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perf sdt: Add scanning of sdt probes arguments 

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>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20161214000732.1710-2-alexis.berlemont@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Alexis Berlemont 2016-12-14 01:07:31 +01:00 committed by Arnaldo Carvalho de Melo
parent 70946723ee
commit be88184b1c
2 changed files with 24 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
tools/perf/util/symbol-elf.c
View File

@ -1828,7 +1828,7 @@ 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;
@ -1887,6 +1887,25 @@ 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;
@ -1898,7 +1917,7 @@ 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 :
@ -1923,6 +1942,8 @@ 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:

1
tools/perf/util/symbol.h
View File

@ -351,6 +351,7 @@ 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];