gdb: make gdbarch_make_corefile_notes return a unique ptr

This patch starts by making the gdbarch_make_corefile_notes function
return a gdb::unique_xmalloc_ptr<char> and takes care of the fallouts,
mostly in linux-tdep.c and fbsd-tdep.c.

The difficulty in these files is that they use the BFD API for writing
core files, where you pass in a pointer to a malloc-ed buffer (or NULL
in the beginning), it re-allocs it if needed, and returns you the
possibly updated pointer.  I therefore used this pattern everywhere:

  note_data.reset (elfcore_write_note (obfd, note_data.release (), ...)

This hands over the ownership of note_data to the BFD function for the
duration of the call, and then puts its back in note_data right after
the call.

gdb/ChangeLog:

	* gdbarch.sh (make_corefile_notes): Return unique pointer.
	* gdbarch.c: Re-generate.
	* gdbarch.h: Re-generate.
	* gcore.c (write_gcore_file_1): Adjust.
	* fbsd-tdep.c (struct fbsd_collect_regset_section_cb_data): Add
	constructor.
	<note_data>: Change type to unique pointer.
	<abort_iteration>: Change type to bool.
	(fbsd_collect_regset_section_cb): Adjust to unique pointer.
	(fbsd_collect_thread_registers): Return void, adjust.
	(struct fbsd_corefile_thread_data): Add construtor.
	<note_data>: Change type to unique pointer.
	(fbsd_corefile_thread): Adjust.
	(fbsd_make_corefile_notes): Return unique pointer, adjust.
	* linux-tdep.c (linux_make_mappings_corefile_notes): Change type
	to unique pointer, adjust.
	(struct linux_collect_regset_section_cb_data): Add constructor.
	<note_data>: Change type to unique pointer.
	<abort_iteration>: Change type to bool.
	(linux_collect_thread_registers): Return void, adjust.
	(struct linux_corefile_thread_data): Add constructor.
	<note_data>: Change type to unique pointer.
	(linux_corefile_thread): Adjust.
	(linux_make_corefile_notes): Return unique pointer, adjust.

Change-Id: I1e03476bb47b87c6acb3e12204d193f38cc4e02b

1 files changed, 72 insertions, 49 deletions

diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index a462e4d..f7ee35b 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -589,13 +589,27 @@ find_signalled_thread (struct thread_info *info, void *data)
 
 struct fbsd_collect_regset_section_cb_data
 {
+  fbsd_collect_regset_section_cb_data (const struct regcache *regcache,
+				       bfd *obfd,
+				       gdb::unique_xmalloc_ptr<char> &note_data,
+				       int *note_size,
+				       unsigned long lwp,
+				       gdb_signal stop_signal)
+    : regcache (regcache),
+      obfd (obfd),
+      note_data (note_data),
+      note_size (note_size),
+      lwp (lwp),
+      stop_signal (stop_signal)
+  {}
+
   const struct regcache *regcache;
   bfd *obfd;
-  char *note_data;
+  gdb::unique_xmalloc_ptr<char> &note_data;
   int *note_size;
   unsigned long lwp;
   enum gdb_signal stop_signal;
-  int abort_iteration;
+  bool abort_iteration = false;
 };
 
 static void
@@ -617,50 +631,58 @@ fbsd_collect_regset_section_cb (const char *sect_name, int supply_size,
 
   /* PRSTATUS still needs to be treated specially.  */
   if (strcmp (sect_name, ".reg") == 0)
-    data->note_data = (char *) elfcore_write_prstatus
-      (data->obfd, data->note_data, data->note_size, data->lwp,
-       gdb_signal_to_host (data->stop_signal), buf);
+    data->note_data.reset (elfcore_write_prstatus
+			     (data->obfd, data->note_data.release (),
+			      data->note_size, data->lwp,
+			      gdb_signal_to_host (data->stop_signal),
+			      buf));
   else
-    data->note_data = (char *) elfcore_write_register_note
-      (data->obfd, data->note_data, data->note_size,
-       sect_name, buf, collect_size);
+    data->note_data.reset (elfcore_write_register_note
+			     (data->obfd, data->note_data.release (),
+			      data->note_size, sect_name, buf,
+			      collect_size));
   xfree (buf);
 
   if (data->note_data == NULL)
-    data->abort_iteration = 1;
+    data->abort_iteration = true;
 }
 
 /* Records the thread's register state for the corefile note
    section.  */
 
-static char *
+static void
 fbsd_collect_thread_registers (const struct regcache *regcache,
 			       ptid_t ptid, bfd *obfd,
-			       char *note_data, int *note_size,
+			       gdb::unique_xmalloc_ptr<char> &note_data,
+			       int *note_size,
 			       enum gdb_signal stop_signal)
 {
-  struct gdbarch *gdbarch = regcache->arch ();
-  struct fbsd_collect_regset_section_cb_data data;
-
-  data.regcache = regcache;
-  data.obfd = obfd;
-  data.note_data = note_data;
-  data.note_size = note_size;
-  data.stop_signal = stop_signal;
-  data.abort_iteration = 0;
-  data.lwp = ptid.lwp ();
-
-  gdbarch_iterate_over_regset_sections (gdbarch,
+  fbsd_collect_regset_section_cb_data data (regcache, obfd, note_data,
+					    note_size, ptid.lwp (),
+					    stop_signal);
+
+  gdbarch_iterate_over_regset_sections (regcache->arch (),
 					fbsd_collect_regset_section_cb,
 					&data, regcache);
-  return data.note_data;
 }
 
 struct fbsd_corefile_thread_data
 {
+  fbsd_corefile_thread_data (struct gdbarch *gdbarch,
+			     bfd *obfd,
+			     gdb::unique_xmalloc_ptr<char> &note_data,
+			     int *note_size,
+			     gdb_signal stop_signal)
+    : gdbarch (gdbarch),
+      obfd (obfd),
+      note_data (note_data),
+      note_size (note_size),
+      stop_signal (stop_signal)
+  {}
+
   struct gdbarch *gdbarch;
   bfd *obfd;
-  char *note_data;
+  gdb::unique_xmalloc_ptr<char> &note_data;
   int *note_size;
   enum gdb_signal stop_signal;
 };
@@ -679,9 +701,9 @@ fbsd_corefile_thread (struct thread_info *info,
 
   target_fetch_registers (regcache, -1);
 
-  args->note_data = fbsd_collect_thread_registers
-    (regcache, info->ptid, args->obfd, args->note_data,
-     args->note_size, args->stop_signal);
+  fbsd_collect_thread_registers (regcache, info->ptid, args->obfd,
+				 args->note_data, args->note_size,
+				 args->stop_signal);
 }
 
 /* Return a byte_vector containing the contents of a core dump note
@@ -709,11 +731,10 @@ fbsd_make_note_desc (enum target_object object, uint32_t structsize)
 /* Create appropriate note sections for a corefile, returning them in
    allocated memory.  */
 
-static char *
+static gdb::unique_xmalloc_ptr<char>
 fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 {
-  struct fbsd_corefile_thread_data thread_args;
-  char *note_data = NULL;
+  gdb::unique_xmalloc_ptr<char> note_data;
   Elf_Internal_Ehdr *i_ehdrp;
   struct thread_info *curr_thr, *signalled_thr;
 
@@ -732,8 +753,9 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
       if (infargs != NULL)
 	psargs = psargs + " " + infargs;
 
-      note_data = elfcore_write_prpsinfo (obfd, note_data, note_size,
-					  fname, psargs.c_str ());
+      note_data.reset (elfcore_write_prpsinfo (obfd, note_data.release (),
+					       note_size, fname,
+					       psargs.c_str ()));
     }
 
   /* Thread register information.  */
@@ -760,11 +782,8 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 	signalled_thr = curr_thr;
     }
 
-  thread_args.gdbarch = gdbarch;
-  thread_args.obfd = obfd;
-  thread_args.note_data = note_data;
-  thread_args.note_size = note_size;
-  thread_args.stop_signal = signalled_thr->suspend.stop_signal;
+  fbsd_corefile_thread_data thread_args (gdbarch, obfd, note_data, note_size,
+					 signalled_thr->suspend.stop_signal);
 
   fbsd_corefile_thread (signalled_thr, &thread_args);
   for (thread_info *thr : current_inferior ()->non_exited_threads ())
@@ -775,17 +794,17 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
       fbsd_corefile_thread (thr, &thread_args);
     }
 
-  note_data = thread_args.note_data;
-
   /* Auxiliary vector.  */
   uint32_t structsize = gdbarch_ptr_bit (gdbarch) / 4; /* Elf_Auxinfo  */
   gdb::optional<gdb::byte_vector> note_desc =
     fbsd_make_note_desc (TARGET_OBJECT_AUXV, structsize);
   if (note_desc && !note_desc->empty ())
     {
-      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
-				      NT_FREEBSD_PROCSTAT_AUXV,
-				      note_desc->data (), note_desc->size ());
+      note_data.reset (elfcore_write_note (obfd, note_data.release (),
+					   note_size, "FreeBSD",
+					   NT_FREEBSD_PROCSTAT_AUXV,
+					   note_desc->data (),
+					   note_desc->size ()));
       if (!note_data)
 	return NULL;
     }
@@ -794,9 +813,11 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
   note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_VMMAP, 0);
   if (note_desc && !note_desc->empty ())
     {
-      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
-				      NT_FREEBSD_PROCSTAT_VMMAP,
-				      note_desc->data (), note_desc->size ());
+      note_data.reset (elfcore_write_note (obfd, note_data.release (),
+					   note_size, "FreeBSD",
+					   NT_FREEBSD_PROCSTAT_VMMAP,
+					   note_desc->data (),
+					   note_desc->size ()));
       if (!note_data)
 	return NULL;
     }
@@ -804,9 +825,11 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
   note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_PS_STRINGS, 0);
   if (note_desc && !note_desc->empty ())
     {
-      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
-				      NT_FREEBSD_PROCSTAT_PSSTRINGS,
-				      note_desc->data (), note_desc->size ());
+      note_data.reset (elfcore_write_note (obfd, note_data.release (),
+					   note_size, "FreeBSD",
+					   NT_FREEBSD_PROCSTAT_PSSTRINGS,
+					   note_desc->data (),
+					   note_desc->size ()));
       if (!note_data)
 	return NULL;
     }