr(-EINVAL); > >> + base_btf = OPTS_GET(opts, base_btf, NULL); > >> + btf_sec = OPTS_GET(opts, btf_sec, NULL); > >> + btf_ext = OPTS_GET(opts, btf_ext, NULL); > >> + return libbpf_ptr(btf_parse(path, btf_sec, base_btf, btf_ext)); > >> } > >> > >> struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) > >> { > >> - return libbpf_ptr(btf_parse(path, NULL, btf_ext)); > >> + return libbpf_ptr(btf_parse(path, NULL, NULL, btf_ext)); > >> } > >> > >> struct btf *btf__parse_split(const char *path, struct btf *base_btf) > >> { > >> - return libbpf_ptr(btf_parse(path, base_btf, NULL)); > >> + return libbpf_ptr(btf_parse(path, NULL, base_btf, NULL)); > >> } > >> > >> static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); > >> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h > >> index 025ed28b7fe8..94dfdfdef617 100644 > >> --- a/tools/lib/bpf/btf.h > >> +++ b/tools/lib/bpf/btf.h > >> @@ -18,6 +18,7 @@ extern "C" { > >> > >> #define BTF_ELF_SEC ".BTF" > >> #define BTF_EXT_ELF_SEC ".BTF.ext" > >> +#define BTF_BASE_ELF_SEC ".BTF.base" > > > > Does libbpf code itself use this? If not, let's get rid of it. > > > > We could, but I wonder would there be value to keeping it around as > multiple consumers need to agree on this name (pahole, resolve_btfids, > bpftool)? Ok, I can see how it might be a bit more generic thing beyond just kernel use, let's keep it then. > > >> #define MAPS_ELF_SEC ".maps" > >> > >> struct btf; > >> @@ -134,6 +135,37 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b > >> LIBBPF_API struct btf *btf__parse_raw(const char *path); > >> LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf); > >> > >> +struct btf_parse_opts { > >> + size_t sz; > >> + /* use base BTF to parse split BTF */ > >> + struct btf *base_btf; > >> + /* retrieve optional .BTF.ext info */ > >> + struct btf_ext **btf_ext; > >> + /* BTF section name */ > > > > let's mention that if not set, libbpf will default to trying to parse > > data as raw BTF, and then will fallback to .BTF in ELF. If it is set > > to non-NULL, we'll assume ELF and use that section to fetch BTF data. > > > > sure, will do. > > >> + const char *btf_sec; > >> + size_t:0; > > > > nit: size_t :0; (consistency) > > > >> +}; > >> + > >> +#define btf_parse_opts__last_field btf_sec > >> + > >> +/* @brief **btf__parse_opts()** parses BTF information from either a > >> + * raw BTF file (*btf_sec* is NULL) or from the specified BTF section, > >> + * also retrieving .BTF.ext info if *btf_ext* is non-NULL. If > >> + * *base_btf* is specified, use it to parse split BTF from the > >> + * specified location. > >> + * > >> + * @return new BTF object instance which has to be eventually freed with > >> + * **btf__free()** > >> + * > >> + * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract > > > > this is false, we don't encode error as pointer anymore. starting from > > v1.0 it's always NULL + errno. > > > > ah good catch, I must have cut-and-pasted this.. > > Thanks again for all the review help! > > Alan > > >> + * error code from such a pointer `libbpf_get_error()` should be used. If > >> + * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is > >> + * returned on error instead. In both cases thread-local `errno` variable is > >> + * always set to error code as well. > >> + */ > >> + > >> +LIBBPF_API struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts); > >> + > >> LIBBPF_API struct btf *btf__load_vmlinux_btf(void); > >> LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf); > >> > >> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map > >> index c4d9bd7d3220..a9151e31dfa9 100644 > >> --- a/tools/lib/bpf/libbpf.map > >> +++ b/tools/lib/bpf/libbpf.map > >> @@ -421,6 +421,7 @@ LIBBPF_1.5.0 { > >> global: > >> bpf_program__attach_sockmap; > >> btf__distill_base; > >> + btf__parse_opts; > >> ring__consume_n; > >> ring_buffer__consume_n; > >> } LIBBPF_1.4.0; > >> -- > >> 2.31.1 > >>
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 419cc4fa2e86..9036c1dc45d0 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1084,7 +1084,7 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) return libbpf_ptr(btf_new(data, size, base_btf)); } -static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, +static struct btf *btf_parse_elf(const char *path, const char *btf_sec, struct btf *base_btf, struct btf_ext **btf_ext) { Elf_Data *btf_data = NULL, *btf_ext_data = NULL; @@ -1146,7 +1146,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, idx, path); goto done; } - if (strcmp(name, BTF_ELF_SEC) == 0) { + if (strcmp(name, btf_sec) == 0) { btf_data = elf_getdata(scn, 0); if (!btf_data) { pr_warn("failed to get section(%d, %s) data from %s\n", @@ -1166,7 +1166,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, } if (!btf_data) { - pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); + pr_warn("failed to find '%s' ELF section in %s\n", btf_sec, path); err = -ENODATA; goto done; } @@ -1212,12 +1212,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) { - return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext)); + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, NULL, btf_ext)); } struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) { - return libbpf_ptr(btf_parse_elf(path, base_btf, NULL)); + return libbpf_ptr(btf_parse_elf(path, BTF_ELF_SEC, base_btf, NULL)); } static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) @@ -1293,7 +1293,8 @@ struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) return libbpf_ptr(btf_parse_raw(path, base_btf)); } -static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) +static struct btf *btf_parse(const char *path, const char *btf_elf_sec, struct btf *base_btf, + struct btf_ext **btf_ext) { struct btf *btf; int err; @@ -1301,23 +1302,42 @@ static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ if (btf_ext) *btf_ext = NULL; - btf = btf_parse_raw(path, base_btf); - err = libbpf_get_error(btf); - if (!err) - return btf; - if (err != -EPROTO) - return ERR_PTR(err); - return btf_parse_elf(path, base_btf, btf_ext); + if (!btf_elf_sec) { + btf = btf_parse_raw(path, base_btf); + err = libbpf_get_error(btf); + if (!err) + return btf; + if (err != -EPROTO) + return ERR_PTR(err); + } + if (!btf_elf_sec) + btf_elf_sec = BTF_ELF_SEC; + + return btf_parse_elf(path, btf_elf_sec, base_btf, btf_ext); +} + +struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts) +{ + struct btf *base_btf; + const char *btf_sec; + struct btf_ext **btf_ext; + + if (!OPTS_VALID(opts, btf_parse_opts)) + return libbpf_err_ptr(-EINVAL); + base_btf = OPTS_GET(opts, base_btf, NULL); + btf_sec = OPTS_GET(opts, btf_sec, NULL); + btf_ext = OPTS_GET(opts, btf_ext, NULL); + return libbpf_ptr(btf_parse(path, btf_sec, base_btf, btf_ext)); } struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) { - return libbpf_ptr(btf_parse(path, NULL, btf_ext)); + return libbpf_ptr(btf_parse(path, NULL, NULL, btf_ext)); } struct btf *btf__parse_split(const char *path, struct btf *base_btf) { - return libbpf_ptr(btf_parse(path, base_btf, NULL)); + return libbpf_ptr(btf_parse(path, NULL, base_btf, NULL)); } static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 025ed28b7fe8..94dfdfdef617 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -18,6 +18,7 @@ extern "C" { #define BTF_ELF_SEC ".BTF" #define BTF_EXT_ELF_SEC ".BTF.ext" +#define BTF_BASE_ELF_SEC ".BTF.base" #define MAPS_ELF_SEC ".maps" struct btf; @@ -134,6 +135,37 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b LIBBPF_API struct btf *btf__parse_raw(const char *path); LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf); +struct btf_parse_opts { + size_t sz; + /* use base BTF to parse split BTF */ + struct btf *base_btf; + /* retrieve optional .BTF.ext info */ + struct btf_ext **btf_ext; + /* BTF section name */ + const char *btf_sec; + size_t:0; +}; + +#define btf_parse_opts__last_field btf_sec + +/* @brief **btf__parse_opts()** parses BTF information from either a + * raw BTF file (*btf_sec* is NULL) or from the specified BTF section, + * also retrieving .BTF.ext info if *btf_ext* is non-NULL. If + * *base_btf* is specified, use it to parse split BTF from the + * specified location. + * + * @return new BTF object instance which has to be eventually freed with + * **btf__free()** + * + * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract + * error code from such a pointer `libbpf_get_error()` should be used. If + * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is + * returned on error instead. In both cases thread-local `errno` variable is + * always set to error code as well. + */ + +LIBBPF_API struct btf *btf__parse_opts(const char *path, struct btf_parse_opts *opts); + LIBBPF_API struct btf *btf__load_vmlinux_btf(void); LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index c4d9bd7d3220..a9151e31dfa9 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -421,6 +421,7 @@ LIBBPF_1.5.0 { global: bpf_program__attach_sockmap; btf__distill_base; + btf__parse_opts; ring__consume_n; ring_buffer__consume_n; } LIBBPF_1.4.0;
Options cover existing parsing scenarios (ELF, raw, retrieving .BTF.ext) and also allow specification of the ELF section name containing BTF. This will allow consumers to retrieve BTF from .BTF.base sections (BTF_BASE_ELF_SEC) also. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> --- tools/lib/bpf/btf.c | 50 ++++++++++++++++++++++++++++------------ tools/lib/bpf/btf.h | 32 +++++++++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 68 insertions(+), 15 deletions(-)