On 10/03/2014 05:09 PM, Masami Hiramatsu wrote:
(2014/10/01 11:47), Hemant Kumar wrote:
This patch serves as the basic support to identify and list SDT events in
binaries.
When programs containing SDT markers are compiled, gcc with the help of
assembler
directives identifies them and places them in the section ".note.stapsdt". To
find
these markers from the binaries, one needs to traverse through this section and
parse the relevant details like the name, type and location of the marker. Also,
the original location could be skewed due to the effect of prelinking. If that
is
the case, the locations need to be adjusted.
The functions in this patch open a given ELF, find out the SDT section, parse
the
relevant details, adjust the location (if necessary) and populate them in a
list.
Made the necessary changes as suggested by Namhyung Kim.
Looks almost good!
I have some comments, please see below.
Ok.
Signed-off-by: Hemant Kumar <hem...@linux.vnet.ibm.com>
---
tools/perf/util/symbol-elf.c | 207 ++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/symbol.h | 19 ++++
2 files changed, 226 insertions(+)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 2a92e10..9702167 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1672,6 +1672,213 @@ void kcore_extract__delete(struct kcore_extract *kce)
unlink(kce->extract_filename);
}
+/*
+ * populate_sdt_note() : Responsible for parsing the section .note.stapsdt and
+ * after adjusting the note's location, returns that to the calling functions.
+ */
+static int populate_sdt_note(Elf **elf, const char *data, size_t len, int type,
+ struct sdt_note **note)
+{
+ const char *provider, *name;
+ struct sdt_note *tmp = NULL;
+ GElf_Ehdr ehdr;
+ GElf_Addr base_off = 0;
+ GElf_Shdr shdr;
+ int ret = -1;
-1 is not an error code. maybe, -EINVAL is better.
Sure, will change this to EINVAL.
+ int i;
+
+ union {
+ Elf64_Addr a64[3];
+ Elf32_Addr a32[3];
+ } buf;
+
+ Elf_Data dst = {
+ .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
+ .d_size = gelf_fsize((*elf), ELF_T_ADDR, 3, EV_CURRENT),
+ .d_off = 0, .d_align = 0
+ };
+ Elf_Data src = {
+ .d_buf = (void *) data, .d_type = ELF_T_ADDR,
+ .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
+ .d_align = 0
+ };
+
+ /* Check the type of each of the notes */
+ if (type != SDT_NOTE_TYPE)
+ goto out_err;
+
+ tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
+
+ INIT_LIST_HEAD(&tmp->note_list);
+
+ if (len < dst.d_size + 3)
+ goto out_free_note;
+
+ /* Translation from file representation to memory representation */
+ if (gelf_xlatetom(*elf, &dst, &src,
+ elf_getident(*elf, NULL)[EI_DATA]) == NULL)
+ printf("gelf_xlatetom : %s\n", elf_errmsg(-1));
pr_err? and shouldn't it goes to out_free_note?
Yes it should go to out_free_note. Will make the change.
[...]
Thank You for reviewing this patch.
--
Thanks,
Hemant Kumar
--
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