linux-stable/tools/perf/util/syscalltbl.c
Arnaldo Carvalho de Melo 30a910d7d3 perf trace: Preallocate the syscall table
We'll continue reading its details from tracefs as we need it, but
preallocate the whole thing otherwise we may realloc and end up with
pointers to the previous buffer.

I.e. in an upcoming algorithm we'll look for syscalls that have function
signatures that are similar to a given syscall to see if we can reuse
its BPF augmenter, so we may be at syscall 42, having a 'struct syscall'
pointing to that slot in trace->syscalls.table[] and try to read the
slot for an yet unread syscall, which would realloc that table to read
the info for syscall 43, say, which would trigger a realoc of
trace->syscalls.table[], and then the pointer we had for syscall 42
would be pointing to the previous block of memory. b00m.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-m3cjzzifibs13imafhkk77a0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-07-29 18:34:42 -03:00

176 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* System call table mapper
*
* (C) 2016 Arnaldo Carvalho de Melo <acme@redhat.com>
*/
#include "syscalltbl.h"
#include <stdlib.h>
#include <linux/compiler.h>
#ifdef HAVE_SYSCALL_TABLE_SUPPORT
#include <linux/zalloc.h>
#include <string.h>
#include "string2.h"
#if defined(__x86_64__)
#include <asm/syscalls_64.c>
const int syscalltbl_native_max_id = SYSCALLTBL_x86_64_MAX_ID;
static const char **syscalltbl_native = syscalltbl_x86_64;
#elif defined(__s390x__)
#include <asm/syscalls_64.c>
const int syscalltbl_native_max_id = SYSCALLTBL_S390_64_MAX_ID;
static const char **syscalltbl_native = syscalltbl_s390_64;
#elif defined(__powerpc64__)
#include <asm/syscalls_64.c>
const int syscalltbl_native_max_id = SYSCALLTBL_POWERPC_64_MAX_ID;
static const char **syscalltbl_native = syscalltbl_powerpc_64;
#elif defined(__powerpc__)
#include <asm/syscalls_32.c>
const int syscalltbl_native_max_id = SYSCALLTBL_POWERPC_32_MAX_ID;
static const char **syscalltbl_native = syscalltbl_powerpc_32;
#elif defined(__aarch64__)
#include <asm/syscalls.c>
const int syscalltbl_native_max_id = SYSCALLTBL_ARM64_MAX_ID;
static const char **syscalltbl_native = syscalltbl_arm64;
#endif
struct syscall {
int id;
const char *name;
};
static int syscallcmpname(const void *vkey, const void *ventry)
{
const char *key = vkey;
const struct syscall *entry = ventry;
return strcmp(key, entry->name);
}
static int syscallcmp(const void *va, const void *vb)
{
const struct syscall *a = va, *b = vb;
return strcmp(a->name, b->name);
}
static int syscalltbl__init_native(struct syscalltbl *tbl)
{
int nr_entries = 0, i, j;
struct syscall *entries;
for (i = 0; i <= syscalltbl_native_max_id; ++i)
if (syscalltbl_native[i])
++nr_entries;
entries = tbl->syscalls.entries = malloc(sizeof(struct syscall) * nr_entries);
if (tbl->syscalls.entries == NULL)
return -1;
for (i = 0, j = 0; i <= syscalltbl_native_max_id; ++i) {
if (syscalltbl_native[i]) {
entries[j].name = syscalltbl_native[i];
entries[j].id = i;
++j;
}
}
qsort(tbl->syscalls.entries, nr_entries, sizeof(struct syscall), syscallcmp);
tbl->syscalls.nr_entries = nr_entries;
tbl->syscalls.max_id = syscalltbl_native_max_id;
return 0;
}
struct syscalltbl *syscalltbl__new(void)
{
struct syscalltbl *tbl = malloc(sizeof(*tbl));
if (tbl) {
if (syscalltbl__init_native(tbl)) {
free(tbl);
return NULL;
}
}
return tbl;
}
void syscalltbl__delete(struct syscalltbl *tbl)
{
zfree(&tbl->syscalls.entries);
free(tbl);
}
const char *syscalltbl__name(const struct syscalltbl *tbl __maybe_unused, int id)
{
return id <= syscalltbl_native_max_id ? syscalltbl_native[id]: NULL;
}
int syscalltbl__id(struct syscalltbl *tbl, const char *name)
{
struct syscall *sc = bsearch(name, tbl->syscalls.entries,
tbl->syscalls.nr_entries, sizeof(*sc),
syscallcmpname);
return sc ? sc->id : -1;
}
int syscalltbl__strglobmatch_next(struct syscalltbl *tbl, const char *syscall_glob, int *idx)
{
int i;
struct syscall *syscalls = tbl->syscalls.entries;
for (i = *idx + 1; i < tbl->syscalls.nr_entries; ++i) {
if (strglobmatch(syscalls[i].name, syscall_glob)) {
*idx = i;
return syscalls[i].id;
}
}
return -1;
}
int syscalltbl__strglobmatch_first(struct syscalltbl *tbl, const char *syscall_glob, int *idx)
{
*idx = -1;
return syscalltbl__strglobmatch_next(tbl, syscall_glob, idx);
}
#else /* HAVE_SYSCALL_TABLE_SUPPORT */
#include <libaudit.h>
struct syscalltbl *syscalltbl__new(void)
{
struct syscalltbl *tbl = malloc(sizeof(*tbl));
if (tbl)
tbl->audit_machine = audit_detect_machine();
return tbl;
}
void syscalltbl__delete(struct syscalltbl *tbl)
{
free(tbl);
}
const char *syscalltbl__name(const struct syscalltbl *tbl, int id)
{
return audit_syscall_to_name(id, tbl->audit_machine);
}
int syscalltbl__id(struct syscalltbl *tbl, const char *name)
{
return audit_name_to_syscall(name, tbl->audit_machine);
}
int syscalltbl__strglobmatch_next(struct syscalltbl *tbl __maybe_unused,
const char *syscall_glob __maybe_unused, int *idx __maybe_unused)
{
return -1;
}
int syscalltbl__strglobmatch_first(struct syscalltbl *tbl, const char *syscall_glob, int *idx)
{
return syscalltbl__strglobmatch_next(tbl, syscall_glob, idx);
}
#endif /* HAVE_SYSCALL_TABLE_SUPPORT */