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-rw-r--r--libnetdata/ebpf/ebpf.c324
1 files changed, 324 insertions, 0 deletions
diff --git a/libnetdata/ebpf/ebpf.c b/libnetdata/ebpf/ebpf.c
new file mode 100644
index 0000000..a9ff21f
--- /dev/null
+++ b/libnetdata/ebpf/ebpf.c
@@ -0,0 +1,324 @@
+// 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"
+
+/*
+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)
+{
+ debug(D_EXIT, "Cleaning parent process events.");
+ 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;
+}
+*/
+
+//----------------------------------------------------------------------------------------------------------------------
+
+int get_kernel_version(char *out, int size)
+{
+ char major[16], minor[16], patch[16];
+ char ver[VERSION_STRING_LEN];
+ char *version = ver;
+
+ out[0] = '\0';
+ 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')
+ *move++ = *version++;
+ *move = '\0';
+
+ fd = snprintf(out, (size_t)size, "%s.%s.%s", major, minor, patch);
+ if (fd > size)
+ error("The buffer to store kernel version is not smaller than necessary.");
+
+ return ((int)(str2l(major) * 65536) + (int)(str2l(minor) * 256) + (int)str2l(patch));
+}
+
+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)) {
+ 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/%s", config_dir, EBPF_KERNEL_REJECT_LIST_FILE);
+ 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/%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)) {
+ info("A buggy kernel is detected");
+ fclose(kernel_reject_list);
+ freez(reject_string);
+ return 1;
+ }
+ }
+ }
+
+ fclose(kernel_reject_list);
+ freez(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;
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+char *ebpf_kernel_suffix(int version, int isrh)
+{
+ if (isrh) {
+ if (version >= NETDATA_EBPF_KERNEL_4_11)
+ return "4.18";
+ else
+ return "3.10";
+ } else {
+ if (version >= NETDATA_EBPF_KERNEL_5_10)
+ return "5.10";
+ else if (version >= NETDATA_EBPF_KERNEL_4_17)
+ return "5.4";
+ else if (version >= NETDATA_EBPF_KERNEL_4_15)
+ return "4.16";
+ else if (version >= NETDATA_EBPF_KERNEL_4_11)
+ return "4.14";
+ }
+
+ return NULL;
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+int ebpf_update_kernel(ebpf_data_t *ed)
+{
+ char *kernel = ebpf_kernel_suffix(ed->running_on_kernel, (ed->isrh < 0) ? 0 : 1);
+ size_t length = strlen(kernel);
+ strncpyz(ed->kernel_string, kernel, length);
+ ed->kernel_string[length] = '\0';
+
+ return 0;
+}
+
+static int select_file(char *name, const char *program, size_t length, int mode, char *kernel_string)
+{
+ int ret = -1;
+ if (!mode)
+ ret = snprintf(name, length, "rnetdata_ebpf_%s.%s.o", program, kernel_string);
+ else if (mode == 1)
+ ret = snprintf(name, length, "dnetdata_ebpf_%s.%s.o", program, kernel_string);
+ else if (mode == 2)
+ ret = snprintf(name, length, "pnetdata_ebpf_%s.%s.o", program, kernel_string);
+
+ return ret;
+}
+
+struct bpf_link **ebpf_load_program(char *plugins_dir, ebpf_module_t *em, char *kernel_string, struct bpf_object **obj, int *map_fd)
+{
+ char lpath[4096];
+ char lname[128];
+ int prog_fd;
+
+ int test = select_file(lname, em->thread_name, (size_t)127, em->mode, kernel_string);
+ if (test < 0 || test > 127)
+ return NULL;
+
+ snprintf(lpath, 4096, "%s/%s", plugins_dir, lname);
+ if (bpf_prog_load(lpath, BPF_PROG_TYPE_KPROBE, obj, &prog_fd)) {
+ em->enabled = CONFIG_BOOLEAN_NO;
+ info("Cannot load program: %s", lpath);
+ return NULL;
+ } else {
+ info("The eBPF program %s was loaded with success.", em->thread_name);
+ }
+
+ struct bpf_map *map;
+ size_t i = 0;
+ bpf_map__for_each(map, *obj)
+ {
+ map_fd[i] = bpf_map__fd(map);
+ i++;
+ }
+
+ struct bpf_program *prog;
+ struct bpf_link **links = callocz(NETDATA_MAX_PROBES , sizeof(struct bpf_link *));
+ i = 0;
+ bpf_object__for_each_program(prog, *obj)
+ {
+ links[i] = bpf_program__attach(prog);
+ i++;
+ }
+
+ return links;
+}