Changeset 740

Timestamp:

07/07/08 15:24:08 (3 months ago)

Author:

mwhitworth

Message:

Add support for TEXTREL and remapping text relocations.

Location:

Whitix/trunk/user/linker

Files:

• elf.h (modified) (2 diffs)
• lib.h (modified) (1 diff)
• load_lib.c (modified) (6 diffs)
• relocate.c (modified) (2 diffs)

Whitix/trunk/user/linker/elf.h

@@ -45 +45 @@
 #define PT_DYNAMIC      2
 #define PT_PHDR         6
+
+#define PROT_EXEC       1
+#define PROT_WRITE      2
+#define PROT_READ       4
 
 struct ElfProgHeader
@@ -120 +124 @@
         unsigned long* elfBuckets,*elfChains;
         struct ElfProgHeader* pHeaders;
+        DWORD textAddr, textLength;
         unsigned long phNum;
         int refs,initFlags;

Whitix/trunk/user/linker/lib.h

@@ -119 +119 @@
         {
                 if (dynEntry->tag < DT_NUM)
+                {
                         dynamicInfo[dynEntry->tag]=dynEntry->val;
-                else if (dynEntry->tag == DT_RELCOUNT)
+
+                        if (dynEntry->tag == DT_TEXTREL)
+                                dynamicInfo[DT_TEXTREL]=1;
+                }else if (dynEntry->tag == DT_RELCOUNT)
                         dynamicInfo[DT_RELCOUNT_IDX]=dynEntry->val;
 

Whitix/trunk/user/linker/load_lib.c

@@ -102 +102 @@
 }
 
-Elf_Addr DlGetDynamicAddress(struct ElfProgHeader* pHeaders, int numEntries, int* picLib)
+Elf_Addr DlGetAddresses(struct ElfProgHeader* pHeaders, int numEntries, int* picLib, DWORD* textAddr, DWORD* textLength)
 {
         int i;
@@ -115 +115 @@
                         /* Is it a position independent library? Most likely not. */
                         *picLib=0;
+
+                if (pHeaders[i].type == PT_LOAD && pHeaders[i].segFlags == (PROT_EXEC | PROT_READ))
+                {
+                        *textAddr=pHeaders[i].vAddr;
+                        *textLength=pHeaders[i].memSize;
+                }
         }
         
@@ -150 +156 @@
                                                                  fd,                                                                                                    /* Backing file */
                                                                  pHeaders[i].fileOffset-PAGE_OFFSET(pHeaders[i].vAddr),  /* File offset */
-                                                                 mmapFlags);                                                                                    /* Flags */
+                                                                 mmapFlags);                                                                    /* Flags */
 
                         if (!mapAddr)
@@ -227 +233 @@
         unsigned long dynEntries[DT_NUM+1];
         int picLib=1;
+        DWORD textAddr, textLength;
 
         /* Check if we've loaded this library into memory already. */
@@ -246 +253 @@
          * has position independent code from here.
          */
-        dynamicAddr=DlGetDynamicAddress(pHeaders, fileHeader.phEntries, &picLib);
+        dynamicAddr=DlGetAddresses(pHeaders, fileHeader.phEntries, &picLib, &textAddr, &textLength);
         
         if (!dynamicAddr)
@@ -271 +278 @@
         ElfParseDynInfo((struct ElfDyn*)dynamicAddr,dynEntries,loadAddr);
 
-        if (dynEntries[DT_TEXTREL])
-        {
-                link_puts("Todo: make pages writeable");
-                SysExit(0);
-        }
-
         entry=DlCreateResolveEntry(name, pHeaders, fileHeader.phEntries, loadAddr, dynamicAddr, dynEntries);
+
+        /* Fill in the rest of the structure. */
+        entry->textAddr=entry->loadAddr+textAddr;
+        entry->textLength=textLength;
 
         /* Initialize the global offset table (GOT) */

Whitix/trunk/user/linker/relocate.c

@@ -235 +235 @@
         relocSize=resolve->dynamicInfo[DT_RELSZ];
 
+        /* May need to make text rewriteable before relocation */
+        if (resolve->dynamicInfo[DT_TEXTREL])
+        {
+                SysMemoryProtect(resolve->textAddr, resolve->textLength, 7);
+        }
+
         if (resolve->dynamicInfo[DT_REL] && !(resolve->initFlags & INIT_RELOCS_DONE))
         {
@@ -255 +261 @@
                 DlParseReloc(symbols,resolve->dynamicInfo[DT_JMPREL], resolve->dynamicInfo[DT_PLTRELSZ], DlDoLazyReloc);
                 resolve->initFlags |= INIT_JMP_RELOCS_DONE;
+        }
+
+        /* May need to make text read-only again. */
+        if (resolve->dynamicInfo[DT_TEXTREL])
+        {
+                SysMemoryProtect(resolve->textAddr, resolve->textLength, 5);
         }
 }