Merge ELF loader.

[netwatch.git] / grubload / loader.c

diff --git a/grubload/loader.c b/grubload/loader.c
new file mode 100644 (file)
index 0000000..4ecba2a
--- /dev/null
+++ b/grubload/loader.c
@@ -0,0 +1,49 @@
+#include "minilib.h"
+#include "../include/elf.h"
+
+static const unsigned char elf_ident[4] = { 0x7F, 'E', 'L', 'F' }; 
+
+int load_elf (char * buf, int size) {
+
+       Elf32_Ehdr * elf_hdr = (Elf32_Ehdr *) buf;
+       Elf32_Shdr * elf_sec_hdrs = (Elf32_Shdr *) (buf + elf_hdr->e_shoff);
+
+       /* Sanity check on ELF file */
+       if (memcmp(elf_hdr->e_ident, elf_ident, sizeof(elf_ident))) return -1;
+       if (elf_hdr->e_type != ET_EXEC) return -1;
+       if (elf_hdr->e_machine != EM_386) return -1;
+       if (elf_hdr->e_version != EV_CURRENT) return -1;
+       if (size < sizeof(Elf32_Ehdr)) return -1;
+       if (((char *)&elf_sec_hdrs[elf_hdr->e_shnum]) > (buf + size)) return -1;
+
+       char * string_table = buf + elf_sec_hdrs[elf_hdr->e_shstrndx].sh_offset;
+
+       if (string_table > (buf + size)) return -1;
+
+       int i;
+       for (i = 0; i < elf_hdr->e_shnum; i++) {
+
+               if (elf_sec_hdrs[i].sh_name == SHN_UNDEF) {
+                       continue;
+               }
+
+               char * section_name = string_table + elf_sec_hdrs[i].sh_name;
+
+               if ((elf_sec_hdrs[i].sh_type != SHT_PROGBITS) || !(elf_sec_hdrs[i].sh_flags & SHF_ALLOC)) {
+                       puts("Skipping ");
+                       puts(section_name);
+                       puts("\n");
+                       continue;
+               }
+
+               puts("Loading ");
+               puts(section_name);
+               puts("\n");
+
+               memcpy(elf_sec_hdrs[i].sh_addr,
+                      buf + elf_sec_hdrs[i].sh_offset,
+                      elf_sec_hdrs[i].sh_size);
+       }
+
+       return 0;
+}