1 files changed, 286 insertions, 0 deletions
diff --git a/elfcopy/binary.c b/elfcopy/binary.c
new file mode 100644
index 0000000000000..65b49fbe874f9
--- /dev/null
+++ b/elfcopy/binary.c
@@ -0,0 +1,286 @@
+/*-
+ * Copyright (c) 2010,2011 Kai Wang
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <err.h>
+#include <gelf.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "elfcopy.h"
+
+ELFTC_VCSID("$Id: binary.c 2358 2011-12-19 18:22:32Z kaiwang27 $");
+
+/*
+ * Convert ELF object to `binary'. Sections with SHF_ALLOC flag set
+ * are copied to the result binary. The relative offsets for each section
+ * are retained, so the result binary file might contain "holes".
+ */
+void
+create_binary(int ifd, int ofd)
+{
+	Elf *e;
+	Elf_Scn *scn;
+	Elf_Data *d;
+	GElf_Shdr sh;
+	off_t base, off;
+	int elferr;
+
+	if ((e = elf_begin(ifd, ELF_C_READ, NULL)) == NULL)
+		errx(EXIT_FAILURE, "elf_begin() failed: %s",
+		    elf_errmsg(-1));
+
+	base = 0;
+	if (lseek(ofd, base, SEEK_SET) < 0)
+		err(EXIT_FAILURE, "lseek failed");
+
+	/*
+	 * Find base offset in the first iteration.
+	 */
+	base = -1;
+	scn = NULL;
+	while ((scn = elf_nextscn(e, scn)) != NULL) {
+		if (gelf_getshdr(scn, &sh) == NULL) {
+			warnx("gelf_getshdr failed: %s", elf_errmsg(-1));
+			(void) elf_errno();
+			continue;
+		}
+		if ((sh.sh_flags & SHF_ALLOC) == 0 ||
+		    sh.sh_type == SHT_NOBITS ||
+		    sh.sh_size == 0)
+			continue;
+		if (base == -1 || (off_t) sh.sh_offset < base)
+			base = sh.sh_offset;
+	}
+	elferr = elf_errno();
+	if (elferr != 0)
+		warnx("elf_nextscn failed: %s", elf_errmsg(elferr));
+
+	if (base == -1)
+		return;
+
+	/*
+	 * Write out sections in the second iteration.
+	 */
+	scn = NULL;
+	while ((scn = elf_nextscn(e, scn)) != NULL) {
+		if (gelf_getshdr(scn, &sh) == NULL) {
+			warnx("gelf_getshdr failed: %s", elf_errmsg(-1));
+			(void) elf_errno();
+			continue;
+		}
+		if ((sh.sh_flags & SHF_ALLOC) == 0 ||
+		    sh.sh_type == SHT_NOBITS ||
+		    sh.sh_size == 0)
+			continue;
+		(void) elf_errno();
+		if ((d = elf_getdata(scn, NULL)) == NULL) {
+			elferr = elf_errno();
+			if (elferr != 0)
+				warnx("elf_getdata failed: %s", elf_errmsg(-1));
+			continue;
+		}
+		if (d->d_buf == NULL || d->d_size == 0)
+			continue;
+
+		/* lseek to section offset relative to `base'. */
+		off = sh.sh_offset - base;
+		if (lseek(ofd, off, SEEK_SET) < 0)
+			err(EXIT_FAILURE, "lseek failed");
+
+		/* Write out section contents. */
+		if (write(ofd, d->d_buf, d->d_size) != (ssize_t) d->d_size)
+			err(EXIT_FAILURE, "write failed");
+	}
+	elferr = elf_errno();
+	if (elferr != 0)
+		warnx("elf_nextscn failed: %s", elf_errmsg(elferr));
+}
+
+#define	_SYMBOL_NAMSZ	1024
+
+/*
+ * Convert `binary' to ELF object. The input `binary' is converted to
+ * a relocatable (.o) file, a few symbols will also be created to make
+ * it easier to access the binary data in other compilation units.
+ */
+void
+create_elf_from_binary(struct elfcopy *ecp, int ifd, const char *ifn)
+{
+	char name[_SYMBOL_NAMSZ];
+	struct section *sec, *sec_temp, *shtab;
+	struct stat sb;
+	GElf_Ehdr oeh;
+	GElf_Shdr sh;
+	void *content;
+	uint64_t off, data_start, data_end, data_size;
+
+	/* Reset internal section list. */
+	if (!TAILQ_EMPTY(&ecp->v_sec))
+		TAILQ_FOREACH_SAFE(sec, &ecp->v_sec, sec_list, sec_temp) {
+			TAILQ_REMOVE(&ecp->v_sec, sec, sec_list);
+			free(sec);
+		}
+
+	if (fstat(ifd, &sb) == -1)
+		err(EXIT_FAILURE, "fstat failed");
+
+	/* Read the input binary file to a internal buffer. */
+	if ((content = malloc(sb.st_size)) == NULL)
+		err(EXIT_FAILURE, "malloc failed");
+	if (read(ifd, content, sb.st_size) != sb.st_size)
+		err(EXIT_FAILURE, "read failed");
+
+	/*
+	 * TODO: copy the input binary to output binary verbatim if -O is not
+	 * specified.
+	 */
+
+	/* Create EHDR for output .o file. */
+	if (gelf_newehdr(ecp->eout, ecp->oec) == NULL)
+		errx(EXIT_FAILURE, "gelf_newehdr failed: %s",
+		    elf_errmsg(-1));
+	if (gelf_getehdr(ecp->eout, &oeh) == NULL)
+		errx(EXIT_FAILURE, "gelf_getehdr() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Initialise e_ident fields. */
+	oeh.e_ident[EI_CLASS] = ecp->oec;
+	oeh.e_ident[EI_DATA] = ecp->oed;
+	/*
+	 * TODO: Set OSABI according to the OS platform where elfcopy(1)
+	 * was build. (probably)
+	 */
+	oeh.e_ident[EI_OSABI] = ELFOSABI_NONE;
+	oeh.e_machine = ecp->oem;
+	oeh.e_type = ET_REL;
+	oeh.e_entry = 0;
+
+	ecp->flags |= RELOCATABLE;
+
+	/* Create .shstrtab section */
+	init_shstrtab(ecp);
+	ecp->shstrtab->off = 0;
+
+	/*
+	 * Create `.data' section which contains the binary data. The
+	 * section is inserted immediately after EHDR.
+	 */
+	off = gelf_fsize(ecp->eout, ELF_T_EHDR, 1, EV_CURRENT);
+	if (off == 0)
+		errx(EXIT_FAILURE, "gelf_fsize() failed: %s", elf_errmsg(-1));
+	(void) create_external_section(ecp, ".data", NULL, content, sb.st_size,
+	    off, SHT_PROGBITS, ELF_T_BYTE, SHF_ALLOC | SHF_WRITE, 1, 0, 1);
+
+	/* Insert .shstrtab after .data section. */
+	if ((ecp->shstrtab->os = elf_newscn(ecp->eout)) == NULL)
+		errx(EXIT_FAILURE, "elf_newscn failed: %s",
+		    elf_errmsg(-1));
+	insert_to_sec_list(ecp, ecp->shstrtab, 1);
+
+	/* Insert section header table here. */
+	shtab = insert_shtab(ecp, 1);
+
+	/* Count in .symtab and .strtab section headers.  */
+	shtab->sz += gelf_fsize(ecp->eout, ELF_T_SHDR, 2, EV_CURRENT);
+
+#define	_GEN_SYMNAME(S) do {						\
+	snprintf(name, sizeof(name), "%s%s%s", "_binary_", ifn, S);	\
+} while (0)
+
+	/*
+	 * Create symbol table.
+	 */
+	create_external_symtab(ecp);
+	data_start = 0;
+	data_end = data_start + sb.st_size;
+	data_size = sb.st_size;
+	_GEN_SYMNAME("_start");
+	add_to_symtab(ecp, name, data_start, 0, 1,
+	    ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE), 0, 1);
+	_GEN_SYMNAME("_end");
+	add_to_symtab(ecp, name, data_end, 0, 1,
+	    ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE), 0, 1);
+	_GEN_SYMNAME("_size");
+	add_to_symtab(ecp, name, data_size, 0, SHN_ABS,
+	    ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE), 0, 1);
+	finalize_external_symtab(ecp);
+	create_symtab_data(ecp);
+#undef	_GEN_SYMNAME
+
+	/*
+	 * Write the underlying ehdr. Note that it should be called
+	 * before elf_setshstrndx() since it will overwrite e->e_shstrndx.
+	 */
+	if (gelf_update_ehdr(ecp->eout, &oeh) == 0)
+		errx(EXIT_FAILURE, "gelf_update_ehdr() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Generate section name string table (.shstrtab). */
+	ecp->flags |= SYMTAB_EXIST;
+	set_shstrtab(ecp);
+
+	/* Update sh_name pointer for each section header entry. */
+	update_shdr(ecp, 0);
+
+	/* Properly set sh_link field of .symtab section. */
+	if (gelf_getshdr(ecp->symtab->os, &sh) == NULL)
+		errx(EXIT_FAILURE, "692 gelf_getshdr() failed: %s",
+		    elf_errmsg(-1));
+	sh.sh_link = elf_ndxscn(ecp->strtab->os);
+	if (!gelf_update_shdr(ecp->symtab->os, &sh))
+		errx(EXIT_FAILURE, "gelf_update_shdr() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Renew oeh to get the updated e_shstrndx. */
+	if (gelf_getehdr(ecp->eout, &oeh) == NULL)
+		errx(EXIT_FAILURE, "gelf_getehdr() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Resync section offsets. */
+	resync_sections(ecp);
+
+	/* Store SHDR offset in EHDR. */
+	oeh.e_shoff = shtab->off;
+
+	/* Update ehdr since we modified e_shoff. */
+	if (gelf_update_ehdr(ecp->eout, &oeh) == 0)
+		errx(EXIT_FAILURE, "gelf_update_ehdr() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Write out the output elf object. */
+	if (elf_update(ecp->eout, ELF_C_WRITE) < 0)
+		errx(EXIT_FAILURE, "elf_update() failed: %s",
+		    elf_errmsg(-1));
+
+	/* Release allocated resource. */
+	free(content);
+	free_elf(ecp);
+}