misc/elf-abi: read arch:abi:endian from an ELF, bug #534206

3 files changed, 334 insertions, 0 deletions

diff --git a/misc/elf-abi/.gitignore b/misc/elf-abi/.gitignore
new file mode 100644
index 0000000..7ec9e50
--- /dev/null
+++ b/misc/elf-abi/.gitignore
@@ -0,0 +1,2 @@
+elf-abi
+!Makefile
diff --git a/misc/elf-abi/Makefile b/misc/elf-abi/Makefile
new file mode 100644
index 0000000..8a75d55
--- /dev/null
+++ b/misc/elf-abi/Makefile
@@ -0,0 +1,18 @@
+CFLAGS ?= -O2 -pipe -g
+CFLAGS += -Wall
+PWD = $$(pwd)
+
+all: elf-abi
+
+elf-abi: elf-abi.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -o $@ $< $(LDLIBS)
+
+PREFIX = /usr
+BINDIR = $(PREFIX)/bin
+install: elf-abi
+	install -m 755 -D elf-abi $(DESTDIR)$(BINDIR)/$<
+
+clean:
+	rm -f *.o *~ elf-abi
+
+.PHONY: all clean install
diff --git a/misc/elf-abi/elf-abi.c b/misc/elf-abi/elf-abi.c
new file mode 100644
index 0000000..589d458
--- /dev/null
+++ b/misc/elf-abi/elf-abi.c
@@ -0,0 +1,314 @@
+/* Copyright 2015 Gentoo Foundation
+ * Distributed under the terms of the GNU General Public License v2
+ *
+ * Compute a multilib ABI identifier, as discussed here:
+ *
+ * 	https://bugs.gentoo.org/show_bug.cgi?id=534206
+ *
+ * Supported identifiers:
+ *
+ *	alpha_32
+ *	arm_{oabi32,32,64}
+ *	hppa_32,64
+ *	ia_64
+ *	m68k_32
+ *	mips_{n32,n64,o32}
+ *	ppc_{32,64}
+ *	s390_32
+ *	sh_32
+ *	sparc_{32,64}
+ *	x86_{32,x32,64}
+ *
+ * NOTES:
+ *
+ * * The ABIs referenced by some of the above *_32 and *_64 identifiers
+ *   may be imaginary, but they are listed anyway, since the goal is to
+ *   establish a naming convention that is as consistent and uniform as
+ *   possible.
+ *
+ * * The Elf header's e_ident[EI_OSABI] byte is completely ignored,
+ *   since OS-independence is one of the goals. The assumption is that,
+ *   for given installation, we are only interested in tracking multilib
+ *   ABIs for a single OS.
+ *
+ * REFERENCE:
+ *
+ *   http://www.sco.com/developers/gabi/2000-07-17/ch4.eheader.html
+ *
+ *
+ * Copyright 2015 Anthony G. Basile - <blueness@gentoo.org>
+ * Copyright 2015 Zac Medico - <zmedico@gentoo.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <err.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <endian.h>
+
+/* We steal this from <elf.h> but don't include it so as to not increase our dependancies. */
+#define	ELFMAG		"\177ELF"
+
+#define ELFCLASS32	1		/* 32-bit objects */
+#define ELFCLASS64	2		/* 64-bit objects */
+#define ELFDATA2LSB	1		/* 2's complement, little endian */
+#define ELFDATA2MSB	2		/* 2's complement, big endian */
+
+#define EM_SPARC	 2		/* SUN SPARC */
+#define EM_386		 3		/* Intel 80386 */
+#define EM_68K		 4		/* Motorola m68k family */
+#define EM_MIPS		 8		/* MIPS R3000 big-endian */
+#define EM_MIPS_RS3_LE	10		/* MIPS R3000 little-endian */
+#define EM_PARISC	15		/* HPPA */
+#define EM_SPARC32PLUS	18		/* Sun's "v8plus" */
+#define EM_PPC		20		/* PowerPC */
+#define EM_PPC64	21		/* PowerPC 64-bit */
+#define EM_S390		22		/* IBM S390 */
+#define EM_ARM		40		/* ARM */
+#define EM_FAKE_ALPHA	41		/* Digital Alpha */
+#define EM_SH		42		/* Hitachi SH */
+#define EM_SPARCV9	43		/* SPARC v9 64-bit */
+#define EM_IA_64	50		/* Intel Merced */
+#define EM_X86_64	62		/* AMD x86-64 architecture */
+#define EM_AARCH64	183		/* ARM AARCH64 */
+#define EM_ALPHA	0x9026
+
+#define EF_MIPS_ABI2		32
+#define EF_MIPS_ABI_ON32	64
+/*
+E_MIPS_ABI_O32     = 0x00001000
+E_MIPS_ABI_O64     = 0x00002000
+E_MIPS_ABI_EABI32  = 0x00003000
+E_MIPS_ABI_EABI64  = 0x00004000
+*/
+
+#define EF_ARM_NEW_ABI		0x80
+#define EF_ARM_OLD_ABI		0x100
+
+
+/*
+def compute_suffix_mips(elf_header):
+	name = None
+	mips_abi = elf_header.e_flags & EF_MIPS_ABI
+	if mips_abi:
+		if mips_abi == E_MIPS_ABI_O32:
+			name = "o32"
+		elif mips_abi == E_MIPS_ABI_O64:
+			name = "o64"
+		elif mips_abi == E_MIPS_ABI_EABI32:
+			name = "eabi32"
+		elif mips_abi == E_MIPS_ABI_EABI64:
+			name = "eabi64"
+
+	elif elf_header.e_flags & EF_MIPS_ABI2:
+		name = "n32"
+	elif elf_header.ei_class == ELFCLASS64:
+		name = "n64"
+
+	return name
+
+def compute_multilib_id(elf_header):
+	prefix = machine_prefix_map.get(elf_header.e_machine)
+	suffix = None
+
+	if prefix == "mips":
+		suffix = compute_suffix_mips(elf_header)
+	elif elf_header.ei_class == ELFCLASS64:
+		suffix = "64"
+	elif elf_header.ei_class == ELFCLASS32:
+		if elf_header.e_machine == EM_X86_64:
+			suffix = "x32"
+		else:
+			suffix = "32"
+
+	if prefix is None or suffix is None:
+		multilib_id = None
+	else:
+		multilib_id = "%s_%s" % (prefix, suffix)
+
+	return multilib_id
+*/
+
+
+#define bswap_16(x) ((uint16_t)((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
+
+/*
+#define bswap_32(x) \
+     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
+      (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
+*/
+
+#define MAX_IDENT	32
+
+int
+main(int argc, char* argv[])
+{
+	char ident[MAX_IDENT];		/* The Gentoo standard arch_abi identifier.		*/
+	char *arch;			/* The Gentoo architecture identifier.			*/
+	int fd;
+	struct stat s;
+	char magic[4];			/* magic number at the begining of the file		*/
+	uint8_t ei_class, width;	/* width = 8 bytes for 32-bits, 16 bytes for 64-bits.	*/
+	uint8_t ei_data, endian;	/* endian = 0 for little, 1 for big endian.		*/
+	uint16_t e_machine;		/* Size is Elf32_Half or Elf64_Half.  Both are 2 bytes.	*/
+	uint32_t e_flags;		/* Size is Elf32_Word or Elf64_Word.  Both are 4 bytes.	*/
+	uint64_t e_flags_offset;	/* Wide enough for either 32 or 64 bits.		*/
+
+	/* Is the second parameter a regular file? */
+	if (argc != 2)
+		errx(1, "Usage: %s <file>", argv[0]);
+	if (stat(argv[1], &s) == -1)
+		errx(1, "%s does not exist", argv[1]);
+	if (!S_ISREG(s.st_mode))
+		errx(1, "%s is not a regular file", argv[1]);
+
+	/* Can we read it and is it an ELF object? */
+	if ((fd = open(argv[1], O_RDONLY)) == -1)
+		err(1, "failed to open %s", argv[1]);
+	if (read(fd, magic, 4) == -1)
+		err(1, "read() magic failed");
+	if (strncmp(magic, ELFMAG, 4) != 0)
+		errx(1, "%s is not an ELF object", argv[1]);
+
+
+	/* 32 or 64 bits? */
+	if (read(fd, &ei_class, 1) == -1)
+		err(1, "read() ei_class failed");
+	switch (ei_class) {
+		case ELFCLASS32:
+			width = 4;
+			printf("32 bit\n");
+			break;
+		case ELFCLASS64:
+			width = 8;
+			printf("64 bit\n");
+			break;
+		default:
+			width = 0;
+			printf("Unknown bit\n");
+	}
+
+	/* Little or Big Endian */
+	if (read(fd, &ei_data, 1) == -1)
+		err(1, "read() ei_data failed");
+	switch (ei_data) {
+		case ELFDATA2LSB:
+			endian = 0;
+			printf("Little Endian\n");
+			break;
+		case ELFDATA2MSB:
+			endian = 1;
+			printf("Big Endian\n");
+			break;
+		default:
+			endian = -1;
+			printf("Unknown Endian\n");
+	}
+
+	/* seek to e_macine = 16 bytes (e_ident[])) + 2 bytes (e_type which is Elf32_Half/Elf64_Half) */
+	if (lseek(fd, 18, SEEK_SET) == -1)
+		err(1, "lseek() e_machine failed");
+
+	/* What is the arch? */
+	if (read(fd, &e_machine, 2) == -1)
+		err(1, "read() e_machine failed");
+	//if (endian == 0)
+	//	e_machine = bswap_16(e_machine);
+	printf("Machine =%d\n", e_machine);
+
+	switch(e_machine) {
+		case EM_ALPHA:
+		case EM_FAKE_ALPHA:
+			arch = "alpha";
+			break;
+		case EM_X86_64:
+			arch = "amd64";
+			break;
+		case EM_ARM:
+			arch = "arm";
+			break;
+		case EM_AARCH64:
+			arch = "arm64";
+			break;
+		case EM_68K:
+			arch = "m68k";
+			break;
+		case EM_MIPS_RS3_LE:
+		case EM_MIPS:
+			arch = "mips";
+			break;
+		case EM_IA_64:
+			arch = "ia64";
+			break;
+		case EM_PARISC:
+			arch = "hppa";
+			break;
+		case EM_PPC:
+			arch = "ppc";
+			break;
+		case EM_PPC64:
+			arch = "ppc64";
+			break;
+		case EM_S390:
+			arch = "s390";
+			break;
+		case EM_SH:
+			arch = "sh";
+			break;
+		case EM_SPARC32PLUS:
+		case EM_SPARCV9:
+		case EM_SPARC:
+			arch = "sparc";
+			break;
+		case EM_386:
+			arch = "x86";
+			break;
+		default:
+			arch = "unknown";
+	}
+
+	printf("%s\n", arch);
+
+
+	/*
+	e_data_offset = 
+	if (lseek(fd, 18, SEEK_SET) == -1)
+		err(1, "lseek() e_machine failed");
+	if (read(fd, &e_flags, 2) == -1)
+		err(1, "read() e_machine failed");
+	*/
+
+	memset(ident, 0, MAX_IDENT);
+
+	close(fd);
+	exit(EXIT_SUCCESS);
+}
+
+/*
+	# E_ENTRY + 3 * sizeof(uintN)
+	e_flags_offset = E_ENTRY + 3 * width // 8
+	f.seek(e_flags_offset)
+	e_flags = uint32(f.read(4))
+
+	return _elf_header(ei_class, ei_data, e_machine, e_flags)
+
+	multilib_id = compute_multilib_id(elf_header)
+*/