Messages in this thread Patch in this message | | | From | Alexis Berlemont <> | Subject | [PATCH v4 1/2] perf sdt: add scanning of sdt probles arguments | Date | Sat, 26 Nov 2016 01:58:02 +0100 |
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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.berlemont@gmail.com> --- tools/perf/util/symbol-elf.c | 25 +++++++++++++++++++++++-- tools/perf/util/symbol.h | 1 + 2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 99400b0..7725c3f 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 +1881,25 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, goto out_free_prov; } + args = memchr(name, '\0', data + len - name); + + /* + * 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); + if (!tmp->args) { + ret = -ENOMEM; + goto out_free_name; + } + } + if (gelf_getclass(*elf) == ELFCLASS32) { memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); tmp->bit32 = true; @@ -1892,7 +1911,7 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, if (!gelf_getehdr(*elf, &ehdr)) { pr_debug("%s : cannot get elf header.\n", __func__); ret = -EBADF; - goto out_free_name; + goto out_free_args; } /* Adjust the prelink effect : @@ -1917,6 +1936,8 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, list_add_tail(&tmp->note_list, sdt_notes); return 0; +out_free_args: + free(tmp->args); out_free_name: free(tmp->name); out_free_prov: diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h index dec7e2d4..db1953e 100644 --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -348,6 +348,7 @@ 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
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