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-rw-r--r--libnetdata/ebpf/ebpf.c1618
1 files changed, 1618 insertions, 0 deletions
diff --git a/libnetdata/ebpf/ebpf.c b/libnetdata/ebpf/ebpf.c
new file mode 100644
index 00000000..99f23b9c
--- /dev/null
+++ b/libnetdata/ebpf/ebpf.c
@@ -0,0 +1,1618 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dlfcn.h>
+#include <sys/utsname.h>
+
+#include "../libnetdata.h"
+
+char *ebpf_user_config_dir = CONFIG_DIR;
+char *ebpf_stock_config_dir = LIBCONFIG_DIR;
+
+/*
+static int clean_kprobe_event(FILE *out, char *filename, char *father_pid, netdata_ebpf_events_t *ptr)
+{
+ int fd = open(filename, O_WRONLY | O_APPEND, 0);
+ if (fd < 0) {
+ if (out) {
+ fprintf(out, "Cannot open %s : %s\n", filename, strerror(errno));
+ }
+ return 1;
+ }
+
+ char cmd[1024];
+ int length = snprintf(cmd, 1023, "-:kprobes/%c_netdata_%s_%s", ptr->type, ptr->name, father_pid);
+ int ret = 0;
+ if (length > 0) {
+ ssize_t written = write(fd, cmd, strlen(cmd));
+ if (written < 0) {
+ if (out) {
+ fprintf(
+ out, "Cannot remove the event (%d, %d) '%s' from %s : %s\n", getppid(), getpid(), cmd, filename,
+ strerror((int)errno));
+ }
+ ret = 1;
+ }
+ }
+
+ close(fd);
+
+ return ret;
+}
+
+int clean_kprobe_events(FILE *out, int pid, netdata_ebpf_events_t *ptr)
+{
+ char filename[FILENAME_MAX + 1];
+ snprintf(filename, FILENAME_MAX, "%s%s", NETDATA_DEBUGFS, "kprobe_events");
+
+ char removeme[16];
+ snprintf(removeme, 15, "%d", pid);
+
+ int i;
+ for (i = 0; ptr[i].name; i++) {
+ if (clean_kprobe_event(out, filename, removeme, &ptr[i])) {
+ break;
+ }
+ }
+
+ return 0;
+}
+*/
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Get Kernel version
+ *
+ * Get the current kernel from /proc and returns an integer value representing it
+ *
+ * @return it returns a value representing the kernel version.
+ */
+int ebpf_get_kernel_version()
+{
+ char major[16], minor[16], patch[16];
+ char ver[VERSION_STRING_LEN];
+ char *version = ver;
+
+ int fd = open("/proc/sys/kernel/osrelease", O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ ssize_t len = read(fd, ver, sizeof(ver));
+ if (len < 0) {
+ close(fd);
+ return -1;
+ }
+
+ close(fd);
+
+ char *move = major;
+ while (*version && *version != '.')
+ *move++ = *version++;
+ *move = '\0';
+
+ version++;
+ move = minor;
+ while (*version && *version != '.')
+ *move++ = *version++;
+ *move = '\0';
+
+ if (*version)
+ version++;
+ else
+ return -1;
+
+ move = patch;
+ while (*version && *version != '\n' && *version != '-')
+ *move++ = *version++;
+ *move = '\0';
+
+ // This new rule is fixing kernel version according the formula:
+ // KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
+ // that was extracted from /usr/include/linux/version.h
+ int ipatch = (int)str2l(patch);
+ if (ipatch > 255)
+ ipatch = 255;
+
+ return ((int)(str2l(major) * 65536) + (int)(str2l(minor) * 256) + ipatch);
+}
+
+/**
+ * Get RH release
+ *
+ * Read Red Hat release from /etc/redhat-release
+ *
+ * @return It returns RH release on success and -1 otherwise
+ */
+int get_redhat_release()
+{
+ char buffer[VERSION_STRING_LEN + 1];
+ int major, minor;
+ FILE *fp = fopen("/etc/redhat-release", "r");
+
+ if (fp) {
+ major = 0;
+ minor = -1;
+ size_t length = fread(buffer, sizeof(char), VERSION_STRING_LEN, fp);
+ if (length > 4) {
+ buffer[length] = '\0';
+ char *end = strchr(buffer, '.');
+ char *start;
+ if (end) {
+ *end = 0x0;
+
+ if (end > buffer) {
+ start = end - 1;
+
+ major = strtol(start, NULL, 10);
+ start = ++end;
+
+ end++;
+ if (end) {
+ end = 0x00;
+ minor = strtol(start, NULL, 10);
+ } else {
+ minor = -1;
+ }
+ }
+ }
+ }
+
+ fclose(fp);
+ return ((major * 256) + minor);
+ } else {
+ return -1;
+ }
+}
+
+/**
+ * Check if the kernel is in a list of rejected ones
+ *
+ * @return Returns 1 if the kernel is rejected, 0 otherwise.
+ */
+static int kernel_is_rejected()
+{
+ // Get kernel version from system
+ char version_string[VERSION_STRING_LEN + 1];
+ int version_string_len = 0;
+
+ if (read_file("/proc/version_signature", version_string, VERSION_STRING_LEN)) {
+ if (read_file("/proc/version", version_string, VERSION_STRING_LEN)) {
+ struct utsname uname_buf;
+ if (!uname(&uname_buf)) {
+ netdata_log_info("Cannot check kernel version");
+ return 0;
+ }
+ version_string_len =
+ snprintfz(version_string, VERSION_STRING_LEN, "%s %s", uname_buf.release, uname_buf.version);
+ }
+ }
+
+ if (!version_string_len)
+ version_string_len = strlen(version_string);
+
+ // Open a file with a list of rejected kernels
+ char *config_dir = getenv("NETDATA_USER_CONFIG_DIR");
+ if (config_dir == NULL) {
+ config_dir = CONFIG_DIR;
+ }
+
+ char filename[FILENAME_MAX + 1];
+ snprintfz(filename, FILENAME_MAX, "%s/ebpf.d/%s", config_dir, EBPF_KERNEL_REJECT_LIST_FILE);
+ FILE *kernel_reject_list = fopen(filename, "r");
+
+ if (!kernel_reject_list) {
+ // Keep this to have compatibility with old versions
+ snprintfz(filename, FILENAME_MAX, "%s/%s", config_dir, EBPF_KERNEL_REJECT_LIST_FILE);
+ kernel_reject_list = fopen(filename, "r");
+
+ if (!kernel_reject_list) {
+ config_dir = getenv("NETDATA_STOCK_CONFIG_DIR");
+ if (config_dir == NULL) {
+ config_dir = LIBCONFIG_DIR;
+ }
+
+ snprintfz(filename, FILENAME_MAX, "%s/ebpf.d/%s", config_dir, EBPF_KERNEL_REJECT_LIST_FILE);
+ kernel_reject_list = fopen(filename, "r");
+
+ if (!kernel_reject_list)
+ return 0;
+ }
+ }
+
+ // Find if the kernel is in the reject list
+ char *reject_string = NULL;
+ size_t buf_len = 0;
+ ssize_t reject_string_len;
+ while ((reject_string_len = getline(&reject_string, &buf_len, kernel_reject_list) - 1) > 0) {
+ if (version_string_len >= reject_string_len) {
+ if (!strncmp(version_string, reject_string, reject_string_len)) {
+ netdata_log_info("A buggy kernel is detected");
+ fclose(kernel_reject_list);
+ freez(reject_string);
+ return 1;
+ }
+ }
+ }
+
+ fclose(kernel_reject_list);
+ free(reject_string);
+
+ return 0;
+}
+
+static int has_ebpf_kernel_version(int version)
+{
+ if (kernel_is_rejected())
+ return 0;
+
+ // Kernel 4.11.0 or RH > 7.5
+ return (version >= NETDATA_MINIMUM_EBPF_KERNEL || get_redhat_release() >= NETDATA_MINIMUM_RH_VERSION);
+}
+
+int has_condition_to_run(int version)
+{
+ if (!has_ebpf_kernel_version(version))
+ return 0;
+
+ return 1;
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Kernel Name
+ *
+ * Select kernel name used by eBPF programs
+ *
+ * Netdata delivers for users eBPF programs with specific suffixes that represent the kernels they were
+ * compiled, when we load the eBPF program, the suffix must be the nereast possible of the kernel running.
+ *
+ * @param selector select the kernel version.
+ *
+ * @return It returns the string to load kernel.
+ */
+static char *ebpf_select_kernel_name(uint32_t selector)
+{
+ static char *kernel_names[] = { NETDATA_IDX_STR_V3_10, NETDATA_IDX_STR_V4_14, NETDATA_IDX_STR_V4_16,
+ NETDATA_IDX_STR_V4_18, NETDATA_IDX_STR_V5_4, NETDATA_IDX_STR_V5_10,
+ NETDATA_IDX_STR_V5_11, NETDATA_IDX_STR_V5_14, NETDATA_IDX_STR_V5_15,
+ NETDATA_IDX_STR_V5_16
+ };
+
+ return kernel_names[selector];
+}
+
+/**
+ * Select Max Index
+ *
+ * Select last index that will be tested on host.
+ *
+ * @param is_rhf is Red Hat fammily?
+ * @param kver the kernel version
+ *
+ * @return it returns the index to access kernel string.
+ */
+static int ebpf_select_max_index(int is_rhf, uint32_t kver)
+{
+ if (is_rhf > 0) { // Is Red Hat family
+ if (kver >= NETDATA_EBPF_KERNEL_5_14)
+ return NETDATA_IDX_V5_14;
+ else if (kver >= NETDATA_EBPF_KERNEL_5_4 && kver < NETDATA_EBPF_KERNEL_5_5) // For Oracle Linux
+ return NETDATA_IDX_V5_4;
+ else if (kver >= NETDATA_EBPF_KERNEL_4_11)
+ return NETDATA_IDX_V4_18;
+ } else { // Kernels from kernel.org
+ if (kver >= NETDATA_EBPF_KERNEL_5_16)
+ return NETDATA_IDX_V5_16;
+ else if (kver >= NETDATA_EBPF_KERNEL_5_15)
+ return NETDATA_IDX_V5_15;
+ else if (kver >= NETDATA_EBPF_KERNEL_5_11)
+ return NETDATA_IDX_V5_11;
+ else if (kver >= NETDATA_EBPF_KERNEL_5_10)
+ return NETDATA_IDX_V5_10;
+ else if (kver >= NETDATA_EBPF_KERNEL_4_17)
+ return NETDATA_IDX_V5_4;
+ else if (kver >= NETDATA_EBPF_KERNEL_4_15)
+ return NETDATA_IDX_V4_16;
+ else if (kver >= NETDATA_EBPF_KERNEL_4_11)
+ return NETDATA_IDX_V4_14;
+ }
+
+ return NETDATA_IDX_V3_10;
+}
+
+/**
+ * Select Index
+ *
+ * Select index to load data.
+ *
+ * @param kernels is the variable with kernel versions.
+ * @param is_rhf is Red Hat fammily?
+ * param kver the kernel version
+ */
+static uint32_t ebpf_select_index(uint32_t kernels, int is_rhf, uint32_t kver)
+{
+ uint32_t start = ebpf_select_max_index(is_rhf, kver);
+ uint32_t idx;
+
+ if (is_rhf == -1)
+ kernels &= ~NETDATA_V5_14;
+
+ for (idx = start; idx; idx--) {
+ if (kernels & 1 << idx)
+ break;
+ }
+
+ return idx;
+}
+
+/**
+ * Mount Name
+ *
+ * Mount name of eBPF program to be loaded.
+ *
+ * Netdata eBPF programs has the following format:
+ *
+ * Tnetdata_ebpf_N.V.o
+ *
+ * where:
+ * T - Is the eBPF type. When starts with 'p', this means we are only adding probes,
+ * and when they start with 'r' we are using retprobes.
+ * N - The eBPF program name.
+ * V - The kernel version in string format.
+ *
+ * @param out the vector where the name will be stored
+ * @param len the size of the out vector.
+ * @param path where the binaries are stored
+ * @param kver the kernel version
+ * @param name the eBPF program name.
+ * @param is_return is return or entry ?
+ */
+static void ebpf_mount_name(char *out, size_t len, char *path, uint32_t kver, const char *name,
+ int is_return, int is_rhf)
+{
+ char *version = ebpf_select_kernel_name(kver);
+ snprintfz(out, len, "%s/ebpf.d/%cnetdata_ebpf_%s.%s%s.o",
+ path,
+ (is_return) ? 'r' : 'p',
+ name,
+ version,
+ (is_rhf != -1) ? ".rhf" : "");
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Statistics from targets
+ *
+ * Count the information from targets.
+ *
+ * @param report the output structure
+ * @param targets vector with information about the eBPF plugin.
+ * @param value factor used to update calculation
+ */
+static void ebpf_stats_targets(ebpf_plugin_stats_t *report, netdata_ebpf_targets_t *targets, int value)
+{
+ if (!targets) {
+ report->probes = report->tracepoints = report->trampolines = 0;
+ return;
+ }
+
+ int i = 0;
+ while (targets[i].name) {
+ switch (targets[i].mode) {
+ case EBPF_LOAD_PROBE: {
+ report->probes += value;
+ break;
+ }
+ case EBPF_LOAD_RETPROBE: {
+ report->retprobes += value;
+ break;
+ }
+ case EBPF_LOAD_TRACEPOINT: {
+ report->tracepoints += value;
+ break;
+ }
+ case EBPF_LOAD_TRAMPOLINE: {
+ report->trampolines += value;
+ break;
+ }
+ }
+
+ i++;
+ }
+}
+
+/**
+ * Update General stats
+ *
+ * Update eBPF plugin statistics that has relationship with the thread.
+ *
+ * This function must be called with mutex associated to charts is locked.
+ *
+ * @param report the output structure
+ * @param em the structure with information about how the module/thread is working.
+ */
+void ebpf_update_stats(ebpf_plugin_stats_t *report, ebpf_module_t *em)
+{
+ int value;
+
+ // It is not necessary to report more information.
+ if (em->enabled > NETDATA_THREAD_EBPF_FUNCTION_RUNNING)
+ value = -1;
+ else
+ value = 1;
+
+ report->threads += value;
+ report->running += value;
+
+ // In theory the `else if` is useless, because when this function is called, the module should not stay in
+ // EBPF_LOAD_PLAY_DICE. We have this additional condition to detect errors from developers.
+ if (em->load & EBPF_LOAD_LEGACY)
+ report->legacy += value;
+ else if (em->load & EBPF_LOAD_CORE)
+ report->core += value;
+
+ if (em->maps_per_core)
+ report->hash_percpu += value;
+ else
+ report->hash_unique += value;
+
+ ebpf_stats_targets(report, em->targets, value);
+}
+
+/**
+ * Update Kernel memory with memory
+ *
+ * This algorithm is an adaptation of https://elixir.bootlin.com/linux/v6.1.14/source/tools/bpf/bpftool/common.c#L402
+ * to get 'memlock' data and update report.
+ *
+ * @param report the output structure
+ * @param map pointer to a map.
+ * @param action What action will be done with this map.
+ */
+void ebpf_update_kernel_memory(ebpf_plugin_stats_t *report, ebpf_local_maps_t *map, ebpf_stats_action_t action)
+{
+ char filename[FILENAME_MAX+1];
+ snprintfz(filename, FILENAME_MAX, "/proc/self/fdinfo/%d", map->map_fd);
+ procfile *ff = procfile_open(filename, " \t", PROCFILE_FLAG_DEFAULT);
+ if(unlikely(!ff)) {
+ netdata_log_error("Cannot open %s", filename);
+ return;
+ }
+
+ ff = procfile_readall(ff);
+ if(unlikely(!ff))
+ return;
+
+ unsigned long j, lines = procfile_lines(ff);
+ char *memlock = { "memlock" };
+ for (j = 0; j < lines ; j++) {
+ char *cmp = procfile_lineword(ff, j,0);
+ if (!strncmp(memlock, cmp, 7)) {
+ uint64_t memsize = (uint64_t) str2l(procfile_lineword(ff, j,1));
+ switch (action) {
+ case EBPF_ACTION_STAT_ADD: {
+ report->memlock_kern += memsize;
+ report->hash_tables += 1;
+#ifdef NETDATA_DEV_MODE
+ netdata_log_info("Hash table %u: %s (FD = %d) is consuming %lu bytes totalizing %lu bytes",
+ report->hash_tables, map->name, map->map_fd, memsize, report->memlock_kern);
+#endif
+ break;
+ }
+ case EBPF_ACTION_STAT_REMOVE: {
+ report->memlock_kern -= memsize;
+ report->hash_tables -= 1;
+#ifdef NETDATA_DEV_MODE
+ netdata_log_info("Hash table %s (FD = %d) was removed releasing %lu bytes, now we have %u tables loaded totalizing %lu bytes.",
+ map->name, map->map_fd, memsize, report->hash_tables, report->memlock_kern);
+#endif
+ break;
+ }
+ default: {
+ break;
+ }
+ }
+ break;
+ }
+ }
+
+ procfile_close(ff);
+}
+
+/**
+ * Update Kernel memory with memory
+ *
+ * This algorithm is an adaptation of https://elixir.bootlin.com/linux/v6.1.14/source/tools/bpf/bpftool/common.c#L402
+ * to get 'memlock' data and update report.
+ *
+ * @param report the output structure
+ * @param map pointer to a map. Last map must fish with name = NULL
+ * @param action should plugin add or remove values from amount.
+ */
+void ebpf_update_kernel_memory_with_vector(ebpf_plugin_stats_t *report,
+ ebpf_local_maps_t *maps,
+ ebpf_stats_action_t action)
+{
+ if (!maps)
+ return;
+
+ ebpf_local_maps_t *map;
+ int i = 0;
+ for (map = &maps[i]; maps[i].name; i++, map = &maps[i]) {
+ int fd = map->map_fd;
+ if (fd == ND_EBPF_MAP_FD_NOT_INITIALIZED)
+ continue;
+
+ ebpf_update_kernel_memory(report, map, action);
+ }
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+void ebpf_update_pid_table(ebpf_local_maps_t *pid, ebpf_module_t *em)
+{
+ pid->user_input = em->pid_map_size;
+}
+
+/**
+ * Update map size
+ *
+ * Update map size with information read from configuration files.
+ *
+ * @param map the structure with file descriptor to update.
+ * @param lmap the structure with information from configuration files.
+ * @param em the structure with information about how the module/thread is working.
+ * @param map_name the name of the file used to log.
+ */
+void ebpf_update_map_size(struct bpf_map *map, ebpf_local_maps_t *lmap, ebpf_module_t *em, const char *map_name __maybe_unused)
+{
+ uint32_t define_size = 0;
+ uint32_t apps_type = NETDATA_EBPF_MAP_PID | NETDATA_EBPF_MAP_RESIZABLE;
+ if (lmap->user_input && lmap->user_input != lmap->internal_input) {
+ define_size = lmap->internal_input;
+#ifdef NETDATA_INTERNAL_CHECKS
+ netdata_log_info("Changing map %s from size %u to %u ", map_name, lmap->internal_input, lmap->user_input);
+#endif
+ } else if (((lmap->type & apps_type) == apps_type) && (!em->apps_charts) && (!em->cgroup_charts)) {
+ lmap->user_input = ND_EBPF_DEFAULT_MIN_PID;
+ } else if (((em->apps_charts) || (em->cgroup_charts)) && (em->apps_level != NETDATA_APPS_NOT_SET)) {
+ switch (em->apps_level) {
+ case NETDATA_APPS_LEVEL_ALL: {
+ define_size = lmap->user_input;
+ break;
+ }
+ case NETDATA_APPS_LEVEL_PARENT: {
+ define_size = ND_EBPF_DEFAULT_PID_SIZE / 2;
+ break;
+ }
+ case NETDATA_APPS_LEVEL_REAL_PARENT:
+ default: {
+ define_size = ND_EBPF_DEFAULT_PID_SIZE / 3;
+ }
+ }
+ }
+
+ if (!define_size)
+ return;
+
+#ifdef LIBBPF_MAJOR_VERSION
+ bpf_map__set_max_entries(map, define_size);
+#else
+ bpf_map__resize(map, define_size);
+#endif
+}
+
+#ifdef LIBBPF_MAJOR_VERSION
+/**
+ * Update map type
+ *
+ * Update map type with information given.
+ *
+ * @param map the map we want to modify
+ * @param w a structure with user input
+ */
+void ebpf_update_map_type(struct bpf_map *map, ebpf_local_maps_t *w)
+{
+ if (bpf_map__set_type(map, w->map_type)) {
+ netdata_log_error("Cannot modify map type for %s", w->name);
+ }
+}
+
+/**
+ * Define map type
+ *
+ * This PR defines the type used by hash tables according user input.
+ *
+ * @param maps the list of maps used with a hash table.
+ * @param maps_per_core define if map type according user specification.
+ * @param kver kernel version host is running.
+ */
+void ebpf_define_map_type(ebpf_local_maps_t *maps, int maps_per_core, int kver)
+{
+ if (!maps)
+ return;
+
+ // Before kernel 4.06 there was not percpu hash tables
+ if (kver < NETDATA_EBPF_KERNEL_4_06)
+ maps_per_core = CONFIG_BOOLEAN_NO;
+
+ int i = 0;
+ while (maps[i].name) {
+ ebpf_local_maps_t *map = &maps[i];
+ // maps_per_core is a boolean value in configuration files.
+ if (maps_per_core) {
+ if (map->map_type == BPF_MAP_TYPE_HASH)
+ map->map_type = BPF_MAP_TYPE_PERCPU_HASH;
+ else if (map->map_type == BPF_MAP_TYPE_ARRAY)
+ map->map_type = BPF_MAP_TYPE_PERCPU_ARRAY;
+ } else {
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH)
+ map->map_type = BPF_MAP_TYPE_HASH;
+ else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ map->map_type = BPF_MAP_TYPE_ARRAY;
+ }
+
+ i++;
+ }
+}
+#endif
+
+/**
+ * Update Legacy map
+ *
+ * Update map for eBPF legacy code.
+ *
+ * @param program the structure with values read from binary.
+ * @param em the structure with information about how the module/thread is working.
+ */
+static void ebpf_update_legacy_map(struct bpf_object *program, ebpf_module_t *em)
+{
+ struct bpf_map *map;
+ ebpf_local_maps_t *maps = em->maps;
+ if (!maps)
+ return;
+
+ bpf_map__for_each(map, program)
+ {
+ const char *map_name = bpf_map__name(map);
+ int i = 0;
+ while (maps[i].name) {
+ ebpf_local_maps_t *w = &maps[i];
+
+ if (!strcmp(w->name, map_name)) {
+ // Modify size
+ if (w->type & NETDATA_EBPF_MAP_RESIZABLE) {
+ ebpf_update_map_size(map, w, em, map_name);
+ }
+
+#ifdef LIBBPF_MAJOR_VERSION
+ ebpf_update_map_type(map, w);
+#endif
+ }
+
+ i++;
+ }
+ }
+}
+
+size_t ebpf_count_programs(struct bpf_object *obj)
+{
+ size_t tot = 0;
+ struct bpf_program *prog;
+ bpf_object__for_each_program(prog, obj)
+ {
+ tot++;
+ }
+
+ return tot;
+}
+
+static ebpf_specify_name_t *ebpf_find_names(ebpf_specify_name_t *names, const char *prog_name)
+{
+ size_t i = 0;
+ while (names[i].program_name) {
+ if (!strcmp(prog_name, names[i].program_name))
+ return &names[i];
+
+ i++;
+ }
+
+ return NULL;
+}
+
+static struct bpf_link **ebpf_attach_programs(struct bpf_object *obj, size_t length, ebpf_specify_name_t *names)
+{
+ struct bpf_link **links = callocz(length , sizeof(struct bpf_link *));
+ size_t i = 0;
+ struct bpf_program *prog;
+ ebpf_specify_name_t *w;
+ bpf_object__for_each_program(prog, obj)
+ {
+ if (names) {
+ const char *name = bpf_program__name(prog);
+ w = ebpf_find_names(names, name);
+ } else
+ w = NULL;
+
+ if (w) {
+ enum bpf_prog_type type = bpf_program__get_type(prog);
+ if (type == BPF_PROG_TYPE_KPROBE)
+ links[i] = bpf_program__attach_kprobe(prog, w->retprobe, w->optional);
+ } else
+ links[i] = bpf_program__attach(prog);
+
+ if (libbpf_get_error(links[i])) {
+ links[i] = NULL;
+ }
+
+ i++;
+ }
+
+ return links;
+}
+
+static void ebpf_update_maps(ebpf_module_t *em, struct bpf_object *obj)
+{
+ if (!em->maps)
+ return;
+
+ ebpf_local_maps_t *maps = em->maps;
+ struct bpf_map *map;
+ bpf_map__for_each(map, obj)
+ {
+ int fd = bpf_map__fd(map);
+ if (maps) {
+ const char *map_name = bpf_map__name(map);
+ int j = 0; ;
+ while (maps[j].name) {
+ ebpf_local_maps_t *w = &maps[j];
+ if (w->map_fd == ND_EBPF_MAP_FD_NOT_INITIALIZED && !strcmp(map_name, w->name))
+ w->map_fd = fd;
+
+ j++;
+ }
+ }
+ }
+}
+
+/**
+ * Update Controller
+ *
+ * Update controller value with user input.
+ *
+ * @param fd the table file descriptor
+ * @param em structure with information about eBPF program we will load.
+ */
+void ebpf_update_controller(int fd, ebpf_module_t *em)
+{
+ uint32_t values[NETDATA_CONTROLLER_END] = {
+ (em->apps_charts & NETDATA_EBPF_APPS_FLAG_YES) | em->cgroup_charts,
+ em->apps_level, 0, 0, 0, 0
+ };
+ uint32_t key;
+ uint32_t end = NETDATA_CONTROLLER_PID_TABLE_ADD;
+
+ for (key = NETDATA_CONTROLLER_APPS_ENABLED; key < end; key++) {
+ int ret = bpf_map_update_elem(fd, &key, &values[key], BPF_ANY);
+ if (ret)
+ netdata_log_error("Add key(%u) for controller table failed.", key);
+ }
+}
+
+/**
+ * Update Legacy controller
+ *
+ * Update legacy controller table when eBPF program has it.
+ *
+ * @param em structure with information about eBPF program we will load.
+ * @param obj bpf object with tables.
+ */
+static void ebpf_update_legacy_controller(ebpf_module_t *em, struct bpf_object *obj)
+{
+ ebpf_local_maps_t *maps = em->maps;
+ if (!maps)
+ return;
+
+ struct bpf_map *map;
+ bpf_map__for_each(map, obj)
+ {
+ size_t i = 0;
+ while (maps[i].name) {
+ ebpf_local_maps_t *w = &maps[i];
+ if (w->map_fd != ND_EBPF_MAP_FD_NOT_INITIALIZED && (w->type & NETDATA_EBPF_MAP_CONTROLLER)) {
+ w->type &= ~NETDATA_EBPF_MAP_CONTROLLER;
+ w->type |= NETDATA_EBPF_MAP_CONTROLLER_UPDATED;
+
+ ebpf_update_controller(w->map_fd, em);
+ }
+ i++;
+ }
+ }
+}
+
+/**
+ * Load Program
+ *
+ * Load eBPF program into kernel
+ *
+ * @param plugins_dir directory where binary are stored
+ * @param em structure with information about eBPF program we will load.
+ * @param kver the kernel version according /usr/include/linux/version.h
+ * @param is_rhf is a kernel from Red Hat Family?
+ * @param obj structure where we will store object loaded.
+ *
+ * @return it returns a link for each target we associated an eBPF program.
+ */
+struct bpf_link **ebpf_load_program(char *plugins_dir, ebpf_module_t *em, int kver, int is_rhf,
+ struct bpf_object **obj)
+{
+ char lpath[4096];
+
+ uint32_t idx = ebpf_select_index(em->kernels, is_rhf, kver);
+
+ ebpf_mount_name(lpath, 4095, plugins_dir, idx, em->info.thread_name, em->mode, is_rhf);
+
+ // When this function is called ebpf.plugin is using legacy code, so we should reset the variable
+ em->load &= ~ NETDATA_EBPF_LOAD_METHODS;
+ em->load |= EBPF_LOAD_LEGACY;
+
+ *obj = bpf_object__open_file(lpath, NULL);
+ if (!*obj)
+ return NULL;
+
+ if (libbpf_get_error(obj)) {
+ bpf_object__close(*obj);
+ return NULL;
+ }
+
+ ebpf_update_legacy_map(*obj, em);
+
+ if (bpf_object__load(*obj)) {
+ netdata_log_error("ERROR: loading BPF object file failed %s\n", lpath);
+ bpf_object__close(*obj);
+ return NULL;
+ }
+
+ ebpf_update_maps(em, *obj);
+ ebpf_update_legacy_controller(em, *obj);
+
+ size_t count_programs = ebpf_count_programs(*obj);
+
+#ifdef NETDATA_INTERNAL_CHECKS
+ netdata_log_info("eBPF program %s loaded with success!", lpath);
+#endif
+
+ return ebpf_attach_programs(*obj, count_programs, em->names);
+}
+
+char *ebpf_find_symbol(char *search)
+{
+ char filename[FILENAME_MAX + 1];
+ char *ret = NULL;
+ snprintfz(filename, FILENAME_MAX, "%s%s", netdata_configured_host_prefix, NETDATA_KALLSYMS);
+ procfile *ff = procfile_open(filename, " \t", PROCFILE_FLAG_DEFAULT);
+ if(unlikely(!ff)) {
+ netdata_log_error("Cannot open %s%s", netdata_configured_host_prefix, NETDATA_KALLSYMS);
+ return ret;
+ }
+
+ ff = procfile_readall(ff);
+ if(unlikely(!ff))
+ return ret;
+
+ unsigned long i, lines = procfile_lines(ff);
+ size_t length = strlen(search);
+ for(i = 0; i < lines ; i++) {
+ char *cmp = procfile_lineword(ff, i,2);;
+ if (!strncmp(search, cmp, length)) {
+ ret = strdupz(cmp);
+ break;
+ }
+ }
+
+ procfile_close(ff);
+
+ return ret;
+}
+
+void ebpf_update_names(ebpf_specify_name_t *opt, ebpf_module_t *em)
+{
+ int mode = em->mode;
+ em->names = opt;
+
+ size_t i = 0;
+ while (opt[i].program_name) {
+ opt[i].retprobe = (mode == MODE_RETURN);
+ opt[i].optional = ebpf_find_symbol(opt[i].function_to_attach);
+
+ i++;
+ }
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+void ebpf_mount_config_name(char *filename, size_t length, char *path, const char *config)
+{
+ snprintf(filename, length, "%s/ebpf.d/%s", path, config);
+}
+
+int ebpf_load_config(struct config *config, char *filename)
+{
+ return appconfig_load(config, filename, 0, NULL);
+}
+
+
+static netdata_run_mode_t ebpf_select_mode(char *mode)
+{
+ if (!strcasecmp(mode,EBPF_CFG_LOAD_MODE_RETURN ))
+ return MODE_RETURN;
+ else if (!strcasecmp(mode, "dev"))
+ return MODE_DEVMODE;
+
+ return MODE_ENTRY;
+}
+
+static void ebpf_select_mode_string(char *output, size_t len, netdata_run_mode_t sel)
+{
+ if (sel == MODE_RETURN)
+ strncpyz(output, EBPF_CFG_LOAD_MODE_RETURN, len);
+ else
+ strncpyz(output, EBPF_CFG_LOAD_MODE_DEFAULT, len);
+}
+
+/**
+ * Convert string to load mode
+ *
+ * Convert the string given as argument to value present in enum.
+ *
+ * @param str value read from configuration file.
+ *
+ * @return It returns the value to be used.
+ */
+netdata_ebpf_load_mode_t epbf_convert_string_to_load_mode(char *str)
+{
+ if (!strcasecmp(str, EBPF_CFG_CORE_PROGRAM))
+ return EBPF_LOAD_CORE;
+ else if (!strcasecmp(str, EBPF_CFG_LEGACY_PROGRAM))
+ return EBPF_LOAD_LEGACY;
+
+ return EBPF_LOAD_PLAY_DICE;
+}
+
+/**
+ * Convert load mode to string
+ *
+ * @param mode value that will select the string
+ *
+ * @return It returns the string associated to mode.
+ */
+static char *ebpf_convert_load_mode_to_string(netdata_ebpf_load_mode_t mode)
+{
+ if (mode & EBPF_LOAD_CORE)
+ return EBPF_CFG_CORE_PROGRAM;
+ else if (mode & EBPF_LOAD_LEGACY)
+ return EBPF_CFG_LEGACY_PROGRAM;
+
+ return EBPF_CFG_DEFAULT_PROGRAM;
+}
+
+/**
+ * Convert collect pid to string
+ *
+ * @param level value that will select the string
+ *
+ * @return It returns the string associated to level.
+ */
+static char *ebpf_convert_collect_pid_to_string(netdata_apps_level_t level)
+{
+ if (level == NETDATA_APPS_LEVEL_REAL_PARENT)
+ return EBPF_CFG_PID_REAL_PARENT;
+ else if (level == NETDATA_APPS_LEVEL_PARENT)
+ return EBPF_CFG_PID_PARENT;
+ else if (level == NETDATA_APPS_LEVEL_ALL)
+ return EBPF_CFG_PID_ALL;
+
+ return EBPF_CFG_PID_INTERNAL_USAGE;
+}
+
+/**
+ * Convert string to apps level
+ *
+ * @param str the argument read from config files
+ *
+ * @return it returns the level associated to the string or default when it is a wrong value
+ */
+netdata_apps_level_t ebpf_convert_string_to_apps_level(char *str)
+{
+ if (!strcasecmp(str, EBPF_CFG_PID_REAL_PARENT))
+ return NETDATA_APPS_LEVEL_REAL_PARENT;
+ else if (!strcasecmp(str, EBPF_CFG_PID_PARENT))
+ return NETDATA_APPS_LEVEL_PARENT;
+ else if (!strcasecmp(str, EBPF_CFG_PID_ALL))
+ return NETDATA_APPS_LEVEL_ALL;
+
+ return NETDATA_APPS_NOT_SET;
+}
+
+/**
+ * CO-RE type
+ *
+ * Select the preferential type of CO-RE
+ *
+ * @param str value read from configuration file.
+ * @param lmode load mode used by collector.
+ */
+netdata_ebpf_program_loaded_t ebpf_convert_core_type(char *str, netdata_run_mode_t lmode)
+{
+ if (!strcasecmp(str, EBPF_CFG_ATTACH_TRACEPOINT))
+ return EBPF_LOAD_TRACEPOINT;
+ else if (!strcasecmp(str, EBPF_CFG_ATTACH_PROBE)) {
+ return (lmode == MODE_ENTRY) ? EBPF_LOAD_PROBE : EBPF_LOAD_RETPROBE;
+ }
+
+ return EBPF_LOAD_TRAMPOLINE;
+}
+
+#ifdef LIBBPF_MAJOR_VERSION
+/**
+ * Adjust Thread Load
+ *
+ * Adjust thread configuration according specified load.
+ *
+ * @param mod the main structure that will be adjusted.
+ * @param file the btf file used with thread.
+ */
+void ebpf_adjust_thread_load(ebpf_module_t *mod, struct btf *file)
+{
+ if (!file) {
+ mod->load &= ~EBPF_LOAD_CORE;
+ mod->load |= EBPF_LOAD_LEGACY;
+ } else if (mod->load == EBPF_LOAD_PLAY_DICE && file) {
+ mod->load &= ~EBPF_LOAD_LEGACY;
+ mod->load |= EBPF_LOAD_CORE;
+ }
+}
+
+/**
+ * Parse BTF file
+ *
+ * Parse a specific BTF file present on filesystem
+ *
+ * @param filename the file that will be parsed.
+ *
+ * @return It returns a pointer for the file on success and NULL otherwise.
+ */
+struct btf *ebpf_parse_btf_file(const char *filename)
+{
+ struct btf *bf = btf__parse(filename, NULL);
+ if (libbpf_get_error(bf)) {
+ fprintf(stderr, "Cannot parse btf file");
+ btf__free(bf);
+ return NULL;
+ }
+
+ return bf;
+}
+
+/**
+ * Load default btf file
+ *
+ * Load the default BTF file on environment.
+ *
+ * @param path is the fullpath
+ * @param filename is the file inside BTF path.
+ */
+struct btf *ebpf_load_btf_file(char *path, char *filename)
+{
+ char fullpath[PATH_MAX + 1];
+ snprintfz(fullpath, PATH_MAX, "%s/%s", path, filename);
+ struct btf *ret = ebpf_parse_btf_file(fullpath);
+ if (!ret)
+ netdata_log_info("Your environment does not have BTF file %s/%s. The plugin will work with 'legacy' code.",
+ path, filename);
+
+ return ret;
+}
+
+/**
+ * Find BTF attach type
+ *
+ * Search type fr current btf file.
+ *
+ * @param file is the structure for the btf file already parsed.
+ */
+static inline const struct btf_type *ebpf_find_btf_attach_type(struct btf *file)
+{
+ int id = btf__find_by_name_kind(file, "bpf_attach_type", BTF_KIND_ENUM);
+ if (id < 0) {
+ fprintf(stderr, "Cannot find 'bpf_attach_type'");
+
+ return NULL;
+ }
+
+ return btf__type_by_id(file, id);
+}
+
+/**
+ * Is function inside BTF
+ *
+ * Look for a specific function inside the given BTF file.
+ *
+ * @param file is the structure for the btf file already parsed.
+ * @param function is the function that we want to find.
+ */
+int ebpf_is_function_inside_btf(struct btf *file, char *function)
+{
+ const struct btf_type *type = ebpf_find_btf_attach_type(file);
+ if (!type)
+ return -1;
+
+ const struct btf_enum *e = btf_enum(type);
+ int i, id;
+ for (id = -1, i = 0; i < btf_vlen(type); i++, e++) {
+ if (!strcmp(btf__name_by_offset(file, e->name_off), "BPF_TRACE_FENTRY")) {
+ id = btf__find_by_name_kind(file, function, BTF_KIND_FUNC);
+ break;
+ }
+ }
+
+ return (id > 0) ? 1 : 0;
+}
+#endif
+
+/**
+ * Update target with configuration
+ *
+ * Update target load mode with value.
+ *
+ * @param em the module structure
+ * @param value value used to update.
+ */
+static void ebpf_update_target_with_conf(ebpf_module_t *em, netdata_ebpf_program_loaded_t value)
+{
+ netdata_ebpf_targets_t *targets = em->targets;
+ if (!targets) {
+ return;
+ }
+
+ int i = 0;
+ while (targets[i].name) {
+ targets[i].mode = value;
+ i++;
+ }
+}
+
+/**
+ * Select Load Mode
+ *
+ * Select the load mode according the given inputs.
+ *
+ * @param btf_file a pointer to the loaded btf file.
+ * @parma load current value.
+ * @param btf_file a pointer to the loaded btf file.
+ * @param is_rhf is Red Hat family?
+ *
+ * @return it returns the new load mode.
+ */
+static netdata_ebpf_load_mode_t ebpf_select_load_mode(struct btf *btf_file, netdata_ebpf_load_mode_t load,
+ int kver, int is_rh)
+{
+#ifdef LIBBPF_MAJOR_VERSION
+ if ((load & EBPF_LOAD_CORE) || (load & EBPF_LOAD_PLAY_DICE)) {
+ // Quick fix for Oracle linux 8.x
+ load = (!btf_file || (is_rh && (kver >= NETDATA_EBPF_KERNEL_5_4 && kver < NETDATA_EBPF_KERNEL_5_5))) ?
+ EBPF_LOAD_LEGACY : EBPF_LOAD_CORE;
+ }
+#else
+ load = EBPF_LOAD_LEGACY;
+#endif
+
+ return load;
+}
+
+/**
+ * Update Module using config
+ *
+ * Update configuration for a specific thread.
+ *
+ * @param modules structure that will be updated
+ * @param origin specify the configuration file loaded
+ * @param btf_file a pointer to the loaded btf file.
+ * @param is_rhf is Red Hat family?
+ */
+void ebpf_update_module_using_config(ebpf_module_t *modules, netdata_ebpf_load_mode_t origin, struct btf *btf_file,
+ int kver, int is_rh)
+{
+ char default_value[EBPF_MAX_MODE_LENGTH + 1];
+ ebpf_select_mode_string(default_value, EBPF_MAX_MODE_LENGTH, modules->mode);
+ char *load_mode = appconfig_get(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_LOAD_MODE, default_value);
+ modules->mode = ebpf_select_mode(load_mode);
+
+ modules->update_every = (int)appconfig_get_number(modules->cfg, EBPF_GLOBAL_SECTION,
+ EBPF_CFG_UPDATE_EVERY, modules->update_every);
+
+ modules->apps_charts = appconfig_get_boolean(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_APPLICATION,
+ (int) (modules->apps_charts & NETDATA_EBPF_APPS_FLAG_YES));
+
+ modules->cgroup_charts = appconfig_get_boolean(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_CGROUP,
+ modules->cgroup_charts);
+
+ modules->pid_map_size = (uint32_t)appconfig_get_number(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_PID_SIZE,
+ modules->pid_map_size);
+
+ modules->lifetime = (uint32_t) appconfig_get_number(modules->cfg, EBPF_GLOBAL_SECTION,
+ EBPF_CFG_LIFETIME, EBPF_DEFAULT_LIFETIME);
+
+ char *value = ebpf_convert_load_mode_to_string(modules->load & NETDATA_EBPF_LOAD_METHODS);
+ char *type_format = appconfig_get(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_TYPE_FORMAT, value);
+ netdata_ebpf_load_mode_t load = epbf_convert_string_to_load_mode(type_format);
+ load = ebpf_select_load_mode(btf_file, load, kver, is_rh);
+ modules->load = origin | load;
+
+ char *core_attach = appconfig_get(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_CORE_ATTACH, EBPF_CFG_ATTACH_TRAMPOLINE);
+ netdata_ebpf_program_loaded_t fill_lm = ebpf_convert_core_type(core_attach, modules->mode);
+ ebpf_update_target_with_conf(modules, fill_lm);
+
+ value = ebpf_convert_collect_pid_to_string(modules->apps_level);
+ char *collect_pid = appconfig_get(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_COLLECT_PID, value);
+ modules->apps_level = ebpf_convert_string_to_apps_level(collect_pid);
+
+ modules->maps_per_core = appconfig_get_boolean(modules->cfg, EBPF_GLOBAL_SECTION, EBPF_CFG_MAPS_PER_CORE,
+ modules->maps_per_core);
+ if (kver < NETDATA_EBPF_KERNEL_4_06)
+ modules->maps_per_core = CONFIG_BOOLEAN_NO;
+
+#ifdef NETDATA_DEV_MODE
+ netdata_log_info("The thread %s was configured with: mode = %s; update every = %d; apps = %s; cgroup = %s; ebpf type format = %s; ebpf co-re tracing = %s; collect pid = %s; maps per core = %s, lifetime=%u",
+ modules->info.thread_name,
+ load_mode,
+ modules->update_every,
+ (modules->apps_charts)?"enabled":"disabled",
+ (modules->cgroup_charts)?"enabled":"disabled",
+ type_format,
+ core_attach,
+ collect_pid,
+ (modules->maps_per_core)?"enabled":"disabled",
+ modules->lifetime
+ );
+#endif
+}
+
+/**
+ * Update module
+ *
+ * When this function is called, it will load the configuration file and after this
+ * it updates the global information of ebpf_module.
+ * If the module has specific configuration, this function will load it, but it will not
+ * update the variables.
+ *
+ * @param em the module structure
+ * @param btf_file a pointer to the loaded btf file.
+ * @param is_rhf is Red Hat family?
+ * @param kver the kernel version
+ */
+void ebpf_update_module(ebpf_module_t *em, struct btf *btf_file, int kver, int is_rh)
+{
+ char filename[FILENAME_MAX+1];
+ netdata_ebpf_load_mode_t origin;
+
+ ebpf_mount_config_name(filename, FILENAME_MAX, ebpf_user_config_dir, em->config_file);
+ if (!ebpf_load_config(em->cfg, filename)) {
+ ebpf_mount_config_name(filename, FILENAME_MAX, ebpf_stock_config_dir, em->config_file);
+ if (!ebpf_load_config(em->cfg, filename)) {
+ netdata_log_error("Cannot load the ebpf configuration file %s", em->config_file);
+ return;
+ }
+ // If user defined data globally, we will have here EBPF_LOADED_FROM_USER, we need to consider this, to avoid
+ // forcing users to configure thread by thread.
+ origin = (!(em->load & NETDATA_EBPF_LOAD_SOURCE)) ? EBPF_LOADED_FROM_STOCK : em->load & NETDATA_EBPF_LOAD_SOURCE;
+ } else
+ origin = EBPF_LOADED_FROM_USER;
+
+ ebpf_update_module_using_config(em, origin, btf_file, kver, is_rh);
+}
+
+/**
+ * Adjust Apps Cgroup
+ *
+ * Apps and cgroup has internal cleanup that needs attaching tracers to release_task, to avoid overload the function
+ * we will enable this integration by default, if and only if, we are running with trampolines.
+ *
+ * @param em a pointer to the main thread structure.
+ * @param mode is the mode used with different
+ */
+void ebpf_adjust_apps_cgroup(ebpf_module_t *em, netdata_ebpf_program_loaded_t mode)
+{
+ if ((em->load & EBPF_LOADED_FROM_STOCK) &&
+ (em->apps_charts || em->cgroup_charts) &&
+ mode != EBPF_LOAD_TRAMPOLINE) {
+ em->apps_charts = NETDATA_EBPF_APPS_FLAG_NO;
+ em->cgroup_charts = 0;
+ }
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Load Address
+ *
+ * Helper used to get address from /proc/kallsym
+ *
+ * @param fa address structure
+ * @param fd file descriptor loaded inside kernel. If a negative value is given
+ * the function will load address and it won't update hash table.
+ */
+void ebpf_load_addresses(ebpf_addresses_t *fa, int fd)
+{
+ if (fa->addr)
+ return ;
+
+ procfile *ff = procfile_open("/proc/kallsyms", " \t:", PROCFILE_FLAG_DEFAULT);
+ if (!ff)
+ return;
+
+ ff = procfile_readall(ff);
+ if (!ff)
+ return;
+
+ fa->hash = simple_hash(fa->function);
+
+ size_t lines = procfile_lines(ff), l;
+ for(l = 0; l < lines ;l++) {
+ char *fcnt = procfile_lineword(ff, l, 2);
+ uint32_t hash = simple_hash(fcnt);
+ if (fa->hash == hash && !strcmp(fcnt, fa->function)) {
+ char *type = procfile_lineword(ff, l, 2);
+ fa->type = type[0];
+ if (fd > 0) {
+ char addr[128];
+ snprintf(addr, 127, "0x%s", procfile_lineword(ff, l, 0));
+ fa->addr = (unsigned long) strtoul(addr, NULL, 16);
+ uint32_t key = 0;
+ bpf_map_update_elem(fd, &key, &fa->addr, BPF_ANY);
+ } else
+ fa->addr = 1;
+ break;
+ }
+ }
+
+ procfile_close(ff);
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Fill Algorithms
+ *
+ * Set one unique dimension for all vector position.
+ *
+ * @param algorithms the output vector
+ * @param length number of elements of algorithms vector
+ * @param algorithm algorithm used on charts.
+*/
+void ebpf_fill_algorithms(int *algorithms, size_t length, int algorithm)
+{
+ size_t i;
+ for (i = 0; i < length; i++) {
+ algorithms[i] = algorithm;
+ }
+}
+
+/**
+ * Fill Histogram dimension
+ *
+ * Fill the histogram dimension with the specified ranges
+ */
+char **ebpf_fill_histogram_dimension(size_t maximum)
+{
+ char *dimensions[] = { "us", "ms", "s"};
+ int previous_dim = 0, current_dim = 0;
+ uint32_t previous_level = 1000, current_level = 1000;
+ uint32_t previous_divisor = 1, current_divisor = 1;
+ uint32_t current = 1, previous = 0;
+ uint32_t selector;
+ char **out = callocz(maximum, sizeof(char *));
+ char range[128];
+ size_t end = maximum - 1;
+ for (selector = 0; selector < end; selector++) {
+ snprintf(range, 127, "%u%s->%u%s", previous/previous_divisor, dimensions[previous_dim],
+ current/current_divisor, dimensions[current_dim]);
+ out[selector] = strdupz(range);
+ previous = current;
+ current <<= 1;
+
+ if (previous_dim != 2 && previous > previous_level) {
+ previous_dim++;
+
+ previous_divisor *= 1000;
+ previous_level *= 1000;
+ }
+
+ if (current_dim != 2 && current > current_level) {
+ current_dim++;
+
+ current_divisor *= 1000;
+ current_level *= 1000;
+ }
+ }
+ snprintf(range, 127, "%u%s->+Inf", previous/previous_divisor, dimensions[previous_dim]);
+ out[selector] = strdupz(range);
+
+ return out;
+}
+
+/**
+ * Histogram dimension cleanup
+ *
+ * Cleanup dimensions allocated with function ebpf_fill_histogram_dimension
+ *
+ * @param ptr
+ * @param length
+ */
+void ebpf_histogram_dimension_cleanup(char **ptr, size_t length)
+{
+ size_t i;
+ for (i = 0; i < length; i++) {
+ freez(ptr[i]);
+ }
+ freez(ptr);
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+/**
+ * Open tracepoint path
+ *
+ * @param filename pointer to store the path
+ * @param length file length
+ * @param subsys is the name of your subsystem.
+ * @param eventname is the name of the event to trace.
+ * @param flags flags used with syscall open
+ *
+ * @return it returns a positive value on success and a negative otherwise.
+ */
+static inline int ebpf_open_tracepoint_path(char *filename, size_t length, char *subsys, char *eventname, int flags)
+{
+ snprintfz(filename, length, "%s/events/%s/%s/enable", NETDATA_DEBUGFS, subsys, eventname);
+ return open(filename, flags, 0);
+}
+
+/**
+ * Is tracepoint enabled
+ *
+ * Check whether the tracepoint is enabled.
+ *
+ * @param subsys is the name of your subsystem.
+ * @param eventname is the name of the event to trace.
+ *
+ * @return it returns 1 when it is enabled, 0 when it is disabled and -1 on error.
+ */
+int ebpf_is_tracepoint_enabled(char *subsys, char *eventname)
+{
+ char text[FILENAME_MAX + 1];
+ int fd = ebpf_open_tracepoint_path(text, FILENAME_MAX, subsys, eventname, O_RDONLY);
+ if (fd < 0) {
+ return -1;
+ }
+
+ ssize_t length = read(fd, text, 1);
+ if (length != 1) {
+ close(fd);
+ return -1;
+ }
+ close(fd);
+
+ return (text[0] == '1') ? CONFIG_BOOLEAN_YES : CONFIG_BOOLEAN_NO;
+}
+
+/**
+ * Change Tracing values
+ *
+ * Change value for specific tracepoint enabling or disabling it according value given.
+ *
+ * @param subsys is the name of your subsystem.
+ * @param eventname is the name of the event to trace.
+ * @param value a value to enable (1) or disable (0) a tracepoint.
+ *
+ * @return It returns 0 on success and -1 otherwise
+ */
+static int ebpf_change_tracing_values(char *subsys, char *eventname, char *value)
+{
+ if (strcmp("0", value) && strcmp("1", value)) {
+ netdata_log_error("Invalid value given to either enable or disable a tracepoint.");
+ return -1;
+ }
+
+ char filename[1024];
+ int fd = ebpf_open_tracepoint_path(filename, 1023, subsys, eventname, O_WRONLY);
+ if (fd < 0) {
+ return -1;
+ }
+
+ ssize_t written = write(fd, value, strlen(value));
+ if (written < 0) {
+ close(fd);
+ return -1;
+ }
+
+ close(fd);
+ return 0;
+}
+
+/**
+ * Enable tracing values
+ *
+ * Enable a tracepoint on a system
+ *
+ * @param subsys is the name of your subsystem.
+ * @param eventname is the name of the event to trace.
+ *
+ * @return It returns 0 on success and -1 otherwise
+ */
+int ebpf_enable_tracing_values(char *subsys, char *eventname)
+{
+ return ebpf_change_tracing_values(subsys, eventname, "1");
+}
+
+/**
+ * Disable tracing values
+ *
+ * Disable tracing points enabled by collector
+ *
+ * @param subsys is the name of your subsystem.
+ * @param eventname is the name of the event to trace.
+ *
+ * @return It returns 0 on success and -1 otherwise
+ */
+int ebpf_disable_tracing_values(char *subsys, char *eventname)
+{
+ return ebpf_change_tracing_values(subsys, eventname, "0");
+}
+
+/**
+ * Select PC prefix
+ *
+ * Identify the prefix to run on PC architecture.
+ *
+ * @return It returns 32 or 64 according to host arch.
+ */
+static uint32_t ebpf_select_pc_prefix()
+{
+ long counter = 1;
+ uint32_t i;
+ for (i = 0; i < 128; i++) {
+ counter <<= 1;
+ if (counter < 0)
+ break;
+ }
+
+ return counter;
+}
+
+/**
+ * Select Host Prefix
+ *
+ * Select prefix to syscall when host is running a kernel newer than 4.17.0
+ *
+ * @param output the vector to store data.
+ * @param length length of output vector.
+ * @param syscall the syscall that prefix will be attached;
+ * @param kver the current kernel version in format MAJOR*65536 + MINOR*256 + PATCH
+ */
+void ebpf_select_host_prefix(char *output, size_t length, char *syscall, int kver)
+{
+ if (kver < NETDATA_EBPF_KERNEL_4_17)
+ snprintfz(output, length, "sys_%s", syscall);
+ else {
+ uint32_t arch = ebpf_select_pc_prefix();
+ // Prefix selected according https://www.kernel.org/doc/html/latest/process/adding-syscalls.html
+ char *prefix = (arch == 32) ? "__ia32" : "__x64";
+ snprintfz(output, length, "%s_sys_%s", prefix, syscall);
+ }
+}
+