backends: Don't depend on linux/bpf.h to compile bpf disassembler.

We only need a few constants and one structure definition from linux/bpf.
Just define those in a local lib/bpf.h file. This makes sure the bpf
disassembler is always build and included even when elfutils is build
on older GNU/Linux systems (and even on other platforms).

Signed-off-by: Mark Wielaard <mark@klomp.org>

15 files changed, 115 insertions, 29 deletions

diff --git a/ChangeLog b/ChangeLog
index c9db732c..b5f7095b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-07-18  Mark Wielaard  <mark@klomp.org>
+
+	* configure.ac: Don't check for linux/bpf.h.
+	* NEWS: Mention always build bpf backend.
+
 2017-07-14  Mark Wielaard  <mark@klomp.org>
 
 	* NEWS: Add 0.170 section and new strip options.
diff --git a/NEWS b/NEWS
index b69aef45..045d579a 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,8 @@ Version 0.170
 
 strip: Add -R, --remove-section=SECTION and --keep-section=SECTION.
 
+backends: The bpf disassembler is now always build on all platforms.
+
 Version 0.169
 
 backends: Add support for EM_PPC64 GNU_ATTRIBUTES.
diff --git a/backends/ChangeLog b/backends/ChangeLog
index 784e6b03..eb7e25f1 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,10 @@
+2017-07-18  Mark Wielaard  <mark@klomp.org>
+
+	* Makefile.am (cpu_bpf): Always define.
+	* bpf_init.c (disasm): Always hook.
+	* bpf_regs.c: Include bpf.h instead of linux/bpf.h. Don't define
+	MAX_BPF_REG.
+
 2017-02-17  Ulf Hermann  <ulf.hermann@qt.io>
 
 	* Makefile.am: Add libeu.
diff --git a/backends/Makefile.am b/backends/Makefile.am
index 996602f2..37dc2d20 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -120,12 +120,7 @@ libebl_m68k_pic_a_SOURCES = $(m68k_SRCS)
 am_libebl_m68k_pic_a_OBJECTS = $(m68k_SRCS:.c=.os)
 
 bpf_SRCS = bpf_init.c bpf_regs.c
-# The disam hook depends on this if we have linux/bpf.h.
-if HAVE_LINUX_BPF_H
 cpu_bpf = ../libcpu/libcpu_bpf.a
-else
-cpu_bpf = 
-endif
 libebl_bpf_pic_a_SOURCES = $(bpf_SRCS)
 am_libebl_bpf_pic_a_OBJECTS = $(bpf_SRCS:.c=.os)
 
diff --git a/backends/bpf_init.c b/backends/bpf_init.c
index 22842e26..8ea1bc1a 100644
--- a/backends/bpf_init.c
+++ b/backends/bpf_init.c
@@ -52,9 +52,7 @@ bpf_init (Elf *elf __attribute__ ((unused)),
   eh->name = "BPF";
   bpf_init_reloc (eh);
   HOOK (eh, register_info);
-#ifdef HAVE_LINUX_BPF_H
   HOOK (eh, disasm);
-#endif
 
   return MODVERSION;
 }
diff --git a/backends/bpf_regs.c b/backends/bpf_regs.c
index 180af83b..1863a164 100644
--- a/backends/bpf_regs.c
+++ b/backends/bpf_regs.c
@@ -32,11 +32,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#ifdef HAVE_LINUX_BPF_H
-#include <linux/bpf.h>
-#else
-#define MAX_BPF_REG 10
-#endif
+#include "bpf.h"
 
 #define BACKEND bpf_
 #include "libebl_CPU.h"
diff --git a/configure.ac b/configure.ac
index c2c1d90b..bb58f4b8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -385,10 +385,6 @@ else
 fi
 AC_SUBST([argp_LDADD])
 
-dnl Check if we have <linux/bpf.h> for EM_BPF disassembly.
-AC_CHECK_HEADERS(linux/bpf.h)
-AM_CONDITIONAL(HAVE_LINUX_BPF_H, [test "x$ac_cv_header_linux_bpf_h" = "xyes"])
-
 dnl The directories with content.
 
 dnl Documentation.
diff --git a/lib/ChangeLog b/lib/ChangeLog
index 1fc1a38c..1f162286 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,8 @@
+2017-07-18  Mark Wielaard  <mark@klomp.org>
+
+	* bpf.h: New file.
+	* Makefile.am (noinst_HEADERS): Add bpf.h
+
 2017-05-05  Mark Wielaard  <mark@klomp.org>
 
 	* printversion.c (print_version): Update copyright year.
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 7a65eb91..ada2030d 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -38,7 +38,7 @@ libeu_a_SOURCES = xstrdup.c xstrndup.c xmalloc.c next_prime.c \
 		  color.c printversion.c
 
 noinst_HEADERS = fixedsizehash.h libeu.h system.h dynamicsizehash.h list.h \
-		 md5.h sha1.h eu-config.h color.h printversion.h
+		 md5.h sha1.h eu-config.h color.h printversion.h bpf.h
 EXTRA_DIST = dynamicsizehash.c
 
 if !GPROF
diff --git a/lib/bpf.h b/lib/bpf.h
new file mode 100644
index 00000000..db80a51e
--- /dev/null
+++ b/lib/bpf.h
@@ -0,0 +1,82 @@
+/* Minimal extended BPF constants as alternative for linux/bpf.h.  */
+
+#ifndef _ELFUTILS_BPF_H
+#define _ELFUTILS_BPF_H 1
+
+#include <stdint.h>
+
+#define BPF_CLASS(code) ((code) & 0x07)
+
+#define BPF_LD    0x00
+#define BPF_LDX   0x01
+#define BPF_ST    0x02
+#define BPF_STX   0x03
+#define BPF_ALU   0x04
+#define BPF_JMP   0x05
+#define BPF_RET   0x06
+#define BPF_MISC  0x07
+
+#define BPF_ALU64 0x07
+
+#define BPF_JNE  0x50
+#define BPF_JSGT 0x60
+#define BPF_JSGE 0x70
+#define BPF_CALL 0x80
+#define BPF_EXIT 0x90
+
+#define BPF_W 0x00
+#define BPF_H 0x08
+#define BPF_B 0x10
+
+#define BPF_IMM 0x00
+#define BPF_ABS 0x20
+#define BPF_IND 0x40
+#define BPF_MEM 0x60
+#define BPF_LEN 0x80
+#define BPF_MSH 0xa0
+
+#define BPF_DW   0x18
+#define BPF_XADD 0xc0
+
+#define BPF_ADD 0x00
+#define BPF_SUB 0x10
+#define BPF_MUL 0x20
+#define BPF_DIV 0x30
+#define BPF_OR  0x40
+#define BPF_AND 0x50
+#define BPF_LSH 0x60
+#define BPF_RSH 0x70
+#define BPF_NEG 0x80
+#define BPF_MOD 0x90
+#define BPF_XOR 0xa0
+
+#define BPF_MOV  0xb0
+#define BPF_ARSH 0xc0
+
+#define BPF_JA   0x00
+#define BPF_JEQ  0x10
+#define BPF_JGT  0x20
+#define BPF_JGE  0x30
+#define BPF_JSET 0x40
+
+#define BPF_K 0x00
+#define BPF_X 0x08
+
+#define BPF_END   0xd0
+#define BPF_TO_LE 0x00
+#define BPF_TO_BE 0x08
+
+#define BPF_PSEUDO_MAP_FD 1
+
+#define MAX_BPF_REG 10
+
+struct bpf_insn
+{
+  uint8_t code;
+  uint8_t dst_reg:4;
+  uint8_t src_reg:4;
+  int16_t off;
+  int32_t imm;
+};
+
+#endif
diff --git a/libcpu/ChangeLog b/libcpu/ChangeLog
index 22bec9b3..28b220fc 100644
--- a/libcpu/ChangeLog
+++ b/libcpu/ChangeLog
@@ -1,3 +1,9 @@
+2017-07-18  Mark Wielaard  <mark@klomp.org>
+
+	* Makefile.am: Don't check HAVE_LINUX_BPF_H, just define libcpu_bpf.
+	* bpf_disasm.c: Include bpf.h instead of linux/bpf.h. Don't define
+	BPF_PSEUDO_MAP_FD.
+
 2017-04-20  Ulf Hermann <ulf.hermann@qt.io>
 
 	* Makefile.am: Add EXEEXT to gendis.
diff --git a/libcpu/Makefile.am b/libcpu/Makefile.am
index 31fc906b..94de56ef 100644
--- a/libcpu/Makefile.am
+++ b/libcpu/Makefile.am
@@ -45,11 +45,9 @@ i386_gendis_SOURCES = i386_gendis.c i386_lex.l i386_parse.y
 i386_disasm.o: i386.mnemonics $(srcdir)/i386_dis.h
 x86_64_disasm.o: x86_64.mnemonics $(srcdir)/x86_64_dis.h
 
-if HAVE_LINUX_BPF_H
 noinst_LIBRARIES += libcpu_bpf.a
 libcpu_bpf_a_SOURCES = bpf_disasm.c
 libcpu_bpf_a_CFLAGS = $(AM_CFLAGS) -Wno-format-nonliteral
-endif
 
 %_defs: $(srcdir)/defs/i386
 	$(AM_V_GEN)m4 -D$* -DDISASSEMBLER $< > $@T
diff --git a/libcpu/bpf_disasm.c b/libcpu/bpf_disasm.c
index e4bbae4a..054aba2b 100644
--- a/libcpu/bpf_disasm.c
+++ b/libcpu/bpf_disasm.c
@@ -35,16 +35,11 @@
 #include <stdio.h>
 #include <gelf.h>
 #include <inttypes.h>
-#include <linux/bpf.h>
+#include "bpf.h"
 
 #include "../libelf/common.h"
 #include "../libebl/libeblP.h"
 
-/* BPF_PSEUDO_MAP_FD was only introduced in linux 3.20.  */
-#ifndef BPF_PSEUDO_MAP_FD
-  #define BPF_PSEUDO_MAP_FD 1
-#endif
-
 static const char class_string[8][8] = {
   [BPF_LD]    = "ld",
   [BPF_LDX]   = "ldx",
diff --git a/tests/ChangeLog b/tests/ChangeLog
index a4404e42..194d019f 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,7 @@
+2017-07-18  Mark Wielaard  <mark@klomp.org>
+
+	* Makefile.am (TESTS): Always add run-disasm-bpf.sh if HAVE_LIBASM.
+
 2017-05-04  Ulf Hermann  <ulf.hermann@qt.io>
 
 	* elfshphehdr.c: For writing, use /dev/null rather than /dev/zero.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 7fd4b211..368e9263 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -156,10 +156,7 @@ endif
 
 if HAVE_LIBASM
 check_PROGRAMS += $(asm_TESTS)
-TESTS += $(asm_TESTS)
-if HAVE_LINUX_BPF_H
-TESTS += run-disasm-bpf.sh
-endif
+TESTS += $(asm_TESTS) run-disasm-bpf.sh
 endif
 
 EXTRA_DIST = run-arextract.sh run-arsymtest.sh \