samples/bpf/bpf_load.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <libelf.h>
 #include <gelf.h>
 #include <errno.h>
 #include <unistd.h>
 #include <string.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <linux/bpf.h>
 #include <linux/filter.h>
 #include <linux/perf_event.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
 #include <linux/types.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <poll.h>
 #include <ctype.h>
 #include <assert.h>
 #include <bpf/bpf.h>
 #include "bpf_load.h"
 #include "perf-sys.h"

 #define DEBUGFS "/sys/kernel/debug/tracing/"

 static char license[128];
 static int kern_version;
 static bool processed_sec[128];
 char bpf_log_buf[BPF_LOG_BUF_SIZE];
 int map_fd[MAX_MAPS];
 int prog_fd[MAX_PROGS];
 int event_fd[MAX_PROGS];
 int prog_cnt;
 int prog_array_fd = -1;

 struct bpf_map_data map_data[MAX_MAPS];
 int map_data_count = 0;

 static int populate_prog_array(const char *event, int prog_fd)
 {
 	int ind = atoi(event), err;

 	err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);
 	if (err < 0) {
 		printf("failed to store prog_fd in prog_array\n");
 		return -1;
 	}
 	return 0;
 }

 static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 {
 	bool is_socket = strncmp(event, "socket", 6) == 0;
 	bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
 	bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
 	bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
 	bool is_raw_tracepoint = strncmp(event, "raw_tracepoint/", 15) == 0;
 	bool is_xdp = strncmp(event, "xdp", 3) == 0;
 	bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
 	bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
 	bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
 	bool is_sockops = strncmp(event, "sockops", 7) == 0;
 	bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
 	bool is_sk_msg = strncmp(event, "sk_msg", 6) == 0;
 	size_t insns_cnt = size / sizeof(struct bpf_insn);
 	enum bpf_prog_type prog_type;
 	char buf[256];
 	int fd, efd, err, id;
 	struct perf_event_attr attr = {};

 	attr.type = PERF_TYPE_TRACEPOINT;
 	attr.sample_type = PERF_SAMPLE_RAW;
 	attr.sample_period = 1;
 	attr.wakeup_events = 1;

 	if (is_socket) {
 		prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
 	} else if (is_kprobe || is_kretprobe) {
 		prog_type = BPF_PROG_TYPE_KPROBE;
 	} else if (is_tracepoint) {
 		prog_type = BPF_PROG_TYPE_TRACEPOINT;
 	} else if (is_raw_tracepoint) {
 		prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT;
 	} else if (is_xdp) {
 		prog_type = BPF_PROG_TYPE_XDP;
 	} else if (is_perf_event) {
 		prog_type = BPF_PROG_TYPE_PERF_EVENT;
 	} else if (is_cgroup_skb) {
 		prog_type = BPF_PROG_TYPE_CGROUP_SKB;
 	} else if (is_cgroup_sk) {
 		prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
 	} else if (is_sockops) {
 		prog_type = BPF_PROG_TYPE_SOCK_OPS;
 	} else if (is_sk_skb) {
 		prog_type = BPF_PROG_TYPE_SK_SKB;
 	} else if (is_sk_msg) {
 		prog_type = BPF_PROG_TYPE_SK_MSG;
 	} else {
 		printf("Unknown event '%s'\n", event);
 		return -1;
 	}

 	fd = bpf_load_program(prog_type, prog, insns_cnt, license, kern_version,
 			      bpf_log_buf, BPF_LOG_BUF_SIZE);
 	if (fd < 0) {
 		printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);
 		return -1;
 	}

 	prog_fd[prog_cnt++] = fd;

 	if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
 		return 0;

 	if (is_socket || is_sockops || is_sk_skb || is_sk_msg) {
 		if (is_socket)
 			event += 6;
 		else
 			event += 7;
 		if (*event != '/')
 			return 0;
 		event++;
 		if (!isdigit(*event)) {
 			printf("invalid prog number\n");
 			return -1;
 		}
 		return populate_prog_array(event, fd);
 	}

 	if (is_raw_tracepoint) {
 		efd = bpf_raw_tracepoint_open(event + 15, fd);
 		if (efd < 0) {
 			printf("tracepoint %s %s\n", event + 15, strerror(errno));
 			return -1;
 		}
 		event_fd[prog_cnt - 1] = efd;
 		return 0;
 	}

 	if (is_kprobe || is_kretprobe) {
 		bool need_normal_check = true;
 		const char *event_prefix = "";

 		if (is_kprobe)
 			event += 7;
 		else
 			event += 10;

 		if (*event == 0) {
 			printf("event name cannot be empty\n");
 			return -1;
 		}

 		if (isdigit(*event))
 			return populate_prog_array(event, fd);

 #ifdef __x86_64__
 		if (strncmp(event, "sys_", 4) == 0) {
 			snprintf(buf, sizeof(buf),
 				 "echo '%c:__x64_%s __x64_%s' >> /sys/kernel/debug/tracing/kprobe_events",
 				 is_kprobe ? 'p' : 'r', event, event);
 			err = system(buf);
 			if (err >= 0) {
 				need_normal_check = false;
 				event_prefix = "__x64_";
 			}
 		}
 #endif
 		if (need_normal_check) {
 			snprintf(buf, sizeof(buf),
 				 "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
 				 is_kprobe ? 'p' : 'r', event, event);
 			err = system(buf);
 			if (err < 0) {
 				printf("failed to create kprobe '%s' error '%s'\n",
 				       event, strerror(errno));
 				return -1;
 			}
 		}

 		strcpy(buf, DEBUGFS);
 		strcat(buf, "events/kprobes/");
 		strcat(buf, event_prefix);
 		strcat(buf, event);
 		strcat(buf, "/id");
 	} else if (is_tracepoint) {
 		event += 11;

 		if (*event == 0) {
 			printf("event name cannot be empty\n");
 			return -1;
 		}
 		strcpy(buf, DEBUGFS);
 		strcat(buf, "events/");
 		strcat(buf, event);
 		strcat(buf, "/id");
 	}

 	efd = open(buf, O_RDONLY, 0);
 	if (efd < 0) {
 		printf("failed to open event %s\n", event);
 		return -1;
 	}

 	err = read(efd, buf, sizeof(buf));
 	if (err < 0 || err >= sizeof(buf)) {
 		printf("read from '%s' failed '%s'\n", event, strerror(errno));
 		return -1;
 	}

 	close(efd);

 	buf[err] = 0;
 	id = atoi(buf);
 	attr.config = id;

 	efd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
 	if (efd < 0) {
 		printf("event %d fd %d err %s\n", id, efd, strerror(errno));
 		return -1;
 	}
 	event_fd[prog_cnt - 1] = efd;
 	err = ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
 	if (err < 0) {
 		printf("ioctl PERF_EVENT_IOC_ENABLE failed err %s\n",
 		       strerror(errno));
 		return -1;
 	}
 	err = ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
 	if (err < 0) {
 		printf("ioctl PERF_EVENT_IOC_SET_BPF failed err %s\n",
 		       strerror(errno));
 		return -1;
 	}

 	return 0;
 }

 static int load_maps(struct bpf_map_data *maps, int nr_maps,
 		     fixup_map_cb fixup_map)
 {
 	int i, numa_node;

 	for (i = 0; i < nr_maps; i++) {
 		if (fixup_map) {
 			fixup_map(&maps[i], i);
 			/* Allow userspace to assign map FD prior to creation */
 			if (maps[i].fd != -1) {
 				map_fd[i] = maps[i].fd;
 				continue;
 			}
 		}

 		numa_node = maps[i].def.map_flags & BPF_F_NUMA_NODE ?
 			maps[i].def.numa_node : -1;

 		if (maps[i].def.type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
 		    maps[i].def.type == BPF_MAP_TYPE_HASH_OF_MAPS) {
 			int inner_map_fd = map_fd[maps[i].def.inner_map_idx];

 			map_fd[i] = bpf_create_map_in_map_node(maps[i].def.type,
 							maps[i].name,
 							maps[i].def.key_size,
 							inner_map_fd,
 							maps[i].def.max_entries,
 							maps[i].def.map_flags,
 							numa_node);
 		} else {
 			map_fd[i] = bpf_create_map_node(maps[i].def.type,
 							maps[i].name,
 							maps[i].def.key_size,
 							maps[i].def.value_size,
 							maps[i].def.max_entries,
 							maps[i].def.map_flags,
 							numa_node);
 		}
 		if (map_fd[i] < 0) {
 			printf("failed to create a map: %d %s\n",
 			       errno, strerror(errno));
 			return 1;
 		}
 		maps[i].fd = map_fd[i];

 		if (maps[i].def.type == BPF_MAP_TYPE_PROG_ARRAY)
 			prog_array_fd = map_fd[i];
 	}
 	return 0;
 }

 static int get_sec(Elf *elf, int i, GElf_Ehdr *ehdr, char **shname,
 		   GElf_Shdr *shdr, Elf_Data **data)
 {
 	Elf_Scn *scn;

 	scn = elf_getscn(elf, i);
 	if (!scn)
 		return 1;

 	if (gelf_getshdr(scn, shdr) != shdr)
 		return 2;

 	*shname = elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name);
 	if (!*shname || !shdr->sh_size)
 		return 3;

 	*data = elf_getdata(scn, 0);
 	if (!*data || elf_getdata(scn, *data) != NULL)
 		return 4;

 	return 0;
 }

 static int parse_relo_and_apply(Elf_Data *data, Elf_Data *symbols,
 				GElf_Shdr *shdr, struct bpf_insn *insn,
 				struct bpf_map_data *maps, int nr_maps)
 {
 	int i, nrels;

 	nrels = shdr->sh_size / shdr->sh_entsize;

 	for (i = 0; i < nrels; i++) {
 		GElf_Sym sym;
 		GElf_Rel rel;
 		unsigned int insn_idx;
 		bool match = false;
 		int j, map_idx;

 		gelf_getrel(data, i, &rel);

 		insn_idx = rel.r_offset / sizeof(struct bpf_insn);

 		gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym);

 		if (insn[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 			printf("invalid relo for insn[%d].code 0x%x\n",
 			       insn_idx, insn[insn_idx].code);
 			return 1;
 		}
 		insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;

 		/* Match FD relocation against recorded map_data[] offset */
 		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 			if (maps[map_idx].elf_offset == sym.st_value) {
 				match = true;
 				break;
 			}
 		}
 		if (match) {
 			insn[insn_idx].imm = maps[map_idx].fd;
 		} else {
 			printf("invalid relo for insn[%d] no map_data match\n",
 			       insn_idx);
 			return 1;
 		}
 	}

 	return 0;
 }

 static int cmp_symbols(const void *l, const void *r)
 {
 	const GElf_Sym *lsym = (const GElf_Sym *)l;
 	const GElf_Sym *rsym = (const GElf_Sym *)r;

 	if (lsym->st_value < rsym->st_value)
 		return -1;
 	else if (lsym->st_value > rsym->st_value)
 		return 1;
 	else
 		return 0;
 }

 static int load_elf_maps_section(struct bpf_map_data *maps, int maps_shndx,
 				 Elf *elf, Elf_Data *symbols, int strtabidx)
 {
 	int map_sz_elf, map_sz_copy;
 	bool validate_zero = false;
 	Elf_Data *data_maps;
 	int i, nr_maps;
 	GElf_Sym *sym;
 	Elf_Scn *scn;
 	int copy_sz;

 	if (maps_shndx < 0)
 		return -EINVAL;
 	if (!symbols)
 		return -EINVAL;

 	/* Get data for maps section via elf index */
 	scn = elf_getscn(elf, maps_shndx);
 	if (scn)
 		data_maps = elf_getdata(scn, NULL);
 	if (!scn || !data_maps) {
 		printf("Failed to get Elf_Data from maps section %d\n",
 		       maps_shndx);
 		return -EINVAL;
 	}

 	/* For each map get corrosponding symbol table entry */
 	sym = calloc(MAX_MAPS+1, sizeof(GElf_Sym));
 	for (i = 0, nr_maps = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 		assert(nr_maps < MAX_MAPS+1);
 		if (!gelf_getsym(symbols, i, &sym[nr_maps]))
 			continue;
 		if (sym[nr_maps].st_shndx != maps_shndx)
 			continue;
 		/* Only increment iif maps section */
 		nr_maps++;
 	}

 	/* Align to map_fd[] order, via sort on offset in sym.st_value */
 	qsort(sym, nr_maps, sizeof(GElf_Sym), cmp_symbols);

 	/* Keeping compatible with ELF maps section changes
 	 * ------------------------------------------------
 	 * The program size of struct bpf_load_map_def is known by loader
 	 * code, but struct stored in ELF file can be different.
 	 *
 	 * Unfortunately sym[i].st_size is zero.  To calculate the
 	 * struct size stored in the ELF file, assume all struct have
 	 * the same size, and simply divide with number of map
 	 * symbols.
 	 */
 	map_sz_elf = data_maps->d_size / nr_maps;
 	map_sz_copy = sizeof(struct bpf_load_map_def);
 	if (map_sz_elf < map_sz_copy) {
 		/*
 		 * Backward compat, loading older ELF file with
 		 * smaller struct, keeping remaining bytes zero.
 		 */
 		map_sz_copy = map_sz_elf;
 	} else if (map_sz_elf > map_sz_copy) {
 		/*
 		 * Forward compat, loading newer ELF file with larger
 		 * struct with unknown features. Assume zero means
 		 * feature not used.  Thus, validate rest of struct
 		 * data is zero.
 		 */
 		validate_zero = true;
 	}

 	/* Memcpy relevant part of ELF maps data to loader maps */
 	for (i = 0; i < nr_maps; i++) {
 		struct bpf_load_map_def *def;
 		unsigned char *addr, *end;
 		const char *map_name;
 		size_t offset;

 		map_name = elf_strptr(elf, strtabidx, sym[i].st_name);
 		maps[i].name = strdup(map_name);
 		if (!maps[i].name) {
 			printf("strdup(%s): %s(%d)\n", map_name,
 			       strerror(errno), errno);
 			free(sym);
 			return -errno;
 		}

 		/* Symbol value is offset into ELF maps section data area */
 		offset = sym[i].st_value;
 		def = (struct bpf_load_map_def *)(data_maps->d_buf + offset);
 		maps[i].elf_offset = offset;
 		memset(&maps[i].def, 0, sizeof(struct bpf_load_map_def));
 		memcpy(&maps[i].def, def, map_sz_copy);

 		/* Verify no newer features were requested */
 		if (validate_zero) {
 			addr = (unsigned char*) def + map_sz_copy;
 			end  = (unsigned char*) def + map_sz_elf;
 			for (; addr < end; addr++) {
 				if (*addr != 0) {
 					free(sym);
 					return -EFBIG;
 				}
 			}
 		}
 	}

 	free(sym);
 	return nr_maps;
 }

 static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
 {
 	int fd, i, ret, maps_shndx = -1, strtabidx = -1;
 	Elf *elf;
 	GElf_Ehdr ehdr;
 	GElf_Shdr shdr, shdr_prog;
 	Elf_Data *data, *data_prog, *data_maps = NULL, *symbols = NULL;
 	char *shname, *shname_prog;
 	int nr_maps = 0;

 	/* reset global variables */
 	kern_version = 0;
 	memset(license, 0, sizeof(license));
 	memset(processed_sec, 0, sizeof(processed_sec));

 	if (elf_version(EV_CURRENT) == EV_NONE)
 		return 1;

 	fd = open(path, O_RDONLY, 0);
 	if (fd < 0)
 		return 1;

 	elf = elf_begin(fd, ELF_C_READ, NULL);

 	if (!elf)
 		return 1;

 	if (gelf_getehdr(elf, &ehdr) != &ehdr)
 		return 1;

 	/* clear all kprobes */
 	i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");

 	/* scan over all elf sections to get license and map info */
 	for (i = 1; i < ehdr.e_shnum; i++) {

 		if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 			continue;

 		if (0) /* helpful for llvm debugging */
 			printf("section %d:%s data %p size %zd link %d flags %d\n",
 			       i, shname, data->d_buf, data->d_size,
 			       shdr.sh_link, (int) shdr.sh_flags);

 		if (strcmp(shname, "license") == 0) {
 			processed_sec[i] = true;
 			memcpy(license, data->d_buf, data->d_size);
 		} else if (strcmp(shname, "version") == 0) {
 			processed_sec[i] = true;
 			if (data->d_size != sizeof(int)) {
 				printf("invalid size of version section %zd\n",
 				       data->d_size);
 				return 1;
 			}
 			memcpy(&kern_version, data->d_buf, sizeof(int));
 		} else if (strcmp(shname, "maps") == 0) {
 			int j;

 			maps_shndx = i;
 			data_maps = data;
 			for (j = 0; j < MAX_MAPS; j++)
 				map_data[j].fd = -1;
 		} else if (shdr.sh_type == SHT_SYMTAB) {
 			strtabidx = shdr.sh_link;
 			symbols = data;
 		}
 	}

 	ret = 1;

 	if (!symbols) {
 		printf("missing SHT_SYMTAB section\n");
 		goto done;
 	}

 	if (data_maps) {
 		nr_maps = load_elf_maps_section(map_data, maps_shndx,
 						elf, symbols, strtabidx);
 		if (nr_maps < 0) {
 			printf("Error: Failed loading ELF maps (errno:%d):%s\n",
 			       nr_maps, strerror(-nr_maps));
 			goto done;
 		}
 		if (load_maps(map_data, nr_maps, fixup_map))
 			goto done;
 		map_data_count = nr_maps;

 		processed_sec[maps_shndx] = true;
 	}

 	/* process all relo sections, and rewrite bpf insns for maps */
 	for (i = 1; i < ehdr.e_shnum; i++) {
 		if (processed_sec[i])
 			continue;

 		if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 			continue;

 		if (shdr.sh_type == SHT_REL) {
 			struct bpf_insn *insns;

 			/* locate prog sec that need map fixup (relocations) */
 			if (get_sec(elf, shdr.sh_info, &ehdr, &shname_prog,
 				    &shdr_prog, &data_prog))
 				continue;

 			if (shdr_prog.sh_type != SHT_PROGBITS ||
 			    !(shdr_prog.sh_flags & SHF_EXECINSTR))
 				continue;

 			insns = (struct bpf_insn *) data_prog->d_buf;
 			processed_sec[i] = true; /* relo section */

 			if (parse_relo_and_apply(data, symbols, &shdr, insns,
 						 map_data, nr_maps))
 				continue;
 		}
 	}

 	/* load programs */
 	for (i = 1; i < ehdr.e_shnum; i++) {

 		if (processed_sec[i])
 			continue;

 		if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 			continue;

 		if (memcmp(shname, "kprobe/", 7) == 0 ||
 		    memcmp(shname, "kretprobe/", 10) == 0 ||
 		    memcmp(shname, "tracepoint/", 11) == 0 ||
 		    memcmp(shname, "raw_tracepoint/", 15) == 0 ||
 		    memcmp(shname, "xdp", 3) == 0 ||
 		    memcmp(shname, "perf_event", 10) == 0 ||
 		    memcmp(shname, "socket", 6) == 0 ||
 		    memcmp(shname, "cgroup/", 7) == 0 ||
 		    memcmp(shname, "sockops", 7) == 0 ||
 		    memcmp(shname, "sk_skb", 6) == 0 ||
 		    memcmp(shname, "sk_msg", 6) == 0) {
 			ret = load_and_attach(shname, data->d_buf,
 					      data->d_size);
 			if (ret != 0)
 				goto done;
 		}
 	}

 done:
 	close(fd);
 	return ret;
 }

 int load_bpf_file(char *path)
 {
 	return do_load_bpf_file(path, NULL);
 }

 int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map)
 {
 	return do_load_bpf_file(path, fixup_map);
 }

 void read_trace_pipe(void)
 {
 	int trace_fd;

 	trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
 	if (trace_fd < 0)
 		return;

 	while (1) {
 		static char buf[4096];
 		ssize_t sz;

 		sz = read(trace_fd, buf, sizeof(buf));
 		if (sz > 0) {
 			buf[sz] = 0;
 			puts(buf);
 		}
 	}
 }
	// SPDX-License-Identifier: GPL-2.0
	#include <stdio.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <libelf.h>
	#include <gelf.h>
	#include <errno.h>
	#include <unistd.h>
	#include <string.h>
	#include <stdbool.h>
	#include <stdlib.h>
	#include <linux/bpf.h>
	#include <linux/filter.h>
	#include <linux/perf_event.h>
	#include <linux/netlink.h>
	#include <linux/rtnetlink.h>
	#include <linux/types.h>
	#include <sys/types.h>
	#include <sys/socket.h>
	#include <sys/syscall.h>
	#include <sys/ioctl.h>
	#include <sys/mman.h>
	#include <poll.h>
	#include <ctype.h>
	#include <assert.h>
	#include <bpf/bpf.h>
	#include "bpf_load.h"
	#include "perf-sys.h"

	#define DEBUGFS "/sys/kernel/debug/tracing/"

	static char license[128];
	static int kern_version;
	static bool processed_sec[128];
	char bpf_log_buf[BPF_LOG_BUF_SIZE];
	int map_fd[MAX_MAPS];
	int prog_fd[MAX_PROGS];
	int event_fd[MAX_PROGS];
	int prog_cnt;
	int prog_array_fd = -1;

	struct bpf_map_data map_data[MAX_MAPS];
	int map_data_count = 0;

	static int populate_prog_array(const char *event, int prog_fd)
	{
	int ind = atoi(event), err;

	err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);
	if (err < 0) {
	printf("failed to store prog_fd in prog_array\n");
	return -1;
	}
	return 0;
	}

	static int load_and_attach(const char event, struct bpf_insn prog, int size)
	{
	bool is_socket = strncmp(event, "socket", 6) == 0;
	bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
	bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
	bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
	bool is_raw_tracepoint = strncmp(event, "raw_tracepoint/", 15) == 0;
	bool is_xdp = strncmp(event, "xdp", 3) == 0;
	bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
	bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
	bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
	bool is_sockops = strncmp(event, "sockops", 7) == 0;
	bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
	bool is_sk_msg = strncmp(event, "sk_msg", 6) == 0;
	size_t insns_cnt = size / sizeof(struct bpf_insn);
	enum bpf_prog_type prog_type;
	char buf[256];
	int fd, efd, err, id;
	struct perf_event_attr attr = {};

	attr.type = PERF_TYPE_TRACEPOINT;
	attr.sample_type = PERF_SAMPLE_RAW;
	attr.sample_period = 1;
	attr.wakeup_events = 1;

	if (is_socket) {
	prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
	} else if (is_kprobe \|\| is_kretprobe) {
	prog_type = BPF_PROG_TYPE_KPROBE;
	} else if (is_tracepoint) {
	prog_type = BPF_PROG_TYPE_TRACEPOINT;
	} else if (is_raw_tracepoint) {
	prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT;
	} else if (is_xdp) {
	prog_type = BPF_PROG_TYPE_XDP;
	} else if (is_perf_event) {
	prog_type = BPF_PROG_TYPE_PERF_EVENT;
	} else if (is_cgroup_skb) {
	prog_type = BPF_PROG_TYPE_CGROUP_SKB;
	} else if (is_cgroup_sk) {
	prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
	} else if (is_sockops) {
	prog_type = BPF_PROG_TYPE_SOCK_OPS;
	} else if (is_sk_skb) {
	prog_type = BPF_PROG_TYPE_SK_SKB;
	} else if (is_sk_msg) {
	prog_type = BPF_PROG_TYPE_SK_MSG;
	} else {
	printf("Unknown event '%s'\n", event);
	return -1;
	}

	fd = bpf_load_program(prog_type, prog, insns_cnt, license, kern_version,
	bpf_log_buf, BPF_LOG_BUF_SIZE);
	if (fd < 0) {
	printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);
	return -1;
	}

	prog_fd[prog_cnt++] = fd;

	if (is_xdp \|\| is_perf_event \|\| is_cgroup_skb \|\| is_cgroup_sk)
	return 0;

	if (is_socket \|\| is_sockops \|\| is_sk_skb \|\| is_sk_msg) {
	if (is_socket)
	event += 6;
	else
	event += 7;
	if (*event != '/')
	return 0;
	event++;
	if (!isdigit(*event)) {
	printf("invalid prog number\n");
	return -1;
	}
	return populate_prog_array(event, fd);
	}

	if (is_raw_tracepoint) {
	efd = bpf_raw_tracepoint_open(event + 15, fd);
	if (efd < 0) {
	printf("tracepoint %s %s\n", event + 15, strerror(errno));
	return -1;
	}
	event_fd[prog_cnt - 1] = efd;
	return 0;
	}

	if (is_kprobe \|\| is_kretprobe) {
	bool need_normal_check = true;
	const char *event_prefix = "";

	if (is_kprobe)
	event += 7;
	else
	event += 10;

	if (*event == 0) {
	printf("event name cannot be empty\n");
	return -1;
	}

	if (isdigit(*event))
	return populate_prog_array(event, fd);

	#ifdef __x86_64__
	if (strncmp(event, "sys_", 4) == 0) {
	snprintf(buf, sizeof(buf),
	"echo '%c:__x64_%s __x64_%s' >> /sys/kernel/debug/tracing/kprobe_events",
	is_kprobe ? 'p' : 'r', event, event);
	err = system(buf);
	if (err >= 0) {
	need_normal_check = false;
	event_prefix = "__x64_";
	}
	}
	#endif
	if (need_normal_check) {
	snprintf(buf, sizeof(buf),
	"echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
	is_kprobe ? 'p' : 'r', event, event);
	err = system(buf);
	if (err < 0) {
	printf("failed to create kprobe '%s' error '%s'\n",
	event, strerror(errno));
	return -1;
	}
	}

	strcpy(buf, DEBUGFS);
	strcat(buf, "events/kprobes/");
	strcat(buf, event_prefix);
	strcat(buf, event);
	strcat(buf, "/id");
	} else if (is_tracepoint) {
	event += 11;

	if (*event == 0) {
	printf("event name cannot be empty\n");
	return -1;
	}
	strcpy(buf, DEBUGFS);
	strcat(buf, "events/");
	strcat(buf, event);
	strcat(buf, "/id");
	}

	efd = open(buf, O_RDONLY, 0);
	if (efd < 0) {
	printf("failed to open event %s\n", event);
	return -1;
	}

	err = read(efd, buf, sizeof(buf));
	if (err < 0 \|\| err >= sizeof(buf)) {
	printf("read from '%s' failed '%s'\n", event, strerror(errno));
	return -1;
	}

	close(efd);

	buf[err] = 0;
	id = atoi(buf);
	attr.config = id;

	efd = sys_perf_event_open(&attr, -1/pid/, 0/cpu/, -1/group_fd/, 0);
	if (efd < 0) {
	printf("event %d fd %d err %s\n", id, efd, strerror(errno));
	return -1;
	}
	event_fd[prog_cnt - 1] = efd;
	err = ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
	if (err < 0) {
	printf("ioctl PERF_EVENT_IOC_ENABLE failed err %s\n",
	strerror(errno));
	return -1;
	}
	err = ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
	if (err < 0) {
	printf("ioctl PERF_EVENT_IOC_SET_BPF failed err %s\n",
	strerror(errno));
	return -1;
	}

	return 0;
	}

	static int load_maps(struct bpf_map_data *maps, int nr_maps,
	fixup_map_cb fixup_map)
	{
	int i, numa_node;

	for (i = 0; i < nr_maps; i++) {
	if (fixup_map) {
	fixup_map(&maps[i], i);
	/* Allow userspace to assign map FD prior to creation */
	if (maps[i].fd != -1) {
	map_fd[i] = maps[i].fd;
	continue;
	}
	}

	numa_node = maps[i].def.map_flags & BPF_F_NUMA_NODE ?
	maps[i].def.numa_node : -1;

	if (maps[i].def.type == BPF_MAP_TYPE_ARRAY_OF_MAPS \|\|
	maps[i].def.type == BPF_MAP_TYPE_HASH_OF_MAPS) {
	int inner_map_fd = map_fd[maps[i].def.inner_map_idx];

	map_fd[i] = bpf_create_map_in_map_node(maps[i].def.type,
	maps[i].name,
	maps[i].def.key_size,
	inner_map_fd,
	maps[i].def.max_entries,
	maps[i].def.map_flags,
	numa_node);
	} else {
	map_fd[i] = bpf_create_map_node(maps[i].def.type,
	maps[i].name,
	maps[i].def.key_size,
	maps[i].def.value_size,
	maps[i].def.max_entries,
	maps[i].def.map_flags,
	numa_node);
	}
	if (map_fd[i] < 0) {
	printf("failed to create a map: %d %s\n",
	errno, strerror(errno));
	return 1;
	}
	maps[i].fd = map_fd[i];

	if (maps[i].def.type == BPF_MAP_TYPE_PROG_ARRAY)
	prog_array_fd = map_fd[i];
	}
	return 0;
	}

	static int get_sec(Elf elf, int i, GElf_Ehdr ehdr, char **shname,
	GElf_Shdr shdr, Elf_Data *data)
	{
	Elf_Scn *scn;

	scn = elf_getscn(elf, i);
	if (!scn)
	return 1;

	if (gelf_getshdr(scn, shdr) != shdr)
	return 2;

	*shname = elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name);
	if (!*shname \|\| !shdr->sh_size)
	return 3;

	*data = elf_getdata(scn, 0);
	if (!data \|\| elf_getdata(scn, data) != NULL)
	return 4;

	return 0;
	}

	static int parse_relo_and_apply(Elf_Data data, Elf_Data symbols,
	GElf_Shdr shdr, struct bpf_insn insn,
	struct bpf_map_data *maps, int nr_maps)
	{
	int i, nrels;

	nrels = shdr->sh_size / shdr->sh_entsize;

	for (i = 0; i < nrels; i++) {
	GElf_Sym sym;
	GElf_Rel rel;
	unsigned int insn_idx;
	bool match = false;
	int j, map_idx;

	gelf_getrel(data, i, &rel);

	insn_idx = rel.r_offset / sizeof(struct bpf_insn);

	gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym);

	if (insn[insn_idx].code != (BPF_LD \| BPF_IMM \| BPF_DW)) {
	printf("invalid relo for insn[%d].code 0x%x\n",
	insn_idx, insn[insn_idx].code);
	return 1;
	}
	insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;

	/* Match FD relocation against recorded map_data[] offset */
	for (map_idx = 0; map_idx < nr_maps; map_idx++) {
	if (maps[map_idx].elf_offset == sym.st_value) {
	match = true;
	break;
	}
	}
	if (match) {
	insn[insn_idx].imm = maps[map_idx].fd;
	} else {
	printf("invalid relo for insn[%d] no map_data match\n",
	insn_idx);
	return 1;
	}
	}

	return 0;
	}

	static int cmp_symbols(const void l, const void r)
	{
	const GElf_Sym lsym = (const GElf_Sym )l;
	const GElf_Sym rsym = (const GElf_Sym )r;

	if (lsym->st_value < rsym->st_value)
	return -1;
	else if (lsym->st_value > rsym->st_value)
	return 1;
	else
	return 0;
	}

	static int load_elf_maps_section(struct bpf_map_data *maps, int maps_shndx,
	Elf elf, Elf_Data symbols, int strtabidx)
	{
	int map_sz_elf, map_sz_copy;
	bool validate_zero = false;
	Elf_Data *data_maps;
	int i, nr_maps;
	GElf_Sym *sym;
	Elf_Scn *scn;
	int copy_sz;

	if (maps_shndx < 0)
	return -EINVAL;
	if (!symbols)
	return -EINVAL;

	/* Get data for maps section via elf index */
	scn = elf_getscn(elf, maps_shndx);
	if (scn)
	data_maps = elf_getdata(scn, NULL);
	if (!scn \|\| !data_maps) {
	printf("Failed to get Elf_Data from maps section %d\n",
	maps_shndx);
	return -EINVAL;
	}

	/* For each map get corrosponding symbol table entry */
	sym = calloc(MAX_MAPS+1, sizeof(GElf_Sym));
	for (i = 0, nr_maps = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
	assert(nr_maps < MAX_MAPS+1);
	if (!gelf_getsym(symbols, i, &sym[nr_maps]))
	continue;
	if (sym[nr_maps].st_shndx != maps_shndx)
	continue;
	/* Only increment iif maps section */
	nr_maps++;
	}

	/* Align to map_fd[] order, via sort on offset in sym.st_value */
	qsort(sym, nr_maps, sizeof(GElf_Sym), cmp_symbols);

	/* Keeping compatible with ELF maps section changes
	* ------------------------------------------------
	* The program size of struct bpf_load_map_def is known by loader
	* code, but struct stored in ELF file can be different.
	*
	* Unfortunately sym[i].st_size is zero. To calculate the
	* struct size stored in the ELF file, assume all struct have
	* the same size, and simply divide with number of map
	* symbols.
	*/
	map_sz_elf = data_maps->d_size / nr_maps;
	map_sz_copy = sizeof(struct bpf_load_map_def);
	if (map_sz_elf < map_sz_copy) {
	/*
	* Backward compat, loading older ELF file with
	* smaller struct, keeping remaining bytes zero.
	*/
	map_sz_copy = map_sz_elf;
	} else if (map_sz_elf > map_sz_copy) {
	/*
	* Forward compat, loading newer ELF file with larger
	* struct with unknown features. Assume zero means
	* feature not used. Thus, validate rest of struct
	* data is zero.
	*/
	validate_zero = true;
	}

	/* Memcpy relevant part of ELF maps data to loader maps */
	for (i = 0; i < nr_maps; i++) {
	struct bpf_load_map_def *def;
	unsigned char addr, end;
	const char *map_name;
	size_t offset;

	map_name = elf_strptr(elf, strtabidx, sym[i].st_name);
	maps[i].name = strdup(map_name);
	if (!maps[i].name) {
	printf("strdup(%s): %s(%d)\n", map_name,
	strerror(errno), errno);
	free(sym);
	return -errno;
	}

	/* Symbol value is offset into ELF maps section data area */
	offset = sym[i].st_value;
	def = (struct bpf_load_map_def *)(data_maps->d_buf + offset);
	maps[i].elf_offset = offset;
	memset(&maps[i].def, 0, sizeof(struct bpf_load_map_def));
	memcpy(&maps[i].def, def, map_sz_copy);

	/* Verify no newer features were requested */
	if (validate_zero) {
	addr = (unsigned char*) def + map_sz_copy;
	end = (unsigned char*) def + map_sz_elf;
	for (; addr < end; addr++) {
	if (*addr != 0) {
	free(sym);
	return -EFBIG;
	}
	}
	}
	}

	free(sym);
	return nr_maps;
	}

	static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
	{
	int fd, i, ret, maps_shndx = -1, strtabidx = -1;
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr, shdr_prog;
	Elf_Data data, data_prog, data_maps = NULL, symbols = NULL;
	char shname, shname_prog;
	int nr_maps = 0;

	/* reset global variables */
	kern_version = 0;
	memset(license, 0, sizeof(license));
	memset(processed_sec, 0, sizeof(processed_sec));

	if (elf_version(EV_CURRENT) == EV_NONE)
	return 1;

	fd = open(path, O_RDONLY, 0);
	if (fd < 0)
	return 1;

	elf = elf_begin(fd, ELF_C_READ, NULL);

	if (!elf)
	return 1;

	if (gelf_getehdr(elf, &ehdr) != &ehdr)
	return 1;

	/* clear all kprobes */
	i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");

	/* scan over all elf sections to get license and map info */
	for (i = 1; i < ehdr.e_shnum; i++) {

	if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
	continue;

	if (0) /* helpful for llvm debugging */
	printf("section %d:%s data %p size %zd link %d flags %d\n",
	i, shname, data->d_buf, data->d_size,
	shdr.sh_link, (int) shdr.sh_flags);

	if (strcmp(shname, "license") == 0) {
	processed_sec[i] = true;
	memcpy(license, data->d_buf, data->d_size);
	} else if (strcmp(shname, "version") == 0) {
	processed_sec[i] = true;
	if (data->d_size != sizeof(int)) {
	printf("invalid size of version section %zd\n",
	data->d_size);
	return 1;
	}
	memcpy(&kern_version, data->d_buf, sizeof(int));
	} else if (strcmp(shname, "maps") == 0) {
	int j;

	maps_shndx = i;
	data_maps = data;
	for (j = 0; j < MAX_MAPS; j++)
	map_data[j].fd = -1;
	} else if (shdr.sh_type == SHT_SYMTAB) {
	strtabidx = shdr.sh_link;
	symbols = data;
	}
	}

	ret = 1;

	if (!symbols) {
	printf("missing SHT_SYMTAB section\n");
	goto done;
	}

	if (data_maps) {
	nr_maps = load_elf_maps_section(map_data, maps_shndx,
	elf, symbols, strtabidx);
	if (nr_maps < 0) {
	printf("Error: Failed loading ELF maps (errno:%d):%s\n",
	nr_maps, strerror(-nr_maps));
	goto done;
	}
	if (load_maps(map_data, nr_maps, fixup_map))
	goto done;
	map_data_count = nr_maps;

	processed_sec[maps_shndx] = true;
	}

	/* process all relo sections, and rewrite bpf insns for maps */
	for (i = 1; i < ehdr.e_shnum; i++) {
	if (processed_sec[i])
	continue;

	if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
	continue;

	if (shdr.sh_type == SHT_REL) {
	struct bpf_insn *insns;

	/* locate prog sec that need map fixup (relocations) */
	if (get_sec(elf, shdr.sh_info, &ehdr, &shname_prog,
	&shdr_prog, &data_prog))
	continue;

	if (shdr_prog.sh_type != SHT_PROGBITS \|\|
	!(shdr_prog.sh_flags & SHF_EXECINSTR))
	continue;

	insns = (struct bpf_insn *) data_prog->d_buf;
	processed_sec[i] = true; /* relo section */

	if (parse_relo_and_apply(data, symbols, &shdr, insns,
	map_data, nr_maps))
	continue;
	}
	}

	/* load programs */
	for (i = 1; i < ehdr.e_shnum; i++) {

	if (processed_sec[i])
	continue;

	if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
	continue;

	if (memcmp(shname, "kprobe/", 7) == 0 \|\|
	memcmp(shname, "kretprobe/", 10) == 0 \|\|
	memcmp(shname, "tracepoint/", 11) == 0 \|\|
	memcmp(shname, "raw_tracepoint/", 15) == 0 \|\|
	memcmp(shname, "xdp", 3) == 0 \|\|
	memcmp(shname, "perf_event", 10) == 0 \|\|
	memcmp(shname, "socket", 6) == 0 \|\|
	memcmp(shname, "cgroup/", 7) == 0 \|\|
	memcmp(shname, "sockops", 7) == 0 \|\|
	memcmp(shname, "sk_skb", 6) == 0 \|\|
	memcmp(shname, "sk_msg", 6) == 0) {
	ret = load_and_attach(shname, data->d_buf,
	data->d_size);
	if (ret != 0)
	goto done;
	}
	}

	done:
	close(fd);
	return ret;
	}

	int load_bpf_file(char *path)
	{
	return do_load_bpf_file(path, NULL);
	}

	int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map)
	{
	return do_load_bpf_file(path, fixup_map);
	}

	void read_trace_pipe(void)
	{
	int trace_fd;

	trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
	if (trace_fd < 0)
	return;

	while (1) {
	static char buf[4096];
	ssize_t sz;

	sz = read(trace_fd, buf, sizeof(buf));
	if (sz > 0) {
	buf[sz] = 0;
	puts(buf);
	}
	}
	}