Re: [Qemu-devel] Patch to fix mapping of elf pheaders specifying both .data and .bss segments

[Kai Backman <kaib@google.com>]

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On Thu, Jun 18, 2009 at 11:57 AM, Riku Voipio<riku.voipio@iki.fi> wrote:
> The patch attached is totally messed up thou.

Sorry for the delay. I was vacationing in Finland (incidentally)..

To restart the thread, I've re-attached the patch.

 Kai

-- 
Kai Backman, Software Engineer, kaib@google.com

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diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 190ad14..e4e75d5 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1211,7 +1211,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
     abi_ulong mapped_addr;
     struct elf_phdr * elf_ppnt;
     struct elf_phdr *elf_phdata;
-    abi_ulong elf_bss, k, elf_brk;
+    abi_ulong elf_bss, last_bss, mapped_bss, k, elf_brk;
     int retval;
     char * elf_interpreter;
     abi_ulong elf_entry, interp_load_addr = 0;
@@ -1271,6 +1271,7 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
     elf_ppnt = elf_phdata;
 
     elf_bss = 0;
+    last_bss = 0;
     elf_brk = 0;
 
 
@@ -1495,12 +1496,24 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
         k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
         if (k > elf_bss)
             elf_bss = k;
+        k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
+        if (k > last_bss)
+            last_bss = k;
         if ((elf_ppnt->p_flags & PF_X) && end_code <  k)
             end_code = k;
         if (end_data < k)
             end_data = k;
         k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
         if (k > elf_brk) elf_brk = k;
+        if (!elf_interpreter && last_bss > elf_bss) {
+      	    padzero(elf_bss, last_bss);
+	    mapped_bss = TARGET_ELF_PAGESTART(elf_bss + qemu_host_page_size - 1);
+
+	    /* Map the last of the bss segment */
+            target_mmap(load_bias + mapped_bss, last_bss-mapped_bss,
+                        PROT_READ|PROT_WRITE|PROT_EXEC,
+                        MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+        }
     }
 
     elf_entry += load_bias;