[PATCH 17/22] libelf: abolish obsolete macros

[Ian Jackson <ian.jackson@eu.citrix.com>]

Abolish ELF_PTRVAL_[CONST_]{CHAR,VOID}; change uses to elf_ptrval.
Abolish ELF_HANDLE_DECL_NONCONST; change uses to ELF_HANDLE_DECL.
Abolish ELF_OBSOLETE_VOIDP_CAST; simply remove all uses.

No functional change.  (Verified by diffing assembler output.)

This is part of the fix to a security issue, XSA-55.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

v2: New patch.
---
 tools/libxc/xc_dom_elfloader.c     |    8 +++---
 tools/xcutils/readnotes.c          |    2 +-
 xen/common/libelf/libelf-dominfo.c |    6 ++--
 xen/common/libelf/libelf-loader.c  |   24 +++++++++---------
 xen/common/libelf/libelf-tools.c   |   24 +++++++++---------
 xen/include/xen/libelf.h           |   48 +++++++++---------------------------
 6 files changed, 44 insertions(+), 68 deletions(-)

diff --git a/tools/libxc/xc_dom_elfloader.c b/tools/libxc/xc_dom_elfloader.c
index 81c2519..1d2727e 100644
--- a/tools/libxc/xc_dom_elfloader.c
+++ b/tools/libxc/xc_dom_elfloader.c
@@ -114,9 +114,9 @@ static elf_errorstatus xc_dom_load_elf_symtab(struct xc_dom_image *dom,
                                   struct elf_binary *elf, bool load)
 {
     struct elf_binary syms;
-    ELF_HANDLE_DECL_NONCONST(elf_shdr) shdr; ELF_HANDLE_DECL(elf_shdr) shdr2;
+    ELF_HANDLE_DECL(elf_shdr) shdr; ELF_HANDLE_DECL(elf_shdr) shdr2;
     xen_vaddr_t symtab, maxaddr;
-    ELF_PTRVAL_CHAR hdr;
+    elf_ptrval hdr;
     size_t size;
     unsigned h, count, type, i, tables = 0;
     unsigned long *strtab_referenced = NULL;
@@ -240,7 +240,7 @@ static elf_errorstatus xc_dom_load_elf_symtab(struct xc_dom_image *dom,
 
     for ( h = 0; h < count; h++ )
     {
-        shdr = ELF_OBSOLETE_VOIDP_CAST elf_shdr_by_index(&syms, h);
+        shdr = elf_shdr_by_index(&syms, h);
         if ( !elf_access_ok(elf, ELF_HANDLE_PTRVAL(shdr), 1) )
             /* input has an insane section header count field */
             break;
@@ -276,7 +276,7 @@ static elf_errorstatus xc_dom_load_elf_symtab(struct xc_dom_image *dom,
             if ( load )
             {
                 shdr2 = elf_shdr_by_index(elf, h);
-                elf_memcpy_safe(elf, ELF_OBSOLETE_VOIDP_CAST elf_section_start(&syms, shdr),
+                elf_memcpy_safe(elf, elf_section_start(&syms, shdr),
                        elf_section_start(elf, shdr2),
                        size);
             }
diff --git a/tools/xcutils/readnotes.c b/tools/xcutils/readnotes.c
index 88a83fa..76c3226 100644
--- a/tools/xcutils/readnotes.c
+++ b/tools/xcutils/readnotes.c
@@ -80,7 +80,7 @@ static void print_l1_mfn_valid_note(const char *prefix, struct elf_binary *elf,
 				    ELF_HANDLE_DECL(elf_note) note)
 {
 	unsigned descsz = elf_uval(elf, note, descsz);
-	ELF_PTRVAL_CONST_VOID desc = elf_note_desc(elf, note);
+	elf_ptrval desc = elf_note_desc(elf, note);
 
 	/* XXX should be able to cope with a list of values. */
 	switch ( descsz / 2 )
diff --git a/xen/common/libelf/libelf-dominfo.c b/xen/common/libelf/libelf-dominfo.c
index b0ba4d8..c368f24 100644
--- a/xen/common/libelf/libelf-dominfo.c
+++ b/xen/common/libelf/libelf-dominfo.c
@@ -220,8 +220,8 @@ elf_errorstatus elf_xen_parse_note(struct elf_binary *elf,
 
 static unsigned elf_xen_parse_notes(struct elf_binary *elf,
                                struct elf_dom_parms *parms,
-                               ELF_PTRVAL_CONST_VOID start,
-                               ELF_PTRVAL_CONST_VOID end,
+                               elf_ptrval start,
+                               elf_ptrval end,
                                unsigned *total_note_count)
 {
     unsigned xen_elfnotes = 0;
@@ -258,7 +258,7 @@ static unsigned elf_xen_parse_notes(struct elf_binary *elf,
 elf_errorstatus elf_xen_parse_guest_info(struct elf_binary *elf,
                              struct elf_dom_parms *parms)
 {
-    ELF_PTRVAL_CONST_CHAR h;
+    elf_ptrval h;
     unsigned char name[32], value[128];
     unsigned len;
 
diff --git a/xen/common/libelf/libelf-loader.c b/xen/common/libelf/libelf-loader.c
index 47957aa..c5e9141 100644
--- a/xen/common/libelf/libelf-loader.c
+++ b/xen/common/libelf/libelf-loader.c
@@ -118,7 +118,7 @@ void elf_set_log(struct elf_binary *elf, elf_log_callback *log_callback,
 }
 
 static elf_errorstatus elf_load_image(struct elf_binary *elf,
-                          ELF_PTRVAL_VOID dst, ELF_PTRVAL_CONST_VOID src,
+                          elf_ptrval dst, elf_ptrval src,
                           uint64_t filesz, uint64_t memsz)
 {
     elf_memcpy_safe(elf, dst, src, filesz);
@@ -132,7 +132,7 @@ void elf_set_verbose(struct elf_binary *elf)
     elf->verbose = 1;
 }
 
-static elf_errorstatus elf_load_image(struct elf_binary *elf, ELF_PTRVAL_VOID dst, ELF_PTRVAL_CONST_VOID src, uint64_t filesz, uint64_t memsz)
+static elf_errorstatus elf_load_image(struct elf_binary *elf, elf_ptrval dst, elf_ptrval src, uint64_t filesz, uint64_t memsz)
 {
     elf_errorstatus rc;
     if ( filesz > ULONG_MAX || memsz > ULONG_MAX )
@@ -187,12 +187,12 @@ void elf_parse_bsdsyms(struct elf_binary *elf, uint64_t pstart)
 
 static void elf_load_bsdsyms(struct elf_binary *elf)
 {
-    ELF_HANDLE_DECL_NONCONST(elf_ehdr) sym_ehdr;
+    ELF_HANDLE_DECL(elf_ehdr) sym_ehdr;
     unsigned long sz;
-    ELF_PTRVAL_VOID maxva;
-    ELF_PTRVAL_VOID symbase;
-    ELF_PTRVAL_VOID symtab_addr;
-    ELF_HANDLE_DECL_NONCONST(elf_shdr) shdr;
+    elf_ptrval maxva;
+    elf_ptrval symbase;
+    elf_ptrval symtab_addr;
+    ELF_HANDLE_DECL(elf_shdr) shdr;
     unsigned i, type;
 
     if ( !elf->bsd_symtab_pstart )
@@ -226,7 +226,7 @@ do {                                            \
     elf_memcpy_safe(elf, ELF_HANDLE_PTRVAL(shdr),
                     ELF_IMAGE_BASE(elf) + elf_uval(elf, elf->ehdr, e_shoff),
                     sz);
-    maxva = ELF_OBSOLETE_VOIDP_CAST elf_round_up(elf, (unsigned long)maxva + sz);
+    maxva = elf_round_up(elf, (unsigned long)maxva + sz);
 
     for ( i = 0; i < elf_shdr_count(elf); i++ )
     {
@@ -242,7 +242,7 @@ do {                                            \
              elf_memcpy_safe(elf, maxva, elf_section_start(elf, shdr), sz);
              /* Mangled to be based on ELF header location. */
              elf_hdr_elm(elf, shdr, sh_offset, maxva - symtab_addr);
-             maxva = ELF_OBSOLETE_VOIDP_CAST elf_round_up(elf, (unsigned long)maxva + sz);
+             maxva = elf_round_up(elf, (unsigned long)maxva + sz);
         }
         old_shdr_p = ELF_HANDLE_PTRVAL(shdr);
         new_shdr_p = old_shdr_p + elf_uval(elf, elf->ehdr, e_shentsize);
@@ -297,7 +297,7 @@ elf_errorstatus elf_load_binary(struct elf_binary *elf)
 {
     ELF_HANDLE_DECL(elf_phdr) phdr;
     uint64_t i, count, paddr, offset, filesz, memsz;
-    ELF_PTRVAL_VOID dest;
+    elf_ptrval dest;
     /*
      * Let bizarre ELFs write the output image up to twice; this
      * calculation is just to ensure our copying loop is no worse than
@@ -334,7 +334,7 @@ elf_errorstatus elf_load_binary(struct elf_binary *elf)
         remain_allow_copy -= memsz;
 
         elf_msg(elf, "%s: phdr %" PRIu64 " at 0x%"ELF_PRPTRVAL" -> 0x%"ELF_PRPTRVAL"\n",
-                __func__, i, dest, (ELF_PTRVAL_VOID)(dest + filesz));
+                __func__, i, dest, (elf_ptrval)(dest + filesz));
         if ( elf_load_image(elf, dest, ELF_IMAGE_BASE(elf) + offset, filesz, memsz) != 0 )
             return -1;
     }
@@ -343,7 +343,7 @@ elf_errorstatus elf_load_binary(struct elf_binary *elf)
     return 0;
 }
 
-ELF_PTRVAL_VOID elf_get_ptr(struct elf_binary *elf, unsigned long addr)
+elf_ptrval elf_get_ptr(struct elf_binary *elf, unsigned long addr)
 {
     return ELF_REALPTR2PTRVAL(elf->dest_base) + addr - elf->pstart;
 }
diff --git a/xen/common/libelf/libelf-tools.c b/xen/common/libelf/libelf-tools.c
index ef13b0d..dae210e 100644
--- a/xen/common/libelf/libelf-tools.c
+++ b/xen/common/libelf/libelf-tools.c
@@ -171,7 +171,7 @@ ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_name(struct elf_binary *elf, const char *n
 ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_index(struct elf_binary *elf, unsigned index)
 {
     uint64_t count = elf_shdr_count(elf);
-    ELF_PTRVAL_CONST_VOID ptr;
+    elf_ptrval ptr;
 
     if ( index >= count )
         return ELF_INVALID_HANDLE(elf_shdr);
@@ -185,7 +185,7 @@ ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_index(struct elf_binary *elf, unsigned ind
 ELF_HANDLE_DECL(elf_phdr) elf_phdr_by_index(struct elf_binary *elf, unsigned index)
 {
     uint64_t count = elf_uval(elf, elf->ehdr, e_phnum);
-    ELF_PTRVAL_CONST_VOID ptr;
+    elf_ptrval ptr;
 
     if ( index >= count )
         return ELF_INVALID_HANDLE(elf_phdr);
@@ -233,24 +233,24 @@ const char *elf_strfmt(struct elf_binary *elf, elf_ptrval start)
     return str;
 }
 
-ELF_PTRVAL_CONST_VOID elf_section_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr)
+elf_ptrval elf_section_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr)
 {
     return ELF_IMAGE_BASE(elf) + elf_uval(elf, shdr, sh_offset);
 }
 
-ELF_PTRVAL_CONST_VOID elf_section_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr)
+elf_ptrval elf_section_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr)
 {
     return ELF_IMAGE_BASE(elf)
         + elf_uval(elf, shdr, sh_offset) + elf_uval(elf, shdr, sh_size);
 }
 
-ELF_PTRVAL_CONST_VOID elf_segment_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr)
+elf_ptrval elf_segment_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr)
 {
     return ELF_IMAGE_BASE(elf)
         + elf_uval(elf, phdr, p_offset);
 }
 
-ELF_PTRVAL_CONST_VOID elf_segment_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr)
+elf_ptrval elf_segment_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr)
 {
     return ELF_IMAGE_BASE(elf)
         + elf_uval(elf, phdr, p_offset) + elf_uval(elf, phdr, p_filesz);
@@ -258,8 +258,8 @@ ELF_PTRVAL_CONST_VOID elf_segment_end(struct elf_binary *elf, ELF_HANDLE_DECL(el
 
 ELF_HANDLE_DECL(elf_sym) elf_sym_by_name(struct elf_binary *elf, const char *symbol)
 {
-    ELF_PTRVAL_CONST_VOID ptr = elf_section_start(elf, elf->sym_tab);
-    ELF_PTRVAL_CONST_VOID end = elf_section_end(elf, elf->sym_tab);
+    elf_ptrval ptr = elf_section_start(elf, elf->sym_tab);
+    elf_ptrval end = elf_section_end(elf, elf->sym_tab);
     ELF_HANDLE_DECL(elf_sym) sym;
     uint64_t info, name;
     const char *sym_name;
@@ -283,7 +283,7 @@ ELF_HANDLE_DECL(elf_sym) elf_sym_by_name(struct elf_binary *elf, const char *sym
 
 ELF_HANDLE_DECL(elf_sym) elf_sym_by_index(struct elf_binary *elf, unsigned index)
 {
-    ELF_PTRVAL_CONST_VOID ptr = elf_section_start(elf, elf->sym_tab);
+    elf_ptrval ptr = elf_section_start(elf, elf->sym_tab);
     ELF_HANDLE_DECL(elf_sym) sym;
 
     sym = ELF_MAKE_HANDLE(elf_sym, ptr + index * elf_size(elf, sym));
@@ -295,7 +295,7 @@ const char *elf_note_name(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note
     return elf_strval(elf, ELF_HANDLE_PTRVAL(note) + elf_size(elf, note));
 }
 
-ELF_PTRVAL_CONST_VOID elf_note_desc(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note)
+elf_ptrval elf_note_desc(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note)
 {
     unsigned namesz = (elf_uval(elf, note, namesz) + 3) & ~3;
 
@@ -304,7 +304,7 @@ ELF_PTRVAL_CONST_VOID elf_note_desc(struct elf_binary *elf, ELF_HANDLE_DECL(elf_
 
 uint64_t elf_note_numeric(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note)
 {
-    ELF_PTRVAL_CONST_VOID desc = elf_note_desc(elf, note);
+    elf_ptrval desc = elf_note_desc(elf, note);
     unsigned descsz = elf_uval(elf, note, descsz);
 
     switch (descsz)
@@ -322,7 +322,7 @@ uint64_t elf_note_numeric(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note
 uint64_t elf_note_numeric_array(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note,
                                 unsigned int unitsz, unsigned int idx)
 {
-    ELF_PTRVAL_CONST_VOID desc = elf_note_desc(elf, note);
+    elf_ptrval desc = elf_note_desc(elf, note);
     unsigned descsz = elf_uval(elf, note, descsz);
 
     if ( descsz % unitsz || idx >= descsz / unitsz )
diff --git a/xen/include/xen/libelf.h b/xen/include/xen/libelf.h
index 4ca6b8f..140effb 100644
--- a/xen/include/xen/libelf.h
+++ b/xen/include/xen/libelf.h
@@ -61,13 +61,8 @@ typedef void elf_log_callback(struct elf_binary*, void *caller_data,
 /*
  * We abstract away the pointerness of these pointers, replacing
  * various void*, char* and struct* with the following:
- *   PTRVAL      A pointer to a byte; one can do pointer arithmetic
+ *   elf_ptrval  A pointer to a byte; one can do pointer arithmetic
  *               on this.
- *               This replaces variables which were char*,void*
- *               and their const versions, so we provide four
- *               different obsolete declaration macros:
- *                   ELF_PTRVAL_{,CONST}{VOID,CHAR}
- *               New code can simply use the elf_ptrval typedef.
  *   HANDLE      A pointer to a struct.  There is one of these types
  *               for each pointer type - that is, for each "structname".
  *               In the arguments to the various HANDLE macros, structname
@@ -76,8 +71,6 @@ typedef void elf_log_callback(struct elf_binary*, void *caller_data,
  *               pointers.  In the current code attempts to do so will
  *               compile, but in the next patch this will become a
  *               compile error.
- *               We also provide a second declaration macro for
- *               pointers which were to const; this is obsolete.
  */
 
 typedef uintptr_t elf_ptrval;
@@ -85,15 +78,9 @@ typedef uintptr_t elf_ptrval;
 #define ELF_REALPTR2PTRVAL(realpointer) ((elf_ptrval)(realpointer))
   /* Converts an actual C pointer into a PTRVAL */
 
-#define ELF_HANDLE_DECL_NONCONST(structname) structname##_handle /*obsolete*/
 #define ELF_HANDLE_DECL(structname)          structname##_handle
   /* Provides a type declaration for a HANDLE. */
 
-#define ELF_PTRVAL_VOID              elf_ptrval /*obsolete*/
-#define ELF_PTRVAL_CHAR              elf_ptrval /*obsolete*/
-#define ELF_PTRVAL_CONST_VOID        elf_ptrval /*obsolete*/
-#define ELF_PTRVAL_CONST_CHAR        elf_ptrval /*obsolete*/
-
 #ifdef __XEN__
 # define ELF_PRPTRVAL "lu"
   /*
@@ -124,17 +111,6 @@ typedef uintptr_t elf_ptrval;
 #define ELF_HANDLE_PTRVAL(handleval)      ((handleval).ptrval)
   /* Converts a HANDLE to a PTRVAL. */
 
-#define ELF_OBSOLETE_VOIDP_CAST /*empty*/
-  /*
-   * In some places the old code used to need to
-   *  - cast away const (the existing code uses const a fair
-   *    bit but actually sometimes wants to write to its input)
-   *    from a PTRVAL.
-   *  - convert an integer representing a pointer to a PTRVAL
-   * Nowadays all of these re uintptr_ts so there is no const problem
-   * and no need for any casting.
-   */
-
 #define ELF_UNSAFE_PTR(ptrval) ((void*)(elf_ptrval)(ptrval))
   /*
    * Turns a PTRVAL into an actual C pointer.  Before this is done
@@ -211,7 +187,7 @@ struct elf_binary {
     char data;
 
     ELF_HANDLE_DECL(elf_ehdr) ehdr;
-    ELF_PTRVAL_CONST_CHAR sec_strtab;
+    elf_ptrval sec_strtab;
     ELF_HANDLE_DECL(elf_shdr) sym_tab;
     uint64_t sym_strtab;
 
@@ -289,7 +265,7 @@ struct elf_binary {
    * str should be a HANDLE.
    */
 
-uint64_t elf_access_unsigned(struct elf_binary *elf, ELF_PTRVAL_CONST_VOID ptr,
+uint64_t elf_access_unsigned(struct elf_binary *elf, elf_ptrval ptr,
                              uint64_t offset, size_t size);
   /* Reads a field at arbitrary offset and alignemnt */
 
@@ -341,17 +317,17 @@ ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_index(struct elf_binary *elf, unsigned ind
 ELF_HANDLE_DECL(elf_phdr) elf_phdr_by_index(struct elf_binary *elf, unsigned index);
 
 const char *elf_section_name(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr); /* might return NULL if inputs are invalid */
-ELF_PTRVAL_CONST_VOID elf_section_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr);
-ELF_PTRVAL_CONST_VOID elf_section_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr);
+elf_ptrval elf_section_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr);
+elf_ptrval elf_section_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_shdr) shdr);
 
-ELF_PTRVAL_CONST_VOID elf_segment_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr);
-ELF_PTRVAL_CONST_VOID elf_segment_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr);
+elf_ptrval elf_segment_start(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr);
+elf_ptrval elf_segment_end(struct elf_binary *elf, ELF_HANDLE_DECL(elf_phdr) phdr);
 
 ELF_HANDLE_DECL(elf_sym) elf_sym_by_name(struct elf_binary *elf, const char *symbol);
 ELF_HANDLE_DECL(elf_sym) elf_sym_by_index(struct elf_binary *elf, unsigned index);
 
 const char *elf_note_name(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note); /* may return NULL */
-ELF_PTRVAL_CONST_VOID elf_note_desc(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note);
+elf_ptrval elf_note_desc(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note);
 uint64_t elf_note_numeric(struct elf_binary *elf, ELF_HANDLE_DECL(elf_note) note);
 uint64_t elf_note_numeric_array(struct elf_binary *, ELF_HANDLE_DECL(elf_note),
                                 unsigned int unitsz, unsigned int idx);
@@ -378,7 +354,7 @@ void elf_set_log(struct elf_binary *elf, elf_log_callback*,
 void elf_parse_binary(struct elf_binary *elf);
 elf_errorstatus elf_load_binary(struct elf_binary *elf);
 
-ELF_PTRVAL_VOID elf_get_ptr(struct elf_binary *elf, unsigned long addr);
+elf_ptrval elf_get_ptr(struct elf_binary *elf, unsigned long addr);
 uint64_t elf_lookup_addr(struct elf_binary *elf, const char *symbol);
 
 void elf_parse_bsdsyms(struct elf_binary *elf, uint64_t pstart); /* private */
@@ -413,9 +389,9 @@ struct xen_elfnote {
 
 struct elf_dom_parms {
     /* raw */
-    ELF_PTRVAL_CONST_CHAR guest_info;
-    ELF_PTRVAL_CONST_VOID elf_note_start;
-    ELF_PTRVAL_CONST_VOID elf_note_end;
+    elf_ptrval guest_info;
+    elf_ptrval elf_note_start;
+    elf_ptrval elf_note_end;
     struct xen_elfnote elf_notes[XEN_ELFNOTE_MAX + 1];
 
     /* parsed */
-- 
1.7.2.5