Rewrite, bootstrap

Rewriting without KVM, huge goals, won't finish, just for fun.

1 files changed, 59 insertions, 0 deletions

diff --git a/src/load.c b/src/load.c
new file mode 100644
index 0000000..ddcd54d
--- /dev/null
+++ b/src/load.c
@@ -0,0 +1,59 @@
+#include <elf.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <load.h>
+#include <log.h>
+
+vaddr load(const char *path)
+{
+	FILE *file = fopen(path, "rb");
+	if (!file) {
+		errln("can't read file %s.", path);
+		return 0;
+	}
+
+	Elf64_Ehdr header = { 0 };
+	fread(&header, sizeof(header), 1, file);
+	if (memcmp(header.e_ident, ELFMAG, SELFMAG)) {
+		errln("invalid ELF %s.", path);
+		return 0;
+	}
+
+	for (int i = 0; i < header.e_phnum; i++) {
+		int offset = header.e_phoff + header.e_phentsize * i;
+		if (fseek(file, offset, SEEK_SET)) {
+			errln("can't seek program to %x", offset);
+			return 0;
+		}
+
+		Elf64_Phdr program = { 0 };
+		if (fread(&program, sizeof(program), 1, file) != 1) {
+			errln("invalid program size %d", i);
+			return 0;
+		}
+
+		if (!program.p_vaddr || program.p_type != PT_LOAD)
+			continue;
+
+		void *addr = mem_alloc(program.p_memsz, program.p_vaddr);
+		if (!addr) {
+			errln("can't allocate %dB at %x", program.p_memsz,
+			      program.p_vaddr);
+			return 0;
+		}
+		if (fseek(file, program.p_offset, SEEK_SET)) {
+			errln("can't seek program to %x", offset);
+			return 0;
+		}
+		if (fread(addr, program.p_filesz, 1, file) != 1) {
+			errln("invalid program size %d", i);
+			return 0;
+		}
+
+		logln("loaded program %d", i);
+	}
+
+	fclose(file);
+	return header.e_entry;
+}