Started working on retrieving ELF metadata

build.sh

@@ -3,4 +3,4 @@
 set -e
 
 mkdir -p build/
-gcc -std=gnu23 -I include/ src/*.c -o build/gandalf
+gcc -std=gnu23 -I include/ src/*.c src/*/*.c -o build/gandalf

include/dwarf/elf.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void parse_elf(FILE *file);

src/dwarf/elf.c

@@ -0,0 +1,88 @@
+#include <elf.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <inttypes.h>
+
+void print_elf64_header(Elf64_Ehdr *header) {
+  char *format = 
+    "Elf64_Ehdr {\n"
+    "  e_ident:      %s\n"
+    "  e_type:       %"PRIu16"\n"
+    "  e_machine:    %"PRIu16"\n"
+    "  e_version:    %"PRIu32"\n"
+    "  e_entry:      %"PRIu64"\n"
+    "  e_phoff:      %"PRIu64"\n"
+    "  e_shoff:      %"PRIu64"\n"
+    "  e_flags:      %"PRIu32"\n"
+    "  e_ehsize:     %"PRIu16"\n"
+    "  e_phentsize:  %"PRIu16"\n"
+    "  e_phnum:      %"PRIu16"\n"
+    "  e_shentsize:  %"PRIu16"\n"
+    "  e_shnum:      %"PRIu16"\n"
+    "  e_shstrndx:   %"PRIu16"\n"
+    "}\n";
+
+  printf(
+    format,
+    header->e_ident,
+    header->e_type,
+    header->e_machine,
+    header->e_version,
+    header->e_entry,
+    header->e_phoff,
+    header->e_shoff,
+    header->e_flags,
+    header->e_ehsize,
+    header->e_phentsize,
+    header->e_phnum,
+    header->e_shentsize,
+    header->e_shnum,
+    header->e_shstrndx
+  );
+}
+
+void print_elf64_section_header(Elf64_Shdr *header) {
+  char *format = 
+    "Elf64_Shdr {\n"
+    "  sh_name:      %"PRIu32"\n"
+    "  sh_type:      %"PRIu32"\n"
+    "  sh_flags:     %"PRIu64"\n"
+    "  sh_addr:      %"PRIu64"\n"
+    "  sh_offset:    %"PRIu64"\n"
+    "  sh_size:      %"PRIu64"\n"
+    "  sh_link:      %"PRIu32"\n"
+    "  sh_info:      %"PRIu32"\n"
+    "  sh_addralign: %"PRIu64"\n"
+    "  sh_entsize:   %"PRIu64"\n"
+    "}\n";
+
+  printf(format,
+    header->sh_name,
+    header->sh_type,
+    header->sh_flags,
+    header->sh_addr,
+    header->sh_offset,
+    header->sh_size,
+    header->sh_link,
+    header->sh_info,
+    header->sh_addralign,
+    header->sh_entsize
+  );
+}
+
+void parse_elf(FILE *file) {
+  printf("fd: %p\n", file);
+  
+  Elf64_Ehdr header;
+  fread(&header, sizeof(header), 1, file);
+  print_elf64_header(&header);
+
+  int ret = fseek(file, header.e_shoff, SEEK_SET);
+  if (ret != 0) { exit(1); }
+  printf("Set file cursor to: %"PRIu64"\n", header.e_shoff);
+  
+  Elf64_Shdr section_header;
+  fread(&header, sizeof(section_header), 1, file);
+  print_elf64_section_header(&section_header);
+}

src/main.c

@@ -1,22 +1,27 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-// #include <sys/
 
-// _start: 
-//   mov sp 0x120
-//   call main
+#include <dwarf/elf.h>
+
 
 int run_child(char *exe) {
   printf("Starting %s\n", exe);
+  execl(exe, (char *) NULL);
 }
 
-
 int main(int argc, char **argv) {
   if (argc != 2) {
     printf("Usage: gandalf <executable>\n");
     return 1;
   }
+  char *child_exe = argv[1];
+  
+  FILE *file = fopen(child_exe, "r");
+  if (!file) {
+    exit(1);
+  }
+  parse_elf(file);
   
   pid_t child = fork();
 
@@ -28,6 +33,5 @@ int main(int argc, char **argv) {
     run_child(argv[1]);
   } else {
     printf("Parent process\n");
-
   }
 }