[PATCH] Use kinfo_getvmmap () on FreeBSD to enumerate memory regions.

[John Baldwin <jhb at freebsd dot org>]

Use kinfo_getvmmap () from libutil on FreeBSD to enumerate memory
regions in a running process instead of /proc/<pid>/map.  FreeBSD systems
do not mount procfs by default, but kinfo_getvmmap () uses a sysctl that
is always available.

Skip memory regions for devices as well as regions an application has
requested to not be dumped via the MAP_NOCORE flag to mmap () or
MADV_NOCORE advice to madvise ().

gdb/ChangeLog:

	* configure.ac: AC_CHECK_LIB(util, kinfo_getvmmap).
	* configure: Regenerate.
	* config.in: Regenerate.
	* fbsd-nat.c (fbsd_find_memory_regions): Use kinfo_getvmmap to
	enumerate memory regions if present.

---
 gdb/configure.ac |  5 +++++
 gdb/fbsd-nat.c   | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/gdb/configure.ac b/gdb/configure.ac
index 6ac8adb..b094164 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -532,6 +532,11 @@ AM_ZLIB
 # On HP/UX we may need libxpdl for dlgetmodinfo (used by solib-pa64.c).
 AC_SEARCH_LIBS(dlgetmodinfo, [dl xpdl])
 
+# On FreeBSD we may need libutil for kinfo_getvmmap (used by fbsd-nat.c).
+AC_CHECK_LIB(util, kinfo_getvmmap,
+  [AC_DEFINE(HAVE_KINFO_GETVMMAP, 1,
+            [Define to 1 if your system has the kinfo_getvmmap function. ])])
+
 AM_ICONV
 
 # GDB may fork/exec the iconv program to get the list of supported character
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 062eede..0369a0a 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -26,6 +26,10 @@
 #include <sys/types.h>
 #include <sys/procfs.h>
 #include <sys/sysctl.h>
+#ifdef HAVE_KINFO_GETVMMAP
+#include <sys/user.h>
+#include <libutil.h>
+#endif
 
 #include "elf-bfd.h"
 #include "fbsd-nat.h"
@@ -62,6 +66,7 @@ fbsd_pid_to_exec_file (struct target_ops *self, int pid)
   return NULL;
 }
 
+#ifndef HAVE_KINFO_GETVMMAP
 static int
 fbsd_read_mapping (FILE *mapfile, unsigned long *start, unsigned long *end,
 		   char *protection)
@@ -82,6 +87,7 @@ fbsd_read_mapping (FILE *mapfile, unsigned long *start, unsigned long *end,
 
   return (ret != 0 && ret != EOF);
 }
+#endif
 
 /* Iterate over all the memory regions in the current inferior,
    calling FUNC for each memory region.  OBFD is passed as the last
@@ -91,6 +97,55 @@ int
 fbsd_find_memory_regions (struct target_ops *self,
 			  find_memory_region_ftype func, void *obfd)
 {
+#ifdef HAVE_KINFO_GETVMMAP
+  pid_t pid = ptid_get_pid (inferior_ptid);
+  struct kinfo_vmentry *vmentl, *kve;
+  uint64_t size;
+  struct cleanup *cleanup;
+  int i, nitems;
+
+  vmentl = kinfo_getvmmap (pid, &nitems);
+  if (vmentl == NULL)
+    perror_with_name (_("Couldn't fetch VM map entries."));
+  cleanup = make_cleanup (free, vmentl);
+
+  for (i = 0; i < nitems; i++)
+    {
+      kve = &vmentl[i];
+
+      /* Skip unreadable segments and those where MAP_NOCORE has been set.  */
+      if (!(kve->kve_protection & KVME_PROT_READ) ||
+	  kve->kve_flags & KVME_FLAG_NOCOREDUMP)
+	continue;
+
+      /* Skip segments with an invalid type.  */
+      if (kve->kve_type != KVME_TYPE_DEFAULT &&
+	  kve->kve_type != KVME_TYPE_VNODE &&
+	  kve->kve_type != KVME_TYPE_SWAP &&
+	  kve->kve_type != KVME_TYPE_PHYS)
+	continue;
+
+      size = kve->kve_end - kve->kve_start;
+      if (info_verbose)
+	{
+	  fprintf_filtered (gdb_stdout, 
+			    "Save segment, %ld bytes at %s (%c%c%c)\n",
+			    (long)size,
+			    paddress (target_gdbarch (), kve->kve_start),
+			    kve->kve_protection & KVME_PROT_READ ? 'r' : '-',
+			    kve->kve_protection & KVME_PROT_WRITE ? 'w' : '-',
+			    kve->kve_protection & KVME_PROT_EXEC ? 'x' : '-');
+	}
+
+      /* Invoke the callback function to create the corefile segment.
+	 Pass MODIFIED as true, we do not know the real modification state.  */
+      func (kve->kve_start, size, kve->kve_protection & KVME_PROT_READ,
+	    kve->kve_protection & KVME_PROT_WRITE,
+	    kve->kve_protection & KVME_PROT_EXEC, 1, obfd);
+    }
+  do_cleanups (cleanup);
+  return 0;
+#else
   pid_t pid = ptid_get_pid (inferior_ptid);
   char *mapfilename;
   FILE *mapfile;
@@ -136,4 +191,5 @@ fbsd_find_memory_regions (struct target_ops *self,
 
   do_cleanups (cleanup);
   return 0;
+#endif
 }
-- 
2.2.1