glibc/glibc-dso_deps.patch

@@ -, +, @@ 
 17645)
---
 elf/Makefile  |   1 +
 elf/dl-deps.c | 143 +++++++++++++++++++++++++++++------------------
 elf/dl-fini.c | 176 +++++++++++++++++++++++++++++++---------------------------
 elf/dl-open.c |  74 ++++++++++++++++++++++++
 4 files changed, 256 insertions(+), 138 deletions(-)
--- a/elf/Makefile	
+++ a/elf/Makefile	
@@ -513,6 +513,7 @@ $(objpfx)unload8mod1.so: $(objpfx)unload8mod2.so
 $(objpfx)unload8mod2.so: $(objpfx)unload8mod3.so
 $(objpfx)unload8mod3.so: $(libdl)
 $(objpfx)tst-initordera2.so: $(objpfx)tst-initordera1.so
+$(objpfx)tst-initorderb1.so: $(objpfx)tst-initordera2.so
 $(objpfx)tst-initorderb2.so: $(objpfx)tst-initorderb1.so $(objpfx)tst-initordera2.so
 $(objpfx)tst-initordera3.so: $(objpfx)tst-initorderb2.so $(objpfx)tst-initorderb1.so
 $(objpfx)tst-initordera4.so: $(objpfx)tst-initordera3.so
--- a/elf/dl-deps.c	
+++ a/elf/dl-deps.c	
@@ -139,6 +139,93 @@ cannot load auxiliary `%s' because of empty dynamic string token "	      \
     __result; })
 
 static void
+weight (struct link_map **maps, size_t nmaps, char *seen, unsigned int *w)
+{
+  int i, c;
+  struct link_map *m, **r;
+
+  /* Start at 1 because the first entry is the binary itself. */
+  for (i = 1; i < nmaps; ++i)
+    {
+      m = maps[i];
+      if ((r = m->l_initfini))
+        {
+	  c = 0;
+	  while (*r)
+	    {
+
+	      /* If not a self reference, not being unloaded, and not
+	         already removed from the list, increment the reference
+	         counter. */
+	      if (*r != m && (*r)->l_idx >= 0 && !seen[(*r)->l_idx])
+		++c;
+	      ++r;
+	    }
+
+	  /* Update the {w}eight vector with {c}ount map(s) dependency */
+	  w[i] = c;
+	}
+      else
+	w[i] = 0;
+    }
+}
+
+static void
+sort (struct link_map **maps, size_t nmaps)
+{
+  int c, i, k;
+  unsigned int w[nmaps];
+  char seen[nmaps];
+  struct link_map *t;
+  memset(seen, 0, nmaps);
+
+  /* Use the l_idx field as an unique identifier. */
+  for (i = 0; i < nmaps; ++i)
+    {
+      /* Ensure to not touch a link_map with l_idx < 0 as it is
+         used to flag a dso is being unloaded.  */
+      if (maps[i]->l_idx >= 0)
+	maps[i]->l_idx = i;
+    }
+
+  /* We can skip looking for the binary itself which is at the front
+     of the search list.  */
+  w[0] = 0;
+  seen[0] = 1;
+
+  /* The list is sorted in place, with entries added from end to start. */
+  weight(maps, k = nmaps, seen, w);
+  c = 0;
+  while (c < k)
+    {
+      for (i = k - 1; i >= 1; --i)
+        {
+	  if (w[i] == c && maps[i]->l_idx >= 0)
+	    {
+	      seen[maps[i]->l_idx] = 1;
+
+	      /* Reducing the number of entries or swaping entries
+		 require remaking the {w}eight map. */
+	      if (--k != i)
+		{
+		  t = maps[k];
+		  maps[k] = maps[i];
+		  maps[i] = t;
+		}
+	      weight(maps, k, seen, w);
+	      c = -1;
+	      break;
+	    }
+	}
+
+      /* If c != 0, there are cycles, and the first entry in the map,
+	 with the lowest reference {c}ount is removed attempting to
+	 to break the cycle. */
+      ++c;
+    }
+}
+
+static void
 preload (struct list *known, unsigned int *nlist, struct link_map *map)
 {
   known[*nlist].done = 0;
@@ -611,61 +698,7 @@ Filters not supported with LD_TRACE_PRELINKING"));
   memcpy (l_initfini, map->l_searchlist.r_list,
 	  nlist * sizeof (struct link_map *));
   if (__glibc_likely (nlist > 1))
-    {
-      /* We can skip looking for the binary itself which is at the front
-	 of the search list.  */
-      i = 1;
-      uint16_t seen[nlist];
-      memset (seen, 0, nlist * sizeof (seen[0]));
-      while (1)
-	{
-	  /* Keep track of which object we looked at this round.  */
-	  ++seen[i];
-	  struct link_map *thisp = l_initfini[i];
-
-	  /* Find the last object in the list for which the current one is
-	     a dependency and move the current object behind the object
-	     with the dependency.  */
-	  unsigned int k = nlist - 1;
-	  while (k > i)
-	    {
-	      struct link_map **runp = l_initfini[k]->l_initfini;
-	      if (runp != NULL)
-		/* Look through the dependencies of the object.  */
-		while (*runp != NULL)
-		  if (__glibc_unlikely (*runp++ == thisp))
-		    {
-		      /* Move the current object to the back past the last
-			 object with it as the dependency.  */
-		      memmove (&l_initfini[i], &l_initfini[i + 1],
-			       (k - i) * sizeof (l_initfini[0]));
-		      l_initfini[k] = thisp;
-
-		      if (seen[i + 1] > nlist - i)
-			{
-			  ++i;
-			  goto next_clear;
-			}
-
-		      uint16_t this_seen = seen[i];
-		      memmove (&seen[i], &seen[i + 1],
-			       (k - i) * sizeof (seen[0]));
-		      seen[k] = this_seen;
-
-		      goto next;
-		    }
-
-	      --k;
-	    }
-
-	  if (++i == nlist)
-	    break;
-	next_clear:
-	  memset (&seen[i], 0, (nlist - i) * sizeof (seen[0]));
-
-	next:;
-	}
-    }
+    sort (l_initfini, nlist);
 
   /* Terminate the list of dependencies.  */
   l_initfini[nlist] = NULL;
--- a/elf/dl-fini.c	
+++ a/elf/dl-fini.c	
@@ -26,102 +26,112 @@ 
 typedef void (*fini_t) (void);
 
 
-void
-internal_function
-_dl_sort_fini (struct link_map **maps, size_t nmaps, char *used, Lmid_t ns)
+static void
+weight (struct link_map **maps, size_t nmaps, char *seen, unsigned int *w, int from)
 {
-  /* A list of one element need not be sorted.  */
-  if (nmaps == 1)
-    return;
+  int i, c;
+  struct link_map *m, **r;
+  for (i = from; i < nmaps; ++i)
+    {
+      m = maps[i];
+      if ((r = m->l_initfini))
+        {
+	  c = 0;
+	  while (*r)
+	    {
+	      /* If not a self reference, not being unloaded, and not
+	         already removed from the list, increment the reference
+	         counter. */
+	      if (*r != m && (*r)->l_idx >= 0 && !seen[(*r)->l_idx])
+		++c;
+	      ++r;
+	    }
+	  /* Update the {w}eight vector with {c}ount map(s) dependency */
+	  w[i] = c;
+	}
+      else
+	w[i] = 0;
+    }
+}
+
+
+static void
+sort (struct link_map **maps, size_t nmaps, char *used, Lmid_t ns)
+{
+  int from;
+  int c, i, k;
+  unsigned int w[nmaps];
+  char seen[nmaps];
+  struct link_map *t;
+
+  memset(seen, 0, nmaps);
+
+  /* Use the l_idx field as an unique identifier. */
+  for (i = 0; i < nmaps; ++i)
+    {
+      /* Ensure to not touch a link_map with l_idx < 0 as it is
+         used to flag a dso is being unloaded.  */
+      if (maps[i]->l_idx >= 0)
+	maps[i]->l_idx = i;
+    }
 
   /* We can skip looking for the binary itself which is at the front
      of the search list for the main namespace.  */
-  unsigned int i = ns == LM_ID_BASE;
-  uint16_t seen[nmaps];
-  memset (seen, 0, nmaps * sizeof (seen[0]));
-  while (1)
+  from = ns == LM_ID_BASE;
+  if (from)
     {
-      /* Keep track of which object we looked at this round.  */
-      ++seen[i];
-      struct link_map *thisp = maps[i];
-
-      /* Do not handle ld.so in secondary namespaces and object which
-	 are not removed.  */
-      if (thisp != thisp->l_real || thisp->l_idx == -1)
-	goto skip;
-
-      /* Find the last object in the list for which the current one is
-	 a dependency and move the current object behind the object
-	 with the dependency.  */
-      unsigned int k = nmaps - 1;
-      while (k > i)
-	{
-	  struct link_map **runp = maps[k]->l_initfini;
-	  if (runp != NULL)
-	    /* Look through the dependencies of the object.  */
-	    while (*runp != NULL)
-	      if (__glibc_unlikely (*runp++ == thisp))
-		{
-		move:
-		  /* Move the current object to the back past the last
-		     object with it as the dependency.  */
-		  memmove (&maps[i], &maps[i + 1],
-			   (k - i) * sizeof (maps[0]));
-		  maps[k] = thisp;
-
-		  if (used != NULL)
-		    {
-		      char here_used = used[i];
-		      memmove (&used[i], &used[i + 1],
-			       (k - i) * sizeof (used[0]));
-		      used[k] = here_used;
-		    }
+      w[0] = 0;
+      seen[0] = 1;
+    }
 
-		  if (seen[i + 1] > nmaps - i)
+  /* The list is sorted in place, with entries added from end to start. */
+  weight(maps, k = nmaps, seen, w, from);
+  c = 0;
+  while (c < k)
+    {
+      for (i = k - 1; i >= from; --i)
+        {
+	  t = maps[i];
+	  /* Do not handle ld.so in secondary namespaces and object which
+	     are not removed.  */
+	  if (w[i] == c && maps[i]->l_idx >= 0 && t->l_real == t)
+	    {
+	      seen[maps[i]->l_idx] = 1;
+	      /* Reducing the number of entries or swaping entries
+		 require remaking the {w}eight map. */
+	      if (--k != i)
+		{
+		  maps[i] = maps[k];
+		  maps[k] = t;
+		  if (used)
 		    {
-		      ++i;
-		      goto next_clear;
+		      char c = used[i];
+		      used[i] = used[k];
+		      used[k] = c;
 		    }
-
-		  uint16_t this_seen = seen[i];
-		  memmove (&seen[i], &seen[i + 1], (k - i) * sizeof (seen[0]));
-		  seen[k] = this_seen;
-
-		  goto next;
 		}
-
-	  if (__glibc_unlikely (maps[k]->l_reldeps != NULL))
-	    {
-	      unsigned int m = maps[k]->l_reldeps->act;
-	      struct link_map **relmaps = &maps[k]->l_reldeps->list[0];
-
-	      /* Look through the relocation dependencies of the object.  */
-	      while (m-- > 0)
-		if (__glibc_unlikely (relmaps[m] == thisp))
-		  {
-		    /* If a cycle exists with a link time dependency,
-		       preserve the latter.  */
-		    struct link_map **runp = thisp->l_initfini;
-		    if (runp != NULL)
-		      while (*runp != NULL)
-			if (__glibc_unlikely (*runp++ == maps[k]))
-			  goto ignore;
-		    goto move;
-		  }
-	    ignore:;
+	      weight(maps, k, seen, w, from);
+	      c = -1;
+	      break;
 	    }
-
-	  --k;
 	}
+      /* If c != 0, there are cycles, and the first entry in the map,
+	 with the lowest reference {c}ount is removed attempting to
+	 to break the cycle. */
+      ++c;
+    }
+}
 
-    skip:
-      if (++i == nmaps)
-	break;
-    next_clear:
-      memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0]));
 
-    next:;
-    }
+void
+internal_function
+_dl_sort_fini (struct link_map **maps, size_t nmaps, char *used, Lmid_t ns)
+{
+  /* A list of one element need not be sorted.  */
+  if (nmaps == 1)
+    return;
+
+  sort (maps, nmaps, used, ns);
 }
 
 
--- a/elf/dl-open.c	
+++ a/elf/dl-open.c	
@@ -182,6 +182,80 @@ _dl_find_dso_for_object (const ElfW(Addr) addr)
 rtld_hidden_def (_dl_find_dso_for_object);
 
 static void
+weight (struct link_map **maps, size_t nmaps, char *seen, unsigned int *w)
+{
+  int i, c;
+  struct link_map *m, **r;
+  for (i = 0; i < nmaps; ++i)
+    {
+      m = maps[i];
+      if ((r = m->l_initfini))
+        {
+	  c = 0;
+	  while (*r)
+	    {
+	      /* If not a self reference, not being unloaded, and not
+	         already removed from the list, increment the reference
+	         counter. */
+	      if (*r != m && (*r)->l_idx >= 0 && !seen[(*r)->l_idx])
+		++c;
+	      ++r;
+	    }
+	  /* Update the {w}eight vector with {c}ount map(s) dependency */
+	  w[i] = c;
+	}
+      else
+	w[i] = 0;
+    }
+}
+
+static void
+sort (struct link_map **maps, size_t nmaps)
+{
+  int c, i, k;
+  unsigned int w[nmaps];
+  char  seen[nmaps];
+  struct link_map *t;
+  memset(seen, 0, nmaps);
+  /* Use the l_idx field as an unique identifier. */
+  for (i = 0; i < nmaps; ++i)
+    {
+      /* Ensure to not touch a link_map with l_idx < 0 as it is
+         used to flag a dso is being unloaded.  */
+      if (maps[i]->l_idx >= 0)
+	maps[i]->l_idx = i;
+    }
+  /* The list is sorted in place, with entries added from end to start. */
+  weight(maps, k = nmaps, seen, w);
+  c = 0;
+  while (c < k)
+    {
+      for (i = k - 1; i >= 0; --i)
+        {
+	  if (w[i] == c && maps[i]->l_idx >= 0)
+	    {
+	      seen[maps[i]->l_idx] = 1;
+	      /* Reducing the number of entries or swaping entries
+		 require remaking the {w}eight map. */
+	      if (--k != i)
+		{
+		  t = maps[k];
+		  maps[k] = maps[i];
+		  maps[i] = t;
+		}
+	      weight(maps, k, seen, w);
+	      c = -1;
+	      break;
+	    }
+	}
+      /* If c != 0, there are cycles, and the first entry in the map,
+	 with the lowest reference {c}ount is removed attempting to
+	 to break the cycle. */
+      ++c;
+    }
+}
+
+static void
 dl_open_worker (void *a)
 {
   struct dl_open_args *args = a;
--