parse elf_header

.gitignore

@@ -1,7 +1,9 @@
 *.o
 *.a
 *.so
-.vscode
+.vscode/*
+!.vscode/launch.json
+!.vscode/tasks.json
 /bld
 /debug_bld
 /out

.vscode/launch.json

@@ -0,0 +1,24 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "self read",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${workspaceFolder}/debug_bld/ft_nm",
+            "args": ["ft_nm"],
+            "preLaunchTask": "build",
+            "stopAtEntry": false,
+            "cwd": "${workspaceFolder}",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "osx": {
+                "MIMode": "lldb"
+            }
+        }
+    ]
+}

.vscode/tasks.json

@@ -0,0 +1,12 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "build",
+            "type": "shell",
+            "command": "ninja -C debug_bld"
+        }
+    ]
+}

meson.build

@@ -35,6 +35,7 @@ libft = subproject('libft')
 
 libft_dep = libft.get_variable('libft_dep')
 
+
 ft_nm = executable(
 	'ft_nm',
 	sources,

src/main.c

@@ -1,7 +1,42 @@
 #include "libft.h"
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <elf.h>
 
-int		main(void)
+int		main(int argc, char **argv)
 {
-	ft_putstr("Hello world!\n");
+	if (argc != 2)
+	{
+		ft_putstr("usage\n");
+		return (1);
+	}
+	int fd = open(argv[1], O_RDONLY);
+	if (fd == -1)
+	{
+		ft_putstr("can't open file\n");
+		return (1);
+	}
+	struct stat stat_buff;
+	stat(argv[1], &stat_buff);
+	if (!S_ISREG(stat_buff.st_mode))
+	{
+		ft_putstr("not a regular file\n");
+		return (1);
+	}
+	Elf64_Ehdr elf_header;
+	read(fd, &elf_header, sizeof(Elf64_Ehdr));
+	if (elf_header.e_ident[EI_MAG0] != ELFMAG0 || 
+		elf_header.e_ident[EI_MAG1] != ELFMAG1 ||
+		elf_header.e_ident[EI_MAG2] != ELFMAG2)
+	{
+		ft_putstr("not a valid magic number for elf binary file\n");
+		return (1);
+	}
+	if (elf_header.e_ident[EI_CLASS] != ELFCLASS64)
+	{
+		ft_putstr("sorry, only 64bit elf binaries for now");
+		return (1);
+	}
+	ft_putstr("symbol table\n");
 	return(0);
 }