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Message-ID: <20190611043505.14664-4-andriin@fb.com>
Date: Mon, 10 Jun 2019 21:35:00 -0700
From: Andrii Nakryiko <andriin@...com>
To: <andrii.nakryiko@...il.com>, <bpf@...r.kernel.org>,
<netdev@...r.kernel.org>, <ast@...com>, <daniel@...earbox.net>,
<kernel-team@...com>
CC: Andrii Nakryiko <andriin@...com>
Subject: [RFC PATCH bpf-next 3/8] libbpf: refactor map initialization
User and global data maps initialization has gotten pretty complicated
and unnecessarily convoluted. This patch splits out the logic for global
data map and user-defined map initialization. It also removes the
restriction of pre-calculating how many maps will be initialized,
instead allowing to keep adding new maps as they are discovered, which
will be used later for BTF-defined map definitions.
Signed-off-by: Andrii Nakryiko <andriin@...com>
---
tools/lib/bpf/libbpf.c | 244 ++++++++++++++++++++++-------------------
1 file changed, 134 insertions(+), 110 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9e39a0a33aeb..c931ee7e1fd2 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -234,6 +234,7 @@ struct bpf_object {
size_t nr_programs;
struct bpf_map *maps;
size_t nr_maps;
+ size_t maps_cap;
struct bpf_secdata sections;
bool loaded;
@@ -763,12 +764,38 @@ int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
return -ENOENT;
}
-static bool bpf_object__has_maps(const struct bpf_object *obj)
+static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
{
- return obj->efile.maps_shndx >= 0 ||
- obj->efile.data_shndx >= 0 ||
- obj->efile.rodata_shndx >= 0 ||
- obj->efile.bss_shndx >= 0;
+ struct bpf_map *new_maps;
+ size_t new_cap;
+ int i;
+
+ if (obj->nr_maps + 1 <= obj->maps_cap)
+ return &obj->maps[obj->nr_maps++];
+
+ new_cap = max(4ul, obj->maps_cap * 3 / 2);
+ new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
+ if (!new_maps) {
+ pr_warning("alloc maps for object failed\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ obj->maps_cap = new_cap;
+ obj->maps = new_maps;
+
+ /* zero out new maps */
+ memset(obj->maps + obj->nr_maps, 0,
+ (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
+ /*
+ * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
+ * when failure (zclose won't close negative fd)).
+ */
+ for (i = obj->nr_maps; i < obj->maps_cap; i++) {
+ obj->maps[i].fd = -1;
+ obj->maps[i].inner_map_fd = -1;
+ }
+
+ return &obj->maps[obj->nr_maps++];
}
static int
@@ -808,29 +835,68 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map,
return 0;
}
-static int bpf_object__init_maps(struct bpf_object *obj, int flags)
+static int bpf_object__init_global_data_maps(struct bpf_object *obj)
+{
+ struct bpf_map *map;
+ int err;
+
+ if (!obj->caps.global_data)
+ return 0;
+ /*
+ * Populate obj->maps with libbpf internal maps.
+ */
+ if (obj->efile.data_shndx >= 0) {
+ map = bpf_object__add_map(obj);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+ err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_DATA,
+ obj->efile.data,
+ &obj->sections.data);
+ if (err)
+ return err;
+ }
+ if (obj->efile.rodata_shndx >= 0) {
+ map = bpf_object__add_map(obj);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+ err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_RODATA,
+ obj->efile.rodata,
+ &obj->sections.rodata);
+ if (err)
+ return err;
+ }
+ if (obj->efile.bss_shndx >= 0) {
+ map = bpf_object__add_map(obj);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+ err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_BSS,
+ obj->efile.bss, NULL);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
{
- int i, map_idx, map_def_sz = 0, nr_syms, nr_maps = 0, nr_maps_glob = 0;
- bool strict = !(flags & MAPS_RELAX_COMPAT);
Elf_Data *symbols = obj->efile.symbols;
+ int i, map_def_sz = 0, nr_maps = 0, nr_syms;
Elf_Data *data = NULL;
- int ret = 0;
+ Elf_Scn *scn;
+
+ if (obj->efile.maps_shndx < 0)
+ return 0;
if (!symbols)
return -EINVAL;
- nr_syms = symbols->d_size / sizeof(GElf_Sym);
-
- if (obj->efile.maps_shndx >= 0) {
- Elf_Scn *scn = elf_getscn(obj->efile.elf,
- obj->efile.maps_shndx);
- if (scn)
- data = elf_getdata(scn, NULL);
- if (!scn || !data) {
- pr_warning("failed to get Elf_Data from map section %d\n",
- obj->efile.maps_shndx);
- return -EINVAL;
- }
+ scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
+ if (scn)
+ data = elf_getdata(scn, NULL);
+ if (!scn || !data) {
+ pr_warning("failed to get Elf_Data from map section %d\n",
+ obj->efile.maps_shndx);
+ return -EINVAL;
}
/*
@@ -840,16 +906,8 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
*
* TODO: Detect array of map and report error.
*/
- if (obj->caps.global_data) {
- if (obj->efile.data_shndx >= 0)
- nr_maps_glob++;
- if (obj->efile.rodata_shndx >= 0)
- nr_maps_glob++;
- if (obj->efile.bss_shndx >= 0)
- nr_maps_glob++;
- }
-
- for (i = 0; data && i < nr_syms; i++) {
+ nr_syms = symbols->d_size / sizeof(GElf_Sym);
+ for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, i, &sym))
@@ -858,79 +916,56 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
continue;
nr_maps++;
}
-
- if (!nr_maps && !nr_maps_glob)
- return 0;
-
/* Assume equally sized map definitions */
- if (data) {
- pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
- nr_maps, data->d_size);
-
- map_def_sz = data->d_size / nr_maps;
- if (!data->d_size || (data->d_size % nr_maps) != 0) {
- pr_warning("unable to determine map definition size "
- "section %s, %d maps in %zd bytes\n",
- obj->path, nr_maps, data->d_size);
- return -EINVAL;
- }
- }
-
- nr_maps += nr_maps_glob;
- 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;
-
- for (i = 0; i < nr_maps; i++) {
- /*
- * 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;
- obj->maps[i].inner_map_fd = -1;
+ pr_debug("maps in %s: %d maps in %zd bytes\n",
+ obj->path, nr_maps, data->d_size);
+
+ map_def_sz = data->d_size / nr_maps;
+ if (!data->d_size || (data->d_size % nr_maps) != 0) {
+ pr_warning("unable to determine map definition size "
+ "section %s, %d maps in %zd bytes\n",
+ obj->path, nr_maps, data->d_size);
+ return -EINVAL;
}
- /*
- * Fill obj->maps using data in "maps" section.
- */
- for (i = 0, map_idx = 0; data && i < nr_syms; i++) {
+ /* Fill obj->maps using data in "maps" section. */
+ for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
const char *map_name;
struct bpf_map_def *def;
+ struct bpf_map *map;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
- map_name = elf_strptr(obj->efile.elf,
- obj->efile.strtabidx,
+ map = bpf_object__add_map(obj);
+ if (IS_ERR(map))
+ return PTR_ERR(map);
+
+ map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!map_name) {
pr_warning("failed to get map #%d name sym string for obj %s\n",
- map_idx, obj->path);
+ i, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
- obj->maps[map_idx].libbpf_type = LIBBPF_MAP_UNSPEC;
- obj->maps[map_idx].offset = sym.st_value;
+ map->libbpf_type = LIBBPF_MAP_UNSPEC;
+ map->offset = sym.st_value;
if (sym.st_value + map_def_sz > data->d_size) {
pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
obj->path, map_name);
return -EINVAL;
}
- obj->maps[map_idx].name = strdup(map_name);
- if (!obj->maps[map_idx].name) {
+ map->name = strdup(map_name);
+ if (!map->name) {
pr_warning("failed to alloc map name\n");
return -ENOMEM;
}
- pr_debug("map %d is \"%s\"\n", map_idx,
- obj->maps[map_idx].name);
+ pr_debug("map %d is \"%s\"\n", i, map->name);
def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
/*
* If the definition of the map in the object file fits in
@@ -939,7 +974,7 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
* calloc above.
*/
if (map_def_sz <= sizeof(struct bpf_map_def)) {
- memcpy(&obj->maps[map_idx].def, def, map_def_sz);
+ memcpy(&map->def, def, map_def_sz);
} else {
/*
* Here the map structure being read is bigger than what
@@ -959,37 +994,30 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
return -EINVAL;
}
}
- memcpy(&obj->maps[map_idx].def, def,
- sizeof(struct bpf_map_def));
+ memcpy(&map->def, def, sizeof(struct bpf_map_def));
}
- map_idx++;
}
+ return 0;
+}
- if (!obj->caps.global_data)
- goto finalize;
+static int bpf_object__init_maps(struct bpf_object *obj, int flags)
+{
+ bool strict = !(flags & MAPS_RELAX_COMPAT);
+ int err;
- /*
- * Populate rest of obj->maps with libbpf internal maps.
- */
- if (obj->efile.data_shndx >= 0)
- ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
- LIBBPF_MAP_DATA,
- obj->efile.data,
- &obj->sections.data);
- if (!ret && obj->efile.rodata_shndx >= 0)
- ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
- LIBBPF_MAP_RODATA,
- obj->efile.rodata,
- &obj->sections.rodata);
- if (!ret && obj->efile.bss_shndx >= 0)
- ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
- LIBBPF_MAP_BSS,
- obj->efile.bss, NULL);
-finalize:
- if (!ret)
+ err = bpf_object__init_user_maps(obj, strict);
+ if (err)
+ return err;
+
+ err = bpf_object__init_global_data_maps(obj);
+ if (err)
+ return err;
+
+ if (obj->nr_maps) {
qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
compare_bpf_map);
- return ret;
+ }
+ return 0;
}
static bool section_have_execinstr(struct bpf_object *obj, int idx)
@@ -1262,14 +1290,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
return -LIBBPF_ERRNO__FORMAT;
}
err = bpf_object__load_btf(obj, btf_data, btf_ext_data);
- if (err)
- return err;
- if (bpf_object__has_maps(obj)) {
+ if (!err)
err = bpf_object__init_maps(obj, flags);
- if (err)
- return err;
- }
- err = bpf_object__init_prog_names(obj);
+ if (!err)
+ err = bpf_object__init_prog_names(obj);
return err;
}
--
2.17.1
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