Add rabin2 -O e/new-entrypoint-address (ELF only atm)

binr/rabin2/rabin2.c

@@ -334,6 +334,10 @@ static int rabin_do_operation(const char *op) {
 	if (!output) output = file;
 
 	switch (arg[0]) {
+	case 'e':
+		rc = r_bin_wr_entry (bin, r_num_math (NULL, ptr));
+		if (rc) rc = r_bin_wr_output (bin, output);
+		break;
 	case 'd':
 		if (!ptr) goto _rabin_do_operation_error;
 		switch (*ptr) {
@@ -578,6 +582,7 @@ int main(int argc, char **argv) {
 			set_action (ACTION_OPERATION);
 			if (isBinopHelp (op)) {
 				printf ("Operation string:\n"
+					"  Change Entrypoint: e/0x8048000\n"
 					"  Dump symbols: d/s/1024\n"
 					"  Dump section: d/S/.text\n"
 					"  Resize section: r/.data/1024\n"

libr/bin/bin_write.c

@@ -11,7 +11,7 @@ R_API ut64 r_bin_wr_scn_resize(RBin *bin, const char *name, ut64 size) {
 	if (plugin && plugin->write && plugin->write->scn_resize) {
 		return plugin->write->scn_resize (bin->cur, name, size);
 	}
-	return R_FALSE;
+	return false;
 }
 
 R_API bool r_bin_wr_scn_perms(RBin *bin, const char *name, int perms) {
@@ -34,7 +34,16 @@ R_API bool r_bin_wr_rpath_del(RBin *bin) {
 
 R_API int r_bin_wr_output(RBin *bin, const char *filename) {
 	RBinFile *binfile = r_bin_cur (bin);
-	if (!filename || !binfile || !binfile->buf) return R_FALSE;
+	if (!filename || !binfile || !binfile->buf) return false;
 	return r_file_dump (filename, binfile->buf->buf,
 			binfile->buf->length, 0);
 }
+
+R_API bool r_bin_wr_entry(RBin *bin, ut64 addr) {
+	RBinFile *binfile = r_bin_cur (bin);
+	RBinPlugin *plugin = r_bin_file_cur_plugin (binfile);
+	if (plugin && plugin->write && plugin->write->entry) {
+		return plugin->write->entry (bin->cur, addr);
+	}
+	return false;
+}

libr/bin/format/elf/elf.h

@@ -131,6 +131,7 @@ struct Elf_(r_bin_elf_obj_t)* Elf_(r_bin_elf_new)(const char* file);
 struct Elf_(r_bin_elf_obj_t)* Elf_(r_bin_elf_new_buf)(struct r_buf_t *buf);
 ut64 Elf_(r_bin_elf_resize_section)(struct Elf_(r_bin_elf_obj_t) *bin, const char *name, ut64 size);
 bool Elf_(r_bin_elf_section_perms)(struct Elf_(r_bin_elf_obj_t) *bin, const char *name, int perms);
+bool Elf_(r_bin_elf_entry_write)(struct Elf_(r_bin_elf_obj_t) *bin, ut64 addr);
 int Elf_(r_bin_elf_del_rpath)(struct Elf_(r_bin_elf_obj_t) *bin);
 int Elf_(r_bin_elf_has_relro)(struct Elf_(r_bin_elf_obj_t) *bin);
 int Elf_(r_bin_elf_has_nx)(struct Elf_(r_bin_elf_obj_t) *bin);

libr/bin/format/elf/elf_write.c

@@ -235,10 +235,22 @@ bool Elf_(r_bin_elf_section_perms)(struct Elf_(r_bin_elf_obj_t) *bin, const char
 			patchoff += ((const ut8*)shdrp - (const ut8*)bin->shdr);
 			patchoff += r_offsetof (Elf_(Shdr), sh_flags);
 			printf ("wx %02x @ 0x%x\n", newperms, patchoff);
-eprintf ("PATCH %p\n", bin->b);
 			r_buf_write_at (bin->b, patchoff, (ut8*)&newperms, 1);
 			return true;
 		}
 	}
 	return false;
 }
+
+bool Elf_(r_bin_elf_entry_write)(struct Elf_(r_bin_elf_obj_t) *bin, ut64 addr) {
+	int patchoff = 0x18;
+#if R_BIN_ELF64
+	printf ("wv8 0x%"PFMT64x" @ 0x%x\n", addr, patchoff);
+	eprintf ("%d\n", r_buf_write_at (bin->b, patchoff, (ut8*)&addr, sizeof (addr)));
+#else
+	ut32 addr32 = (ut32)addr;
+	printf ("wv4 0x%x @ 0x%x\n", addr32, patchoff);
+	r_buf_write_at (bin->b, patchoff, (ut8*)&addr32, sizeof (addr32));
+#endif
+	return true;
+}

libr/bin/p/bin_write_elf.c

@@ -1,4 +1,4 @@
-/* radare - LGPL - Copyright 2009-2015 - pancake, nibble */
+/* radare - LGPL - Copyright 2009-2016 - pancake, nibble */
 
 #include <r_types.h>
 #include <r_bin.h>
@@ -31,10 +31,20 @@ static int rpath_del(RBinFile *arch) {
 	return ret;
 }
 
+static bool chentry(RBinFile *arch, ut64 addr) {
+	struct Elf_(r_bin_elf_obj_t) *obj = arch->o->bin_obj;
+	int ret = Elf_(r_bin_elf_entry_write) (arch->o->bin_obj, addr);
+	r_buf_free (arch->buf);
+	arch->buf = obj->b;
+	obj->b = NULL;
+	return ret;
+}
+
 #if !R_BIN_ELF64
 RBinWrite r_bin_write_elf = {
 	.scn_resize = &scn_resize,
 	.scn_perms = &scn_perms,
 	.rpath_del = &rpath_del,
+	.entry = &chentry,
 };
 #endif

libr/bin/p/bin_write_elf64.c

@@ -1,4 +1,4 @@
-/* radare - LGPL - Copyright 2009-2015 pancake, nibble */
+/* radare - LGPL - Copyright 2009-2016 pancake */
 
 #define R_BIN_ELF64 1
 #include "bin_write_elf.c"
@@ -7,4 +7,5 @@ RBinWrite r_bin_write_elf64 = {
 	.scn_resize = &scn_resize,
 	.scn_perms = &scn_perms,
 	.rpath_del = &rpath_del,
+	.entry = &chentry,
 };

libr/include/r_bin.h

@@ -377,6 +377,7 @@ typedef struct r_bin_write_t {
 	ut64 (*scn_resize)(RBinFile *arch, const char *name, ut64 size);
 	bool (*scn_perms)(RBinFile *arch, const char *name, int perms);
 	int (*rpath_del)(RBinFile *arch);
+	bool (*entry)(RBinFile *arch, ut64 addr);
 } RBinWrite;
 
 // TODO: deprecate r_bin_is_big_endian
@@ -506,6 +507,7 @@ R_API char *r_bin_addr2fileline(RBin *bin, ut64 addr);
 R_API ut64 r_bin_wr_scn_resize(RBin *bin, const char *name, ut64 size);
 R_API bool r_bin_wr_scn_perms(RBin *bin, const char *name, int perms);
 R_API bool r_bin_wr_rpath_del(RBin *bin);
+R_API bool r_bin_wr_entry(RBin *bin, ut64 addr);
 R_API int r_bin_wr_output(RBin *bin, const char *filename);
 R_API int r_bin_dwarf_parse_info(RBinDwarfDebugAbbrev *da, RBin *a, int mode);
 R_API RList *r_bin_dwarf_parse_line(RBin *a, int mode);