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authorH.J. Lu <hjl.tools@gmail.com>2022-01-29 10:56:45 -0800
committerH.J. Lu <hjl.tools@gmail.com>2022-01-31 07:05:48 -0800
commit3fb18fd80c5900cc82748f3320b30516c57d24da (patch)
tree3b31e62ff66968dc1b17408ceb4a601a0a6eefc5 /elf
parent829ea0caca35800c4ffbebced7c3271293811144 (diff)
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elf: Add <dl-r_debug.h>
Add <dl-r_debug.h> to get the adddress of the r_debug structure after
relocation and its offset before relocation from the PT_DYNAMIC segment
to support DT_DEBUG, DT_MIPS_RLD_MAP_REL and DT_MIPS_RLD_MAP.

Co-developed-by: Xi Ruoyao <xry111@mengyan1223.wang>
Diffstat (limited to 'elf')
-rw-r--r--elf/pldd-xx.c34
-rw-r--r--elf/tst-dlmopen4.c15
2 files changed, 24 insertions, 25 deletions
diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
index 1cdfb49c53..30513b423f 100644
--- a/elf/pldd-xx.c
+++ b/elf/pldd-xx.c
@@ -22,6 +22,8 @@
 #define EW_(e, w, t) EW__(e, w, _##t)
 #define EW__(e, w, t) e##w##t
 
+#include <dl-r_debug.h>
+
 struct E(link_map)
 {
   EW(Addr) l_addr;
@@ -126,21 +128,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
 	    != p[i].p_filesz)
 	  error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
 
-	/* Search for the DT_DEBUG entry.  */
+	/* Search for the struct r_debug.  */
 	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
-	  if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
-	    {
-	      struct E(r_debug) r;
-	      if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
-		  != sizeof (r))
-		error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
-
-	      if (r.r_map != 0)
-		{
-		  list = r.r_map;
-		  break;
-		}
-	    }
+	  {
+	    EW(Addr) off = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
+	    off = E(r_debug_offset) (&dyn[j], memfd, off);
+	    if (off != 0)
+	      {
+		struct E(r_debug) r;
+		if (pread (memfd, &r, sizeof (r), off)
+		    != sizeof (r))
+		  error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
+
+		if (r.r_map != 0)
+		  {
+		    list = r.r_map;
+		    break;
+		  }
+	      }
+	  }
 
 	free (dyn);
 	break;
diff --git a/elf/tst-dlmopen4.c b/elf/tst-dlmopen4.c
index d8bcf7e9d5..8456f89053 100644
--- a/elf/tst-dlmopen4.c
+++ b/elf/tst-dlmopen4.c
@@ -25,16 +25,9 @@
 #include <support/check.h>
 #include <support/test-driver.h>
 
-#ifndef ELF_MACHINE_GET_R_DEBUG
-# define ELF_MACHINE_GET_R_DEBUG(d) \
-    (__extension__ ({ 						\
-      struct r_debug_extended *debug;				\
-      if ((d)->d_tag == DT_DEBUG)				\
-	debug = (struct r_debug_extended *) (d)->d_un.d_ptr;	\
-      else							\
-	debug = NULL;						\
-      debug; }))
-#endif
+#define E(x) x
+#define EW(x) ElfW(x)
+#include <dl-r_debug.h>
 
 static int
 do_test (void)
@@ -44,7 +37,7 @@ do_test (void)
 
   for (d = _DYNAMIC; d->d_tag != DT_NULL; ++d)
     {
-      debug = ELF_MACHINE_GET_R_DEBUG (d);
+      debug = (struct r_debug_extended *) r_debug_address (d);
       if (debug != NULL)
 	break;
     }