From: Alexei Starovoitov <ast@xxxxxxxxxx>
Add -L flag to bpftool to use libbpf gen_trace facility and syscall/loader program
for skeleton generation and program loading.
"bpftool gen skeleton -L" command will generate a "light skeleton" or "loader skeleton"
that is similar to existing skeleton, but has one major difference:
$ bpftool gen skeleton lsm.o > lsm.skel.h
$ bpftool gen skeleton -L lsm.o > lsm.lskel.h
$ diff lsm.skel.h lsm.lskel.h
@@ -5,34 +4,34 @@
#define __LSM_SKEL_H__
#include <stdlib.h>
-#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
The light skeleton does not use majority of libbpf infrastructure.
It doesn't need libelf. It doesn't parse .o file.
It only needs few sys_bpf wrappers. All of them are in bpf/bpf.h file.
In future libbpf/bpf.c can be inlined into bpf.h, so not even libbpf.a would be
needed to work with light skeleton.
"bpftool prog load -L file.o" command is introduced for debugging of syscall/loader
program generation. Just like the same command without -L it will try to load
the programs from file.o into the kernel. It won't even try to pin them.
"bpftool prog load -L -d file.o" command will provide additional debug messages
on how syscall/loader program was generated.
Also the execution of syscall/loader program will use bpf_trace_printk() for
each step of loading BTF, creating maps, and loading programs.
The user can do "cat /.../trace_pipe" for further debug.
An example of fexit_sleep.lskel.h generated from progs/fexit_sleep.c:
struct fexit_sleep {
struct bpf_loader_ctx ctx;
struct {
struct bpf_map_desc bss;
} maps;
struct {
struct bpf_prog_desc nanosleep_fentry;
struct bpf_prog_desc nanosleep_fexit;
} progs;
struct {
int nanosleep_fentry_fd;
int nanosleep_fexit_fd;
} links;
struct fexit_sleep__bss {
int pid;
int fentry_cnt;
int fexit_cnt;
} *bss;
};
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
tools/bpf/bpftool/Makefile | 2 +-
tools/bpf/bpftool/gen.c | 330 ++++++++++++++++++++++++++++--
tools/bpf/bpftool/main.c | 7 +-
tools/bpf/bpftool/main.h | 1 +
tools/bpf/bpftool/prog.c | 81 ++++++++
tools/bpf/bpftool/xlated_dumper.c | 3 +
6 files changed, 401 insertions(+), 23 deletions(-)
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index b3073ae84018..d16d289ade7a 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -136,7 +136,7 @@ endif
BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
-BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o)
+BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o xlated_dumper.o btf_dumper.o) $(OUTPUT)disasm.o
OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 31ade77f5ef8..7dd7f0b72a15 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -18,6 +18,7 @@
#include <sys/stat.h>
#include <sys/mman.h>
#include <bpf/btf.h>
+#include <bpf/bpf_gen_internal.h>
#include "json_writer.h"
#include "main.h"
@@ -268,6 +269,271 @@ static void codegen(const char *template, ...)
free(s);
}
+static void print_hex(const char *obj_data, int file_sz)
+{
+ int i, len;
+
+ for (i = 0, len = 0; i < file_sz; i++) {
+ int w = obj_data[i] ? 4 : 2;
+
+ len += w;
+ if (len > 78) {
+ printf("\\\n");
+ len = w;
+ }
+ if (!obj_data[i])
+ printf("\\0");
+ else
+ printf("\\x%02x", (unsigned char)obj_data[i]);
+ }
+}
+
+static size_t bpf_map_mmap_sz(const struct bpf_map *map)
+{
+ long page_sz = sysconf(_SC_PAGE_SIZE);
+ size_t map_sz;
+
+ map_sz = (size_t)roundup(bpf_map__value_size(map), 8) * bpf_map__max_entries(map);
+ map_sz = roundup(map_sz, page_sz);
+ return map_sz;
+}
+
+static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name)
+{
+ struct bpf_program *prog;
+
+ bpf_object__for_each_program(prog, obj) {
+ codegen("\
+ \n\
+ \n\
+ static inline int \n\
+ %1$s__%2$s__attach(struct %1$s *skel) \n\
+ { \n\
+ int fd = bpf_raw_tracepoint_open( \
+ ", obj_name, bpf_program__name(prog));
+
+ switch (bpf_program__get_type(prog)) {
+ case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ putchar('"');
+ fputs(strchr(bpf_program__section_name(prog), '/') + 1, stdout);
+ putchar('"');
+ break;
+ default:
+ fputs("NULL", stdout);
+ break;
+ }
+ codegen("\
+ \n\
+ , skel->progs.%1$s.prog_fd); \n\
+ if (fd > 0) skel->links.%1$s_fd = fd; \n\
+ return fd; \n\
+ } \n\
+ ", bpf_program__name(prog));
+ }
+
+ codegen("\
+ \n\
+ \n\
+ static inline int \n\
+ %1$s__attach(struct %1$s *skel) \n\
+ { \n\
+ int ret = 0; \n\
+ ", obj_name);
+
+ bpf_object__for_each_program(prog, obj) {
+ codegen("\
+ \n\
+ ret = ret < 0 ? ret : %1$s__%2$s__attach(skel); \n\
+ ", obj_name, bpf_program__name(prog));
+ }
+
+ codegen("\
+ \n\
+ return ret < 0 ? ret : 0; \n\
+ } \n\
+ \n\
+ static inline void \n\
+ %1$s__detach(struct %1$s *skel) \n\
+ { \n\
+ ", obj_name);
+ bpf_object__for_each_program(prog, obj) {
+ printf("\tif (skel->links.%1$s_fd > 0) close(skel->links.%1$s_fd);\n",
+ bpf_program__name(prog));
+ }
+ codegen("\
+ \n\
+ } \n\
+ ");
+}
+
+static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
+{
+ struct bpf_program *prog;
+ struct bpf_map *map;
+
+ codegen("\
+ \n\
+ static void \n\
+ %1$s__destroy(struct %1$s *skel) \n\
+ { \n\
+ if (!skel) \n\
+ return; \n\
+ %1$s__detach(skel); \n\
+ ",
+ obj_name);
+ bpf_object__for_each_program(prog, obj) {
+ printf("\tif (skel->progs.%1$s.prog_fd > 0) close(skel->progs.%1$s.prog_fd);\n",
+ bpf_program__name(prog));
+ }
+ bpf_object__for_each_map(map, obj) {
+ const char * ident;
+
+ ident = get_map_ident(map);
+ if (!ident)
+ continue;
+ if (bpf_map__is_internal(map) &&
+ (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
+ printf("\tmunmap(skel->%1$s, %2$zd);\n",
+ ident, bpf_map_mmap_sz(map));
+ printf("\tif (skel->maps.%1$s.map_fd > 0) close(skel->maps.%1$s.map_fd);\n", ident);
+ }
+ codegen("\
+ \n\
+ free(skel); \n\
+ } \n\
+ ",
+ obj_name);
+}
+
+static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard)
+{
+ struct bpf_object_load_attr load_attr = {};
+ DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
+ struct bpf_map *map;
+ int err = 0;
+
+ err = bpf_object__gen_loader(obj, &opts);
+ if (err)
+ return err;
+
+ load_attr.obj = obj;
+ if (verifier_logs)
+ /* log_level1 + log_level2 + stats, but not stable UAPI */
+ load_attr.log_level = 1 + 2 + 4;
+
+ err = bpf_object__load_xattr(&load_attr);
+ if (err) {
+ p_err("failed to load object file");
+ goto out;
+ }
+ /* If there was no error during load then gen_loader_opts
+ * are populated with the loader program.
+ */
+
+ /* finish generating 'struct skel' */
+ codegen("\
+ \n\
+ }; \n\
+ ", obj_name);
+
+
+ codegen_attach_detach(obj, obj_name);
+
+ codegen_destroy(obj, obj_name);
+
+ codegen("\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open(void) \n\
+ { \n\
+ struct %1$s *skel; \n\
+ \n\
+ skel = calloc(sizeof(*skel), 1); \n\
+ if (!skel) \n\
+ return NULL; \n\
+ skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
+ return skel; \n\
+ } \n\
+ \n\
+ static inline int \n\
+ %1$s__load(struct %1$s *skel) \n\
+ { \n\
+ struct bpf_load_and_run_opts opts = {}; \n\
+ int err; \n\
+ \n\
+ opts.ctx = (struct bpf_loader_ctx *)skel; \n\
+ opts.data_sz = %2$d; \n\
+ opts.data = (void *)\"\\ \n\
+ ",
+ obj_name, opts.data_sz);
+ print_hex(opts.data, opts.data_sz);
+ codegen("\
+ \n\
+ \"; \n\
+ ");
+
+ codegen("\
+ \n\
+ opts.insns_sz = %d; \n\
+ opts.insns = (void *)\"\\ \n\
+ ",
+ opts.insns_sz);
+ print_hex(opts.insns, opts.insns_sz);
+ codegen("\
+ \n\
+ \"; \n\
+ err = bpf_load_and_run(&opts); \n\
+ if (err < 0) \n\
+ return err; \n\
+ ", obj_name);
+ bpf_object__for_each_map(map, obj) {
+ const char * ident;
+
+ ident = get_map_ident(map);
+ if (!ident)
+ continue;
+
+ if (!bpf_map__is_internal(map) ||
+ !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
+ continue;
+
+ printf("\tskel->%1$s =\n"
+ "\t\tmmap(NULL, %2$zd, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED,\n"
+ "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
+ ident, bpf_map_mmap_sz(map));
+ }
+ codegen("\
+ \n\
+ return 0; \n\
+ } \n\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open_and_load(void) \n\
+ { \n\
+ struct %1$s *skel; \n\
+ \n\
+ skel = %1$s__open(); \n\
+ if (!skel) \n\
+ return NULL; \n\
+ if (%1$s__load(skel)) { \n\
+ %1$s__destroy(skel); \n\
+ return NULL; \n\
+ } \n\
+ return skel; \n\
+ } \n\
+ ", obj_name);
+
+ codegen("\
+ \n\
+ \n\
+ #endif /* %s */ \n\
+ ",
+ header_guard);
+ err = 0;
+out:
+ return err;
+}
+
static int do_skeleton(int argc, char **argv)
{
char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
@@ -277,7 +543,7 @@ static int do_skeleton(int argc, char **argv)
struct bpf_object *obj = NULL;
const char *file, *ident;
struct bpf_program *prog;
- int fd, len, err = -1;
+ int fd, err = -1;
struct bpf_map *map;
struct btf *btf;
struct stat st;
@@ -359,7 +625,25 @@ static int do_skeleton(int argc, char **argv)
}
get_header_guard(header_guard, obj_name);
- codegen("\
+ if (use_loader) {
+ codegen("\
+ \n\
+ /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
+ /* THIS FILE IS AUTOGENERATED! */ \n\
+ #ifndef %2$s \n\
+ #define %2$s \n\
+ \n\
+ #include <stdlib.h> \n\
+ #include <bpf/bpf.h> \n\
+ #include <bpf/skel_internal.h> \n\
+ \n\
+ struct %1$s { \n\
+ struct bpf_loader_ctx ctx; \n\
+ ",
+ obj_name, header_guard
+ );
+ } else {
+ codegen("\
\n\
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
\n\
@@ -375,7 +659,8 @@ static int do_skeleton(int argc, char **argv)
struct bpf_object *obj; \n\
",
obj_name, header_guard
- );
+ );
+ }
if (map_cnt) {
printf("\tstruct {\n");
@@ -383,7 +668,10 @@ static int do_skeleton(int argc, char **argv)
ident = get_map_ident(map);
if (!ident)
continue;
- printf("\t\tstruct bpf_map *%s;\n", ident);
+ if (use_loader)
+ printf("\t\tstruct bpf_map_desc %s;\n", ident);
+ else
+ printf("\t\tstruct bpf_map *%s;\n", ident);
}
printf("\t} maps;\n");
}
@@ -391,14 +679,22 @@ static int do_skeleton(int argc, char **argv)
if (prog_cnt) {
printf("\tstruct {\n");
bpf_object__for_each_program(prog, obj) {
- printf("\t\tstruct bpf_program *%s;\n",
- bpf_program__name(prog));
+ if (use_loader)
+ printf("\t\tstruct bpf_prog_desc %s;\n",
+ bpf_program__name(prog));
+ else
+ printf("\t\tstruct bpf_program *%s;\n",
+ bpf_program__name(prog));
}
printf("\t} progs;\n");
printf("\tstruct {\n");
bpf_object__for_each_program(prog, obj) {
- printf("\t\tstruct bpf_link *%s;\n",
- bpf_program__name(prog));
+ if (use_loader)
+ printf("\t\tint %s_fd;\n",
+ bpf_program__name(prog));
+ else
+ printf("\t\tstruct bpf_link *%s;\n",
+ bpf_program__name(prog));
}
printf("\t} links;\n");
}
@@ -409,6 +705,10 @@ static int do_skeleton(int argc, char **argv)
if (err)
goto out;
}
+ if (use_loader) {
+ err = gen_trace(obj, obj_name, header_guard);
+ goto out;
+ }
codegen("\
\n\
@@ -578,19 +878,7 @@ static int do_skeleton(int argc, char **argv)
file_sz);
/* embed contents of BPF object file */
- for (i = 0, len = 0; i < file_sz; i++) {
- int w = obj_data[i] ? 4 : 2;
-
- len += w;
- if (len > 78) {
- printf("\\\n");
- len = w;
- }
- if (!obj_data[i])
- printf("\\0");
- else
- printf("\\x%02x", (unsigned char)obj_data[i]);
- }
+ print_hex(obj_data, file_sz);
codegen("\
\n\
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index d9afb730136a..7f2817d97079 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -29,6 +29,7 @@ bool show_pinned;
bool block_mount;
bool verifier_logs;
bool relaxed_maps;
+bool use_loader;
struct btf *base_btf;
struct pinned_obj_table prog_table;
struct pinned_obj_table map_table;
@@ -392,6 +393,7 @@ int main(int argc, char **argv)
{ "mapcompat", no_argument, NULL, 'm' },
{ "nomount", no_argument, NULL, 'n' },
{ "debug", no_argument, NULL, 'd' },
+ { "use-loader", no_argument, NULL, 'L' },
{ "base-btf", required_argument, NULL, 'B' },
{ 0 }
};
@@ -409,7 +411,7 @@ int main(int argc, char **argv)
hash_init(link_table.table);
opterr = 0;
- while ((opt = getopt_long(argc, argv, "VhpjfmndB:",
+ while ((opt = getopt_long(argc, argv, "VhpjfLmndB:",
options, NULL)) >= 0) {
switch (opt) {
case 'V':
@@ -452,6 +454,9 @@ int main(int argc, char **argv)
return -1;
}
break;
+ case 'L':
+ use_loader = true;
+ break;
default:
p_err("unrecognized option '%s'", argv[optind - 1]);
if (json_output)
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 76e91641262b..c1cf29798b99 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -90,6 +90,7 @@ extern bool show_pids;
extern bool block_mount;
extern bool verifier_logs;
extern bool relaxed_maps;
+extern bool use_loader;
extern struct btf *base_btf;
extern struct pinned_obj_table prog_table;
extern struct pinned_obj_table map_table;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 3f067d2d7584..fd1234d4c63d 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -24,6 +24,8 @@
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
+#include <bpf/bpf_gen_internal.h>
+#include <bpf/skel_internal.h>
#include "cfg.h"
#include "main.h"
@@ -1645,8 +1647,87 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
return -1;
}
+static int try_loader(struct gen_loader_opts *gen)
+{
+ struct bpf_load_and_run_opts opts = {};
+ struct bpf_loader_ctx *ctx;
+ int ctx_sz = sizeof(*ctx) + 64 * max(sizeof(struct bpf_map_desc), sizeof(struct bpf_prog_desc));
+ int log_buf_sz = (1u << 24) - 1;
+ char *log_buf;
+ int err;
+
+ ctx = alloca(ctx_sz);
+ memset(ctx, 0, ctx_sz);
+ ctx->sz = ctx_sz;
+ ctx->log_level = 1;
+ ctx->log_size = log_buf_sz;
+ log_buf = malloc(log_buf_sz);
+ if (!log_buf)
+ return -ENOMEM;
+ ctx->log_buf = (long) log_buf;
+ opts.ctx = ctx;
+ opts.data = gen->data;
+ opts.data_sz = gen->data_sz;
+ opts.insns = gen->insns;
+ opts.insns_sz = gen->insns_sz;
+ err = bpf_load_and_run(&opts);
+ if (err < 0)
+ fprintf(stderr, "err %d\n%s\n%s", err, opts.errstr, log_buf);
+ free(log_buf);
+ return err;
+}
+
+static int do_loader(int argc, char **argv)
+{
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts);
+ DECLARE_LIBBPF_OPTS(gen_loader_opts, gen);
+ struct bpf_object_load_attr load_attr = {};
+ struct bpf_object *obj;
+ const char *file;
+ int err = 0;
+
+ if (!REQ_ARGS(1))
+ return -1;
+ file = GET_ARG();
+
+ obj = bpf_object__open_file(file, &open_opts);
+ if (IS_ERR_OR_NULL(obj)) {
+ p_err("failed to open object file");
+ goto err_close_obj;
+ }
+
+ err = bpf_object__gen_loader(obj, &gen);
+ if (err)
+ goto err_close_obj;
+
+ load_attr.obj = obj;
+ if (verifier_logs)
+ /* log_level1 + log_level2 + stats, but not stable UAPI */
+ load_attr.log_level = 1 + 2 + 4;
+
+ err = bpf_object__load_xattr(&load_attr);
+ if (err) {
+ p_err("failed to load object file");
+ goto err_close_obj;
+ }
+
+ if (verifier_logs) {
+ struct dump_data dd = {};
+
+ kernel_syms_load(&dd);
+ dump_xlated_plain(&dd, (void *)gen.insns, gen.insns_sz, false, false);
+ kernel_syms_destroy(&dd);
+ }
+ err = try_loader(&gen);
+err_close_obj:
+ bpf_object__close(obj);
+ return err;
+}
+
static int do_load(int argc, char **argv)
{
+ if (use_loader)
+ return do_loader(argc, argv);
return load_with_options(argc, argv, true);
}
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 6fc3e6f7f40c..f1f32e21d5cd 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -196,6 +196,9 @@ static const char *print_imm(void *private_data,
else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
"map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
+ else if (insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE)
+ snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
+ "map[idx:%u]+%u", insn->imm, (insn + 1)->imm);
else if (insn->src_reg == BPF_PSEUDO_FUNC)
snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
"subprog[%+d]", insn->imm);
--
2.30.2
