mboot.c32:load ELF segments from the segment header

Load sections from the ELF section headers as well as the program headers,
for kernels which need symbol and debug info but don't ask for them in
the program headers.

Bump the version number to reflect this change.

Signed-off-by: Tim Deegan <Tim.Deegan@cl.cam.ac.uk>

1 files changed, 60 insertions, 4 deletions

diff --git a/com32/modules/mboot.c b/com32/modules/mboot.c
index 96e41023..0fe82995 100644
--- a/com32/modules/mboot.c
+++ b/com32/modules/mboot.c
@@ -6,6 +6,7 @@
  *  Copyright (C) 2005 Tim Deegan <Tim.Deegan@cl.cam.ac.uk>
  *  Parts based on GNU GRUB, Copyright (C) 2000  Free Software Foundation, Inc.
  *  Parts based on SYSLINUX, Copyright (C) 1994-2005  H. Peter Anvin.
+ *  Thanks to Ram Yalamanchili for the ELF section-header loading.
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License as
@@ -86,8 +87,8 @@ struct lidt_operand {
 } __attribute__((packed));
 
 /* Magic strings */
-static const char version_string[]   = "COM32 Multiboot loader v0.1";
-static const char copyright_string[] = "Copyright (C) 2005 Tim Deegan.";
+static const char version_string[]   = "COM32 Multiboot loader v0.2";
+static const char copyright_string[] = "Copyright (C) 2005-2006 Tim Deegan.";
 static const char module_separator[] = "---";
 
 
@@ -524,7 +525,7 @@ static void load_file(char *filename, char **startp, size_t *sizep)
 }
 
 
-static size_t load_kernel(char *cmdline) 
+static size_t load_kernel(struct multiboot_info *mbi, char *cmdline) 
     /* Load a multiboot/elf32 kernel and allocate run-time memory for it.
      * Returns the kernel's entry address.  */
 {
@@ -534,9 +535,11 @@ static size_t load_kernel(char *cmdline)
     char *seg_addr;                   /* Where a segment was loaded */
     size_t seg_size, bss_size;                     /* How big it is */
     size_t run_addr, run_size;            /* Where it should be put */
+    size_t shdr_run_addr;
     char *p; 
     Elf32_Ehdr *ehdr;
     Elf32_Phdr *phdr;
+    Elf32_Shdr *shdr;
     struct multiboot_header *mbh;
 
     printf("Kernel: %s\n", cmdline);
@@ -697,6 +700,59 @@ static size_t load_kernel(char *cmdline)
                 }
             }
          
+            if (ehdr->e_shoff != 0) {
+#ifdef DEBUG
+                printf("Loading ELF section table.\n");
+#endif
+                /* Section Header */
+                shdr = (Elf32_Shdr *)(load_addr + ehdr->e_shoff);
+
+                /* Section Header Table size */
+                run_size = ehdr->e_shentsize * ehdr->e_shnum;
+                shdr_run_addr = place_module_section(run_size, 0x1000); 
+                if (shdr_run_addr == 0) {
+                    printf("Warning: Not enough memory to load the "
+                           "section table.\n");
+                    return ehdr->e_entry;
+                }
+                add_section(shdr_run_addr, (void*) shdr, run_size);
+
+                /* Load section tables not loaded thru program segments */
+                for (i = 0; i < ehdr->e_shnum; i++) {
+                   /* This case is when this section is already included in 
+                    * program header or it's 0 size, so no need to load */
+                   if (shdr[i].sh_addr != 0 || !shdr[i].sh_size)
+                       continue;
+
+                   if (shdr[i].sh_addralign == 0)
+                       shdr[i].sh_addralign = 1;
+                   
+                   run_addr = place_module_section(shdr[i].sh_size, 
+                                                   shdr[i].sh_addralign); 
+                   if (run_addr == 0) {
+                       printf("Warning: Not enough memory to load "
+                              "section %d.\n", i);
+                       return ehdr->e_entry;
+                   }
+                   shdr[i].sh_addr = run_addr;
+                   add_section(run_addr, 
+                               (void*) (shdr[i].sh_offset + load_addr),
+                               shdr[i].sh_size);
+                }
+
+                mbi->flags |= MB_INFO_ELF_SHDR;
+                mbi->syms.e.num = ehdr->e_shnum;
+                mbi->syms.e.size = ehdr->e_shentsize;
+                mbi->syms.e.shndx = ehdr->e_shstrndx;
+                mbi->syms.e.addr = shdr_run_addr;
+#ifdef DEBUG
+                printf("Section information: shnum: %lu, entSize: %lu, "
+                       "shstrndx: %lu, addr: 0x%lx\n", 
+                       mbi->syms.e.num, mbi->syms.e.size, 
+                       mbi->syms.e.shndx, mbi->syms.e.addr);
+#endif                    
+            }
+
             /* Done! */
             return ehdr->e_entry;
         }
@@ -967,7 +1023,7 @@ int main(int argc, char **argv)
     p += strlen(version_string) + 1;
 
     /* Now, do all the loading, and boot it */
-    entry = load_kernel((char *)(mbi->cmdline + mbi_reloc_offset));
+    entry = load_kernel(mbi, (char *)(mbi->cmdline + mbi_reloc_offset));
     for (i=0; i<modules; i++) {
         load_module(&(modp[i]), (char *)(modp[i].cmdline + mbi_reloc_offset));
     }