4 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
5 * Copyright (C) 2015 Huawei Inc.
8 #include <bpf/libbpf.h>
12 #include "bpf-loader.h"
13 #include "probe-event.h"
14 #include "probe-finder.h" // for MAX_PROBES
15 #include "llvm-utils.h"
17 #define DEFINE_PRINT_FN(name, level) \
18 static int libbpf_##name(const char *fmt, ...) \
23 va_start(args, fmt); \
24 ret = veprintf(level, verbose, pr_fmt(fmt), args);\
29 DEFINE_PRINT_FN(warning, 1)
30 DEFINE_PRINT_FN(info, 1)
31 DEFINE_PRINT_FN(debug, 1)
33 struct bpf_prog_priv {
34 struct perf_probe_event pev;
37 static bool libbpf_initialized;
40 bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
42 struct bpf_object *obj;
44 if (!libbpf_initialized) {
45 libbpf_set_print(libbpf_warning,
48 libbpf_initialized = true;
51 obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, name);
53 pr_debug("bpf: failed to load buffer\n");
54 return ERR_PTR(-EINVAL);
60 struct bpf_object *bpf__prepare_load(const char *filename, bool source)
62 struct bpf_object *obj;
64 if (!libbpf_initialized) {
65 libbpf_set_print(libbpf_warning,
68 libbpf_initialized = true;
76 err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz);
78 return ERR_PTR(-BPF_LOADER_ERRNO__COMPILE);
79 obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, filename);
82 obj = bpf_object__open(filename);
85 pr_debug("bpf: failed to load %s\n", filename);
94 struct bpf_object *obj, *tmp;
96 bpf_object__for_each_safe(obj, tmp) {
98 bpf_object__close(obj);
103 bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
106 struct bpf_prog_priv *priv = _priv;
108 cleanup_perf_probe_events(&priv->pev, 1);
113 config_bpf_program(struct bpf_program *prog)
115 struct perf_probe_event *pev = NULL;
116 struct bpf_prog_priv *priv = NULL;
117 const char *config_str;
120 config_str = bpf_program__title(prog, false);
121 if (IS_ERR(config_str)) {
122 pr_debug("bpf: unable to get title for program\n");
123 return PTR_ERR(config_str);
126 priv = calloc(sizeof(*priv), 1);
128 pr_debug("bpf: failed to alloc priv\n");
133 pr_debug("bpf: config program '%s'\n", config_str);
134 err = parse_perf_probe_command(config_str, pev);
136 pr_debug("bpf: '%s' is not a valid config string\n",
138 err = -BPF_LOADER_ERRNO__CONFIG;
142 if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) {
143 pr_debug("bpf: '%s': group for event is set and not '%s'.\n",
144 config_str, PERF_BPF_PROBE_GROUP);
145 err = -BPF_LOADER_ERRNO__GROUP;
147 } else if (!pev->group)
148 pev->group = strdup(PERF_BPF_PROBE_GROUP);
151 pr_debug("bpf: strdup failed\n");
157 pr_debug("bpf: '%s': event name is missing. Section name should be 'key=value'\n",
159 err = -BPF_LOADER_ERRNO__EVENTNAME;
162 pr_debug("bpf: config '%s' is ok\n", config_str);
164 err = bpf_program__set_private(prog, priv, bpf_prog_priv__clear);
166 pr_debug("Failed to set priv for program '%s'\n", config_str);
174 clear_perf_probe_event(pev);
179 static int bpf__prepare_probe(void)
182 static bool initialized = false;
185 * Make err static, so if init failed the first, bpf__prepare_probe()
186 * fails each time without calling init_probe_symbol_maps multiple
193 err = init_probe_symbol_maps(false);
195 pr_debug("Failed to init_probe_symbol_maps\n");
196 probe_conf.max_probes = MAX_PROBES;
200 int bpf__probe(struct bpf_object *obj)
203 struct bpf_program *prog;
204 struct bpf_prog_priv *priv;
205 struct perf_probe_event *pev;
207 err = bpf__prepare_probe();
209 pr_debug("bpf__prepare_probe failed\n");
213 bpf_object__for_each_program(prog, obj) {
214 err = config_bpf_program(prog);
218 err = bpf_program__get_private(prog, (void **)&priv);
223 err = convert_perf_probe_events(pev, 1);
225 pr_debug("bpf_probe: failed to convert perf probe events");
229 err = apply_perf_probe_events(pev, 1);
231 pr_debug("bpf_probe: failed to apply perf probe events");
236 return err < 0 ? err : 0;
239 #define EVENTS_WRITE_BUFSIZE 4096
240 int bpf__unprobe(struct bpf_object *obj)
243 struct bpf_program *prog;
244 struct bpf_prog_priv *priv;
246 bpf_object__for_each_program(prog, obj) {
249 err = bpf_program__get_private(prog, (void **)&priv);
253 for (i = 0; i < priv->pev.ntevs; i++) {
254 struct probe_trace_event *tev = &priv->pev.tevs[i];
255 char name_buf[EVENTS_WRITE_BUFSIZE];
256 struct strfilter *delfilter;
258 snprintf(name_buf, EVENTS_WRITE_BUFSIZE,
259 "%s:%s", tev->group, tev->event);
260 name_buf[EVENTS_WRITE_BUFSIZE - 1] = '\0';
262 delfilter = strfilter__new(name_buf, NULL);
264 pr_debug("Failed to create filter for unprobing\n");
269 err = del_perf_probe_events(delfilter);
270 strfilter__delete(delfilter);
272 pr_debug("Failed to delete %s\n", name_buf);
281 int bpf__load(struct bpf_object *obj)
285 err = bpf_object__load(obj);
287 pr_debug("bpf: load objects failed\n");
293 int bpf__foreach_tev(struct bpf_object *obj,
294 bpf_prog_iter_callback_t func,
297 struct bpf_program *prog;
300 bpf_object__for_each_program(prog, obj) {
301 struct probe_trace_event *tev;
302 struct perf_probe_event *pev;
303 struct bpf_prog_priv *priv;
306 err = bpf_program__get_private(prog,
309 pr_debug("bpf: failed to get private field\n");
310 return -BPF_LOADER_ERRNO__INTERNAL;
314 for (i = 0; i < pev->ntevs; i++) {
317 fd = bpf_program__fd(prog);
319 pr_debug("bpf: failed to get file descriptor\n");
323 err = (*func)(tev, fd, arg);
325 pr_debug("bpf: call back failed, stop iterate\n");
333 #define ERRNO_OFFSET(e) ((e) - __BPF_LOADER_ERRNO__START)
334 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
335 #define NR_ERRNO (__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
337 static const char *bpf_loader_strerror_table[NR_ERRNO] = {
338 [ERRCODE_OFFSET(CONFIG)] = "Invalid config string",
339 [ERRCODE_OFFSET(GROUP)] = "Invalid group name",
340 [ERRCODE_OFFSET(EVENTNAME)] = "No event name found in config string",
341 [ERRCODE_OFFSET(INTERNAL)] = "BPF loader internal error",
342 [ERRCODE_OFFSET(COMPILE)] = "Error when compiling BPF scriptlet",
346 bpf_loader_strerror(int err, char *buf, size_t size)
348 char sbuf[STRERR_BUFSIZE];
354 err = err > 0 ? err : -err;
356 if (err >= __LIBBPF_ERRNO__START)
357 return libbpf_strerror(err, buf, size);
359 if (err >= __BPF_LOADER_ERRNO__START && err < __BPF_LOADER_ERRNO__END) {
360 msg = bpf_loader_strerror_table[ERRNO_OFFSET(err)];
361 snprintf(buf, size, "%s", msg);
362 buf[size - 1] = '\0';
366 if (err >= __BPF_LOADER_ERRNO__END)
367 snprintf(buf, size, "Unknown bpf loader error %d", err);
369 snprintf(buf, size, "%s",
370 strerror_r(err, sbuf, sizeof(sbuf)));
372 buf[size - 1] = '\0';
376 #define bpf__strerror_head(err, buf, size) \
377 char sbuf[STRERR_BUFSIZE], *emsg;\
382 bpf_loader_strerror(err, sbuf, sizeof(sbuf));\
386 scnprintf(buf, size, "%s", emsg);\
389 #define bpf__strerror_entry(val, fmt...)\
391 scnprintf(buf, size, fmt);\
395 #define bpf__strerror_end(buf, size)\
397 buf[size - 1] = '\0';
399 int bpf__strerror_prepare_load(const char *filename, bool source,
400 int err, char *buf, size_t size)
405 n = snprintf(buf, size, "Failed to load %s%s: ",
406 filename, source ? " from source" : "");
408 buf[size - 1] = '\0';
414 ret = bpf_loader_strerror(err, buf, size);
415 buf[size - 1] = '\0';
419 int bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
420 int err, char *buf, size_t size)
422 bpf__strerror_head(err, buf, size);
423 bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'");
424 bpf__strerror_entry(EACCES, "You need to be root");
425 bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0");
426 bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file");
427 bpf__strerror_end(buf, size);
431 int bpf__strerror_load(struct bpf_object *obj,
432 int err, char *buf, size_t size)
434 bpf__strerror_head(err, buf, size);
435 case LIBBPF_ERRNO__KVER: {
436 unsigned int obj_kver = bpf_object__get_kversion(obj);
437 unsigned int real_kver;
439 if (fetch_kernel_version(&real_kver, NULL, 0)) {
440 scnprintf(buf, size, "Unable to fetch kernel version");
444 if (obj_kver != real_kver) {
446 "'version' ("KVER_FMT") doesn't match running kernel ("KVER_FMT")",
447 KVER_PARAM(obj_kver),
448 KVER_PARAM(real_kver));
452 scnprintf(buf, size, "Failed to load program for unknown reason");
455 bpf__strerror_end(buf, size);