Changeset 78a95d6f in mainline for generic/src/lib/elf.c

Timestamp:

2006-03-13T16:05:43Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

6d9c49a

Parents:

0967877

Message:

Support for loading segments containing .bss section.

File:

• generic/src/lib/elf.c (modified) (9 diffs)

generic/src/lib/elf.c

@@ -33 +33 @@
 #include <mm/as.h>
 #include <mm/frame.h>
+#include <mm/slab.h>
 #include <print.h>
 #include <align.h>
+#include <memstr.h>
+#include <macros.h>
 
 static char *error_codes[] = {
@@ -45 +48 @@
 };
 
-static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
-static int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
+static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
+static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as);
+static int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
 
 /** ELF loader
@@ -71 +75 @@
         }
 
-        if (header->e_phentsize != sizeof(elf_ph_entry_t))
+        if (header->e_phentsize != sizeof(elf_segment_header_t))
+                return EE_INCOMPATIBLE;
+
+        if (header->e_shentsize != sizeof(elf_section_header_t))
                 return EE_INCOMPATIBLE;
 
@@ -78 +85 @@
                 return EE_UNSUPPORTED;
 
-        /* Walk through all program header entries and process them. */
+        /* Walk through all segment headers and process them. */
         for (i = 0; i < header->e_phnum; i++) {
-                rc = program_header_entry(header, &((elf_ph_entry_t *)(((__u8 *) header) + header->e_phoff))[i], as);
+                rc = segment_header(&((elf_segment_header_t *)(((__u8 *) header) + header->e_phoff))[i], header, as);
                 if (rc != EE_OK)
                         return rc;
         }
 
+        /* Inspect all section headers and proccess them. */
+        for (i = 0; i < header->e_shnum; i++) {
+                rc = section_header(&((elf_section_header_t *)(((__u8 *) header) + header->e_shoff))[i], header, as);
+                if (rc != EE_OK)
+                        return rc;
+        }
+
         return EE_OK;
 }
@@ -101 +115 @@
 }
 
-/** Process program header entry.
- *
- * @param entry Program header entry.
+/** Process segment header.
+ *
+ * @param entry Segment header.
+ * @param elf ELF header.
  * @param as Address space into wich the ELF is being loaded.
  *
  * @return EE_OK on success, error code otherwise.
  */
-static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
+static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
 {
         switch (entry->p_type) {
@@ -115 +130 @@
                 break;
             case PT_LOAD:
-                return load_segment(header, entry, as);
+                return load_segment(entry, elf, as);
                 break;
             case PT_DYNAMIC:
@@ -133 +148 @@
  *
  * @param entry Program header entry describing segment to be loaded.
+ * @param elf ELF header.
  * @parma as Address space into wich the ELF is being loaded.
  *
  * @return EE_OK on success, error code otherwise.
  */
-int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
+int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
 {
         as_area_t *a;
         int i, type = 0;
+        size_t segment_size;
+        __u8 *segment;
 
         if (entry->p_align > 1) {
@@ -162 +180 @@
         }
 
+        /*
+         * Check if the virtual address starts on page boundary.
+         */
+        if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr)
+                return EE_UNSUPPORTED;
+
+        /*
+         * Copying the segment out is certainly necessary for segments with p_filesz < p_memsz
+         * because of the effect of .bss-like sections. For security reasons, it looks like a
+         * good idea to copy the segment anyway.
+         */
+        segment_size = ALIGN_UP(max(entry->p_filesz, entry->p_memsz), PAGE_SIZE);
+        segment = malloc(segment_size, 0);
+        if (entry->p_filesz < entry->p_memsz)
+                memsetb((__address) (segment + entry->p_filesz), segment_size - entry->p_filesz, 0);
+        memcpy(segment, (void *) (((__address) elf) + entry->p_offset), entry->p_filesz);
+
         a = as_area_create(as, AS_AREA_TEXT, SIZE2FRAMES(entry->p_memsz), entry->p_vaddr);
         if (!a)
@@ -167 +202 @@
         
         for (i = 0; i < SIZE2FRAMES(entry->p_filesz); i++) {
-                as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) header) + entry->p_offset + i*PAGE_SIZE));
-        }
-        
-        return EE_OK;
-}
+                as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) segment) + i*PAGE_SIZE));
+        }
+        
+        return EE_OK;
+}
+
+/** Process section header.
+ *
+ * @param entry Segment header.
+ * @param elf ELF header.
+ * @param as Address space into wich the ELF is being loaded.
+ *
+ * @return EE_OK on success, error code otherwise.
+ */
+static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as)
+{
+        switch (entry->sh_type) {
+            default:
+                break;
+        }
+        
+        return EE_OK;
+}