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![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
In places where the equivalent was already being done, i.e.: free(a); a = NULL; And in placs where struct members are being freed so that if we have some erroneous reference to its struct, then accesses to freed members will result in segfaults, which we can detect faster than use after free to areas that may still have something seemingly valid. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-jatyoofo5boc1bsvoig6bb6i@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
251 lines
4.9 KiB
C
251 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "../perf.h"
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#include <subcmd/parse-options.h>
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#include "evsel.h"
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#include "cgroup.h"
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#include "evlist.h"
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#include <linux/stringify.h>
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#include <linux/zalloc.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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int nr_cgroups;
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static int
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cgroupfs_find_mountpoint(char *buf, size_t maxlen)
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{
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FILE *fp;
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char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
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char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
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char *token, *saved_ptr = NULL;
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fp = fopen("/proc/mounts", "r");
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if (!fp)
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return -1;
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/*
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* in order to handle split hierarchy, we need to scan /proc/mounts
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* and inspect every cgroupfs mount point to find one that has
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* perf_event subsystem
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*/
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path_v1[0] = '\0';
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path_v2[0] = '\0';
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while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
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__stringify(PATH_MAX)"s %*d %*d\n",
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mountpoint, type, tokens) == 3) {
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if (!path_v1[0] && !strcmp(type, "cgroup")) {
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token = strtok_r(tokens, ",", &saved_ptr);
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while (token != NULL) {
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if (!strcmp(token, "perf_event")) {
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strcpy(path_v1, mountpoint);
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break;
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}
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token = strtok_r(NULL, ",", &saved_ptr);
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}
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}
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if (!path_v2[0] && !strcmp(type, "cgroup2"))
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strcpy(path_v2, mountpoint);
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if (path_v1[0] && path_v2[0])
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break;
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}
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fclose(fp);
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if (path_v1[0])
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path = path_v1;
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else if (path_v2[0])
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path = path_v2;
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else
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return -1;
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if (strlen(path) < maxlen) {
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strcpy(buf, path);
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return 0;
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}
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return -1;
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}
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static int open_cgroup(const char *name)
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{
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char path[PATH_MAX + 1];
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char mnt[PATH_MAX + 1];
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int fd;
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if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
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return -1;
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scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
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fd = open(path, O_RDONLY);
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if (fd == -1)
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fprintf(stderr, "no access to cgroup %s\n", path);
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return fd;
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}
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static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
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{
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struct perf_evsel *counter;
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/*
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* check if cgrp is already defined, if so we reuse it
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*/
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evlist__for_each_entry(evlist, counter) {
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if (!counter->cgrp)
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continue;
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if (!strcmp(counter->cgrp->name, str))
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return cgroup__get(counter->cgrp);
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}
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return NULL;
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}
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static struct cgroup *cgroup__new(const char *name)
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{
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struct cgroup *cgroup = zalloc(sizeof(*cgroup));
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if (cgroup != NULL) {
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refcount_set(&cgroup->refcnt, 1);
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cgroup->name = strdup(name);
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if (!cgroup->name)
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goto out_err;
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cgroup->fd = open_cgroup(name);
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if (cgroup->fd == -1)
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goto out_free_name;
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}
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return cgroup;
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out_free_name:
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zfree(&cgroup->name);
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out_err:
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free(cgroup);
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return NULL;
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}
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struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
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{
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struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
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return cgroup ?: cgroup__new(name);
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}
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static int add_cgroup(struct perf_evlist *evlist, const char *str)
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{
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struct perf_evsel *counter;
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struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
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int n;
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if (!cgrp)
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return -1;
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/*
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* find corresponding event
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* if add cgroup N, then need to find event N
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*/
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n = 0;
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evlist__for_each_entry(evlist, counter) {
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if (n == nr_cgroups)
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goto found;
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n++;
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}
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cgroup__put(cgrp);
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return -1;
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found:
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counter->cgrp = cgrp;
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return 0;
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}
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static void cgroup__delete(struct cgroup *cgroup)
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{
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close(cgroup->fd);
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zfree(&cgroup->name);
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free(cgroup);
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}
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void cgroup__put(struct cgroup *cgrp)
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{
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if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
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cgroup__delete(cgrp);
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}
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}
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struct cgroup *cgroup__get(struct cgroup *cgroup)
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{
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if (cgroup)
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refcount_inc(&cgroup->refcnt);
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return cgroup;
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}
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static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
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{
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if (evsel->cgrp == NULL)
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evsel->cgrp = cgroup__get(cgroup);
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}
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void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
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{
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struct perf_evsel *evsel;
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evlist__for_each_entry(evlist, evsel)
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evsel__set_default_cgroup(evsel, cgroup);
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}
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int parse_cgroups(const struct option *opt, const char *str,
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int unset __maybe_unused)
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{
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struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
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struct perf_evsel *counter;
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struct cgroup *cgrp = NULL;
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const char *p, *e, *eos = str + strlen(str);
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char *s;
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int ret, i;
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if (list_empty(&evlist->entries)) {
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fprintf(stderr, "must define events before cgroups\n");
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return -1;
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}
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for (;;) {
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p = strchr(str, ',');
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e = p ? p : eos;
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/* allow empty cgroups, i.e., skip */
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if (e - str) {
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/* termination added */
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s = strndup(str, e - str);
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if (!s)
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return -1;
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ret = add_cgroup(evlist, s);
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free(s);
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if (ret)
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return -1;
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}
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/* nr_cgroups is increased een for empty cgroups */
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nr_cgroups++;
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if (!p)
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break;
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str = p+1;
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}
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/* for the case one cgroup combine to multiple events */
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i = 0;
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if (nr_cgroups == 1) {
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evlist__for_each_entry(evlist, counter) {
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if (i == 0)
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cgrp = counter->cgrp;
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else {
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counter->cgrp = cgrp;
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refcount_inc(&cgrp->refcnt);
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}
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i++;
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}
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}
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return 0;
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}
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