--- /dev/null
+/*
+ * bpf-loader.c
+ *
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ */
+
+#include <bpf/libbpf.h>
+#include <linux/err.h>
+#include "perf.h"
+#include "debug.h"
+#include "bpf-loader.h"
+#include "probe-event.h"
+#include "probe-finder.h" // for MAX_PROBES
+#include "llvm-utils.h"
+
+#define DEFINE_PRINT_FN(name, level) \
+static int libbpf_##name(const char *fmt, ...) \
+{ \
+ va_list args; \
+ int ret; \
+ \
+ va_start(args, fmt); \
+ ret = veprintf(level, verbose, pr_fmt(fmt), args);\
+ va_end(args); \
+ return ret; \
+}
+
+DEFINE_PRINT_FN(warning, 1)
+DEFINE_PRINT_FN(info, 1)
+DEFINE_PRINT_FN(debug, 1)
+
+struct bpf_prog_priv {
+ struct perf_probe_event pev;
+};
+
+static bool libbpf_initialized;
+
+struct bpf_object *
+bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz, const char *name)
+{
+ struct bpf_object *obj;
+
+ if (!libbpf_initialized) {
+ libbpf_set_print(libbpf_warning,
+ libbpf_info,
+ libbpf_debug);
+ libbpf_initialized = true;
+ }
+
+ obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, name);
+ if (IS_ERR(obj)) {
+ pr_debug("bpf: failed to load buffer\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return obj;
+}
+
+struct bpf_object *bpf__prepare_load(const char *filename, bool source)
+{
+ struct bpf_object *obj;
+
+ if (!libbpf_initialized) {
+ libbpf_set_print(libbpf_warning,
+ libbpf_info,
+ libbpf_debug);
+ libbpf_initialized = true;
+ }
+
+ if (source) {
+ int err;
+ void *obj_buf;
+ size_t obj_buf_sz;
+
+ err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz);
+ if (err)
+ return ERR_PTR(-BPF_LOADER_ERRNO__COMPILE);
+ obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, filename);
+ free(obj_buf);
+ } else
+ obj = bpf_object__open(filename);
+
+ if (IS_ERR(obj)) {
+ pr_debug("bpf: failed to load %s\n", filename);
+ return obj;
+ }
+
+ return obj;
+}
+
+void bpf__clear(void)
+{
+ struct bpf_object *obj, *tmp;
+
+ bpf_object__for_each_safe(obj, tmp) {
+ bpf__unprobe(obj);
+ bpf_object__close(obj);
+ }
+}
+
+static void
+bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
+ void *_priv)
+{
+ struct bpf_prog_priv *priv = _priv;
+
+ cleanup_perf_probe_events(&priv->pev, 1);
+ free(priv);
+}
+
+static int
+config_bpf_program(struct bpf_program *prog)
+{
+ struct perf_probe_event *pev = NULL;
+ struct bpf_prog_priv *priv = NULL;
+ const char *config_str;
+ int err;
+
+ config_str = bpf_program__title(prog, false);
+ if (IS_ERR(config_str)) {
+ pr_debug("bpf: unable to get title for program\n");
+ return PTR_ERR(config_str);
+ }
+
+ priv = calloc(sizeof(*priv), 1);
+ if (!priv) {
+ pr_debug("bpf: failed to alloc priv\n");
+ return -ENOMEM;
+ }
+ pev = &priv->pev;
+
+ pr_debug("bpf: config program '%s'\n", config_str);
+ err = parse_perf_probe_command(config_str, pev);
+ if (err < 0) {
+ pr_debug("bpf: '%s' is not a valid config string\n",
+ config_str);
+ err = -BPF_LOADER_ERRNO__CONFIG;
+ goto errout;
+ }
+
+ if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) {
+ pr_debug("bpf: '%s': group for event is set and not '%s'.\n",
+ config_str, PERF_BPF_PROBE_GROUP);
+ err = -BPF_LOADER_ERRNO__GROUP;
+ goto errout;
+ } else if (!pev->group)
+ pev->group = strdup(PERF_BPF_PROBE_GROUP);
+
+ if (!pev->group) {
+ pr_debug("bpf: strdup failed\n");
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ if (!pev->event) {
+ pr_debug("bpf: '%s': event name is missing. Section name should be 'key=value'\n",
+ config_str);
+ err = -BPF_LOADER_ERRNO__EVENTNAME;
+ goto errout;
+ }
+ pr_debug("bpf: config '%s' is ok\n", config_str);
+
+ err = bpf_program__set_private(prog, priv, bpf_prog_priv__clear);
+ if (err) {
+ pr_debug("Failed to set priv for program '%s'\n", config_str);
+ goto errout;
+ }
+
+ return 0;
+
+errout:
+ if (pev)
+ clear_perf_probe_event(pev);
+ free(priv);
+ return err;
+}
+
+static int bpf__prepare_probe(void)
+{
+ static int err = 0;
+ static bool initialized = false;
+
+ /*
+ * Make err static, so if init failed the first, bpf__prepare_probe()
+ * fails each time without calling init_probe_symbol_maps multiple
+ * times.
+ */
+ if (initialized)
+ return err;
+
+ initialized = true;
+ err = init_probe_symbol_maps(false);
+ if (err < 0)
+ pr_debug("Failed to init_probe_symbol_maps\n");
+ probe_conf.max_probes = MAX_PROBES;
+ return err;
+}
+
+int bpf__probe(struct bpf_object *obj)
+{
+ int err = 0;
+ struct bpf_program *prog;
+ struct bpf_prog_priv *priv;
+ struct perf_probe_event *pev;
+
+ err = bpf__prepare_probe();
+ if (err) {
+ pr_debug("bpf__prepare_probe failed\n");
+ return err;
+ }
+
+ bpf_object__for_each_program(prog, obj) {
+ err = config_bpf_program(prog);
+ if (err)
+ goto out;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv)
+ goto out;
+ pev = &priv->pev;
+
+ err = convert_perf_probe_events(pev, 1);
+ if (err < 0) {
+ pr_debug("bpf_probe: failed to convert perf probe events");
+ goto out;
+ }
+
+ err = apply_perf_probe_events(pev, 1);
+ if (err < 0) {
+ pr_debug("bpf_probe: failed to apply perf probe events");
+ goto out;
+ }
+ }
+out:
+ return err < 0 ? err : 0;
+}
+
+#define EVENTS_WRITE_BUFSIZE 4096
+int bpf__unprobe(struct bpf_object *obj)
+{
+ int err, ret = 0;
+ struct bpf_program *prog;
+ struct bpf_prog_priv *priv;
+
+ bpf_object__for_each_program(prog, obj) {
+ int i;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv)
+ continue;
+
+ for (i = 0; i < priv->pev.ntevs; i++) {
+ struct probe_trace_event *tev = &priv->pev.tevs[i];
+ char name_buf[EVENTS_WRITE_BUFSIZE];
+ struct strfilter *delfilter;
+
+ snprintf(name_buf, EVENTS_WRITE_BUFSIZE,
+ "%s:%s", tev->group, tev->event);
+ name_buf[EVENTS_WRITE_BUFSIZE - 1] = '\0';
+
+ delfilter = strfilter__new(name_buf, NULL);
+ if (!delfilter) {
+ pr_debug("Failed to create filter for unprobing\n");
+ ret = -ENOMEM;
+ continue;
+ }
+
+ err = del_perf_probe_events(delfilter);
+ strfilter__delete(delfilter);
+ if (err) {
+ pr_debug("Failed to delete %s\n", name_buf);
+ ret = err;
+ continue;
+ }
+ }
+ }
+ return ret;
+}
+
+int bpf__load(struct bpf_object *obj)
+{
+ int err;
+
+ err = bpf_object__load(obj);
+ if (err) {
+ pr_debug("bpf: load objects failed\n");
+ return err;
+ }
+ return 0;
+}
+
+int bpf__foreach_tev(struct bpf_object *obj,
+ bpf_prog_iter_callback_t func,
+ void *arg)
+{
+ struct bpf_program *prog;
+ int err;
+
+ bpf_object__for_each_program(prog, obj) {
+ struct probe_trace_event *tev;
+ struct perf_probe_event *pev;
+ struct bpf_prog_priv *priv;
+ int i, fd;
+
+ err = bpf_program__get_private(prog,
+ (void **)&priv);
+ if (err || !priv) {
+ pr_debug("bpf: failed to get private field\n");
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
+
+ pev = &priv->pev;
+ for (i = 0; i < pev->ntevs; i++) {
+ tev = &pev->tevs[i];
+
+ fd = bpf_program__fd(prog);
+ if (fd < 0) {
+ pr_debug("bpf: failed to get file descriptor\n");
+ return fd;
+ }
+
+ err = (*func)(tev, fd, arg);
+ if (err) {
+ pr_debug("bpf: call back failed, stop iterate\n");
+ return err;
+ }
+ }
+ }
+ return 0;
+}
+
+#define ERRNO_OFFSET(e) ((e) - __BPF_LOADER_ERRNO__START)
+#define ERRCODE_OFFSET(c) ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
+#define NR_ERRNO (__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
+
+static const char *bpf_loader_strerror_table[NR_ERRNO] = {
+ [ERRCODE_OFFSET(CONFIG)] = "Invalid config string",
+ [ERRCODE_OFFSET(GROUP)] = "Invalid group name",
+ [ERRCODE_OFFSET(EVENTNAME)] = "No event name found in config string",
+ [ERRCODE_OFFSET(INTERNAL)] = "BPF loader internal error",
+ [ERRCODE_OFFSET(COMPILE)] = "Error when compiling BPF scriptlet",
+};
+
+static int
+bpf_loader_strerror(int err, char *buf, size_t size)
+{
+ char sbuf[STRERR_BUFSIZE];
+ const char *msg;
+
+ if (!buf || !size)
+ return -1;
+
+ err = err > 0 ? err : -err;
+
+ if (err >= __LIBBPF_ERRNO__START)
+ return libbpf_strerror(err, buf, size);
+
+ if (err >= __BPF_LOADER_ERRNO__START && err < __BPF_LOADER_ERRNO__END) {
+ msg = bpf_loader_strerror_table[ERRNO_OFFSET(err)];
+ snprintf(buf, size, "%s", msg);
+ buf[size - 1] = '\0';
+ return 0;
+ }
+
+ if (err >= __BPF_LOADER_ERRNO__END)
+ snprintf(buf, size, "Unknown bpf loader error %d", err);
+ else
+ snprintf(buf, size, "%s",
+ strerror_r(err, sbuf, sizeof(sbuf)));
+
+ buf[size - 1] = '\0';
+ return -1;
+}
+
+#define bpf__strerror_head(err, buf, size) \
+ char sbuf[STRERR_BUFSIZE], *emsg;\
+ if (!size)\
+ return 0;\
+ if (err < 0)\
+ err = -err;\
+ bpf_loader_strerror(err, sbuf, sizeof(sbuf));\
+ emsg = sbuf;\
+ switch (err) {\
+ default:\
+ scnprintf(buf, size, "%s", emsg);\
+ break;
+
+#define bpf__strerror_entry(val, fmt...)\
+ case val: {\
+ scnprintf(buf, size, fmt);\
+ break;\
+ }
+
+#define bpf__strerror_end(buf, size)\
+ }\
+ buf[size - 1] = '\0';
+
+int bpf__strerror_prepare_load(const char *filename, bool source,
+ int err, char *buf, size_t size)
+{
+ size_t n;
+ int ret;
+
+ n = snprintf(buf, size, "Failed to load %s%s: ",
+ filename, source ? " from source" : "");
+ if (n >= size) {
+ buf[size - 1] = '\0';
+ return 0;
+ }
+ buf += n;
+ size -= n;
+
+ ret = bpf_loader_strerror(err, buf, size);
+ buf[size - 1] = '\0';
+ return ret;
+}
+
+int bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
+ int err, char *buf, size_t size)
+{
+ bpf__strerror_head(err, buf, size);
+ bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'");
+ bpf__strerror_entry(EACCES, "You need to be root");
+ bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0");
+ bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file");
+ bpf__strerror_end(buf, size);
+ return 0;
+}
+
+int bpf__strerror_load(struct bpf_object *obj,
+ int err, char *buf, size_t size)
+{
+ bpf__strerror_head(err, buf, size);
+ case LIBBPF_ERRNO__KVER: {
+ unsigned int obj_kver = bpf_object__get_kversion(obj);
+ unsigned int real_kver;
+
+ if (fetch_kernel_version(&real_kver, NULL, 0)) {
+ scnprintf(buf, size, "Unable to fetch kernel version");
+ break;
+ }
+
+ if (obj_kver != real_kver) {
+ scnprintf(buf, size,
+ "'version' ("KVER_FMT") doesn't match running kernel ("KVER_FMT")",
+ KVER_PARAM(obj_kver),
+ KVER_PARAM(real_kver));
+ break;
+ }
+
+ scnprintf(buf, size, "Failed to load program for unknown reason");
+ break;
+ }
+ bpf__strerror_end(buf, size);
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff