elf/x86: Issue an error on discarded output .plt section

[binutils-gdb.git] / gdb / corelow.c

diff --git a/gdb/corelow.c b/gdb/corelow.c
index 4f3c88020205133bf4ed2a7ffef878c0ca4e7539..10942e6af01fe2859ec175922fd52dfed70ef226 100644 (file)
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -1,6 +1,6 @@
 /* Core dump and executable file functions below target vector, for GDB.
 
-   Copyright (C) 1986-2020 Free Software Foundation, Inc.
+   Copyright (C) 1986-2021 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -49,6 +49,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include "gdbcmd.h"
+#include "xml-tdesc.h"
 
 #ifndef O_LARGEFILE
 #define O_LARGEFILE 0
@@ -153,8 +154,22 @@ private: /* per-core data */
 
 core_target::core_target ()
 {
+  /* Find a first arch based on the BFD.  We need the initial gdbarch so
+     we can setup the hooks to find a target description.  */
   m_core_gdbarch = gdbarch_from_bfd (core_bfd);
 
+  /* If the arch is able to read a target description from the core, it
+     could yield a more specific gdbarch.  */
+  const struct target_desc *tdesc = read_description ();
+
+  if (tdesc != nullptr)
+    {
+      struct gdbarch_info info;
+      info.abfd = core_bfd;
+      info.target_desc = tdesc;
+      m_core_gdbarch = gdbarch_find_by_info (info);
+    }
+
   if (!m_core_gdbarch
       || !gdbarch_iterate_over_regset_sections_p (m_core_gdbarch))
     error (_("\"%s\": Core file format not supported"),
@@ -199,7 +214,7 @@ core_target::build_file_mappings ()
     /* read_core_file_mappings will invoke this lambda for each mapping
        that it finds.  */
     [&] (int num, ULONGEST start, ULONGEST end, ULONGEST file_ofs,
-         const char *filename, const void *other)
+        const char *filename, const bfd_build_id *build_id)
       {
        /* Architecture-specific read_core_mapping methods are expected to
           weed out non-file-backed mappings.  */
@@ -226,7 +241,7 @@ core_target::build_file_mappings ()
              }
 
            bfd = bfd_map[filename] = bfd_openr (expanded_fname.get (),
-                                                "binary");
+                                                "binary");
 
            if (bfd == nullptr || !bfd_check_format (bfd, bfd_object))
              {
@@ -287,7 +302,7 @@ core_target::close ()
       exit_inferior_silent (current_inferior ());
 
       /* Clear out solib state while the bfd is still open.  See
-         comments in clear_solib in solib.c.  */
+        comments in clear_solib in solib.c.  */
       clear_solib ();
 
       current_program_space->cbfd.reset (nullptr);
@@ -413,7 +428,8 @@ core_target_open (const char *arg, int from_tty)
     }
 
   gdb::unique_xmalloc_ptr<char> filename (tilde_expand (arg));
-  if (!IS_ABSOLUTE_PATH (filename.get ()))
+  if (strlen (filename.get ()) != 0
+      && !IS_ABSOLUTE_PATH (filename.get ()))
     filename = gdb_abspath (filename.get ());
 
   flags = O_BINARY | O_LARGEFILE;
@@ -421,7 +437,7 @@ core_target_open (const char *arg, int from_tty)
     flags |= O_RDWR;
   else
     flags |= O_RDONLY;
-  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0);
+  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0).release ();
   if (scratch_chan < 0)
     perror_with_name (filename.get ());
 
@@ -435,8 +451,8 @@ core_target_open (const char *arg, int from_tty)
     {
       /* Do it after the err msg */
       /* FIXME: should be checking for errors from bfd_close (for one
-         thing, on error it does not free all the storage associated
-         with the bfd).  */
+        thing, on error it does not free all the storage associated
+        with the bfd).  */
       error (_("\"%s\" is not a core dump: %s"),
             filename.get (), bfd_errmsg (bfd_get_error ()));
     }
@@ -454,10 +470,10 @@ core_target_open (const char *arg, int from_tty)
      core file.  We don't do this unconditionally since an exec file
      typically contains more information that helps us determine the
      architecture than a core file.  */
-  if (!exec_bfd)
+  if (!current_program_space->exec_bfd ())
     set_gdbarch_from_file (core_bfd);
 
-  push_target (std::move (target_holder));
+  current_inferior ()->push_target (std::move (target_holder));
 
   switch_to_no_thread ();
 
@@ -495,7 +511,7 @@ core_target_open (const char *arg, int from_tty)
       switch_to_thread (thread);
     }
 
-  if (exec_bfd == nullptr)
+  if (current_program_space->exec_bfd () == nullptr)
     locate_exec_from_corefile_build_id (core_bfd, from_tty);
 
   post_create_inferior (from_tty);
@@ -579,7 +595,7 @@ core_target::detach (inferior *inf, int from_tty)
   /* Note that 'this' is dangling after this call.  unpush_target
      closes the target, and our close implementation deletes
      'this'.  */
-  unpush_target (this);
+  inf->unpush_target (this);
 
   /* Clear the register cache and the frame cache.  */
   registers_changed ();
@@ -760,7 +776,7 @@ core_target::xfer_memory_via_mappings (gdb_byte *readbuf,
   for (const auto &mr : m_core_unavailable_mappings)
     {
       if (address_in_mem_range (memaddr, &mr))
-        {
+       {
          if (!address_in_mem_range (memend, &mr))
            len = mr.start + mr.length - memaddr;
 
@@ -1000,6 +1016,29 @@ core_target::thread_alive (ptid_t ptid)
 const struct target_desc *
 core_target::read_description ()
 {
+  /* If the core file contains a target description note then we will use
+     that in preference to anything else.  */
+  bfd_size_type tdesc_note_size = 0;
+  struct bfd_section *tdesc_note_section
+    = bfd_get_section_by_name (core_bfd, ".gdb-tdesc");
+  if (tdesc_note_section != nullptr)
+    tdesc_note_size = bfd_section_size (tdesc_note_section);
+  if (tdesc_note_size > 0)
+    {
+      gdb::char_vector contents (tdesc_note_size + 1);
+      if (bfd_get_section_contents (core_bfd, tdesc_note_section,
+                                   contents.data (), (file_ptr) 0,
+                                   tdesc_note_size))
+       {
+         /* Ensure we have a null terminator.  */
+         contents[tdesc_note_size] = '\0';
+         const struct target_desc *result
+           = string_read_description_xml (contents.data ());
+         if (result != nullptr)
+           return result;
+       }
+    }
+
   if (m_core_gdbarch && gdbarch_core_read_description_p (m_core_gdbarch))
     {
       const struct target_desc *result;
@@ -1167,7 +1206,7 @@ _initialize_corelow ()
 {
   add_target (core_target_info, core_target_open, filename_completer);
   add_cmd ("core-file-backed-mappings", class_maintenance,
-           maintenance_print_core_file_backed_mappings,
+          maintenance_print_core_file_backed_mappings,
           _("Print core file's file-backed mappings."),
           &maintenanceprintlist);
 }