1 files changed, 173 insertions, 31 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 5aa45f89da93..71ddc481f349 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: LGPL-2.1
+
 /*
  * Common eBPF ELF object loading operations.
  *
@@ -106,6 +108,8 @@ static const char *libbpf_strerror_table[NR_ERRNO] = {
         [ERRCODE_OFFSET(PROG2BIG)]      = "Program too big",
         [ERRCODE_OFFSET(KVER)]          = "Incorrect kernel version",
         [ERRCODE_OFFSET(PROGTYPE)]      = "Kernel doesn't support this program type",
+        [ERRCODE_OFFSET(WRNGPID)]       = "Wrong pid in netlink message",
+        [ERRCODE_OFFSET(INVSEQ)]        = "Invalid netlink sequence",
 };
 
 int libbpf_strerror(int err, char *buf, size_t size)
@@ -174,12 +178,19 @@ struct bpf_program {
         char *name;
         char *section_name;
         struct bpf_insn *insns;
-        size_t insns_cnt;
+        size_t insns_cnt, main_prog_cnt;
         enum bpf_prog_type type;
 
-        struct {
+        struct reloc_desc {
+                enum {
+                        RELO_LD64,
+                        RELO_CALL,
+                } type;
                 int insn_idx;
-                int map_idx;
+                union {
+                        int map_idx;
+                        int text_off;
+                };
         } *reloc_desc;
         int nr_reloc;
 
@@ -234,6 +245,7 @@ struct bpf_object {
                 } *reloc;
                 int nr_reloc;
                 int maps_shndx;
+                int text_shndx;
         } efile;
         /*
          * All loaded bpf_object is linked in a list, which is
@@ -375,9 +387,13 @@ bpf_object__init_prog_names(struct bpf_object *obj)
         size_t pi, si;
 
         for (pi = 0; pi < obj->nr_programs; pi++) {
-                char *name = NULL;
+                const char *name = NULL;
 
                 prog = &obj->programs[pi];
+                if (prog->idx == obj->efile.text_shndx) {
+                        name = ".text";
+                        goto skip_search;
+                }
 
                 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
                      si++) {
@@ -387,6 +403,8 @@ bpf_object__init_prog_names(struct bpf_object *obj)
                                 continue;
                         if (sym.st_shndx != prog->idx)
                                 continue;
+                        if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
+                                continue;
 
                         name = elf_strptr(obj->efile.elf,
                                           obj->efile.strtabidx,
@@ -403,7 +421,7 @@ bpf_object__init_prog_names(struct bpf_object *obj)
                                    prog->section_name);
                         return -EINVAL;
                 }
-
+skip_search:
                 prog->name = strdup(name);
                 if (!prog->name) {
                         pr_warning("failed to allocate memory for prog sym %s\n",
@@ -793,6 +811,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
                 } else if ((sh.sh_type == SHT_PROGBITS) &&
                            (sh.sh_flags & SHF_EXECINSTR) &&
                            (data->d_size > 0)) {
+                        if (strcmp(name, ".text") == 0)
+                                obj->efile.text_shndx = idx;
                         err = bpf_object__add_program(obj, data->d_buf,
                                                       data->d_size, name, idx);
                         if (err) {
@@ -854,11 +874,14 @@ bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 }
 
 static int
-bpf_program__collect_reloc(struct bpf_program *prog,
-                           size_t nr_maps, GElf_Shdr *shdr,
-                           Elf_Data *data, Elf_Data *symbols,
-                           int maps_shndx, struct bpf_map *maps)
+bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
+                           Elf_Data *data, struct bpf_object *obj)
 {
+        Elf_Data *symbols = obj->efile.symbols;
+        int text_shndx = obj->efile.text_shndx;
+        int maps_shndx = obj->efile.maps_shndx;
+        struct bpf_map *maps = obj->maps;
+        size_t nr_maps = obj->nr_maps;
         int i, nrels;
 
         pr_debug("collecting relocating info for: '%s'\n",
@@ -891,8 +914,11 @@ bpf_program__collect_reloc(struct bpf_program *prog,
                                    GELF_R_SYM(rel.r_info));
                         return -LIBBPF_ERRNO__FORMAT;
                 }
+                pr_debug("relo for %lld value %lld name %d\n",
+                         (long long) (rel.r_info >> 32),
+                         (long long) sym.st_value, sym.st_name);
 
-                if (sym.st_shndx != maps_shndx) {
+                if (sym.st_shndx != maps_shndx && sym.st_shndx != text_shndx) {
                         pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
                                    prog->section_name, sym.st_shndx);
                         return -LIBBPF_ERRNO__RELOC;
@@ -901,6 +927,17 @@ bpf_program__collect_reloc(struct bpf_program *prog,
                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 
+                if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
+                        if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
+                                pr_warning("incorrect bpf_call opcode\n");
+                                return -LIBBPF_ERRNO__RELOC;
+                        }
+                        prog->reloc_desc[i].type = RELO_CALL;
+                        prog->reloc_desc[i].insn_idx = insn_idx;
+                        prog->reloc_desc[i].text_off = sym.st_value;
+                        continue;
+                }
+
                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
                                    insn_idx, insns[insn_idx].code);
@@ -922,6 +959,7 @@ bpf_program__collect_reloc(struct bpf_program *prog,
                         return -LIBBPF_ERRNO__RELOC;
                 }
 
+                prog->reloc_desc[i].type = RELO_LD64;
                 prog->reloc_desc[i].insn_idx = insn_idx;
                 prog->reloc_desc[i].map_idx = map_idx;
         }
@@ -961,27 +999,76 @@ bpf_object__create_maps(struct bpf_object *obj)
 }
 
 static int
+bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
+                        struct reloc_desc *relo)
+{
+        struct bpf_insn *insn, *new_insn;
+        struct bpf_program *text;
+        size_t new_cnt;
+
+        if (relo->type != RELO_CALL)
+                return -LIBBPF_ERRNO__RELOC;
+
+        if (prog->idx == obj->efile.text_shndx) {
+                pr_warning("relo in .text insn %d into off %d\n",
+                           relo->insn_idx, relo->text_off);
+                return -LIBBPF_ERRNO__RELOC;
+        }
+
+        if (prog->main_prog_cnt == 0) {
+                text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
+                if (!text) {
+                        pr_warning("no .text section found yet relo into text exist\n");
+                        return -LIBBPF_ERRNO__RELOC;
+                }
+                new_cnt = prog->insns_cnt + text->insns_cnt;
+                new_insn = realloc(prog->insns, new_cnt * sizeof(*insn));
+                if (!new_insn) {
+                        pr_warning("oom in prog realloc\n");
+                        return -ENOMEM;
+                }
+                memcpy(new_insn + prog->insns_cnt, text->insns,
+                       text->insns_cnt * sizeof(*insn));
+                prog->insns = new_insn;
+                prog->main_prog_cnt = prog->insns_cnt;
+                prog->insns_cnt = new_cnt;
+        }
+        insn = &prog->insns[relo->insn_idx];
+        insn->imm += prog->main_prog_cnt - relo->insn_idx;
+        pr_debug("added %zd insn from %s to prog %s\n",
+                 text->insns_cnt, text->section_name, prog->section_name);
+        return 0;
+}
+
+static int
 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
 {
-        int i;
+        int i, err;
 
         if (!prog || !prog->reloc_desc)
                 return 0;
 
         for (i = 0; i < prog->nr_reloc; i++) {
-                int insn_idx, map_idx;
-                struct bpf_insn *insns = prog->insns;
+                if (prog->reloc_desc[i].type == RELO_LD64) {
+                        struct bpf_insn *insns = prog->insns;
+                        int insn_idx, map_idx;
 
-                insn_idx = prog->reloc_desc[i].insn_idx;
-                map_idx = prog->reloc_desc[i].map_idx;
+                        insn_idx = prog->reloc_desc[i].insn_idx;
+                        map_idx = prog->reloc_desc[i].map_idx;
 
-                if (insn_idx >= (int)prog->insns_cnt) {
-                        pr_warning("relocation out of range: '%s'\n",
-                                   prog->section_name);
-                        return -LIBBPF_ERRNO__RELOC;
+                        if (insn_idx >= (int)prog->insns_cnt) {
+                                pr_warning("relocation out of range: '%s'\n",
+                                           prog->section_name);
+                                return -LIBBPF_ERRNO__RELOC;
+                        }
+                        insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
+                        insns[insn_idx].imm = obj->maps[map_idx].fd;
+                } else {
+                        err = bpf_program__reloc_text(prog, obj,
+                                                      &prog->reloc_desc[i]);
+                        if (err)
+                                return err;
                 }
-                insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
-                insns[insn_idx].imm = obj->maps[map_idx].fd;
         }
 
         zfree(&prog->reloc_desc);
@@ -1024,7 +1111,6 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
                 Elf_Data *data = obj->efile.reloc[i].data;
                 int idx = shdr->sh_info;
                 struct bpf_program *prog;
-                size_t nr_maps = obj->nr_maps;
 
                 if (shdr->sh_type != SHT_REL) {
                         pr_warning("internal error at %d\n", __LINE__);
@@ -1038,11 +1124,9 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
                         return -LIBBPF_ERRNO__RELOC;
                 }
 
-                err = bpf_program__collect_reloc(prog, nr_maps,
+                err = bpf_program__collect_reloc(prog,
                                                  shdr, data,
-                                                 obj->efile.symbols,
-                                                 obj->efile.maps_shndx,
-                                                 obj->maps);
+                                                 obj);
                 if (err)
                         return err;
         }
@@ -1195,6 +1279,8 @@ bpf_object__load_progs(struct bpf_object *obj)
         int err;
 
         for (i = 0; i < obj->nr_programs; i++) {
+                if (obj->programs[i].idx == obj->efile.text_shndx)
+                        continue;
                 err = bpf_program__load(&obj->programs[i],
                                         obj->license,
                                         obj->kern_version);
@@ -1721,6 +1807,45 @@ BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
+#define BPF_PROG_SEC(string, type) { string, sizeof(string) - 1, type }
+static const struct {
+        const char *sec;
+        size_t len;
+        enum bpf_prog_type prog_type;
+} section_names[] = {
+        BPF_PROG_SEC("socket",          BPF_PROG_TYPE_SOCKET_FILTER),
+        BPF_PROG_SEC("kprobe/",         BPF_PROG_TYPE_KPROBE),
+        BPF_PROG_SEC("kretprobe/",      BPF_PROG_TYPE_KPROBE),
+        BPF_PROG_SEC("tracepoint/",     BPF_PROG_TYPE_TRACEPOINT),
+        BPF_PROG_SEC("xdp",             BPF_PROG_TYPE_XDP),
+        BPF_PROG_SEC("perf_event",      BPF_PROG_TYPE_PERF_EVENT),
+        BPF_PROG_SEC("cgroup/skb",      BPF_PROG_TYPE_CGROUP_SKB),
+        BPF_PROG_SEC("cgroup/sock",     BPF_PROG_TYPE_CGROUP_SOCK),
+        BPF_PROG_SEC("cgroup/dev",      BPF_PROG_TYPE_CGROUP_DEVICE),
+        BPF_PROG_SEC("sockops",         BPF_PROG_TYPE_SOCK_OPS),
+        BPF_PROG_SEC("sk_skb",          BPF_PROG_TYPE_SK_SKB),
+};
+#undef BPF_PROG_SEC
+
+static enum bpf_prog_type bpf_program__guess_type(struct bpf_program *prog)
+{
+        int i;
+
+        if (!prog->section_name)
+                goto err;
+
+        for (i = 0; i < ARRAY_SIZE(section_names); i++)
+                if (strncmp(prog->section_name, section_names[i].sec,
+                            section_names[i].len) == 0)
+                        return section_names[i].prog_type;
+
+err:
+        pr_warning("failed to guess program type based on section name %s\n",
+                   prog->section_name);
+
+        return BPF_PROG_TYPE_UNSPEC;
+}
+
 int bpf_map__fd(struct bpf_map *map)
 {
         return map ? map->fd : -EINVAL;
@@ -1818,7 +1943,7 @@ long libbpf_get_error(const void *ptr)
 int bpf_prog_load(const char *file, enum bpf_prog_type type,
                   struct bpf_object **pobj, int *prog_fd)
 {
-        struct bpf_program *prog;
+        struct bpf_program *prog, *first_prog = NULL;
         struct bpf_object *obj;
         int err;
 
@@ -1826,13 +1951,30 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type,
         if (IS_ERR(obj))
                 return -ENOENT;
 
-        prog = bpf_program__next(NULL, obj);
-        if (!prog) {
+        bpf_object__for_each_program(prog, obj) {
+                /*
+                 * If type is not specified, try to guess it based on
+                 * section name.
+                 */
+                if (type == BPF_PROG_TYPE_UNSPEC) {
+                        type = bpf_program__guess_type(prog);
+                        if (type == BPF_PROG_TYPE_UNSPEC) {
+                                bpf_object__close(obj);
+                                return -EINVAL;
+                        }
+                }
+
+                bpf_program__set_type(prog, type);
+                if (prog->idx != obj->efile.text_shndx && !first_prog)
+                        first_prog = prog;
+        }
+
+        if (!first_prog) {
+                pr_warning("object file doesn't contain bpf program\n");
                 bpf_object__close(obj);
                 return -ENOENT;
         }
 
-        bpf_program__set_type(prog, type);
         err = bpf_object__load(obj);
         if (err) {
                 bpf_object__close(obj);
@@ -1840,6 +1982,6 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type,
         }
 
         *pobj = obj;
-        *prog_fd = bpf_program__fd(prog);
+        *prog_fd = bpf_program__fd(first_prog);
         return 0;
 }