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--- a/src/libbpf.c
+++ b/src/libbpf.c
@@ -620,6 +620,93 @@ bpf_object__init_prog_names(struct bpf_object *obj)
return 0;
}
+static __u32 choose_specific_version0(int fd, __u32 current)
+{
+ char ver[256];
+ __u32 v_major, v_minor, v_patch;
+ ssize_t len = read(fd, ver, sizeof(ver));
+ if (len < 0) {
+ return 0;
+ }
+ ver[len] = '\0';
+
+ char *first = strchr(ver, ' ');
+ if (!first) {
+ return 0;
+ }
+
+ first++;
+ char *version = strchr(first, ' ');
+ if (!version) {
+ return 0;
+ }
+
+ version++;
+ if (sscanf(version, "%u.%u.%u", &v_major, &v_minor, &v_patch) != 3)
+ return current;
+
+ return KERNEL_VERSION(v_major, v_minor, v_patch);
+}
+
+static __u32 choose_kernel_version(__u32 current)
+{
+ FILE *fp_d = fopen("/etc/debian_version","r");
+ int fp_u = open("/proc/version_signature", O_RDONLY);
+ FILE *fp_rh = fopen("/etc/redhat-release","r");
+ char tmp[32];
+ int de = 0;
+ __u32 ret;
+
+ if (!fp_d && !fp_rh && fp_u == -1)
+ return current;
+
+ struct utsname u;
+ uname(&u);
+
+ if (fp_d) {
+ fclose(fp_d);
+ de = 1;
+ }
+
+ if (fp_rh) {
+ fclose(fp_rh);
+ de = 0;
+ }
+
+ if ( fp_u > 0 ) {
+ ret = choose_specific_version0(fp_u, current);
+ close(fp_u);
+ return (!ret)?current:ret;
+ }
+
+ __u32 v_kernel,v_major, v_minor, v_patch;
+ __u32 r_kernel,r_major, r_minor, r_patch;
+
+ if (sscanf(u.release, "%u.%u.%u-%u", &v_kernel, &v_major, &v_minor, &v_patch) != 4)
+ return current;
+
+ int length = snprintf(tmp, 31, "%u.%u", v_kernel, v_major);
+ tmp[length] = '\0';
+
+ char *parse = strstr(u.version, tmp);
+ if (!parse) {
+ return current;
+ }
+
+ char *space = strchr(parse, ' ');
+ if(space) {
+ length = (int)(space - parse);
+ strncpy(tmp, parse, (size_t)length);
+ tmp[length] = '\0';
+ }
+
+ if (sscanf(tmp, "%u.%u.%u-%u", &r_kernel, &r_major, &r_minor, &r_patch) != 4)
+ return current;
+
+ ret = (de)?KERNEL_VERSION(r_kernel, r_major, r_minor):KERNEL_VERSION(r_kernel, r_major, r_minor) + r_patch;
+ return (ret > current)?ret:current;
+}
+
static __u32 get_kernel_version(void)
{
__u32 major, minor, patch;
@@ -628,7 +715,11 @@ static __u32 get_kernel_version(void)
uname(&info);
if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
return 0;
- return KERNEL_VERSION(major, minor, patch);
+
+ if (major < 5)
+ return choose_kernel_version(KERNEL_VERSION(major, minor, patch));
+ else
+ return KERNEL_VERSION(major, minor, patch);
}
static const struct btf_member *
@@ -3239,6 +3330,10 @@ int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
static int
bpf_object__probe_loading(struct bpf_object *obj)
{
+ // Don't probe loading for very old kernels. CentOS 7 can't load this probe.
+ if (obj->kern_version <= KERNEL_VERSION(3, 10, 0))
+ return 0;
+
struct bpf_load_program_attr attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
@@ -7612,6 +7707,88 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
return pfd;
}
+static int perf_event_open_old_kprobe(bool retprobe, const char *name)
+{
+#define DEBUG_FS "/sys/kernel/debug/tracing/"
+ struct perf_event_attr attr = {};
+ char errmsg[STRERR_BUFSIZE];
+ int kfd = -1, ret = -1, err;
+ char event_alias[256], buf[PATH_MAX];
+ const char *event_prefix = "";
+ bool event_was_written = false;
+
+ kfd = open(DEBUG_FS "kprobe_events", O_WRONLY | O_APPEND, 0);
+ if (kfd < 0) {
+ pr_warn("failed to open '%s%s': %s\n",
+ DEBUG_FS,
+ "kprobe_events",
+ libbpf_strerror_r(kfd, errmsg, sizeof(errmsg)));
+ return kfd;
+ }
+
+ char type = retprobe ? 'r' : 'p';
+ snprintf(event_alias, sizeof(event_alias), "%c_netdata_%s_%d", type, name, getpid());
+
+#ifdef __x86_64__
+ if (strncmp(name, "sys_", 4) == 0) {
+ snprintf(buf, sizeof(buf), "%c:__x64_%s __x64_%s",
+ type, event_alias, name);
+ ret = write(kfd, buf, strlen(buf));
+
+ if (ret >= 0) {
+ event_was_written = true;
+ event_prefix = "__x64_";
+ }
+ }
+#endif
+
+ if (!event_was_written) {
+ snprintf(buf, sizeof(buf), "%c:%s %s",
+ type, event_alias, name);
+ ret = write(kfd, buf, strlen(buf));
+ if (ret < 0) {
+ pr_warn("failed to create kprobe '%s': %s\n",
+ name,
+ libbpf_strerror_r(ret, errmsg, sizeof(errmsg)));
+ close(kfd);
+ return ret;
+ }
+ }
+
+ close(kfd);
+
+ snprintf(buf, sizeof(buf), DEBUG_FS "events/kprobes/%s%s/id",
+ event_prefix,
+ event_alias);
+
+ ret = parse_uint_from_file(buf, "%d\n");
+ if (ret < 0) {
+ pr_warn("failed to determine event id: %s\n",
+ libbpf_strerror_r(ret, errmsg, sizeof(errmsg)));
+ return ret;
+ }
+ attr.config = ret;
+
+ attr.size = sizeof(attr);
+ attr.type = PERF_TYPE_TRACEPOINT;
+ attr.config1 = ptr_to_u64(name); /* kprobe_func */
+ attr.config2 = 0; /* kprobe_addr */
+
+ /* pid filter is meaningful only for uprobes */
+ kfd = syscall(__NR_perf_event_open, &attr,
+ -1 /* pid */,
+ 0 /* cpu */,
+ -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
+ if (kfd < 0) {
+ err = -errno;
+ pr_warn("%s perf_event_open_old_kprobe() failed: %s\n",
+ "kprobe",
+ libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+ return err;
+ }
+ return kfd;
+}
+
struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
bool retprobe,
const char *func_name)
@@ -7623,11 +7800,14 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
0 /* offset */, -1 /* pid */);
if (pfd < 0) {
- pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
- bpf_program__title(prog, false),
- retprobe ? "kretprobe" : "kprobe", func_name,
- libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
- return ERR_PTR(pfd);
+ pfd = perf_event_open_old_kprobe(retprobe, func_name);
+ if (pfd < 0) {
+ pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
+ bpf_program__title(prog, false),
+ retprobe ? "kretprobe" : "kprobe", func_name,
+ libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
+ return ERR_PTR(pfd);
+ }
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
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