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bpftool: make libbfd optional

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Make it possible to build bpftool without libbfd. libbfd and libopcodes are
typically provided in dev/dbg packages (binutils-dev in debian) which we
usually don't have installed on the fleet machines and we'd like a way to have
bpftool version that works without installing any additional packages.
This excludes support for disassembling jit-ted code and prints an error if
the user tries to use these features.

Tested by:
cat > FEATURES_DUMP.bpftool <<EOF
feature-libbfd=0
feature-disassembler-four-args=1
feature-reallocarray=0
feature-libelf=1
feature-libelf-mmap=1
feature-bpf=1
EOF
FEATURES_DUMP=$PWD/FEATURES_DUMP.bpftool make
ldd bpftool | grep libbfd

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Stanislav Fomichev 2018-11-12 13:44:10 -08:00 committed by Alexei Starovoitov
parent ae9435f696
commit 29a9c10e41
5 changed files with 35 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

13
tools/bpf/bpftool/Makefile
View file

@ -53,7 +53,7 @@ ifneq ($(EXTRA_LDFLAGS),)
LDFLAGS += $(EXTRA_LDFLAGS)
endif
LIBS = -lelf -lbfd -lopcodes $(LIBBPF)
LIBS = -lelf $(LIBBPF)
INSTALL ?= install
RM ?= rm -f
@ -90,7 +90,16 @@ include $(wildcard $(OUTPUT)*.d)
all: $(OUTPUT)bpftool
SRCS = $(wildcard *.c)
BFD_SRCS = jit_disasm.c
SRCS = $(filter-out $(BFD_SRCS),$(wildcard *.c))
ifeq ($(feature-libbfd),1)
CFLAGS += -DHAVE_LIBBFD_SUPPORT
SRCS += $(BFD_SRCS)
LIBS += -lbfd -lopcodes
endif
OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
$(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c

8
tools/bpf/bpftool/jit_disasm.c
View file

@ -109,7 +109,7 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
if (inf) {
bfdf->arch_info = inf;
} else {
p_err("No libfd support for %s", arch);
p_err("No libbfd support for %s", arch);
return;
}
}
@ -183,3 +183,9 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
bfd_close(bfdf);
}
int disasm_init(void)
{
bfd_init();
return 0;
}

3
tools/bpf/bpftool/main.c
View file

@ -31,7 +31,6 @@
* SOFTWARE.
*/
#include <bfd.h>
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
@ -399,8 +398,6 @@ int main(int argc, char **argv)
if (argc < 0)
usage();
bfd_init();
ret = cmd_select(cmds, argc, argv, do_help);
if (json_output)

14
tools/bpf/bpftool/main.h
View file

@ -147,8 +147,22 @@ int prog_parse_fd(int *argc, char ***argv);
int map_parse_fd(int *argc, char ***argv);
int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len);
#ifdef HAVE_LIBBFD_SUPPORT
void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch, const char *disassembler_options);
int disasm_init(void);
#else
static inline
void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch, const char *disassembler_options)
{
}
static inline int disasm_init(void)
{
p_err("No libbfd support");
return -1;
}
#endif
void print_data_json(uint8_t *data, size_t len);
void print_hex_data_json(uint8_t *data, size_t len);

3
tools/bpf/bpftool/prog.c
View file

@ -467,6 +467,9 @@ static int do_dump(int argc, char **argv)
int fd;
if (is_prefix(*argv, "jited")) {
if (disasm_init())
return -1;
member_len = &info.jited_prog_len;
member_ptr = &info.jited_prog_insns;
} else if (is_prefix(*argv, "xlated")) {