Quelle  openat-syscall-all-cpus.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <inttypes.h>
/* For the CPU_* macros */
#include <sched.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <api/fs/fs.h>
#include <linux/err.h>
#include <linux/string.h>
#include <api/fs/tracing_path.h>
#include "evsel.h"
#include "tests.h"
#include "thread_map.h"
#include <perf/cpumap.h>
#include "debug.h"
#include "stat.h"
#include "util/counts.h"

static int test__openat_syscall_event_on_all_cpus(struct test_suite *test __maybe_unused,
        int subtest __maybe_unused)
{
 int err = TEST_FAIL, fd, idx;
 struct perf_cpu cpu;
 struct perf_cpu_map *cpus;
 struct evsel *evsel;
 unsigned int nr_openat_calls = 111, i;
 cpu_set_t cpu_set;
 struct perf_thread_map *threads = thread_map__new_by_tid(getpid());
 char sbuf[STRERR_BUFSIZE];
 char errbuf[BUFSIZ];

 if (threads == NULL) {
  pr_debug("thread_map__new\n");
  return -1;
 }

 cpus = perf_cpu_map__new_online_cpus();
 if (cpus == NULL) {
  pr_debug("perf_cpu_map__new\n");
  goto out_thread_map_delete;
 }

 CPU_ZERO(&cpu_set);

 evsel = evsel__newtp("syscalls", "sys_enter_openat");
 if (IS_ERR(evsel)) {
  tracing_path__strerror_open_tp(errno, errbuf, sizeof(errbuf), "syscalls", "sys_enter_openat");
  pr_debug("%s\n", errbuf);
  err = TEST_SKIP;
  goto out_cpu_map_delete;
 }

 if (evsel__open(evsel, cpus, threads) < 0) {
  pr_debug("failed to open counter: %s, "
    "tweak /proc/sys/kernel/perf_event_paranoid?\n",
    str_error_r(errno, sbuf, sizeof(sbuf)));
  err = TEST_SKIP;
  goto out_evsel_delete;
 }

 perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
  unsigned int ncalls = nr_openat_calls + idx;
  /*
 * XXX eventually lift this restriction in a way that
 * keeps perf building on older glibc installations
 * without CPU_ALLOC. 1024 cpus in 2010 still seems
 * a reasonable upper limit tho :-)
 */
  if (cpu.cpu >= CPU_SETSIZE) {
   pr_debug("Ignoring CPU %d\n", cpu.cpu);
   continue;
  }

  CPU_SET(cpu.cpu, &cpu_set);
  if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
   pr_debug("sched_setaffinity() failed on CPU %d: %s ",
     cpu.cpu,
     str_error_r(errno, sbuf, sizeof(sbuf)));
   goto out_close_fd;
  }
  for (i = 0; i < ncalls; ++i) {
   fd = openat(0, "/etc/passwd", O_RDONLY);
   close(fd);
  }
  CPU_CLR(cpu.cpu, &cpu_set);
 }

 evsel->core.cpus = perf_cpu_map__get(cpus);

 err = TEST_OK;

 perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
  unsigned int expected;

  if (cpu.cpu >= CPU_SETSIZE)
   continue;

  if (evsel__read_on_cpu(evsel, idx, 0) < 0) {
   pr_debug("evsel__read_on_cpu\n");
   err = TEST_FAIL;
   break;
  }

  expected = nr_openat_calls + idx;
  if (perf_counts(evsel->counts, idx, 0)->val != expected) {
   pr_debug("evsel__read_on_cpu: expected to intercept %d calls on cpu %d, got %" PRIu64 "\n",
     expected, cpu.cpu, perf_counts(evsel->counts, idx, 0)->val);
   err = TEST_FAIL;
  }
 }

 evsel__free_counts(evsel);
out_close_fd:
 perf_evsel__close_fd(&evsel->core);
out_evsel_delete:
 evsel__delete(evsel);
out_cpu_map_delete:
 perf_cpu_map__put(cpus);
out_thread_map_delete:
 perf_thread_map__put(threads);
 return err;
}


static struct test_case tests__openat_syscall_event_on_all_cpus[] = {
 TEST_CASE_REASON("Detect openat syscall event on all cpus",
    openat_syscall_event_on_all_cpus,
    "permissions"),
 { .name = NULL, }
};

struct test_suite suite__openat_syscall_event_on_all_cpus = {
 .desc = "Detect openat syscall event on all cpus",
 .test_cases = tests__openat_syscall_event_on_all_cpus,
};