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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
commit03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch)
treefa581f6dc1c0596391690d1f67eceef3af8246dc /tools/lib/bpf
parentd4e493caf788ef44982e131ff9c786546904d934 (diff)
Linux-libre 4.5-gnu
Diffstat (limited to 'tools/lib/bpf')
-rw-r--r--tools/lib/bpf/Makefile32
-rw-r--r--tools/lib/bpf/bpf.c18
-rw-r--r--tools/lib/bpf/bpf.h2
-rw-r--r--tools/lib/bpf/libbpf.c412
-rw-r--r--tools/lib/bpf/libbpf.h88
5 files changed, 468 insertions, 84 deletions
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index a3caaf3ea..fc1bc75ae 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -6,6 +6,12 @@ BPF_EXTRAVERSION = 1
MAKEFLAGS += --no-print-directory
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(shell pwd)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
# Makefiles suck: This macro sets a default value of $(2) for the
# variable named by $(1), unless the variable has been set by
@@ -31,7 +37,8 @@ INSTALL = install
DESTDIR ?=
DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
-LP64 := $(shell echo __LP64__ | ${CC} ${CFLAGS} -E -x c - | tail -n 1)
+include $(srctree)/tools/scripts/Makefile.arch
+
ifeq ($(LP64), 1)
libdir_relative = lib64
else
@@ -57,13 +64,6 @@ ifndef VERBOSE
VERBOSE = 0
endif
-ifeq ($(srctree),)
-srctree := $(patsubst %/,%,$(dir $(shell pwd)))
-srctree := $(patsubst %/,%,$(dir $(srctree)))
-srctree := $(patsubst %/,%,$(dir $(srctree)))
-#$(info Determined 'srctree' to be $(srctree))
-endif
-
FEATURE_USER = .libbpf
FEATURE_TESTS = libelf libelf-getphdrnum libelf-mmap bpf
FEATURE_DISPLAY = libelf bpf
@@ -71,7 +71,21 @@ FEATURE_DISPLAY = libelf bpf
INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/arch/$(ARCH)/include/uapi -I$(srctree)/include/uapi
FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES)
+check_feat := 1
+NON_CHECK_FEAT_TARGETS := clean TAGS tags cscope help
+ifdef MAKECMDGOALS
+ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
+ check_feat := 0
+endif
+endif
+
+ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
+endif
export prefix libdir src obj
@@ -178,7 +192,7 @@ config-clean:
$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null
clean:
- $(call QUIET_CLEAN, libbpf) $(RM) *.o *~ $(TARGETS) *.a *.so $(VERSION_FILES) .*.d \
+ $(call QUIET_CLEAN, libbpf) $(RM) *.o *~ $(TARGETS) *.a *.so $(VERSION_FILES) .*.d .*.cmd \
$(RM) LIBBPF-CFLAGS
$(call QUIET_CLEAN, core-gen) $(RM) $(OUTPUT)FEATURE-DUMP.libbpf
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index a6331050a..1f91cc941 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -14,8 +14,8 @@
#include "bpf.h"
/*
- * When building perf, unistd.h is override. Define __NR_bpf is
- * required to be defined.
+ * When building perf, unistd.h is overrided. __NR_bpf is
+ * required to be defined explicitly.
*/
#ifndef __NR_bpf
# if defined(__i386__)
@@ -83,3 +83,17 @@ int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
log_buf[0] = 0;
return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
+
+int bpf_map_update_elem(int fd, void *key, void *value,
+ u64 flags)
+{
+ union bpf_attr attr;
+
+ bzero(&attr, sizeof(attr));
+ attr.map_fd = fd;
+ attr.key = ptr_to_u64(key);
+ attr.value = ptr_to_u64(value);
+ attr.flags = flags;
+
+ return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 854b7361b..a76465541 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -20,4 +20,6 @@ int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
u32 kern_version, char *log_buf,
size_t log_buf_sz);
+int bpf_map_update_elem(int fd, void *key, void *value,
+ u64 flags);
#endif
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e176bad19..8334a5a9d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -152,29 +152,36 @@ struct bpf_program {
} *reloc_desc;
int nr_reloc;
- int fd;
+ struct {
+ int nr;
+ int *fds;
+ } instances;
+ bpf_program_prep_t preprocessor;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
};
+struct bpf_map {
+ int fd;
+ char *name;
+ struct bpf_map_def def;
+ void *priv;
+ bpf_map_clear_priv_t clear_priv;
+};
+
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char license[64];
u32 kern_version;
- void *maps_buf;
- size_t maps_buf_sz;
struct bpf_program *programs;
size_t nr_programs;
- int *map_fds;
- /*
- * This field is required because maps_buf will be freed and
- * maps_buf_sz will be set to 0 after loaded.
- */
- size_t nr_map_fds;
+ struct bpf_map *maps;
+ size_t nr_maps;
+
bool loaded;
/*
@@ -188,6 +195,7 @@ struct bpf_object {
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
+ size_t strtabidx;
struct {
GElf_Shdr shdr;
Elf_Data *data;
@@ -206,10 +214,25 @@ struct bpf_object {
static void bpf_program__unload(struct bpf_program *prog)
{
+ int i;
+
if (!prog)
return;
- zclose(prog->fd);
+ /*
+ * If the object is opened but the program was never loaded,
+ * it is possible that prog->instances.nr == -1.
+ */
+ if (prog->instances.nr > 0) {
+ for (i = 0; i < prog->instances.nr; i++)
+ zclose(prog->instances.fds[i]);
+ } else if (prog->instances.nr != -1) {
+ pr_warning("Internal error: instances.nr is %d\n",
+ prog->instances.nr);
+ }
+
+ prog->instances.nr = -1;
+ zfree(&prog->instances.fds);
}
static void bpf_program__exit(struct bpf_program *prog)
@@ -260,7 +283,8 @@ bpf_program__init(void *data, size_t size, char *name, int idx,
memcpy(prog->insns, data,
prog->insns_cnt * sizeof(struct bpf_insn));
prog->idx = idx;
- prog->fd = -1;
+ prog->instances.fds = NULL;
+ prog->instances.nr = -1;
return 0;
errout:
@@ -469,21 +493,77 @@ static int
bpf_object__init_maps(struct bpf_object *obj, void *data,
size_t size)
{
- if (size == 0) {
+ size_t nr_maps;
+ int i;
+
+ nr_maps = size / sizeof(struct bpf_map_def);
+ if (!data || !nr_maps) {
pr_debug("%s doesn't need map definition\n",
obj->path);
return 0;
}
- obj->maps_buf = malloc(size);
- if (!obj->maps_buf) {
- pr_warning("malloc maps failed: %s\n", obj->path);
+ pr_debug("maps in %s: %zd bytes\n", obj->path, size);
+
+ obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
+ if (!obj->maps) {
+ pr_warning("alloc maps for object failed\n");
return -ENOMEM;
}
+ obj->nr_maps = nr_maps;
- obj->maps_buf_sz = size;
- memcpy(obj->maps_buf, data, size);
- pr_debug("maps in %s: %ld bytes\n", obj->path, (long)size);
+ for (i = 0; i < nr_maps; i++) {
+ struct bpf_map_def *def = &obj->maps[i].def;
+
+ /*
+ * fill all fd with -1 so won't close incorrect
+ * fd (fd=0 is stdin) when failure (zclose won't close
+ * negative fd)).
+ */
+ obj->maps[i].fd = -1;
+
+ /* Save map definition into obj->maps */
+ *def = ((struct bpf_map_def *)data)[i];
+ }
+ return 0;
+}
+
+static int
+bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx)
+{
+ int i;
+ Elf_Data *symbols = obj->efile.symbols;
+
+ if (!symbols || maps_shndx < 0)
+ return -EINVAL;
+
+ for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+ GElf_Sym sym;
+ size_t map_idx;
+ const char *map_name;
+
+ if (!gelf_getsym(symbols, i, &sym))
+ continue;
+ if (sym.st_shndx != maps_shndx)
+ continue;
+
+ map_name = elf_strptr(obj->efile.elf,
+ obj->efile.strtabidx,
+ sym.st_name);
+ map_idx = sym.st_value / sizeof(struct bpf_map_def);
+ if (map_idx >= obj->nr_maps) {
+ pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
+ map_name, map_idx, obj->nr_maps);
+ continue;
+ }
+ obj->maps[map_idx].name = strdup(map_name);
+ if (!obj->maps[map_idx].name) {
+ pr_warning("failed to alloc map name\n");
+ return -ENOMEM;
+ }
+ pr_debug("map %zu is \"%s\"\n", map_idx,
+ obj->maps[map_idx].name);
+ }
return 0;
}
@@ -492,7 +572,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
Elf_Scn *scn = NULL;
- int idx = 0, err = 0;
+ int idx = 0, err = 0, maps_shndx = -1;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
@@ -542,16 +622,19 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
- else if (strcmp(name, "maps") == 0)
+ else if (strcmp(name, "maps") == 0) {
err = bpf_object__init_maps(obj, data->d_buf,
data->d_size);
- else if (sh.sh_type == SHT_SYMTAB) {
+ maps_shndx = idx;
+ } else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warning("bpf: multiple SYMTAB in %s\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;
- } else
+ } else {
obj->efile.symbols = data;
+ obj->efile.strtabidx = sh.sh_link;
+ }
} else if ((sh.sh_type == SHT_PROGBITS) &&
(sh.sh_flags & SHF_EXECINSTR) &&
(data->d_size > 0)) {
@@ -586,6 +669,13 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
if (err)
goto out;
}
+
+ if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
+ pr_warning("Corrupted ELF file: index of strtab invalid\n");
+ return LIBBPF_ERRNO__FORMAT;
+ }
+ if (maps_shndx >= 0)
+ err = bpf_object__init_maps_name(obj, maps_shndx);
out:
return err;
}
@@ -668,37 +758,15 @@ static int
bpf_object__create_maps(struct bpf_object *obj)
{
unsigned int i;
- size_t nr_maps;
- int *pfd;
-
- nr_maps = obj->maps_buf_sz / sizeof(struct bpf_map_def);
- if (!obj->maps_buf || !nr_maps) {
- pr_debug("don't need create maps for %s\n",
- obj->path);
- return 0;
- }
-
- obj->map_fds = malloc(sizeof(int) * nr_maps);
- if (!obj->map_fds) {
- pr_warning("realloc perf_bpf_map_fds failed\n");
- return -ENOMEM;
- }
- obj->nr_map_fds = nr_maps;
- /* fill all fd with -1 */
- memset(obj->map_fds, -1, sizeof(int) * nr_maps);
-
- pfd = obj->map_fds;
- for (i = 0; i < nr_maps; i++) {
- struct bpf_map_def def;
+ for (i = 0; i < obj->nr_maps; i++) {
+ struct bpf_map_def *def = &obj->maps[i].def;
+ int *pfd = &obj->maps[i].fd;
- def = *(struct bpf_map_def *)(obj->maps_buf +
- i * sizeof(struct bpf_map_def));
-
- *pfd = bpf_create_map(def.type,
- def.key_size,
- def.value_size,
- def.max_entries);
+ *pfd = bpf_create_map(def->type,
+ def->key_size,
+ def->value_size,
+ def->max_entries);
if (*pfd < 0) {
size_t j;
int err = *pfd;
@@ -706,22 +774,17 @@ bpf_object__create_maps(struct bpf_object *obj)
pr_warning("failed to create map: %s\n",
strerror(errno));
for (j = 0; j < i; j++)
- zclose(obj->map_fds[j]);
- obj->nr_map_fds = 0;
- zfree(&obj->map_fds);
+ zclose(obj->maps[j].fd);
return err;
}
pr_debug("create map: fd=%d\n", *pfd);
- pfd++;
}
- zfree(&obj->maps_buf);
- obj->maps_buf_sz = 0;
return 0;
}
static int
-bpf_program__relocate(struct bpf_program *prog, int *map_fds)
+bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
{
int i;
@@ -741,7 +804,7 @@ bpf_program__relocate(struct bpf_program *prog, int *map_fds)
return -LIBBPF_ERRNO__RELOC;
}
insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
- insns[insn_idx].imm = map_fds[map_idx];
+ insns[insn_idx].imm = obj->maps[map_idx].fd;
}
zfree(&prog->reloc_desc);
@@ -760,7 +823,7 @@ bpf_object__relocate(struct bpf_object *obj)
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
- err = bpf_program__relocate(prog, obj->map_fds);
+ err = bpf_program__relocate(prog, obj);
if (err) {
pr_warning("failed to relocate '%s'\n",
prog->section_name);
@@ -784,8 +847,7 @@ 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->maps_buf_sz /
- sizeof(struct bpf_map_def);
+ size_t nr_maps = obj->nr_maps;
if (shdr->sh_type != SHT_REL) {
pr_warning("internal error at %d\n", __LINE__);
@@ -860,13 +922,73 @@ static int
bpf_program__load(struct bpf_program *prog,
char *license, u32 kern_version)
{
- int err, fd;
+ int err = 0, fd, i;
- err = load_program(prog->insns, prog->insns_cnt,
- license, kern_version, &fd);
- if (!err)
- prog->fd = fd;
+ if (prog->instances.nr < 0 || !prog->instances.fds) {
+ if (prog->preprocessor) {
+ pr_warning("Internal error: can't load program '%s'\n",
+ prog->section_name);
+ return -LIBBPF_ERRNO__INTERNAL;
+ }
+
+ prog->instances.fds = malloc(sizeof(int));
+ if (!prog->instances.fds) {
+ pr_warning("Not enough memory for BPF fds\n");
+ return -ENOMEM;
+ }
+ prog->instances.nr = 1;
+ prog->instances.fds[0] = -1;
+ }
+
+ if (!prog->preprocessor) {
+ if (prog->instances.nr != 1) {
+ pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
+ prog->section_name, prog->instances.nr);
+ }
+ err = load_program(prog->insns, prog->insns_cnt,
+ license, kern_version, &fd);
+ if (!err)
+ prog->instances.fds[0] = fd;
+ goto out;
+ }
+
+ for (i = 0; i < prog->instances.nr; i++) {
+ struct bpf_prog_prep_result result;
+ bpf_program_prep_t preprocessor = prog->preprocessor;
+
+ bzero(&result, sizeof(result));
+ err = preprocessor(prog, i, prog->insns,
+ prog->insns_cnt, &result);
+ if (err) {
+ pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
+ i, prog->section_name);
+ goto out;
+ }
+
+ if (!result.new_insn_ptr || !result.new_insn_cnt) {
+ pr_debug("Skip loading the %dth instance of program '%s'\n",
+ i, prog->section_name);
+ prog->instances.fds[i] = -1;
+ if (result.pfd)
+ *result.pfd = -1;
+ continue;
+ }
+
+ err = load_program(result.new_insn_ptr,
+ result.new_insn_cnt,
+ license, kern_version, &fd);
+
+ if (err) {
+ pr_warning("Loading the %dth instance of program '%s' failed\n",
+ i, prog->section_name);
+ goto out;
+ }
+ if (result.pfd)
+ *result.pfd = fd;
+ prog->instances.fds[i] = fd;
+ }
+out:
if (err)
pr_warning("failed to load program '%s'\n",
prog->section_name);
@@ -970,10 +1092,8 @@ int bpf_object__unload(struct bpf_object *obj)
if (!obj)
return -EINVAL;
- for (i = 0; i < obj->nr_map_fds; i++)
- zclose(obj->map_fds[i]);
- zfree(&obj->map_fds);
- obj->nr_map_fds = 0;
+ for (i = 0; i < obj->nr_maps; i++)
+ zclose(obj->maps[i].fd);
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
@@ -1016,7 +1136,16 @@ void bpf_object__close(struct bpf_object *obj)
bpf_object__elf_finish(obj);
bpf_object__unload(obj);
- zfree(&obj->maps_buf);
+ for (i = 0; i < obj->nr_maps; i++) {
+ zfree(&obj->maps[i].name);
+ if (obj->maps[i].clear_priv)
+ obj->maps[i].clear_priv(&obj->maps[i],
+ obj->maps[i].priv);
+ obj->maps[i].priv = NULL;
+ obj->maps[i].clear_priv = NULL;
+ }
+ zfree(&obj->maps);
+ obj->nr_maps = 0;
if (obj->programs && obj->nr_programs) {
for (i = 0; i < obj->nr_programs; i++)
@@ -1121,5 +1250,142 @@ const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
int bpf_program__fd(struct bpf_program *prog)
{
- return prog->fd;
+ return bpf_program__nth_fd(prog, 0);
+}
+
+int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
+ bpf_program_prep_t prep)
+{
+ int *instances_fds;
+
+ if (nr_instances <= 0 || !prep)
+ return -EINVAL;
+
+ if (prog->instances.nr > 0 || prog->instances.fds) {
+ pr_warning("Can't set pre-processor after loading\n");
+ return -EINVAL;
+ }
+
+ instances_fds = malloc(sizeof(int) * nr_instances);
+ if (!instances_fds) {
+ pr_warning("alloc memory failed for fds\n");
+ return -ENOMEM;
+ }
+
+ /* fill all fd with -1 */
+ memset(instances_fds, -1, sizeof(int) * nr_instances);
+
+ prog->instances.nr = nr_instances;
+ prog->instances.fds = instances_fds;
+ prog->preprocessor = prep;
+ return 0;
+}
+
+int bpf_program__nth_fd(struct bpf_program *prog, int n)
+{
+ int fd;
+
+ if (n >= prog->instances.nr || n < 0) {
+ pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
+ n, prog->section_name, prog->instances.nr);
+ return -EINVAL;
+ }
+
+ fd = prog->instances.fds[n];
+ if (fd < 0) {
+ pr_warning("%dth instance of program '%s' is invalid\n",
+ n, prog->section_name);
+ return -ENOENT;
+ }
+
+ return fd;
+}
+
+int bpf_map__get_fd(struct bpf_map *map)
+{
+ if (!map)
+ return -EINVAL;
+
+ return map->fd;
+}
+
+int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef)
+{
+ if (!map || !pdef)
+ return -EINVAL;
+
+ *pdef = map->def;
+ return 0;
+}
+
+const char *bpf_map__get_name(struct bpf_map *map)
+{
+ if (!map)
+ return NULL;
+ return map->name;
+}
+
+int bpf_map__set_private(struct bpf_map *map, void *priv,
+ bpf_map_clear_priv_t clear_priv)
+{
+ if (!map)
+ return -EINVAL;
+
+ if (map->priv) {
+ if (map->clear_priv)
+ map->clear_priv(map, map->priv);
+ }
+
+ map->priv = priv;
+ map->clear_priv = clear_priv;
+ return 0;
+}
+
+int bpf_map__get_private(struct bpf_map *map, void **ppriv)
+{
+ if (!map)
+ return -EINVAL;
+
+ if (ppriv)
+ *ppriv = map->priv;
+ return 0;
+}
+
+struct bpf_map *
+bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
+{
+ size_t idx;
+ struct bpf_map *s, *e;
+
+ if (!obj || !obj->maps)
+ return NULL;
+
+ s = obj->maps;
+ e = obj->maps + obj->nr_maps;
+
+ if (prev == NULL)
+ return s;
+
+ if ((prev < s) || (prev >= e)) {
+ pr_warning("error in %s: map handler doesn't belong to object\n",
+ __func__);
+ return NULL;
+ }
+
+ idx = (prev - obj->maps) + 1;
+ if (idx >= obj->nr_maps)
+ return NULL;
+ return &obj->maps[idx];
+}
+
+struct bpf_map *
+bpf_object__get_map_by_name(struct bpf_object *obj, const char *name)
+{
+ struct bpf_map *pos;
+
+ bpf_map__for_each(pos, obj) {
+ if (pos->name && !strcmp(pos->name, name))
+ return pos;
+ }
+ return NULL;
}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c9a9aef28..a51594c7b 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -88,6 +88,70 @@ const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
int bpf_program__fd(struct bpf_program *prog);
+struct bpf_insn;
+
+/*
+ * Libbpf allows callers to adjust BPF programs before being loaded
+ * into kernel. One program in an object file can be transform into
+ * multiple variants to be attached to different code.
+ *
+ * bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
+ * are APIs for this propose.
+ *
+ * - bpf_program_prep_t:
+ * It defines 'preprocessor', which is a caller defined function
+ * passed to libbpf through bpf_program__set_prep(), and will be
+ * called before program is loaded. The processor should adjust
+ * the program one time for each instances according to the number
+ * passed to it.
+ *
+ * - bpf_program__set_prep:
+ * Attachs a preprocessor to a BPF program. The number of instances
+ * whould be created is also passed through this function.
+ *
+ * - bpf_program__nth_fd:
+ * After the program is loaded, get resuling fds from bpf program for
+ * each instances.
+ *
+ * If bpf_program__set_prep() is not used, the program whould be loaded
+ * without adjustment during bpf_object__load(). The program has only
+ * one instance. In this case bpf_program__fd(prog) is equal to
+ * bpf_program__nth_fd(prog, 0).
+ */
+
+struct bpf_prog_prep_result {
+ /*
+ * If not NULL, load new instruction array.
+ * If set to NULL, don't load this instance.
+ */
+ struct bpf_insn *new_insn_ptr;
+ int new_insn_cnt;
+
+ /* If not NULL, result fd is set to it */
+ int *pfd;
+};
+
+/*
+ * Parameters of bpf_program_prep_t:
+ * - prog: The bpf_program being loaded.
+ * - n: Index of instance being generated.
+ * - insns: BPF instructions array.
+ * - insns_cnt:Number of instructions in insns.
+ * - res: Output parameter, result of transformation.
+ *
+ * Return value:
+ * - Zero: pre-processing success.
+ * - Non-zero: pre-processing, stop loading.
+ */
+typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
+ struct bpf_insn *insns, int insns_cnt,
+ struct bpf_prog_prep_result *res);
+
+int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
+ bpf_program_prep_t prep);
+
+int bpf_program__nth_fd(struct bpf_program *prog, int n);
+
/*
* We don't need __attribute__((packed)) now since it is
* unnecessary for 'bpf_map_def' because they are all aligned.
@@ -101,4 +165,28 @@ struct bpf_map_def {
unsigned int max_entries;
};
+/*
+ * There is another 'struct bpf_map' in include/linux/map.h. However,
+ * it is not a uapi header so no need to consider name clash.
+ */
+struct bpf_map;
+struct bpf_map *
+bpf_object__get_map_by_name(struct bpf_object *obj, const char *name);
+
+struct bpf_map *
+bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
+#define bpf_map__for_each(pos, obj) \
+ for ((pos) = bpf_map__next(NULL, (obj)); \
+ (pos) != NULL; \
+ (pos) = bpf_map__next((pos), (obj)))
+
+int bpf_map__get_fd(struct bpf_map *map);
+int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef);
+const char *bpf_map__get_name(struct bpf_map *map);
+
+typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
+int bpf_map__set_private(struct bpf_map *map, void *priv,
+ bpf_map_clear_priv_t clear_priv);
+int bpf_map__get_private(struct bpf_map *map, void **ppriv);
+
#endif