Em Sat, Nov 19, 2016 at 12:56:36AM +0100, Alexis Berlemont escreveu:
> During a "perf buildid-cache --add" command, the section
> ".note.stapsdt" of the "added" binary is scanned in order to list the
> available SDT markers available in a binary. The parts containing the
> probes arguments were left unscanned.
>
> The whole section is now parsed; the probe arguments are extracted for
> later use.
>
> Signed-off-by: Alexis Berlemont <alexis.berlem...@gmail.com>
> ---
> tools/perf/util/symbol-elf.c | 16 +++++++++++++++-
> tools/perf/util/symbol.h | 1 +
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 99400b0..0fbe0b2 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -1822,7 +1822,7 @@ void kcore_extract__delete(struct kcore_extract *kce)
> static int populate_sdt_note(Elf **elf, const char *data, size_t len,
> struct list_head *sdt_notes)
> {
> - const char *provider, *name;
> + const char *provider, *name, *args;
> struct sdt_note *tmp = NULL;
> GElf_Ehdr ehdr;
> GElf_Addr base_off = 0;
> @@ -1881,6 +1881,20 @@ static int populate_sdt_note(Elf **elf, const char
> *data, size_t len,
> goto out_free_prov;
> }
>
> + args = (const char *)memchr(name, '\0', data + len - name);
Humm, no need for casting?
> +
> + /*
> + * There is no argument if:
> + * - We reached the end of the note;
> + * - There is not enough room to hold a potential string;
> + * - The argument string is empty or just contains ':'.
> + */
> + if (args == NULL || data + len - args < 2 ||
> + args[1] == ':' || args[1] == '\0')
> + tmp->args = NULL;
> + else
> + tmp->args = strdup(++args);
Shouldn't we check this and do error back propagation? I.e. if there are
args and we don't handle them, silently, that looks bad
> +
> if (gelf_getclass(*elf) == ELFCLASS32) {
> memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
> tmp->bit32 = true;
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 2d0a905..913be07 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -347,6 +347,7 @@ int arch__choose_best_symbol(struct symbol *syma, struct
> symbol *symb);
> struct sdt_note {
> char *name; /* name of the note*/
> char *provider; /* provider name */
> + char *args;
> bool bit32; /* whether the location is 32 bits? */
> union { /* location, base and semaphore addrs */
> Elf64_Addr a64[3];
> --
> 2.10.2
