};
};
-typedef int (*libbpf_prog_setup_fn_t)(struct bpf_program *prog, long cookie);
-typedef int (*libbpf_prog_prepare_load_fn_t)(struct bpf_program *prog,
- struct bpf_prog_load_opts *opts, long cookie);
-/* If auto-attach is not supported, callback should return 0 and set link to NULL */
-typedef int (*libbpf_prog_attach_fn_t)(const struct bpf_program *prog, long cookie,
- struct bpf_link **link);
-
/* stored as sec_def->cookie for all libbpf-supported SEC()s */
enum sec_def_flags {
SEC_NONE = 0,
};
struct bpf_sec_def {
- const char *sec;
+ char *sec;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
long cookie;
+ int handler_id;
libbpf_prog_setup_fn_t prog_setup_fn;
libbpf_prog_prepare_load_fn_t prog_prepare_load_fn;
}
#define SEC_DEF(sec_pfx, ptype, atype, flags, ...) { \
- .sec = sec_pfx, \
+ .sec = (char *)sec_pfx, \
.prog_type = BPF_PROG_TYPE_##ptype, \
.expected_attach_type = atype, \
.cookie = (long)(flags), \
SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
};
-#define MAX_TYPE_NAME_SIZE 32
+static size_t custom_sec_def_cnt;
+static struct bpf_sec_def *custom_sec_defs;
+static struct bpf_sec_def custom_fallback_def;
+static bool has_custom_fallback_def;
-static const struct bpf_sec_def *find_sec_def(const char *sec_name)
+static int last_custom_sec_def_handler_id;
+
+int libbpf_register_prog_handler(const char *sec,
+ enum bpf_prog_type prog_type,
+ enum bpf_attach_type exp_attach_type,
+ const struct libbpf_prog_handler_opts *opts)
{
- const struct bpf_sec_def *sec_def;
- enum sec_def_flags sec_flags;
- int i, n = ARRAY_SIZE(section_defs), len;
- bool strict = libbpf_mode & LIBBPF_STRICT_SEC_NAME;
+ struct bpf_sec_def *sec_def;
- for (i = 0; i < n; i++) {
- sec_def = §ion_defs[i];
- sec_flags = sec_def->cookie;
- len = strlen(sec_def->sec);
+ if (!OPTS_VALID(opts, libbpf_prog_handler_opts))
+ return libbpf_err(-EINVAL);
- /* "type/" always has to have proper SEC("type/extras") form */
- if (sec_def->sec[len - 1] == '/') {
- if (str_has_pfx(sec_name, sec_def->sec))
- return sec_def;
- continue;
- }
+ if (last_custom_sec_def_handler_id == INT_MAX) /* prevent overflow */
+ return libbpf_err(-E2BIG);
- /* "type+" means it can be either exact SEC("type") or
- * well-formed SEC("type/extras") with proper '/' separator
- */
- if (sec_def->sec[len - 1] == '+') {
- len--;
- /* not even a prefix */
- if (strncmp(sec_name, sec_def->sec, len) != 0)
- continue;
- /* exact match or has '/' separator */
- if (sec_name[len] == '\0' || sec_name[len] == '/')
- return sec_def;
- continue;
- }
+ if (sec) {
+ sec_def = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt + 1,
+ sizeof(*sec_def));
+ if (!sec_def)
+ return libbpf_err(-ENOMEM);
- /* SEC_SLOPPY_PFX definitions are allowed to be just prefix
- * matches, unless strict section name mode
- * (LIBBPF_STRICT_SEC_NAME) is enabled, in which case the
- * match has to be exact.
- */
- if ((sec_flags & SEC_SLOPPY_PFX) && !strict) {
- if (str_has_pfx(sec_name, sec_def->sec))
- return sec_def;
- continue;
- }
+ custom_sec_defs = sec_def;
+ sec_def = &custom_sec_defs[custom_sec_def_cnt];
+ } else {
+ if (has_custom_fallback_def)
+ return libbpf_err(-EBUSY);
- /* Definitions not marked SEC_SLOPPY_PFX (e.g.,
- * SEC("syscall")) are exact matches in both modes.
- */
- if (strcmp(sec_name, sec_def->sec) == 0)
+ sec_def = &custom_fallback_def;
+ }
+
+ sec_def->sec = sec ? strdup(sec) : NULL;
+ if (sec && !sec_def->sec)
+ return libbpf_err(-ENOMEM);
+
+ sec_def->prog_type = prog_type;
+ sec_def->expected_attach_type = exp_attach_type;
+ sec_def->cookie = OPTS_GET(opts, cookie, 0);
+
+ sec_def->prog_setup_fn = OPTS_GET(opts, prog_setup_fn, NULL);
+ sec_def->prog_prepare_load_fn = OPTS_GET(opts, prog_prepare_load_fn, NULL);
+ sec_def->prog_attach_fn = OPTS_GET(opts, prog_attach_fn, NULL);
+
+ sec_def->handler_id = ++last_custom_sec_def_handler_id;
+
+ if (sec)
+ custom_sec_def_cnt++;
+ else
+ has_custom_fallback_def = true;
+
+ return sec_def->handler_id;
+}
+
+int libbpf_unregister_prog_handler(int handler_id)
+{
+ struct bpf_sec_def *sec_defs;
+ int i;
+
+ if (handler_id <= 0)
+ return libbpf_err(-EINVAL);
+
+ if (has_custom_fallback_def && custom_fallback_def.handler_id == handler_id) {
+ memset(&custom_fallback_def, 0, sizeof(custom_fallback_def));
+ has_custom_fallback_def = false;
+ return 0;
+ }
+
+ for (i = 0; i < custom_sec_def_cnt; i++) {
+ if (custom_sec_defs[i].handler_id == handler_id)
+ break;
+ }
+
+ if (i == custom_sec_def_cnt)
+ return libbpf_err(-ENOENT);
+
+ free(custom_sec_defs[i].sec);
+ for (i = i + 1; i < custom_sec_def_cnt; i++)
+ custom_sec_defs[i - 1] = custom_sec_defs[i];
+ custom_sec_def_cnt--;
+
+ /* try to shrink the array, but it's ok if we couldn't */
+ sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs));
+ if (sec_defs)
+ custom_sec_defs = sec_defs;
+
+ return 0;
+}
+
+static bool sec_def_matches(const struct bpf_sec_def *sec_def, const char *sec_name,
+ bool allow_sloppy)
+{
+ size_t len = strlen(sec_def->sec);
+
+ /* "type/" always has to have proper SEC("type/extras") form */
+ if (sec_def->sec[len - 1] == '/') {
+ if (str_has_pfx(sec_name, sec_def->sec))
+ return true;
+ return false;
+ }
+
+ /* "type+" means it can be either exact SEC("type") or
+ * well-formed SEC("type/extras") with proper '/' separator
+ */
+ if (sec_def->sec[len - 1] == '+') {
+ len--;
+ /* not even a prefix */
+ if (strncmp(sec_name, sec_def->sec, len) != 0)
+ return false;
+ /* exact match or has '/' separator */
+ if (sec_name[len] == '\0' || sec_name[len] == '/')
+ return true;
+ return false;
+ }
+
+ /* SEC_SLOPPY_PFX definitions are allowed to be just prefix
+ * matches, unless strict section name mode
+ * (LIBBPF_STRICT_SEC_NAME) is enabled, in which case the
+ * match has to be exact.
+ */
+ if (allow_sloppy && str_has_pfx(sec_name, sec_def->sec))
+ return true;
+
+ /* Definitions not marked SEC_SLOPPY_PFX (e.g.,
+ * SEC("syscall")) are exact matches in both modes.
+ */
+ return strcmp(sec_name, sec_def->sec) == 0;
+}
+
+static const struct bpf_sec_def *find_sec_def(const char *sec_name)
+{
+ const struct bpf_sec_def *sec_def;
+ int i, n;
+ bool strict = libbpf_mode & LIBBPF_STRICT_SEC_NAME, allow_sloppy;
+
+ n = custom_sec_def_cnt;
+ for (i = 0; i < n; i++) {
+ sec_def = &custom_sec_defs[i];
+ if (sec_def_matches(sec_def, sec_name, false))
+ return sec_def;
+ }
+
+ n = ARRAY_SIZE(section_defs);
+ for (i = 0; i < n; i++) {
+ sec_def = §ion_defs[i];
+ allow_sloppy = (sec_def->cookie & SEC_SLOPPY_PFX) && !strict;
+ if (sec_def_matches(sec_def, sec_name, allow_sloppy))
return sec_def;
}
+
+ if (has_custom_fallback_def)
+ return &custom_fallback_def;
+
return NULL;
}
+#define MAX_TYPE_NAME_SIZE 32
+
static char *libbpf_get_type_names(bool attach_type)
{
int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);
LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);
+/*
+ * Custom handling of BPF program's SEC() definitions
+ */
+
+struct bpf_prog_load_opts; /* defined in bpf.h */
+
+/* Called during bpf_object__open() for each recognized BPF program. Callback
+ * can use various bpf_program__set_*() setters to adjust whatever properties
+ * are necessary.
+ */
+typedef int (*libbpf_prog_setup_fn_t)(struct bpf_program *prog, long cookie);
+
+/* Called right before libbpf performs bpf_prog_load() to load BPF program
+ * into the kernel. Callback can adjust opts as necessary.
+ */
+typedef int (*libbpf_prog_prepare_load_fn_t)(struct bpf_program *prog,
+ struct bpf_prog_load_opts *opts, long cookie);
+
+/* Called during skeleton attach or through bpf_program__attach(). If
+ * auto-attach is not supported, callback should return 0 and set link to
+ * NULL (it's not considered an error during skeleton attach, but it will be
+ * an error for bpf_program__attach() calls). On error, error should be
+ * returned directly and link set to NULL. On success, return 0 and set link
+ * to a valid struct bpf_link.
+ */
+typedef int (*libbpf_prog_attach_fn_t)(const struct bpf_program *prog, long cookie,
+ struct bpf_link **link);
+
+struct libbpf_prog_handler_opts {
+ /* size of this struct, for forward/backward compatiblity */
+ size_t sz;
+ /* User-provided value that is passed to prog_setup_fn,
+ * prog_prepare_load_fn, and prog_attach_fn callbacks. Allows user to
+ * register one set of callbacks for multiple SEC() definitions and
+ * still be able to distinguish them, if necessary. For example,
+ * libbpf itself is using this to pass necessary flags (e.g.,
+ * sleepable flag) to a common internal SEC() handler.
+ */
+ long cookie;
+ /* BPF program initialization callback (see libbpf_prog_setup_fn_t).
+ * Callback is optional, pass NULL if it's not necessary.
+ */
+ libbpf_prog_setup_fn_t prog_setup_fn;
+ /* BPF program loading callback (see libbpf_prog_prepare_load_fn_t).
+ * Callback is optional, pass NULL if it's not necessary.
+ */
+ libbpf_prog_prepare_load_fn_t prog_prepare_load_fn;
+ /* BPF program attach callback (see libbpf_prog_attach_fn_t).
+ * Callback is optional, pass NULL if it's not necessary.
+ */
+ libbpf_prog_attach_fn_t prog_attach_fn;
+};
+#define libbpf_prog_handler_opts__last_field prog_attach_fn
+
+/**
+ * @brief **libbpf_register_prog_handler()** registers a custom BPF program
+ * SEC() handler.
+ * @param sec section prefix for which custom handler is registered
+ * @param prog_type BPF program type associated with specified section
+ * @param exp_attach_type Expected BPF attach type associated with specified section
+ * @param opts optional cookie, callbacks, and other extra options
+ * @return Non-negative handler ID is returned on success. This handler ID has
+ * to be passed to *libbpf_unregister_prog_handler()* to unregister such
+ * custom handler. Negative error code is returned on error.
+ *
+ * *sec* defines which SEC() definitions are handled by this custom handler
+ * registration. *sec* can have few different forms:
+ * - if *sec* is just a plain string (e.g., "abc"), it will match only
+ * SEC("abc"). If BPF program specifies SEC("abc/whatever") it will result
+ * in an error;
+ * - if *sec* is of the form "abc/", proper SEC() form is
+ * SEC("abc/something"), where acceptable "something" should be checked by
+ * *prog_init_fn* callback, if there are additional restrictions;
+ * - if *sec* is of the form "abc+", it will successfully match both
+ * SEC("abc") and SEC("abc/whatever") forms;
+ * - if *sec* is NULL, custom handler is registered for any BPF program that
+ * doesn't match any of the registered (custom or libbpf's own) SEC()
+ * handlers. There could be only one such generic custom handler registered
+ * at any given time.
+ *
+ * All custom handlers (except the one with *sec* == NULL) are processed
+ * before libbpf's own SEC() handlers. It is allowed to "override" libbpf's
+ * SEC() handlers by registering custom ones for the same section prefix
+ * (i.e., it's possible to have custom SEC("perf_event/LLC-load-misses")
+ * handler).
+ *
+ * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
+ * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
+ * to ensure synchronization if there is a risk of running this API from
+ * multiple threads simultaneously.
+ */
+LIBBPF_API int libbpf_register_prog_handler(const char *sec,
+ enum bpf_prog_type prog_type,
+ enum bpf_attach_type exp_attach_type,
+ const struct libbpf_prog_handler_opts *opts);
+/**
+ * @brief *libbpf_unregister_prog_handler()* unregisters previously registered
+ * custom BPF program SEC() handler.
+ * @param handler_id handler ID returned by *libbpf_register_prog_handler()*
+ * after successful registration
+ * @return 0 on success, negative error code if handler isn't found
+ *
+ * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
+ * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
+ * to ensure synchronization if there is a risk of running this API from
+ * multiple threads simultaneously.
+ */
+LIBBPF_API int libbpf_unregister_prog_handler(int handler_id);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
projects / linux-2.6-microblaze.git / commitdiff