[PATCH v3 bpf-next 0/4] libbpf: minimize feature detection (reallocarray, libelf-mmap)

[PATCH v3 bpf-next 0/4] libbpf: minimize feature detection (reallocarray, libelf-mmap)

[Andrii Nakryiko]

Get rid of two feature detectors: reallocarray and libelf-mmap. Optional
feature detections complicate libbpf Makefile and cause more troubles for
various applications that want to integrate libbpf as part of their build.

Patch #1 replaces all reallocarray() uses into libbpf-internal reallocarray()
implementation. Patches #2 and #3 makes sure we won't re-introduce
reallocarray() accidentally. Patch #2 also removes last use of
libbpf_internal.h header inside bpftool. There is still nlattr.h that's used
by both libbpf and bpftool, but that's left for a follow up patch to split.
Patch #4 removed libelf-mmap feature detector and all its uses, as it's
trivial to handle missing mmap support in libbpf, the way objtool has been
doing it for a while.

v1->v2 and v2->v3:
  - rebase to latest bpf-next (Alexei).

Andrii Nakryiko (4):
  libbpf: remove any use of reallocarray() in libbpf
  tools/bpftool: remove libbpf_internal.h usage in bpftool
  libbpf: centralize poisoning and poison reallocarray()
  tools: remove feature-libelf-mmap feature detection

 tools/bpf/bpftool/gen.c                |   2 -
 tools/bpf/bpftool/net.c                | 299 +++++++++++++++++++++++--
 tools/build/Makefile.feature           |   1 -
 tools/build/feature/Makefile           |   4 -
 tools/build/feature/test-all.c         |   4 -
 tools/build/feature/test-libelf-mmap.c |   9 -
 tools/lib/bpf/Makefile                 |  10 +-
 tools/lib/bpf/bpf.c                    |   3 -
 tools/lib/bpf/bpf_prog_linfo.c         |   3 -
 tools/lib/bpf/btf.c                    |  14 +-
 tools/lib/bpf/btf_dump.c               |   9 +-
 tools/lib/bpf/hashmap.c                |   3 +
 tools/lib/bpf/libbpf.c                 |  38 ++--
 tools/lib/bpf/libbpf_internal.h        |  44 +++-
 tools/lib/bpf/libbpf_probes.c          |   3 -
 tools/lib/bpf/netlink.c                | 128 +----------
 tools/lib/bpf/nlattr.c                 |   9 +-
 tools/lib/bpf/ringbuf.c                |   8 +-
 tools/lib/bpf/xsk.c                    |   3 -
 tools/perf/Makefile.config             |   4 -
 tools/perf/util/symbol.h               |   2 +-
 21 files changed, 353 insertions(+), 247 deletions(-)
 delete mode 100644 tools/build/feature/test-libelf-mmap.c

-- 
2.24.1

[PATCH v3 bpf-next 1/4] libbpf: remove any use of reallocarray() in libbpf

[Andrii Nakryiko]

Re-implement glibc's reallocarray() for libbpf internal-only use.
reallocarray(), unfortunately, is not available in all versions of glibc, so
requires extra feature detection and using reallocarray() stub from
<tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates build
of libbpf unnecessarily and is just a maintenance burden. Instead, it's
trivial to implement libbpf-specific internal version and use it throughout
libbpf.

Which is what this patch does, along with converting some realloc() uses that
should really have been reallocarray() in the first place.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/lib/bpf/Makefile          |  6 +-----
 tools/lib/bpf/btf.c             | 11 +++++------
 tools/lib/bpf/btf_dump.c        |  6 ++----
 tools/lib/bpf/libbpf.c          | 21 ++++++++++-----------
 tools/lib/bpf/libbpf_internal.h | 25 +++++++++++++++++++++++++
 tools/lib/bpf/ringbuf.c         |  5 ++---
 6 files changed, 45 insertions(+), 29 deletions(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 95c946e94ca5..621ad96d06fd 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -56,7 +56,7 @@ ifndef VERBOSE
 endif
 
 FEATURE_USER = .libbpf
-FEATURE_TESTS = libelf libelf-mmap zlib bpf reallocarray
+FEATURE_TESTS = libelf libelf-mmap zlib bpf
 FEATURE_DISPLAY = libelf zlib bpf
 
 INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
@@ -102,10 +102,6 @@ ifeq ($(feature-libelf-mmap), 1)
   override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
 endif
 
-ifeq ($(feature-reallocarray), 0)
-  override CFLAGS += -DCOMPAT_NEED_REALLOCARRAY
-endif
-
 # Append required CFLAGS
 override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
 override CFLAGS += -Werror -Wall
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1deedbd19c6c..1b7d85d94a07 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -61,7 +61,7 @@ static int btf_add_type(struct btf *btf, struct btf_type *t)
 		expand_by = max(btf->types_size >> 2, 16U);
 		new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
 
-		new_types = realloc(btf->types, sizeof(*new_types) * new_size);
+		new_types = libbpf_reallocarray(btf->types, new_size, sizeof(*new_types));
 		if (!new_types)
 			return -ENOMEM;
 
@@ -1574,7 +1574,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d,
 		__u32 *new_list;
 
 		d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
-		new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap);
+		new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
 		if (!new_list)
 			return -ENOMEM;
 		d->hypot_list = new_list;
@@ -1870,8 +1870,7 @@ static int btf_dedup_strings(struct btf_dedup *d)
 			struct btf_str_ptr *new_ptrs;
 
 			strs.cap += max(strs.cnt / 2, 16U);
-			new_ptrs = realloc(strs.ptrs,
-					   sizeof(strs.ptrs[0]) * strs.cap);
+			new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0]));
 			if (!new_ptrs) {
 				err = -ENOMEM;
 				goto done;
@@ -2956,8 +2955,8 @@ static int btf_dedup_compact_types(struct btf_dedup *d)
 	d->btf->nr_types = next_type_id - 1;
 	d->btf->types_size = d->btf->nr_types;
 	d->btf->hdr->type_len = p - types_start;
-	new_types = realloc(d->btf->types,
-			    (1 + d->btf->nr_types) * sizeof(struct btf_type *));
+	new_types = libbpf_reallocarray(d->btf->types, (1 + d->btf->nr_types),
+					sizeof(struct btf_type *));
 	if (!new_types)
 		return -ENOMEM;
 	d->btf->types = new_types;
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index fe39bd774697..1ad852ad0a86 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -323,8 +323,7 @@ static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id)
 
 	if (d->emit_queue_cnt >= d->emit_queue_cap) {
 		new_cap = max(16, d->emit_queue_cap * 3 / 2);
-		new_queue = realloc(d->emit_queue,
-				    new_cap * sizeof(new_queue[0]));
+		new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0]));
 		if (!new_queue)
 			return -ENOMEM;
 		d->emit_queue = new_queue;
@@ -1003,8 +1002,7 @@ static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
 
 	if (d->decl_stack_cnt >= d->decl_stack_cap) {
 		new_cap = max(16, d->decl_stack_cap * 3 / 2);
-		new_stack = realloc(d->decl_stack,
-				    new_cap * sizeof(new_stack[0]));
+		new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0]));
 		if (!new_stack)
 			return -ENOMEM;
 		d->decl_stack = new_stack;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0276cf85d763..2653bcee73b7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -44,7 +44,6 @@
 #include <sys/vfs.h>
 #include <sys/utsname.h>
 #include <sys/resource.h>
-#include <tools/libc_compat.h>
 #include <libelf.h>
 #include <gelf.h>
 #include <zlib.h>
@@ -567,7 +566,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 	progs = obj->programs;
 	nr_progs = obj->nr_programs;
 
-	progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
+	progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
 	if (!progs) {
 		/*
 		 * In this case the original obj->programs
@@ -1292,7 +1291,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 		return &obj->maps[obj->nr_maps++];
 
 	new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
-	new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
+	new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps));
 	if (!new_maps) {
 		pr_warn("alloc maps for object failed\n");
 		return ERR_PTR(-ENOMEM);
@@ -2721,8 +2720,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
 				continue;
 			}
 
-			sects = reallocarray(sects, nr_sects + 1,
-					     sizeof(*obj->efile.reloc_sects));
+			sects = libbpf_reallocarray(sects, nr_sects + 1,
+						    sizeof(*obj->efile.reloc_sects));
 			if (!sects) {
 				pr_warn("reloc_sects realloc failed\n");
 				return -ENOMEM;
@@ -2925,7 +2924,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 			continue;
 
 		ext = obj->externs;
-		ext = reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
+		ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
 		if (!ext)
 			return -ENOMEM;
 		obj->externs = ext;
@@ -4362,9 +4361,9 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
 			pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n",
 				 local_type_id, btf_kind_str(local_t),
 				 local_name, i, targ_kind, targ_name);
-			new_ids = reallocarray(cand_ids->data,
-					       cand_ids->len + 1,
-					       sizeof(*cand_ids->data));
+			new_ids = libbpf_reallocarray(cand_ids->data,
+						      cand_ids->len + 1,
+						      sizeof(*cand_ids->data));
 			if (!new_ids) {
 				err = -ENOMEM;
 				goto err_out;
@@ -5231,7 +5230,7 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
 			return -LIBBPF_ERRNO__RELOC;
 		}
 		new_cnt = prog->insns_cnt + text->insns_cnt;
-		new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
+		new_insn = libbpf_reallocarray(prog->insns, new_cnt, sizeof(*insn));
 		if (!new_insn) {
 			pr_warn("oom in prog realloc\n");
 			return -ENOMEM;
@@ -5473,7 +5472,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
 		moff /= bpf_ptr_sz;
 		if (moff >= map->init_slots_sz) {
 			new_sz = moff + 1;
-			tmp = realloc(map->init_slots, new_sz * host_ptr_sz);
+			tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz);
 			if (!tmp)
 				return -ENOMEM;
 			map->init_slots = tmp;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index b776a7125c92..954bc2bd040c 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -9,6 +9,7 @@
 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
 #define __LIBBPF_LIBBPF_INTERNAL_H
 
+#include <stdlib.h>
 #include "libbpf.h"
 
 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
@@ -23,6 +24,12 @@
 #define BTF_PARAM_ENC(name, type) (name), (type)
 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
 
+#ifndef likely
+#define likely(x) __builtin_expect(!!(x), 1)
+#endif
+#ifndef unlikely
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
 #ifndef min
 # define min(x, y) ((x) < (y) ? (x) : (y))
 #endif
@@ -63,6 +70,24 @@ do {				\
 #define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
 #define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
 
+/*
+ * Re-implement glibc's reallocarray() for libbpf internal-only use.
+ * reallocarray(), unfortunately, is not available in all versions of glibc,
+ * so requires extra feature detection and using reallocarray() stub from
+ * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
+ * build of libbpf unnecessarily and is just a maintenance burden. Instead,
+ * it's trivial to implement libbpf-specific internal version and use it
+ * throughout libbpf.
+ */
+static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
+{
+	size_t total;
+
+	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
+		return NULL;
+	return realloc(ptr, total);
+}
+
 static inline bool libbpf_validate_opts(const char *opts,
 					size_t opts_sz, size_t user_sz,
 					const char *type_name)
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 4fc6c6cbb4eb..5bd234be8a14 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -16,7 +16,6 @@
 #include <asm/barrier.h>
 #include <sys/mman.h>
 #include <sys/epoll.h>
-#include <tools/libc_compat.h>
 
 #include "libbpf.h"
 #include "libbpf_internal.h"
@@ -82,12 +81,12 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 		return -EINVAL;
 	}
 
-	tmp = reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings));
+	tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings));
 	if (!tmp)
 		return -ENOMEM;
 	rb->rings = tmp;
 
-	tmp = reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events));
+	tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events));
 	if (!tmp)
 		return -ENOMEM;
 	rb->events = tmp;
-- 
2.24.1

[PATCH v3 bpf-next 2/4] tools/bpftool: remove libbpf_internal.h usage in bpftool

[Andrii Nakryiko]

Most netlink-related functions were unique to bpftool usage, so I moved them
into net.c. Few functions are still used by both bpftool and libbpf itself
internally, so I've copy-pasted them (libbpf_nl_get_link,
libbpf_netlink_open). It's a bit of duplication of code, but better separation
of libbpf as a library with public API and bpftool, relying on unexposed
functions in libbpf.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/bpf/bpftool/gen.c         |   2 -
 tools/bpf/bpftool/net.c         | 299 ++++++++++++++++++++++++++++++--
 tools/lib/bpf/libbpf_internal.h |  12 --
 tools/lib/bpf/netlink.c         | 125 +------------
 4 files changed, 288 insertions(+), 150 deletions(-)

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index f61184653633..4033c46d83e7 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -19,11 +19,9 @@
 #include <sys/mman.h>
 #include <bpf/btf.h>
 
-#include "bpf/libbpf_internal.h"
 #include "json_writer.h"
 #include "main.h"
 
-
 #define MAX_OBJ_NAME_LEN 64
 
 static void sanitize_identifier(char *name)
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
index 56c3a2bae3ef..910e7bac6e9e 100644
--- a/tools/bpf/bpftool/net.c
+++ b/tools/bpf/bpftool/net.c
@@ -6,22 +6,27 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <unistd.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 #include <net/if.h>
 #include <linux/if.h>
 #include <linux/rtnetlink.h>
+#include <linux/socket.h>
 #include <linux/tc_act/tc_bpf.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
 #include "bpf/nlattr.h"
-#include "bpf/libbpf_internal.h"
 #include "main.h"
 #include "netlink_dumper.h"
 
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
 struct ip_devname_ifindex {
 	char	devname[64];
 	int	ifindex;
@@ -85,6 +90,266 @@ static enum net_attach_type parse_attach_type(const char *str)
 	return net_attach_type_size;
 }
 
+typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+
+typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
+
+static int netlink_open(__u32 *nl_pid)
+{
+	struct sockaddr_nl sa;
+	socklen_t addrlen;
+	int one = 1, ret;
+	int sock;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock < 0)
+		return -errno;
+
+	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
+		       &one, sizeof(one)) < 0) {
+		p_err("Netlink error reporting not supported");
+	}
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	addrlen = sizeof(sa);
+	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	if (addrlen != sizeof(sa)) {
+		ret = -LIBBPF_ERRNO__INTERNAL;
+		goto cleanup;
+	}
+
+	*nl_pid = sa.nl_pid;
+	return sock;
+
+cleanup:
+	close(sock);
+	return ret;
+}
+
+static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
+			    __dump_nlmsg_t _fn, dump_nlmsg_t fn,
+			    void *cookie)
+{
+	bool multipart = true;
+	struct nlmsgerr *err;
+	struct nlmsghdr *nh;
+	char buf[4096];
+	int len, ret;
+
+	while (multipart) {
+		multipart = false;
+		len = recv(sock, buf, sizeof(buf), 0);
+		if (len < 0) {
+			ret = -errno;
+			goto done;
+		}
+
+		if (len == 0)
+			break;
+
+		for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
+		     nh = NLMSG_NEXT(nh, len)) {
+			if (nh->nlmsg_pid != nl_pid) {
+				ret = -LIBBPF_ERRNO__WRNGPID;
+				goto done;
+			}
+			if (nh->nlmsg_seq != seq) {
+				ret = -LIBBPF_ERRNO__INVSEQ;
+				goto done;
+			}
+			if (nh->nlmsg_flags & NLM_F_MULTI)
+				multipart = true;
+			switch (nh->nlmsg_type) {
+			case NLMSG_ERROR:
+				err = (struct nlmsgerr *)NLMSG_DATA(nh);
+				if (!err->error)
+					continue;
+				ret = err->error;
+				libbpf_nla_dump_errormsg(nh);
+				goto done;
+			case NLMSG_DONE:
+				return 0;
+			default:
+				break;
+			}
+			if (_fn) {
+				ret = _fn(nh, fn, cookie);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+	ret = 0;
+done:
+	return ret;
+}
+
+static int __dump_class_nlmsg(struct nlmsghdr *nlh,
+			      dump_nlmsg_t dump_class_nlmsg,
+			      void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_class_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_class(int sock, unsigned int nl_pid, int ifindex,
+			     dump_nlmsg_t dump_class_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETTCLASS,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
+			    dump_class_nlmsg, cookie);
+}
+
+static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
+			      dump_nlmsg_t dump_qdisc_nlmsg,
+			      void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_qdisc_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
+			     dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETQDISC,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
+			    dump_qdisc_nlmsg, cookie);
+}
+
+static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
+			       dump_nlmsg_t dump_filter_nlmsg,
+			       void *cookie)
+{
+	struct nlattr *tb[TCA_MAX + 1], *attr;
+	struct tcmsg *t = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
+	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
+	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_filter_nlmsg(cookie, t, tb);
+}
+
+static int netlink_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
+			      dump_nlmsg_t dump_filter_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct tcmsg t;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
+		.nlh.nlmsg_type = RTM_GETTFILTER,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.t.tcm_family = AF_UNSPEC,
+		.t.tcm_ifindex = ifindex,
+		.t.tcm_parent = handle,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
+			    dump_filter_nlmsg, cookie);
+}
+
+static int __dump_link_nlmsg(struct nlmsghdr *nlh,
+			     dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct nlattr *tb[IFLA_MAX + 1], *attr;
+	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+	attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
+	if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_link_nlmsg(cookie, ifi, tb);
+}
+
+static int netlink_get_link(int sock, unsigned int nl_pid,
+			    dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct ifinfomsg ifm;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.nlh.nlmsg_type = RTM_GETLINK,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.ifm.ifi_family = AF_PACKET,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
+			    dump_link_nlmsg, cookie);
+}
+
 static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 {
 	struct bpf_netdev_t *netinfo = cookie;
@@ -168,14 +433,14 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	tcinfo.array_len = 0;
 
 	tcinfo.is_qdisc = false;
-	ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
-				  dump_class_qdisc_nlmsg, &tcinfo);
+	ret = netlink_get_class(sock, nl_pid, dev->ifindex,
+				dump_class_qdisc_nlmsg, &tcinfo);
 	if (ret)
 		goto out;
 
 	tcinfo.is_qdisc = true;
-	ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
-				  dump_class_qdisc_nlmsg, &tcinfo);
+	ret = netlink_get_qdisc(sock, nl_pid, dev->ifindex,
+				dump_class_qdisc_nlmsg, &tcinfo);
 	if (ret)
 		goto out;
 
@@ -183,9 +448,9 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	filter_info.ifindex = dev->ifindex;
 	for (i = 0; i < tcinfo.used_len; i++) {
 		filter_info.kind = tcinfo.handle_array[i].kind;
-		ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
-					   tcinfo.handle_array[i].handle,
-					   dump_filter_nlmsg, &filter_info);
+		ret = netlink_get_filter(sock, nl_pid, dev->ifindex,
+					 tcinfo.handle_array[i].handle,
+					 dump_filter_nlmsg, &filter_info);
 		if (ret)
 			goto out;
 	}
@@ -193,22 +458,22 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 	/* root, ingress and egress handle */
 	handle = TC_H_ROOT;
 	filter_info.kind = "root";
-	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-				   dump_filter_nlmsg, &filter_info);
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
 	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
 	filter_info.kind = "clsact/ingress";
-	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-				   dump_filter_nlmsg, &filter_info);
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
 	handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
 	filter_info.kind = "clsact/egress";
-	ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
-				   dump_filter_nlmsg, &filter_info);
+	ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
+				 dump_filter_nlmsg, &filter_info);
 	if (ret)
 		goto out;
 
@@ -386,7 +651,7 @@ static int do_show(int argc, char **argv)
 	struct bpf_attach_info attach_info = {};
 	int i, sock, ret, filter_idx = -1;
 	struct bpf_netdev_t dev_array;
-	unsigned int nl_pid;
+	unsigned int nl_pid = 0;
 	char err_buf[256];
 
 	if (argc == 2) {
@@ -401,7 +666,7 @@ static int do_show(int argc, char **argv)
 	if (ret)
 		return -1;
 
-	sock = libbpf_netlink_open(&nl_pid);
+	sock = netlink_open(&nl_pid);
 	if (sock < 0) {
 		fprintf(stderr, "failed to open netlink sock\n");
 		return -1;
@@ -416,7 +681,7 @@ static int do_show(int argc, char **argv)
 		jsonw_start_array(json_wtr);
 	NET_START_OBJECT;
 	NET_START_ARRAY("xdp", "%s:\n");
-	ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
+	ret = netlink_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
 	NET_END_ARRAY("\n");
 
 	if (!ret) {
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 954bc2bd040c..65931e989eea 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -130,18 +130,6 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
 				__u32 *off);
 
-struct nlattr;
-typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
-int libbpf_netlink_open(unsigned int *nl_pid);
-int libbpf_nl_get_link(int sock, unsigned int nl_pid,
-		       libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie);
-int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
-			libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie);
-int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
-			libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie);
-int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
-			 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie);
-
 struct btf_ext_info {
 	/*
 	 * info points to the individual info section (e.g. func_info and
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 312f887570b2..2465538a5ba9 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -22,6 +22,8 @@
 #define SOL_NETLINK 270
 #endif
 
+typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+
 typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
 			      void *cookie);
 
@@ -31,7 +33,7 @@ struct xdp_id_md {
 	struct xdp_link_info info;
 };
 
-int libbpf_netlink_open(__u32 *nl_pid)
+static int libbpf_netlink_open(__u32 *nl_pid)
 {
 	struct sockaddr_nl sa;
 	socklen_t addrlen;
@@ -283,6 +285,9 @@ static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
 	return 0;
 }
 
+static int libbpf_nl_get_link(int sock, unsigned int nl_pid,
+			      libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie);
+
 int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
 			  size_t info_size, __u32 flags)
 {
@@ -368,121 +373,3 @@ int libbpf_nl_get_link(int sock, unsigned int nl_pid,
 	return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
 				dump_link_nlmsg, cookie);
 }
-
-static int __dump_class_nlmsg(struct nlmsghdr *nlh,
-			      libbpf_dump_nlmsg_t dump_class_nlmsg,
-			      void *cookie)
-{
-	struct nlattr *tb[TCA_MAX + 1], *attr;
-	struct tcmsg *t = NLMSG_DATA(nlh);
-	int len;
-
-	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
-	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
-	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
-		return -LIBBPF_ERRNO__NLPARSE;
-
-	return dump_class_nlmsg(cookie, t, tb);
-}
-
-int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
-			libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie)
-{
-	struct {
-		struct nlmsghdr nlh;
-		struct tcmsg t;
-	} req = {
-		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
-		.nlh.nlmsg_type = RTM_GETTCLASS,
-		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
-		.t.tcm_family = AF_UNSPEC,
-		.t.tcm_ifindex = ifindex,
-	};
-	int seq = time(NULL);
-
-	req.nlh.nlmsg_seq = seq;
-	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
-		return -errno;
-
-	return bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
-				dump_class_nlmsg, cookie);
-}
-
-static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
-			      libbpf_dump_nlmsg_t dump_qdisc_nlmsg,
-			      void *cookie)
-{
-	struct nlattr *tb[TCA_MAX + 1], *attr;
-	struct tcmsg *t = NLMSG_DATA(nlh);
-	int len;
-
-	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
-	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
-	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
-		return -LIBBPF_ERRNO__NLPARSE;
-
-	return dump_qdisc_nlmsg(cookie, t, tb);
-}
-
-int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
-			libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
-{
-	struct {
-		struct nlmsghdr nlh;
-		struct tcmsg t;
-	} req = {
-		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
-		.nlh.nlmsg_type = RTM_GETQDISC,
-		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
-		.t.tcm_family = AF_UNSPEC,
-		.t.tcm_ifindex = ifindex,
-	};
-	int seq = time(NULL);
-
-	req.nlh.nlmsg_seq = seq;
-	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
-		return -errno;
-
-	return bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
-				dump_qdisc_nlmsg, cookie);
-}
-
-static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
-			       libbpf_dump_nlmsg_t dump_filter_nlmsg,
-			       void *cookie)
-{
-	struct nlattr *tb[TCA_MAX + 1], *attr;
-	struct tcmsg *t = NLMSG_DATA(nlh);
-	int len;
-
-	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
-	attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
-	if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
-		return -LIBBPF_ERRNO__NLPARSE;
-
-	return dump_filter_nlmsg(cookie, t, tb);
-}
-
-int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
-			 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie)
-{
-	struct {
-		struct nlmsghdr nlh;
-		struct tcmsg t;
-	} req = {
-		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
-		.nlh.nlmsg_type = RTM_GETTFILTER,
-		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
-		.t.tcm_family = AF_UNSPEC,
-		.t.tcm_ifindex = ifindex,
-		.t.tcm_parent = handle,
-	};
-	int seq = time(NULL);
-
-	req.nlh.nlmsg_seq = seq;
-	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
-		return -errno;
-
-	return bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
-				dump_filter_nlmsg, cookie);
-}
-- 
2.24.1

[PATCH v3 bpf-next 3/4] libbpf: centralize poisoning and poison reallocarray()

[Andrii Nakryiko]

Most of libbpf source files already include libbpf_internal.h, so it's a good
place to centralize identifier poisoning. So move kernel integer type
poisoning there. And also add reallocarray to a poison list to prevent
accidental use of it. libbpf_reallocarray() should be used universally
instead.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/lib/bpf/bpf.c             | 3 ---
 tools/lib/bpf/bpf_prog_linfo.c  | 3 ---
 tools/lib/bpf/btf.c             | 3 ---
 tools/lib/bpf/btf_dump.c        | 3 ---
 tools/lib/bpf/hashmap.c         | 3 +++
 tools/lib/bpf/libbpf.c          | 3 ---
 tools/lib/bpf/libbpf_internal.h | 7 +++++++
 tools/lib/bpf/libbpf_probes.c   | 3 ---
 tools/lib/bpf/netlink.c         | 3 ---
 tools/lib/bpf/nlattr.c          | 9 +++------
 tools/lib/bpf/ringbuf.c         | 3 ---
 tools/lib/bpf/xsk.c             | 3 ---
 12 files changed, 13 insertions(+), 33 deletions(-)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 0750681057c2..82b983ff6569 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -32,9 +32,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 /*
  * When building perf, unistd.h is overridden. __NR_bpf is
  * required to be defined explicitly.
diff --git a/tools/lib/bpf/bpf_prog_linfo.c b/tools/lib/bpf/bpf_prog_linfo.c
index bafca49cb1e6..3ed1a27b5f7c 100644
--- a/tools/lib/bpf/bpf_prog_linfo.c
+++ b/tools/lib/bpf/bpf_prog_linfo.c
@@ -8,9 +8,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 struct bpf_prog_linfo {
 	void *raw_linfo;
 	void *raw_jited_linfo;
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1b7d85d94a07..a3d259e614b0 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -21,9 +21,6 @@
 #include "libbpf_internal.h"
 #include "hashmap.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #define BTF_MAX_NR_TYPES 0x7fffffffU
 #define BTF_MAX_STR_OFFSET 0x7fffffffU
 
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 1ad852ad0a86..0eaafd9bcfea 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -19,9 +19,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
 static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
 
diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c
index a405dad068f5..3c20b126d60d 100644
--- a/tools/lib/bpf/hashmap.c
+++ b/tools/lib/bpf/hashmap.c
@@ -15,6 +15,9 @@
 /* make sure libbpf doesn't use kernel-only integer typedefs */
 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
 
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
 /* start with 4 buckets */
 #define HASHMAP_MIN_CAP_BITS 2
 
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2653bcee73b7..4b96e0eefea8 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -55,9 +55,6 @@
 #include "libbpf_internal.h"
 #include "hashmap.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef EM_BPF
 #define EM_BPF 247
 #endif
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 65931e989eea..c8ed352671d5 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -10,6 +10,13 @@
 #define __LIBBPF_LIBBPF_INTERNAL_H
 
 #include <stdlib.h>
+
+/* make sure libbpf doesn't use kernel-only integer typedefs */
+#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
 #include "libbpf.h"
 
 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 5a3d3f078408..010c9a76fd2b 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -17,9 +17,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 static bool grep(const char *buffer, const char *pattern)
 {
 	return !!strstr(buffer, pattern);
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 2465538a5ba9..4dd73de00b6f 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -15,9 +15,6 @@
 #include "libbpf_internal.h"
 #include "nlattr.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef SOL_NETLINK
 #define SOL_NETLINK 270
 #endif
diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c
index 0ad41dfea8eb..b607fa9852b1 100644
--- a/tools/lib/bpf/nlattr.c
+++ b/tools/lib/bpf/nlattr.c
@@ -7,14 +7,11 @@
  */
 
 #include <errno.h>
-#include "nlattr.h"
-#include "libbpf_internal.h"
-#include <linux/rtnetlink.h>
 #include <string.h>
 #include <stdio.h>
-
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+#include <linux/rtnetlink.h>
+#include "nlattr.h"
+#include "libbpf_internal.h"
 
 static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = {
 	[LIBBPF_NLA_U8]		= sizeof(uint8_t),
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 5bd234be8a14..5c6522c89af1 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -21,9 +21,6 @@
 #include "libbpf_internal.h"
 #include "bpf.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 struct ring {
 	ring_buffer_sample_fn sample_cb;
 	void *ctx;
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index f7f4efb70a4c..a9b02103767b 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -32,9 +32,6 @@
 #include "libbpf_internal.h"
 #include "xsk.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef SOL_XDP
  #define SOL_XDP 283
 #endif
-- 
2.24.1

[PATCH v3 bpf-next 4/4] tools: remove feature-libelf-mmap feature detection

[Andrii Nakryiko]

It's trivial to handle missing ELF_C_MMAP_READ support in libelf the way that
objtool has solved it in
("774bec3fddcc objtool: Add fallback from ELF_C_READ_MMAP to ELF_C_READ").

So instead of having an entire feature detector for that, just do what objtool
does for perf and libbpf. And keep their Makefiles a bit simpler.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/build/Makefile.feature           |  1 -
 tools/build/feature/Makefile           |  4 ----
 tools/build/feature/test-all.c         |  4 ----
 tools/build/feature/test-libelf-mmap.c |  9 ---------
 tools/lib/bpf/Makefile                 |  6 +-----
 tools/lib/bpf/libbpf.c                 | 14 ++++++--------
 tools/perf/Makefile.config             |  4 ----
 tools/perf/util/symbol.h               |  2 +-
 8 files changed, 8 insertions(+), 36 deletions(-)
 delete mode 100644 tools/build/feature/test-libelf-mmap.c

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index c1daf4d57518..38415d251075 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -46,7 +46,6 @@ FEATURE_TESTS_BASIC :=                  \
         libelf-getphdrnum               \
         libelf-gelf_getnote             \
         libelf-getshdrstrndx            \
-        libelf-mmap                     \
         libnuma                         \
         numa_num_possible_cpus          \
         libperl                         \
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index d220fe952747..b2a2347c67ed 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -25,7 +25,6 @@ FILES=                                          \
          test-libelf-getphdrnum.bin             \
          test-libelf-gelf_getnote.bin           \
          test-libelf-getshdrstrndx.bin          \
-         test-libelf-mmap.bin                   \
          test-libdebuginfod.bin                 \
          test-libnuma.bin                       \
          test-numa_num_possible_cpus.bin        \
@@ -146,9 +145,6 @@ $(OUTPUT)test-dwarf.bin:
 $(OUTPUT)test-dwarf_getlocations.bin:
 	$(BUILD) $(DWARFLIBS)
 
-$(OUTPUT)test-libelf-mmap.bin:
-	$(BUILD) -lelf
-
 $(OUTPUT)test-libelf-getphdrnum.bin:
 	$(BUILD) -lelf
 
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 5479e543b194..5284e6e9c756 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -30,10 +30,6 @@
 # include "test-libelf.c"
 #undef main
 
-#define main main_test_libelf_mmap
-# include "test-libelf-mmap.c"
-#undef main
-
 #define main main_test_get_current_dir_name
 # include "test-get_current_dir_name.c"
 #undef main
diff --git a/tools/build/feature/test-libelf-mmap.c b/tools/build/feature/test-libelf-mmap.c
deleted file mode 100644
index 2c3ef81affe2..000000000000
--- a/tools/build/feature/test-libelf-mmap.c
+++ /dev/null
@@ -1,9 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <libelf.h>
-
-int main(void)
-{
-	Elf *elf = elf_begin(0, ELF_C_READ_MMAP, 0);
-
-	return (long)elf;
-}
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 621ad96d06fd..c5dbfafdf889 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -56,7 +56,7 @@ ifndef VERBOSE
 endif
 
 FEATURE_USER = .libbpf
-FEATURE_TESTS = libelf libelf-mmap zlib bpf
+FEATURE_TESTS = libelf zlib bpf
 FEATURE_DISPLAY = libelf zlib bpf
 
 INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
@@ -98,10 +98,6 @@ else
   CFLAGS := -g -Wall
 endif
 
-ifeq ($(feature-libelf-mmap), 1)
-  override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
-endif
-
 # Append required CFLAGS
 override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
 override CFLAGS += -Werror -Wall
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4b96e0eefea8..4a81c6b2d21b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -150,12 +150,6 @@ static void pr_perm_msg(int err)
 	___err; })
 #endif
 
-#ifdef HAVE_LIBELF_MMAP_SUPPORT
-# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
-#else
-# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
-#endif
-
 static inline __u64 ptr_to_u64(const void *ptr)
 {
 	return (__u64) (unsigned long) ptr;
@@ -1064,6 +1058,11 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
 	obj->efile.obj_buf_sz = 0;
 }
 
+/* if libelf is old and doesn't support mmap(), fall back to read() */
+#ifndef ELF_C_READ_MMAP
+#define ELF_C_READ_MMAP ELF_C_READ
+#endif
+
 static int bpf_object__elf_init(struct bpf_object *obj)
 {
 	int err = 0;
@@ -1092,8 +1091,7 @@ static int bpf_object__elf_init(struct bpf_object *obj)
 			return err;
 		}
 
-		obj->efile.elf = elf_begin(obj->efile.fd,
-					   LIBBPF_ELF_C_READ_MMAP, NULL);
+		obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL);
 	}
 
 	if (!obj->efile.elf) {
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 190be4fa5c21..81bb099f6f06 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -483,10 +483,6 @@ ifndef NO_LIBELF
   EXTLIBS += -lelf
   $(call detected,CONFIG_LIBELF)
 
-  ifeq ($(feature-libelf-mmap), 1)
-    CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
-  endif
-
   ifeq ($(feature-libelf-getphdrnum), 1)
     CFLAGS += -DHAVE_ELF_GETPHDRNUM_SUPPORT
   endif
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index ff4f4c47e148..03e264a27cd3 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -28,7 +28,7 @@ struct option;
  * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP;
  * for newer versions we can use mmap to reduce memory usage:
  */
-#ifdef HAVE_LIBELF_MMAP_SUPPORT
+#ifdef ELF_C_READ_MMAP
 # define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 #else
 # define PERF_ELF_C_READ_MMAP ELF_C_READ
-- 
2.24.1

Re: [PATCH v3 bpf-next 0/4] libbpf: minimize feature detection (reallocarray, libelf-mmap)

[Alexei Starovoitov]

On 8/18/20 6:36 PM, Andrii Nakryiko wrote:
> Get rid of two feature detectors: reallocarray and libelf-mmap. Optional
> feature detections complicate libbpf Makefile and cause more troubles for
> various applications that want to integrate libbpf as part of their build.
> 
> Patch #1 replaces all reallocarray() uses into libbpf-internal reallocarray()
> implementation. Patches #2 and #3 makes sure we won't re-introduce
> reallocarray() accidentally. Patch #2 also removes last use of
> libbpf_internal.h header inside bpftool. There is still nlattr.h that's used
> by both libbpf and bpftool, but that's left for a follow up patch to split.
> Patch #4 removed libelf-mmap feature detector and all its uses, as it's
> trivial to handle missing mmap support in libbpf, the way objtool has been
> doing it for a while.
> 
> v1->v2 and v2->v3:
>    - rebase to latest bpf-next (Alexei).

Applied. Thanks