gdb/

	* Makefile.in (XMLFILES): Add library-list-svr4.dtd.
	* features/library-list-svr4.dtd: New file.
	* remote.c (PACKET_qXfer_libraries_svr4): New.
	(remote_protocol_features): new entry for PACKET_qXfer_libraries_svr4.
	(remote_xfer_partial): Handle TARGET_OBJECT_LIBRARIES_SVR4.
	* solib-svr4.c (struct svr4_library_list): New.
	[HAVE_LIBEXPAT]: Include xml-support.h.
	[HAVE_LIBEXPAT] (svr4_library_list_start_library)
	[HAVE_LIBEXPAT] (svr4_library_list_start_list, svr4_library_attributes)
	[HAVE_LIBEXPAT] (svr4_library_list_children)
	[HAVE_LIBEXPAT] (svr4_library_list_attributes)
	[HAVE_LIBEXPAT] (svr4_library_list_elements, svr4_parse_libraries)
	[HAVE_LIBEXPAT] (svr4_current_sos_via_xfer_libraries)
	[!HAVE_LIBEXPAT] (svr4_current_sos_via_xfer_libraries): New.
	(svr4_read_so_list): Extend the corruption message by addresses.
	(svr4_current_sos): New variable library_list, call
	svr4_current_sos_via_xfer_libraries.
	* target.h (enum target_object): New TARGET_OBJECT_LIBRARIES_SVR4.

gdb/gdbserver/
	* linux-low.c (get_phdr_phnum_from_proc_auxv, get_dynamic, get_r_debug)
	(read_one_ptr, struct link_map_offsets, linux_qxfer_libraries_svr4):
	New.
	(struct linux_target_ops): Install linux_qxfer_libraries_svr4.
	* linux-low.h (struct process_info_private): New member r_debug.
	* server.c (handle_qxfer_libraries): Call
	the_target->qxfer_libraries_svr4.
	(handle_qxfer_libraries_svr4): New function.
	(qxfer_packets): New entry "libraries-svr4".
	(handle_query): Check QXFER_LIBRARIES_SVR4 and report libraries-svr4.
	* target.h (struct target_ops): New member qxfer_libraries_svr4.
	* remote.c (remote_xfer_partial): Call add_packet_config_cmd for
	PACKET_qXfer_libraries_svr4.

gdb/doc/
	* gdb.texinfo (Requirements, Remote Protocol): Reference also `Library
	List Format for SVR4 Targets'.
	(General Query Packets): New item qXfer:libraries-svr4:read.
	(Library List Format for SVR4 Targets): New node.

gdb/testsuite/
	* gdb.base/solib-corrupted.exp: Suppress test on is_remote target.
	(corrupted list): Adjust the expectation.

1 files changed, 377 insertions, 0 deletions

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 2b973c6..539b63a 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4964,6 +4964,382 @@ linux_get_min_fast_tracepoint_insn_len (void)
   return (*the_low_target.get_min_fast_tracepoint_insn_len) ();
 }
 
+/* Extract &phdr and num_phdr in the inferior.  Return 0 on success.  */
+
+static int
+get_phdr_phnum_from_proc_auxv (const int pid, const int is_elf64,
+			       CORE_ADDR *phdr_memaddr, int *num_phdr)
+{
+  char filename[PATH_MAX];
+  int fd;
+  const int auxv_size = is_elf64
+    ? sizeof (Elf64_auxv_t) : sizeof (Elf32_auxv_t);
+  char buf[sizeof (Elf64_auxv_t)];  /* The larger of the two.  */
+
+  xsnprintf (filename, sizeof filename, "/proc/%d/auxv", pid);
+
+  fd = open (filename, O_RDONLY);
+  if (fd < 0)
+    return 1;
+
+  *phdr_memaddr = 0;
+  *num_phdr = 0;
+  while (read (fd, buf, auxv_size) == auxv_size
+	 && (*phdr_memaddr == 0 || *num_phdr == 0))
+    {
+      if (is_elf64)
+	{
+	  Elf64_auxv_t *const aux = (Elf64_auxv_t *) buf;
+
+	  switch (aux->a_type)
+	    {
+	    case AT_PHDR:
+	      *phdr_memaddr = aux->a_un.a_val;
+	      break;
+	    case AT_PHNUM:
+	      *num_phdr = aux->a_un.a_val;
+	      break;
+	    }
+	}
+      else
+	{
+	  Elf32_auxv_t *const aux = (Elf32_auxv_t *) buf;
+
+	  switch (aux->a_type)
+	    {
+	    case AT_PHDR:
+	      *phdr_memaddr = aux->a_un.a_val;
+	      break;
+	    case AT_PHNUM:
+	      *num_phdr = aux->a_un.a_val;
+	      break;
+	    }
+	}
+    }
+
+  close (fd);
+
+  if (*phdr_memaddr == 0 || *num_phdr == 0)
+    {
+      warning ("Unexpected missing AT_PHDR and/or AT_PHNUM: "
+	       "phdr_memaddr = %ld, phdr_num = %d",
+	       (long) *phdr_memaddr, *num_phdr);
+      return 2;
+    }
+
+  return 0;
+}
+
+/* Return &_DYNAMIC (via PT_DYNAMIC) in the inferior, or 0 if not present.  */
+
+static CORE_ADDR
+get_dynamic (const int pid, const int is_elf64)
+{
+  CORE_ADDR phdr_memaddr, relocation;
+  int num_phdr, i;
+  unsigned char *phdr_buf;
+  const int phdr_size = is_elf64 ? sizeof (Elf64_Phdr) : sizeof (Elf32_Phdr);
+
+  if (get_phdr_phnum_from_proc_auxv (pid, is_elf64, &phdr_memaddr, &num_phdr))
+    return 0;
+
+  gdb_assert (num_phdr < 100);  /* Basic sanity check.  */
+  phdr_buf = alloca (num_phdr * phdr_size);
+
+  if (linux_read_memory (phdr_memaddr, phdr_buf, num_phdr * phdr_size))
+    return 0;
+
+  /* Compute relocation: it is expected to be 0 for "regular" executables,
+     non-zero for PIE ones.  */
+  relocation = -1;
+  for (i = 0; relocation == -1 && i < num_phdr; i++)
+    if (is_elf64)
+      {
+	Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size);
+
+	if (p->p_type == PT_PHDR)
+	  relocation = phdr_memaddr - p->p_vaddr;
+      }
+    else
+      {
+	Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size);
+
+	if (p->p_type == PT_PHDR)
+	  relocation = phdr_memaddr - p->p_vaddr;
+      }
+
+  if (relocation == -1)
+    {
+      warning ("Unexpected missing PT_PHDR");
+      return 0;
+    }
+
+  for (i = 0; i < num_phdr; i++)
+    {
+      if (is_elf64)
+	{
+	  Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size);
+
+	  if (p->p_type == PT_DYNAMIC)
+	    return p->p_vaddr + relocation;
+	}
+      else
+	{
+	  Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size);
+
+	  if (p->p_type == PT_DYNAMIC)
+	    return p->p_vaddr + relocation;
+	}
+    }
+
+  return 0;
+}
+
+/* Return &_r_debug in the inferior, or -1 if not present.  Return value
+   can be 0 if the inferior does not yet have the library list initialized.  */
+
+static CORE_ADDR
+get_r_debug (const int pid, const int is_elf64)
+{
+  CORE_ADDR dynamic_memaddr;
+  const int dyn_size = is_elf64 ? sizeof (Elf64_Dyn) : sizeof (Elf32_Dyn);
+  unsigned char buf[sizeof (Elf64_Dyn)];  /* The larger of the two.  */
+
+  dynamic_memaddr = get_dynamic (pid, is_elf64);
+  if (dynamic_memaddr == 0)
+    return (CORE_ADDR) -1;
+
+  while (linux_read_memory (dynamic_memaddr, buf, dyn_size) == 0)
+    {
+      if (is_elf64)
+	{
+	  Elf64_Dyn *const dyn = (Elf64_Dyn *) buf;
+
+	  if (dyn->d_tag == DT_DEBUG)
+	    return dyn->d_un.d_val;
+
+	  if (dyn->d_tag == DT_NULL)
+	    break;
+	}
+      else
+	{
+	  Elf32_Dyn *const dyn = (Elf32_Dyn *) buf;
+
+	  if (dyn->d_tag == DT_DEBUG)
+	    return dyn->d_un.d_val;
+
+	  if (dyn->d_tag == DT_NULL)
+	    break;
+	}
+
+      dynamic_memaddr += dyn_size;
+    }
+
+  return (CORE_ADDR) -1;
+}
+
+/* Read one pointer from MEMADDR in the inferior.  */
+
+static int
+read_one_ptr (CORE_ADDR memaddr, CORE_ADDR *ptr, int ptr_size)
+{
+  *ptr = 0;
+  return linux_read_memory (memaddr, (unsigned char *) ptr, ptr_size);
+}
+
+struct link_map_offsets
+  {
+    /* Offset and size of r_debug.r_version.  */
+    int r_version_offset;
+
+    /* Offset and size of r_debug.r_map.  */
+    int r_map_offset;
+
+    /* Offset to l_addr field in struct link_map.  */
+    int l_addr_offset;
+
+    /* Offset to l_name field in struct link_map.  */
+    int l_name_offset;
+
+    /* Offset to l_ld field in struct link_map.  */
+    int l_ld_offset;
+
+    /* Offset to l_next field in struct link_map.  */
+    int l_next_offset;
+
+    /* Offset to l_prev field in struct link_map.  */
+    int l_prev_offset;
+  };
+
+/* Construct qXfer:libraries:read reply.  */
+
+static int
+linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
+			    unsigned const char *writebuf,
+			    CORE_ADDR offset, int len)
+{
+  char *document;
+  unsigned document_len;
+  struct process_info_private *const priv = current_process ()->private;
+  char filename[PATH_MAX];
+  int pid, is_elf64;
+
+  static const struct link_map_offsets lmo_32bit_offsets =
+    {
+      0,     /* r_version offset. */
+      4,     /* r_debug.r_map offset.  */
+      0,     /* l_addr offset in link_map.  */
+      4,     /* l_name offset in link_map.  */
+      8,     /* l_ld offset in link_map.  */
+      12,    /* l_next offset in link_map.  */
+      16     /* l_prev offset in link_map.  */
+    };
+
+  static const struct link_map_offsets lmo_64bit_offsets =
+    {
+      0,     /* r_version offset. */
+      8,     /* r_debug.r_map offset.  */
+      0,     /* l_addr offset in link_map.  */
+      8,     /* l_name offset in link_map.  */
+      16,    /* l_ld offset in link_map.  */
+      24,    /* l_next offset in link_map.  */
+      32     /* l_prev offset in link_map.  */
+    };
+  const struct link_map_offsets *lmo;
+
+  if (writebuf != NULL)
+    return -2;
+  if (readbuf == NULL)
+    return -1;
+
+  pid = lwpid_of (get_thread_lwp (current_inferior));
+  xsnprintf (filename, sizeof filename, "/proc/%d/exe", pid);
+  is_elf64 = elf_64_file_p (filename);
+  lmo = is_elf64 ? &lmo_64bit_offsets : &lmo_32bit_offsets;
+
+  if (priv->r_debug == 0)
+    priv->r_debug = get_r_debug (pid, is_elf64);
+
+  if (priv->r_debug == (CORE_ADDR) -1 || priv->r_debug == 0)
+    {
+      document = xstrdup ("<library-list-svr4 version=\"1.0\"/>\n");
+    }
+  else
+    {
+      int allocated = 1024;
+      char *p;
+      const int ptr_size = is_elf64 ? 8 : 4;
+      CORE_ADDR lm_addr, lm_prev, l_name, l_addr, l_ld, l_next, l_prev;
+      int r_version, header_done = 0;
+
+      document = xmalloc (allocated);
+      strcpy (document, "<library-list-svr4 version=\"1.0\"");
+      p = document + strlen (document);
+
+      r_version = 0;
+      if (linux_read_memory (priv->r_debug + lmo->r_version_offset,
+			     (unsigned char *) &r_version,
+			     sizeof (r_version)) != 0
+	  || r_version != 1)
+	{
+	  warning ("unexpected r_debug version %d", r_version);
+	  goto done;
+	}
+
+      if (read_one_ptr (priv->r_debug + lmo->r_map_offset,
+			&lm_addr, ptr_size) != 0)
+	{
+	  warning ("unable to read r_map from 0x%lx",
+		   (long) priv->r_debug + lmo->r_map_offset);
+	  goto done;
+	}
+
+      lm_prev = 0;
+      while (read_one_ptr (lm_addr + lmo->l_name_offset,
+			   &l_name, ptr_size) == 0
+	     && read_one_ptr (lm_addr + lmo->l_addr_offset,
+			      &l_addr, ptr_size) == 0
+	     && read_one_ptr (lm_addr + lmo->l_ld_offset,
+			      &l_ld, ptr_size) == 0
+	     && read_one_ptr (lm_addr + lmo->l_prev_offset,
+			      &l_prev, ptr_size) == 0
+	     && read_one_ptr (lm_addr + lmo->l_next_offset,
+			      &l_next, ptr_size) == 0)
+	{
+	  unsigned char libname[PATH_MAX];
+
+	  if (lm_prev != l_prev)
+	    {
+	      warning ("Corrupted shared library list: 0x%lx != 0x%lx",
+		       (long) lm_prev, (long) l_prev);
+	      break;
+	    }
+
+	  /* Not checking for error because reading may stop before
+	     we've got PATH_MAX worth of characters.  */
+	  libname[0] = '\0';
+	  linux_read_memory (l_name, libname, sizeof (libname) - 1);
+	  libname[sizeof (libname) - 1] = '\0';
+	  if (libname[0] != '\0')
+	    {
+	      /* 6x the size for xml_escape_text below.  */
+	      size_t len = 6 * strlen ((char *) libname);
+	      char *name;
+
+	      if (!header_done)
+		{
+		  /* Terminate `<library-list-svr4'.  */
+		  *p++ = '>';
+		  header_done = 1;
+		}
+
+	      while (allocated < p - document + len + 200)
+		{
+		  /* Expand to guarantee sufficient storage.  */
+		  uintptr_t document_len = p - document;
+
+		  document = xrealloc (document, 2 * allocated);
+		  allocated *= 2;
+		  p = document + document_len;
+		}
+
+	      name = xml_escape_text ((char *) libname);
+	      p += sprintf (p, "<library name=\"%s\" lm=\"0x%lx\" "
+			       "l_addr=\"0x%lx\" l_ld=\"0x%lx\"/>",
+			    name, (unsigned long) lm_addr,
+			    (unsigned long) l_addr, (unsigned long) l_ld);
+	      free (name);
+	    }
+	  else if (lm_prev == 0)
+	    {
+	      sprintf (p, " main-lm=\"0x%lx\"", (unsigned long) lm_addr);
+	      p = p + strlen (p);
+	    }
+
+	  if (l_next == 0)
+	    break;
+
+	  lm_prev = lm_addr;
+	  lm_addr = l_next;
+	}
+    done:
+      strcpy (p, "</library-list-svr4>");
+    }
+
+  document_len = strlen (document);
+  if (offset < document_len)
+    document_len -= offset;
+  else
+    document_len = 0;
+  if (len > document_len)
+    len = document_len;
+
+  memcpy (readbuf, document + offset, len);
+  xfree (document);
+
+  return len;
+}
+
 static struct target_ops linux_target_ops = {
   linux_create_inferior,
   linux_attach,
@@ -5026,6 +5402,7 @@ static struct target_ops linux_target_ops = {
   linux_emit_ops,
   linux_supports_disable_randomization,
   linux_get_min_fast_tracepoint_insn_len,
+  linux_qxfer_libraries_svr4,
 };
 
 static void