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bpftool: Support multiple .rodata/.data internal maps in skeleton
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Remove the assumption about only single instance of each of .rodata and
.data internal maps. Nothing changes for '.rodata' and '.data' maps, but new
'.rodata.something' map will get 'rodata_something' section in BPF
skeleton for them (as well as having struct bpf_map * field in maps
section with the same field name).

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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@anakryiko
anakryiko authored and Alexei Starovoitov committed Oct 22, 2021
1 parent 25bbbd7 commit 8654b4d
Showing 1 changed file with 60 additions and 47 deletions.
107 changes: 60 additions & 47 deletions tools/bpf/bpftool/gen.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,11 @@ static void sanitize_identifier(char *name)
name[i] = '_';
}

static bool str_has_prefix(const char *str, const char *prefix)
{
return strncmp(str, prefix, strlen(prefix)) == 0;
}

static bool str_has_suffix(const char *str, const char *suffix)
{
size_t i, n1 = strlen(str), n2 = strlen(suffix);
Expand Down Expand Up @@ -67,23 +72,47 @@ static void get_header_guard(char *guard, const char *obj_name)
guard[i] = toupper(guard[i]);
}

static const char *get_map_ident(const struct bpf_map *map)
static bool get_map_ident(const struct bpf_map *map, char *buf, size_t buf_sz)
{
static const char *sfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
const char *name = bpf_map__name(map);
int i, n;

if (!bpf_map__is_internal(map)) {
snprintf(buf, buf_sz, "%s", name);
return true;
}

for (i = 0, n = ARRAY_SIZE(sfxs); i < n; i++) {
const char *sfx = sfxs[i], *p;

p = strstr(name, sfx);
if (p) {
snprintf(buf, buf_sz, "%s", p + 1);
sanitize_identifier(buf);
return true;
}
}

if (!bpf_map__is_internal(map))
return name;

if (str_has_suffix(name, ".data"))
return "data";
else if (str_has_suffix(name, ".rodata"))
return "rodata";
else if (str_has_suffix(name, ".bss"))
return "bss";
else if (str_has_suffix(name, ".kconfig"))
return "kconfig";
else
return NULL;
return false;
}

static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz)
{
static const char *pfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
int i, n;

for (i = 0, n = ARRAY_SIZE(pfxs); i < n; i++) {
const char *pfx = pfxs[i];

if (str_has_prefix(sec_name, pfx)) {
snprintf(buf, buf_sz, "%s", sec_name + 1);
sanitize_identifier(buf);
return true;
}
}

return false;
}

static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
Expand All @@ -100,24 +129,14 @@ static int codegen_datasec_def(struct bpf_object *obj,
const char *sec_name = btf__name_by_offset(btf, sec->name_off);
const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
const char *sec_ident;
char var_ident[256];
char var_ident[256], sec_ident[256];
bool strip_mods = false;

if (strcmp(sec_name, ".data") == 0) {
sec_ident = "data";
strip_mods = true;
} else if (strcmp(sec_name, ".bss") == 0) {
sec_ident = "bss";
strip_mods = true;
} else if (strcmp(sec_name, ".rodata") == 0) {
sec_ident = "rodata";
strip_mods = true;
} else if (strcmp(sec_name, ".kconfig") == 0) {
sec_ident = "kconfig";
} else {
if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident)))
return 0;
}

if (strcmp(sec_name, ".kconfig") != 0)
strip_mods = true;

printf(" struct %s__%s {\n", obj_name, sec_ident);
for (i = 0; i < vlen; i++, sec_var++) {
Expand Down Expand Up @@ -385,6 +404,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
{
struct bpf_program *prog;
struct bpf_map *map;
char ident[256];

codegen("\
\n\
Expand All @@ -405,10 +425,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
}

bpf_object__for_each_map(map, obj) {
const char *ident;

ident = get_map_ident(map);
if (!ident)
if (!get_map_ident(map, ident, sizeof(ident)))
continue;
if (bpf_map__is_internal(map) &&
(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
Expand All @@ -432,6 +449,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
struct bpf_object_load_attr load_attr = {};
DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
struct bpf_map *map;
char ident[256];
int err = 0;

err = bpf_object__gen_loader(obj, &opts);
Expand Down Expand Up @@ -477,12 +495,10 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
",
obj_name, opts.data_sz);
bpf_object__for_each_map(map, obj) {
const char *ident;
const void *mmap_data = NULL;
size_t mmap_size = 0;

ident = get_map_ident(map);
if (!ident)
if (!get_map_ident(map, ident, sizeof(ident)))
continue;

if (!bpf_map__is_internal(map) ||
Expand Down Expand Up @@ -544,15 +560,15 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
return err; \n\
", obj_name);
bpf_object__for_each_map(map, obj) {
const char *ident, *mmap_flags;
const char *mmap_flags;

ident = get_map_ident(map);
if (!ident)
if (!get_map_ident(map, ident, sizeof(ident)))
continue;

if (!bpf_map__is_internal(map) ||
!(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
continue;

if (bpf_map__def(map)->map_flags & BPF_F_RDONLY_PROG)
mmap_flags = "PROT_READ";
else
Expand Down Expand Up @@ -602,7 +618,8 @@ static int do_skeleton(int argc, char **argv)
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
struct bpf_object *obj = NULL;
const char *file, *ident;
const char *file;
char ident[256];
struct bpf_program *prog;
int fd, err = -1;
struct bpf_map *map;
Expand Down Expand Up @@ -673,8 +690,7 @@ static int do_skeleton(int argc, char **argv)
}

bpf_object__for_each_map(map, obj) {
ident = get_map_ident(map);
if (!ident) {
if (!get_map_ident(map, ident, sizeof(ident))) {
p_err("ignoring unrecognized internal map '%s'...",
bpf_map__name(map));
continue;
Expand Down Expand Up @@ -727,8 +743,7 @@ static int do_skeleton(int argc, char **argv)
if (map_cnt) {
printf("\tstruct {\n");
bpf_object__for_each_map(map, obj) {
ident = get_map_ident(map);
if (!ident)
if (!get_map_ident(map, ident, sizeof(ident)))
continue;
if (use_loader)
printf("\t\tstruct bpf_map_desc %s;\n", ident);
Expand Down Expand Up @@ -897,9 +912,7 @@ static int do_skeleton(int argc, char **argv)
);
i = 0;
bpf_object__for_each_map(map, obj) {
ident = get_map_ident(map);

if (!ident)
if (!get_map_ident(map, ident, sizeof(ident)))
continue;

codegen("\
Expand Down

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