[PATCH 09/11] elf: call _dl_map_segment() via premap callback

[Stas Sergeev <stsp2@yandex.ru>]

This allows to install custom premap callbacks in the subsequent
patches.

The test-suite was run on x86_64/64 and showed no regressions.

Signed-off-by: Stas Sergeev <stsp2@yandex.ru>
---
 elf/dl-load.c         | 15 ++++++++++++---
 elf/dl-load.h         |  7 ++++++-
 elf/dl-map-segments.h |  8 +++++---
 3 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/elf/dl-load.c b/elf/dl-load.c
index 17f16c7dd0..6415e2517d 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -959,7 +959,8 @@ _ld_map_object_1 (struct link_map *l, void *fd,
                   int mode, struct link_map *loader,
                   void **stack_endp, int *errval_p,
                   const char **errstring_p,
-                  __typeof (do_mmap) *m_map)
+                  __typeof (do_mmap) *m_map,
+                  dl_premap_t *premap)
 {
   const ElfW(Ehdr) *header;
   const ElfW(Phdr) *phdr;
@@ -1159,7 +1160,7 @@ _ld_map_object_1 (struct link_map *l, void *fd,
        l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr
      */
     errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
-				  maplength, has_holes, loader, m_map);
+				  maplength, has_holes, loader, m_map, premap);
     if (__glibc_unlikely (errstring != NULL))
       {
 	/* Mappings can be in an inconsistent state: avoid unmap.  */
@@ -1434,6 +1435,14 @@ do_mmap (void *addr, size_t length, int prot, int flags,
   return __mmap (addr, length, prot, flags, fd, offset);
 }
 
+static void *
+do_map_segment (void *mappref, size_t maplength, size_t mapalign,
+                unsigned prot, void *cookie)
+{
+  return (void *) _dl_map_segment ((ElfW(Addr)) mappref, maplength,
+                                   mapalign, prot);
+}
+
 #ifndef EXTERNAL_MAP_FROM_FD
 static
 #endif
@@ -1564,7 +1573,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
     }
 
   if (_ld_map_object_1 (l, &fd, fbp, mode, loader, stack_endp, &errval,
-                        &errstring, do_mmap))
+                        &errstring, do_mmap, do_map_segment))
     goto lose;
 
   /* We are done mapping in the file.  We no longer need the descriptor.  */
diff --git a/elf/dl-load.h b/elf/dl-load.h
index eff5146acd..00d74979e6 100644
--- a/elf/dl-load.h
+++ b/elf/dl-load.h
@@ -84,6 +84,10 @@ static void *
 do_mmap (void *addr, size_t length, int prot, int flags,
          void *arg, off_t offset);
 
+typedef void *
+(dl_premap_t) (void *mappref, size_t maplength, size_t mapalign,
+	       unsigned prot, void *cookie);
+
 /* This is a subroutine of _dl_map_segments.  It should be called for each
    load command, some time after L->l_addr has been set correctly.  It is
    responsible for setting up the l_text_end and l_phdr fields.  */
@@ -123,7 +127,8 @@ static const char *_dl_map_segments (struct link_map *l, void *fd,
                                      const size_t maplength,
                                      bool has_holes,
                                      struct link_map *loader,
-                                     __typeof (do_mmap) *m_map);
+                                     __typeof (do_mmap) *m_map,
+                                     dl_premap_t *premap);
 
 /* All the error message strings _dl_map_segments might return are
    listed here so that different implementations in different sysdeps
diff --git a/elf/dl-map-segments.h b/elf/dl-map-segments.h
index c5c9bb4163..ca5b2a85d2 100644
--- a/elf/dl-map-segments.h
+++ b/elf/dl-map-segments.h
@@ -82,7 +82,8 @@ _dl_map_segments (struct link_map *l, void *fd,
                   const ElfW(Ehdr) *header, int type,
                   const struct loadcmd loadcmds[], size_t nloadcmds,
                   const size_t maplength, bool has_holes,
-                  struct link_map *loader, __typeof (do_mmap) *m_map)
+                  struct link_map *loader, __typeof (do_mmap) *m_map,
+                  dl_premap_t *premap)
 {
   const struct loadcmd *c = loadcmds;
 
@@ -104,8 +105,9 @@ _dl_map_segments (struct link_map *l, void *fd,
            - MAP_BASE_ADDR (l));
 
       /* Remember which part of the address space this object uses.  */
-      l->l_map_start = _dl_map_segment (mappref, maplength, c->mapalign,
-                                        c->prot);
+      l->l_map_start = (ElfW(Addr)) premap ((void *) mappref,
+                                            maplength, c->mapalign,
+                                            c->prot, fd);
       if (__glibc_unlikely ((void *) l->l_map_start == MAP_FAILED))
         return DL_MAP_SEGMENTS_ERROR_MAP_SEGMENT;
 
-- 
2.37.2