Implement loading .text section from ELF binary

1 files changed, 26 insertions, 10 deletions

diff --git a/elf.c b/elf.c
index cc90b18..439433b 100644
--- a/elf.c
+++ b/elf.c
@@ -23,10 +23,9 @@
  * http://elftoolchain.sourceforge.net/for-review/libelf-by-example-20100112.pdf
  */
 
-static int elf_read_sections(Elf *e)
+static int elf_read_sections(Elf *e, struct memory *mem)
 {
 	Elf_Scn *scn = NULL;
-	GElf_Shdr shdr;
 	size_t shstrndx;
 	char *name;
 
@@ -36,25 +35,42 @@ static int elf_read_sections(Elf *e)
 	}
 
 	while ((scn = elf_nextscn(e, scn)) != NULL) {
+		GElf_Shdr shdr;
 		GElf_Phdr phdr;
 
-		if (gelf_getshdr(scn, &shdr) != &shdr) {
+		if (gelf_getshdr(scn, &shdr) == NULL) {
 			err("Couldn't get section header: %s\n", elf_errmsg(-1));
 			return -1;
 		}
 
-		if ((name = elf_strptr(e, shstrndx, shdr.sh_name)) == NULL) {
-			err("Couldn't get section name: %s\n", elf_errmsg(-1));
-			return -1;
-		}
+		/* Is it a .text section? */
+		if (shdr.sh_type == SHT_PROGBITS
+		    && (shdr.sh_flags & ~SHF_WRITE) == (SHF_ALLOC | SHF_EXECINSTR)) {
+			Elf_Data *data;
+			size_t n;
+
+			if ((name = elf_strptr(e, shstrndx, shdr.sh_name)) == NULL) {
+				err("Couldn't get section name: %s\n", elf_errmsg(-1));
+				return -1;
+			}
 
-		dbg("Section %zu: %s\n", elf_ndxscn(scn), name);
+			dbg("Section %zu: %s (size=%zu, flags=%08lx, addr=%08lx, off=%08lx)\n", elf_ndxscn(scn), name, shdr.sh_size, shdr.sh_flags, shdr.sh_addr, shdr.sh_offset);
+
+			data = NULL;
+			n = 0;
+			while (n < shdr.sh_size &&
+					(data = elf_getdata(scn, data)) != NULL) {
+				memcpy(&mem->base[(shdr.sh_addr + n) / 4], data->d_buf, data->d_size);
+
+				n += data->d_size;
+			}
+		}
 	}
 
 	return 0;
 }
 
-int elf_load(FILE *fp, const char *name, uint8_t *mem_base, size_t mem_size)
+int elf_load(FILE *fp, const char *name, struct memory *mem)
 {
 	int fd = fileno(fp);
 	int ret;
@@ -99,7 +115,7 @@ int elf_load(FILE *fp, const char *name, uint8_t *mem_base, size_t mem_size)
 		goto out;
 	}
 
-	ret = elf_read_sections(e);
+	ret = elf_read_sections(e, mem);
 out:
 	elf_end(e);
 	return ret;