Rewrite the bits of the solib code to handle implentations where dlopen

may insert into the list of loaded libraries (ours is one) instead of
appending to the end of the list.  Also cope with dlclose() removing
libraries from the list.

1 files changed, 196 insertions, 86 deletions

diff --git a/contrib/gdb/gdb/solib.c b/contrib/gdb/gdb/solib.c
index 61b68ad..b4d3e30 100644
--- a/contrib/gdb/gdb/solib.c
+++ b/contrib/gdb/gdb/solib.c
@@ -170,7 +170,13 @@ static int
 symbol_add_stub PARAMS ((char *));
 
 static struct so_list *
-find_solib PARAMS ((struct so_list *));
+alloc_solib PARAMS ((struct link_map *));
+
+static void
+free_solib PARAMS ((struct so_list *));
+
+static struct so_list *
+find_solib PARAMS ((struct so_list *, int maybe_changed));
 
 static struct link_map *
 first_link_map_member PARAMS ((void));
@@ -845,11 +851,106 @@ first_link_map_member ()
 
 LOCAL FUNCTION
 
+	free_solib -- free a so_list structure
+
+SYNOPSIS
+
+	void free_solib (struct so_list *so_list_ptr)
+
+DESCRIPTION
+
+	Free the memory used by a struct so_list.
+
+ */
+
+void
+free_solib (so)
+     struct so_list *so;
+{
+  char *bfd_filename;
+  if (so -> sections)
+    {
+      free ((PTR)so -> sections);
+    }
+  if (so -> abfd)
+    {
+      bfd_filename = bfd_get_filename (so -> abfd);
+      if (!bfd_close (so -> abfd))
+	warning ("cannot close \"%s\": %s",
+		 bfd_filename, bfd_errmsg (bfd_get_error ()));
+    }
+  else
+    /* This happens for the executable on SVR4.  */
+    bfd_filename = NULL;
+      
+  if (bfd_filename)
+    free ((PTR)bfd_filename);
+  free ((PTR)so);
+}
+
+/*
+
+LOCAL FUNCTION
+
+	alloc_solib -- free a so_list structure
+
+SYNOPSIS
+
+	struct so_list *alloc_solib (struct link_map *lm)
+
+DESCRIPTION
+
+	Allocate the struct so_list to cache debugging information
+	for a struct link_map entry in the target.
+
+ */
+
+struct so_list *
+alloc_solib (lm)
+     struct link_map *lm;
+{
+  struct so_list *new;
+
+  /* Get next link map structure from inferior image and build a local
+	 abbreviated load_map structure */
+  new = (struct so_list *) xmalloc (sizeof (struct so_list));
+  memset ((char *) new, 0, sizeof (struct so_list));
+  new -> lmaddr = lm;
+
+  read_memory ((CORE_ADDR) lm, (char *) &(new -> lm),
+	       sizeof (struct link_map));
+  /* For SVR4 versions, the first entry in the link map is for the
+	 inferior executable, so we must ignore it.  For some versions of
+	 SVR4, it has no name.  For others (Solaris 2.3 for example), it
+	 does have a name, so we can no longer use a missing name to
+	 decide when to ignore it. */
+  if (!IGNORE_FIRST_LINK_MAP_ENTRY (new -> lm))
+    {
+      int errcode;
+      char *buffer;
+      target_read_string ((CORE_ADDR) LM_NAME (new), &buffer,
+			  MAX_PATH_SIZE - 1, &errcode);
+      if (errcode != 0)
+	error ("find_solib: Can't read pathname for load map: %s\n",
+	       safe_strerror (errcode));
+      strncpy (new -> so_name, buffer, MAX_PATH_SIZE - 1);
+      new -> so_name[MAX_PATH_SIZE - 1] = '\0';
+      free (buffer);
+      solib_map_sections (new);
+    }      
+
+  return new;
+}
+
+/*
+
+LOCAL FUNCTION
+
 	find_solib -- step through list of shared objects
 
 SYNOPSIS
 
-	struct so_list *find_solib (struct so_list *so_list_ptr)
+	struct so_list *find_solib (struct so_list *so_list_ptr, int maybe_changed)
 
 DESCRIPTION
 
@@ -862,95 +963,122 @@ DESCRIPTION
 
 	The arg and return value are "struct link_map" pointers, as defined
 	in <link.h>.
+
+	If it is expected that the contents of the shared library list has changed
+	(e.g. when the special shared library breakpoint is hit) then pass non-zero
+	for maybe_changed, otherwise zero.
  */
 
 static struct so_list *
-find_solib (so_list_ptr)
+find_solib (so_list_ptr, maybe_changed)
      struct so_list *so_list_ptr;	/* Last lm or NULL for first one */
+     int maybe_changed;			/* non-zero if shlib list might have changed */
 {
-  struct so_list *so_list_next = NULL;
   struct link_map *lm = NULL;
   struct so_list *new;
+  struct so_list *p, **prev;
   
   if (so_list_ptr == NULL)
     {
-      /* We are setting up for a new scan through the loaded images. */
-      if ((so_list_next = so_list_head) == NULL)
+      struct so_list **map;
+
+      /* If we have not already read in the dynamic linking structures
+	 from the inferior, lookup the address of the base structure. */
+      if (debug_base == 0)
+	debug_base = locate_base ();
+      if (debug_base != 0)
 	{
-	  /* We have not already read in the dynamic linking structures
-	     from the inferior, lookup the address of the base structure. */
-	  debug_base = locate_base ();
-	  if (debug_base != 0)
-	    {
-	      /* Read the base structure in and find the address of the first
-		 link map list member. */
-	      lm = first_link_map_member ();
-	    }
+	  /* Read the base structure in and find the address of the first
+	     link map list member. */
+	  lm = first_link_map_member ();
 	}
+      else
+	lm = NULL;
+
+      prev = &so_list_head;
+      so_list_ptr = so_list_head;
     }
   else
     {
       /* We have been called before, and are in the process of walking
-	 the shared library list.  Advance to the next shared object. */
-      if ((lm = LM_NEXT (so_list_ptr)) == NULL)
+	 the shared library list.  Advance to the next shared object.
+
+	 Always read from the target to check to see if any were
+	 added, but be quiet if we can't read from the target any more. */
+      int status = target_read_memory ((CORE_ADDR) so_list_ptr -> lmaddr,
+				       (char *) &(so_list_ptr -> lm),
+				       sizeof (struct link_map));
+
+      if (status == 0)
 	{
-	  /* We have hit the end of the list, so check to see if any were
-	     added, but be quiet if we can't read from the target any more. */
-	  int status = target_read_memory ((CORE_ADDR) so_list_ptr -> lmaddr,
-					   (char *) &(so_list_ptr -> lm),
-					   sizeof (struct link_map));
-	  if (status == 0)
+	  lm = LM_NEXT (so_list_ptr);
+	}
+      else
+	{
+	  lm = NULL;
+	}
+
+      prev = &so_list_ptr -> next;
+      so_list_ptr = so_list_ptr -> next;
+    }
+
+  /* If we don't believe that the list has changed, just return the cached copy. */
+  if (!maybe_changed)
+      return (so_list_ptr);
+
+  /* At this point, lm is the address of the next list element in the target and
+     so_list_ptr is our cached entry for it. */
+
+  if (lm != NULL)
+    {
+      if (so_list_ptr == NULL || so_list_ptr -> lmaddr != lm)
+	{
+	  /* We have detected a change in the list.  Check for a deletion by searching
+	     forward in the cached list */
+	  if (so_list_ptr)
 	    {
-	      lm = LM_NEXT (so_list_ptr);
+	      for (p = so_list_ptr -> next; p; p = p -> next)
+		if (p -> lmaddr == lm)
+		  break;
 	    }
 	  else
+	    p = NULL;
+
+	  if (p)
 	    {
-	      lm = NULL;
+	      /* This lib has been deleted */
+	      while (so_list_ptr != p)
+		{
+		  *prev = so_list_ptr -> next;
+		  free_solib (so_list_ptr);
+		  so_list_ptr = *prev;
+		}
+	    }
+	  else
+	    {
+	      /* A new lib has been inserted into the list */
+	      new = alloc_solib (lm);
+	      new -> next = so_list_ptr;
+	      *prev = new;
+	      so_list_ptr = new;
 	    }
 	}
-      so_list_next = so_list_ptr -> next;
     }
-  if ((so_list_next == NULL) && (lm != NULL))
+  else
     {
-      /* Get next link map structure from inferior image and build a local
-	 abbreviated load_map structure */
-      new = (struct so_list *) xmalloc (sizeof (struct so_list));
-      memset ((char *) new, 0, sizeof (struct so_list));
-      new -> lmaddr = lm;
-      /* Add the new node as the next node in the list, or as the root
-	 node if this is the first one. */
       if (so_list_ptr != NULL)
 	{
-	  so_list_ptr -> next = new;
+	  /* Libs have been deleted from the end of the list */
+	  while (so_list_ptr != NULL)
+	    {
+	      *prev = so_list_ptr -> next;
+	      free_solib (so_list_ptr);
+	      so_list_ptr = *prev;
+	    }
 	}
-      else
-	{
-	  so_list_head = new;
-	}      
-      so_list_next = new;
-      read_memory ((CORE_ADDR) lm, (char *) &(new -> lm),
-		   sizeof (struct link_map));
-      /* For SVR4 versions, the first entry in the link map is for the
-	 inferior executable, so we must ignore it.  For some versions of
-	 SVR4, it has no name.  For others (Solaris 2.3 for example), it
-	 does have a name, so we can no longer use a missing name to
-	 decide when to ignore it. */
-      if (!IGNORE_FIRST_LINK_MAP_ENTRY (new -> lm))
-	{
-	  int errcode;
-	  char *buffer;
-	  target_read_string ((CORE_ADDR) LM_NAME (new), &buffer,
-			      MAX_PATH_SIZE - 1, &errcode);
-	  if (errcode != 0)
-	    error ("find_solib: Can't read pathname for load map: %s\n",
-		   safe_strerror (errcode));
-	  strncpy (new -> so_name, buffer, MAX_PATH_SIZE - 1);
-	  new -> so_name[MAX_PATH_SIZE - 1] = '\0';
-	  free (buffer);
-	  solib_map_sections (new);
-	}      
     }
-  return (so_list_next);
+
+  return (so_list_ptr);
 }
 
 /* A small stub to get us past the arg-passing pinhole of catch_errors.  */
@@ -1029,7 +1157,7 @@ solib_add (arg_string, from_tty, target)
       /* Count how many new section_table entries there are.  */
       so = NULL;
       count = 0;
-      while ((so = find_solib (so)) != NULL)
+      while ((so = find_solib (so, 1)) != NULL)
 	{
 	  if (so -> so_name[0] && !match_main (so -> so_name))
 	    {
@@ -1071,7 +1199,7 @@ solib_add (arg_string, from_tty, target)
 	    }
 
 	  /* Add these section table entries to the target's table.  */
-	  while ((so = find_solib (so)) != NULL)
+	  while ((so = find_solib (so, 1)) != NULL)
 	    {
 	      if (so -> so_name[0])
 		{
@@ -1086,7 +1214,7 @@ solib_add (arg_string, from_tty, target)
     }
   
   /* Now add the symbol files.  */
-  while ((so = find_solib (so)) != NULL)
+  while ((so = find_solib (so, 1)) != NULL)
     {
       if (so -> so_name[0] && re_exec (so -> so_name) && 
       !match_main (so -> so_name))
@@ -1148,7 +1276,7 @@ info_sharedlibrary_command (ignore, from_tty)
       printf_unfiltered ("No exec file.\n");
       return;
     }
-  while ((so = find_solib (so)) != NULL)
+  while ((so = find_solib (so, 0)) != NULL)
     {
       if (so -> so_name[0])
 	{
@@ -1206,7 +1334,7 @@ solib_address (address)
 {
   register struct so_list *so = 0;   	/* link map state variable */
   
-  while ((so = find_solib (so)) != NULL)
+  while ((so = find_solib (so, 0)) != NULL)
     {
       if (so -> so_name[0])
 	{
@@ -1224,29 +1352,11 @@ void
 clear_solib()
 {
   struct so_list *next;
-  char *bfd_filename;
   
   while (so_list_head)
     {
-      if (so_list_head -> sections)
-	{
-	  free ((PTR)so_list_head -> sections);
-	}
-      if (so_list_head -> abfd)
-	{
-	  bfd_filename = bfd_get_filename (so_list_head -> abfd);
-	  if (!bfd_close (so_list_head -> abfd))
-	    warning ("cannot close \"%s\": %s",
-		     bfd_filename, bfd_errmsg (bfd_get_error ()));
-	}
-      else
-	/* This happens for the executable on SVR4.  */
-	bfd_filename = NULL;
-      
       next = so_list_head -> next;
-      if (bfd_filename)
-	free ((PTR)bfd_filename);
-      free ((PTR)so_list_head);
+      free_solib (so_list_head);
       so_list_head = next;
     }
   debug_base = 0;