Reorganize source tree to use single autotools instance

Change-Id: I7b51f88292e057c6443b12224486f2d0c9f8ae23
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 1237 insertions, 0 deletions

diff --git a/src/svm/svm.c b/src/svm/svm.c
new file mode 100644
index 00000000000..e4ca98e1ed2
--- /dev/null
+++ b/src/svm/svm.c
@@ -0,0 +1,1237 @@
+/*
+ *------------------------------------------------------------------
+ * svm.c - shared VM allocation, mmap(...MAP_FIXED...)
+ * library
+ *
+ * Copyright (c) 2009 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <time.h>
+#include <fcntl.h>
+#include <string.h>
+#include <vppinfra/clib.h>
+#include <vppinfra/vec.h>
+#include <vppinfra/hash.h>
+#include <vppinfra/bitmap.h>
+#include <vppinfra/fifo.h>
+#include <vppinfra/time.h>
+#include <vppinfra/mheap.h>
+#include <vppinfra/heap.h>
+#include <vppinfra/pool.h>
+#include <vppinfra/format.h>
+
+#include "svm.h"
+
+static svm_region_t *root_rp;
+static int root_rp_refcount;
+
+#define MAXLOCK 2
+static pthread_mutex_t *mutexes_held[MAXLOCK];
+static int nheld;
+
+svm_region_t *
+svm_get_root_rp (void)
+{
+  return root_rp;
+}
+
+#define MUTEX_DEBUG
+
+static void
+region_lock (svm_region_t * rp, int tag)
+{
+  pthread_mutex_lock (&rp->mutex);
+#ifdef MUTEX_DEBUG
+  rp->mutex_owner_pid = getpid ();
+  rp->mutex_owner_tag = tag;
+#endif
+  ASSERT (nheld < MAXLOCK);
+  /*
+   * Keep score of held mutexes so we can try to exit
+   * cleanly if the world comes to an end at the worst possible
+   * moment
+   */
+  mutexes_held[nheld++] = &rp->mutex;
+}
+
+static void
+region_unlock (svm_region_t * rp)
+{
+  int i, j;
+#ifdef MUTEX_DEBUG
+  rp->mutex_owner_pid = 0;
+  rp->mutex_owner_tag = 0;
+#endif
+
+  for (i = nheld - 1; i >= 0; i--)
+    {
+      if (mutexes_held[i] == &rp->mutex)
+	{
+	  for (j = i; j < MAXLOCK - 1; j++)
+	    mutexes_held[j] = mutexes_held[j + 1];
+	  nheld--;
+	  goto found;
+	}
+    }
+  ASSERT (0);
+
+found:
+  CLIB_MEMORY_BARRIER ();
+  pthread_mutex_unlock (&rp->mutex);
+}
+
+
+static u8 *
+format_svm_flags (u8 * s, va_list * args)
+{
+  uword f = va_arg (*args, uword);
+
+  if (f & SVM_FLAGS_MHEAP)
+    s = format (s, "MHEAP ");
+  if (f & SVM_FLAGS_FILE)
+    s = format (s, "FILE ");
+  if (f & SVM_FLAGS_NODATA)
+    s = format (s, "NODATA ");
+  if (f & SVM_FLAGS_NEED_DATA_INIT)
+    s = format (s, "INIT ");
+
+  return (s);
+}
+
+static u8 *
+format_svm_size (u8 * s, va_list * args)
+{
+  uword size = va_arg (*args, uword);
+
+  if (size >= (1 << 20))
+    {
+      s = format (s, "(%d mb)", size >> 20);
+    }
+  else if (size >= (1 << 10))
+    {
+      s = format (s, "(%d kb)", size >> 10);
+    }
+  else
+    {
+      s = format (s, "(%d bytes)", size);
+    }
+  return (s);
+}
+
+u8 *
+format_svm_region (u8 * s, va_list * args)
+{
+  svm_region_t *rp = va_arg (*args, svm_region_t *);
+  int verbose = va_arg (*args, int);
+  int i;
+  uword lo, hi;
+
+  s = format (s, "%s: base va 0x%x size 0x%x %U\n",
+	      rp->region_name, rp->virtual_base,
+	      rp->virtual_size, format_svm_size, rp->virtual_size);
+  s = format (s, "  user_ctx 0x%x, bitmap_size %d\n",
+	      rp->user_ctx, rp->bitmap_size);
+
+  if (verbose)
+    {
+      s = format (s, "  flags: 0x%x %U\n", rp->flags,
+		  format_svm_flags, rp->flags);
+      s = format (s,
+		  "  region_heap 0x%x data_base 0x%x data_heap 0x%x\n",
+		  rp->region_heap, rp->data_base, rp->data_heap);
+    }
+
+  s = format (s, "  %d clients, pids: ", vec_len (rp->client_pids));
+
+  for (i = 0; i < vec_len (rp->client_pids); i++)
+    s = format (s, "%d ", rp->client_pids[i]);
+
+  s = format (s, "\n");
+
+  if (verbose)
+    {
+      lo = hi = ~0;
+
+      s = format (s, "  VM in use: ");
+
+      for (i = 0; i < rp->bitmap_size; i++)
+	{
+	  if (clib_bitmap_get_no_check (rp->bitmap, i) != 0)
+	    {
+	      if (lo == ~0)
+		{
+		  hi = lo = rp->virtual_base + i * MMAP_PAGESIZE;
+		}
+	      else
+		{
+		  hi = rp->virtual_base + i * MMAP_PAGESIZE;
+		}
+	    }
+	  else
+	    {
+	      if (lo != ~0)
+		{
+		  hi = rp->virtual_base + i * MMAP_PAGESIZE - 1;
+		  s = format (s, "   0x%x - 0x%x (%dk)\n", lo, hi,
+			      (hi - lo) >> 10);
+		  lo = hi = ~0;
+		}
+	    }
+	}
+      s = format (s, "  rgn heap stats: %U", format_mheap,
+		  rp->region_heap, 0);
+      if ((rp->flags & SVM_FLAGS_MHEAP) && rp->data_heap)
+	{
+	  s = format (s, "\n  data heap stats: %U", format_mheap,
+		      rp->data_heap, 1);
+	}
+      s = format (s, "\n");
+    }
+
+  return (s);
+}
+
+/*
+ * rnd_pagesize
+ * Round to a pagesize multiple, presumably 4k works
+ */
+static u64
+rnd_pagesize (u64 size)
+{
+  u64 rv;
+
+  rv = (size + (MMAP_PAGESIZE - 1)) & ~(MMAP_PAGESIZE - 1);
+  return (rv);
+}
+
+/*
+ * svm_data_region_setup
+ */
+static int
+svm_data_region_create (svm_map_region_args_t * a, svm_region_t * rp)
+{
+  int fd;
+  u8 junk = 0;
+  uword map_size;
+
+  map_size = rp->virtual_size - (MMAP_PAGESIZE +
+				 (a->pvt_heap_size ? a->pvt_heap_size :
+				  SVM_PVT_MHEAP_SIZE));
+
+  if (a->flags & SVM_FLAGS_FILE)
+    {
+      struct stat statb;
+
+      fd = open (a->backing_file, O_RDWR | O_CREAT, 0777);
+
+      if (fd < 0)
+	{
+	  clib_unix_warning ("open");
+	  return -1;
+	}
+
+      if (fstat (fd, &statb) < 0)
+	{
+	  clib_unix_warning ("fstat");
+	  close (fd);
+	  return -2;
+	}
+
+      if (statb.st_mode & S_IFREG)
+	{
+	  if (statb.st_size == 0)
+	    {
+	      if (lseek (fd, map_size, SEEK_SET) == (off_t) - 1)
+		{
+		  clib_unix_warning ("seek region size");
+		  close (fd);
+		  return -3;
+		}
+	      if (write (fd, &junk, 1) != 1)
+		{
+		  clib_unix_warning ("set region size");
+		  close (fd);
+		  return -3;
+		}
+	    }
+	  else
+	    {
+	      map_size = rnd_pagesize (statb.st_size);
+	    }
+	}
+      else
+	{
+	  map_size = a->backing_mmap_size;
+	}
+
+      ASSERT (map_size <= rp->virtual_size -
+	      (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE));
+
+      if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE,
+		MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED)
+	{
+	  clib_unix_warning ("mmap");
+	  close (fd);
+	  return -3;
+	}
+      close (fd);
+      rp->backing_file = (char *) format (0, "%s\0", a->backing_file);
+      rp->flags |= SVM_FLAGS_FILE;
+    }
+
+  if (a->flags & SVM_FLAGS_MHEAP)
+    {
+      rp->data_heap =
+	mheap_alloc_with_flags ((void *) (rp->data_base), map_size,
+				MHEAP_FLAG_DISABLE_VM);
+      rp->flags |= SVM_FLAGS_MHEAP;
+    }
+  return 0;
+}
+
+static int
+svm_data_region_map (svm_map_region_args_t * a, svm_region_t * rp)
+{
+  int fd;
+  u8 junk = 0;
+  uword map_size;
+  struct stat statb;
+
+  map_size = rp->virtual_size -
+    (MMAP_PAGESIZE
+     + (a->pvt_heap_size ? a->pvt_heap_size : SVM_PVT_MHEAP_SIZE));
+
+  if (a->flags & SVM_FLAGS_FILE)
+    {
+
+      fd = open (a->backing_file, O_RDWR, 0777);
+
+      if (fd < 0)
+	{
+	  clib_unix_warning ("open");
+	  return -1;
+	}
+
+      if (fstat (fd, &statb) < 0)
+	{
+	  clib_unix_warning ("fstat");
+	  close (fd);
+	  return -2;
+	}
+
+      if (statb.st_mode & S_IFREG)
+	{
+	  if (statb.st_size == 0)
+	    {
+	      if (lseek (fd, map_size, SEEK_SET) == (off_t) - 1)
+		{
+		  clib_unix_warning ("seek region size");
+		  close (fd);
+		  return -3;
+		}
+	      if (write (fd, &junk, 1) != 1)
+		{
+		  clib_unix_warning ("set region size");
+		  close (fd);
+		  return -3;
+		}
+	    }
+	  else
+	    {
+	      map_size = rnd_pagesize (statb.st_size);
+	    }
+	}
+      else
+	{
+	  map_size = a->backing_mmap_size;
+	}
+
+      ASSERT (map_size <= rp->virtual_size
+	      - (MMAP_PAGESIZE
+		 +
+		 (a->pvt_heap_size ? a->pvt_heap_size : SVM_PVT_MHEAP_SIZE)));
+
+      if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE,
+		MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED)
+	{
+	  clib_unix_warning ("mmap");
+	  close (fd);
+	  return -3;
+	}
+      close (fd);
+    }
+  return 0;
+}
+
+u8 *
+shm_name_from_svm_map_region_args (svm_map_region_args_t * a)
+{
+  u8 *path;
+  u8 *shm_name;
+  u8 *split_point;
+  u8 *mkdir_arg = 0;
+  int root_path_offset = 0;
+  int name_offset = 0;
+
+  if (a->root_path)
+    {
+      /* Tolerate present or absent slashes */
+      if (a->root_path[0] == '/')
+	root_path_offset++;
+
+      /* create the root_path under /dev/shm
+         iterate through path creating directories */
+
+      path = format (0, "/dev/shm/%s%c", &a->root_path[root_path_offset], 0);
+      split_point = path + 1;
+      vec_add1 (mkdir_arg, '-');
+
+      while (*split_point)
+	{
+	  while (*split_point && *split_point != '/')
+	    {
+	      vec_add1 (mkdir_arg, *split_point);
+	      split_point++;
+	    }
+	  vec_add1 (mkdir_arg, 0);
+
+	  /* ready to descend another level */
+	  mkdir_arg[vec_len (mkdir_arg) - 1] = '-';
+	  split_point++;
+	}
+      vec_free (mkdir_arg);
+      vec_free (path);
+
+      if (a->name[0] == '/')
+	name_offset = 1;
+
+      shm_name = format (0, "/%s-%s%c", a->root_path,
+			 &a->name[name_offset], 0);
+    }
+  else
+    shm_name = format (0, "%s%c", a->name, 0);
+  return (shm_name);
+}
+
+/*
+ * svm_map_region
+ */
+void *
+svm_map_region (svm_map_region_args_t * a)
+{
+  int svm_fd;
+  svm_region_t *rp;
+  pthread_mutexattr_t attr;
+  pthread_condattr_t cattr;
+  int deadman = 0;
+  u8 junk = 0;
+  void *oldheap;
+  int overhead_space;
+  int rv;
+  uword data_base;
+  int nbits, words, bit;
+  int pid_holding_region_lock;
+  u8 *shm_name;
+  int dead_region_recovery = 0;
+  int time_left;
+  struct stat stat;
+  struct timespec ts, tsrem;
+
+  if (CLIB_DEBUG > 1)
+    clib_warning ("[%d] map region %s", getpid (), a->name);
+
+  ASSERT ((a->size & ~(MMAP_PAGESIZE - 1)) == a->size);
+  ASSERT (a->name);
+
+  shm_name = shm_name_from_svm_map_region_args (a);
+
+  svm_fd = shm_open ((char *) shm_name, O_RDWR | O_CREAT | O_EXCL, 0777);
+
+  if (svm_fd >= 0)
+    {
+      if (fchmod (svm_fd, 0770) < 0)
+	clib_unix_warning ("segment chmod");
+      /* This turns out to fail harmlessly if the client starts first */
+      if (fchown (svm_fd, a->uid, a->gid) < 0)
+	clib_unix_warning ("segment chown [ok if client starts first]");
+
+      vec_free (shm_name);
+
+      if (lseek (svm_fd, a->size, SEEK_SET) == (off_t) - 1)
+	{
+	  clib_warning ("seek region size");
+	  close (svm_fd);
+	  return (0);
+	}
+      if (write (svm_fd, &junk, 1) != 1)
+	{
+	  clib_warning ("set region size");
+	  close (svm_fd);
+	  return (0);
+	}
+
+      rp = mmap ((void *) a->baseva, a->size,
+		 PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, svm_fd, 0);
+
+      if (rp == (svm_region_t *) MAP_FAILED)
+	{
+	  clib_unix_warning ("mmap create");
+	  close (svm_fd);
+	  return (0);
+	}
+      close (svm_fd);
+      memset (rp, 0, sizeof (*rp));
+
+      if (pthread_mutexattr_init (&attr))
+	clib_unix_warning ("mutexattr_init");
+
+      if (pthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED))
+	clib_unix_warning ("mutexattr_setpshared");
+
+      if (pthread_mutex_init (&rp->mutex, &attr))
+	clib_unix_warning ("mutex_init");
+
+      if (pthread_mutexattr_destroy (&attr))
+	clib_unix_warning ("mutexattr_destroy");
+
+      if (pthread_condattr_init (&cattr))
+	clib_unix_warning ("condattr_init");
+
+      if (pthread_condattr_setpshared (&cattr, PTHREAD_PROCESS_SHARED))
+	clib_unix_warning ("condattr_setpshared");
+
+      if (pthread_cond_init (&rp->condvar, &cattr))
+	clib_unix_warning ("cond_init");
+
+      if (pthread_condattr_destroy (&cattr))
+	clib_unix_warning ("condattr_destroy");
+
+      region_lock (rp, 1);
+
+      rp->virtual_base = a->baseva;
+      rp->virtual_size = a->size;
+
+      rp->region_heap =
+	mheap_alloc_with_flags ((void *) (a->baseva + MMAP_PAGESIZE),
+				(a->pvt_heap_size != 0) ?
+				a->pvt_heap_size : SVM_PVT_MHEAP_SIZE,
+				MHEAP_FLAG_DISABLE_VM);
+      oldheap = svm_push_pvt_heap (rp);
+
+      rp->region_name = (char *) format (0, "%s%c", a->name, 0);
+      vec_add1 (rp->client_pids, getpid ());
+
+      nbits = rp->virtual_size / MMAP_PAGESIZE;
+
+      ASSERT (nbits > 0);
+      rp->bitmap_size = nbits;
+      words = (nbits + BITS (uword) - 1) / BITS (uword);
+      vec_validate (rp->bitmap, words - 1);
+
+      overhead_space = MMAP_PAGESIZE /* header */  +
+	((a->pvt_heap_size != 0) ? a->pvt_heap_size : SVM_PVT_MHEAP_SIZE);
+
+      bit = 0;
+      data_base = (uword) rp->virtual_base;
+
+      if (a->flags & SVM_FLAGS_NODATA)
+	rp->flags |= SVM_FLAGS_NEED_DATA_INIT;
+
+      do
+	{
+	  clib_bitmap_set_no_check (rp->bitmap, bit, 1);
+	  bit++;
+	  overhead_space -= MMAP_PAGESIZE;
+	  data_base += MMAP_PAGESIZE;
+	}
+      while (overhead_space > 0);
+
+      rp->data_base = (void *) data_base;
+
+      /*
+       * Note: although the POSIX spec guarantees that only one
+       * process enters this block, we have to play games
+       * to hold off clients until e.g. the mutex is ready
+       */
+      rp->version = SVM_VERSION;
+
+      /* setup the data portion of the region */
+
+      rv = svm_data_region_create (a, rp);
+      if (rv)
+	{
+	  clib_warning ("data_region_create: %d", rv);
+	}
+
+      region_unlock (rp);
+
+      svm_pop_heap (oldheap);
+
+      return ((void *) rp);
+    }
+  else
+    {
+      svm_fd = shm_open ((char *) shm_name, O_RDWR, 0777);
+
+      vec_free (shm_name);
+
+      if (svm_fd < 0)
+	{
+	  perror ("svm_region_map(mmap open)");
+	  return (0);
+	}
+
+      time_left = 20;
+      while (1)
+	{
+	  if (0 != fstat (svm_fd, &stat))
+	    {
+	      clib_warning ("fstat failed: %d", errno);
+	      close (svm_fd);
+	      return (0);
+	    }
+	  if (stat.st_size > 0)
+	    {
+	      break;
+	    }
+	  if (0 == time_left)
+	    {
+	      clib_warning ("waiting for resize of shm file timed out");
+	      close (svm_fd);
+	      return (0);
+	    }
+	  ts.tv_sec = 0;
+	  ts.tv_nsec = 100000000;
+	  while (nanosleep (&ts, &tsrem) < 0)
+	    ts = tsrem;
+	  time_left--;
+	}
+
+      rp = mmap (0, MMAP_PAGESIZE,
+		 PROT_READ | PROT_WRITE, MAP_SHARED, svm_fd, 0);
+
+      if (rp == (svm_region_t *) MAP_FAILED)
+	{
+	  close (svm_fd);
+	  clib_warning ("mmap");
+	  return (0);
+	}
+      /*
+       * We lost the footrace to create this region; make sure
+       * the winner has crossed the finish line.
+       */
+      while (rp->version == 0 && deadman++ < 5)
+	{
+	  sleep (1);
+	}
+
+      /*
+       * <bleep>-ed?
+       */
+      if (rp->version == 0)
+	{
+	  clib_warning ("rp->version %d not %d", rp->version, SVM_VERSION);
+	  close (svm_fd);
+	  munmap (rp, a->size);
+	  return (0);
+	}
+      /* Remap now that the region has been placed */
+      a->baseva = rp->virtual_base;
+      a->size = rp->virtual_size;
+      munmap (rp, MMAP_PAGESIZE);
+
+      rp = (void *) mmap ((void *) a->baseva, a->size,
+			  PROT_READ | PROT_WRITE,
+			  MAP_SHARED | MAP_FIXED, svm_fd, 0);
+      if ((uword) rp == (uword) MAP_FAILED)
+	{
+	  clib_unix_warning ("mmap");
+	  close (svm_fd);
+	  return (0);
+	}
+
+      if ((uword) rp != rp->virtual_base)
+	{
+	  clib_warning ("mmap botch");
+	}
+
+      /*
+       * Try to fix the region mutex if it is held by
+       * a dead process
+       */
+      pid_holding_region_lock = rp->mutex_owner_pid;
+      if (pid_holding_region_lock && kill (pid_holding_region_lock, 0) < 0)
+	{
+	  clib_warning
+	    ("region %s mutex held by dead pid %d, tag %d, force unlock",
+	     rp->region_name, pid_holding_region_lock, rp->mutex_owner_tag);
+	  /* owner pid is nonexistent */
+	  rp->mutex.__data.__owner = 0;
+	  rp->mutex.__data.__lock = 0;
+	  dead_region_recovery = 1;
+	}
+
+      if (dead_region_recovery)
+	clib_warning ("recovery: attempt to re-lock region");
+
+      region_lock (rp, 2);
+      oldheap = svm_push_pvt_heap (rp);
+      vec_add1 (rp->client_pids, getpid ());
+
+      if (dead_region_recovery)
+	clib_warning ("recovery: attempt svm_data_region_map");
+
+      rv = svm_data_region_map (a, rp);
+      if (rv)
+	{
+	  clib_warning ("data_region_map: %d", rv);
+	}
+
+      if (dead_region_recovery)
+	clib_warning ("unlock and continue");
+
+      region_unlock (rp);
+
+      svm_pop_heap (oldheap);
+
+      return ((void *) rp);
+
+    }
+  return 0;			/* NOTREACHED */
+}
+
+static void
+svm_mutex_cleanup (void)
+{
+  int i;
+  for (i = 0; i < nheld; i++)
+    {
+      pthread_mutex_unlock (mutexes_held[i]);
+    }
+}
+
+static void
+svm_region_init_internal (svm_map_region_args_t * a)
+{
+  svm_region_t *rp;
+  u64 ticks = clib_cpu_time_now ();
+  uword randomize_baseva;
+
+  /* guard against klutz calls */
+  if (root_rp)
+    return;
+
+  root_rp_refcount++;
+
+  atexit (svm_mutex_cleanup);
+
+  /* Randomize the shared-VM base at init time */
+  if (MMAP_PAGESIZE <= (4 << 10))
+    randomize_baseva = (ticks & 15) * MMAP_PAGESIZE;
+  else
+    randomize_baseva = (ticks & 3) * MMAP_PAGESIZE;
+
+  a->baseva += randomize_baseva;
+
+  rp = svm_map_region (a);
+  ASSERT (rp);
+
+  region_lock (rp, 3);
+
+  /* Set up the main region data structures */
+  if (rp->flags & SVM_FLAGS_NEED_DATA_INIT)
+    {
+      svm_main_region_t *mp = 0;
+      void *oldheap;
+
+      rp->flags &= ~(SVM_FLAGS_NEED_DATA_INIT);
+
+      oldheap = svm_push_pvt_heap (rp);
+      vec_validate (mp, 0);
+      mp->name_hash = hash_create_string (0, sizeof (uword));
+      mp->root_path = a->root_path ? format (0, "%s%c", a->root_path, 0) : 0;
+      rp->data_base = mp;
+      svm_pop_heap (oldheap);
+    }
+  region_unlock (rp);
+  root_rp = rp;
+}
+
+void
+svm_region_init (void)
+{
+  svm_map_region_args_t _a, *a = &_a;
+
+  memset (a, 0, sizeof (*a));
+  a->root_path = 0;
+  a->name = SVM_GLOBAL_REGION_NAME;
+  a->baseva = SVM_GLOBAL_REGION_BASEVA;
+  a->size = SVM_GLOBAL_REGION_SIZE;
+  a->flags = SVM_FLAGS_NODATA;
+  a->uid = 0;
+  a->gid = 0;
+
+  svm_region_init_internal (a);
+}
+
+void
+svm_region_init_chroot (char *root_path)
+{
+  svm_map_region_args_t _a, *a = &_a;
+
+  memset (a, 0, sizeof (*a));
+  a->root_path = root_path;
+  a->name = SVM_GLOBAL_REGION_NAME;
+  a->baseva = SVM_GLOBAL_REGION_BASEVA;
+  a->size = SVM_GLOBAL_REGION_SIZE;
+  a->flags = SVM_FLAGS_NODATA;
+  a->uid = 0;
+  a->gid = 0;
+
+  svm_region_init_internal (a);
+}
+
+void
+svm_region_init_chroot_uid_gid (char *root_path, int uid, int gid)
+{
+  svm_map_region_args_t _a, *a = &_a;
+
+  memset (a, 0, sizeof (*a));
+  a->root_path = root_path;
+  a->name = SVM_GLOBAL_REGION_NAME;
+  a->baseva = SVM_GLOBAL_REGION_BASEVA;
+  a->size = SVM_GLOBAL_REGION_SIZE;
+  a->flags = SVM_FLAGS_NODATA;
+  a->uid = uid;
+  a->gid = gid;
+
+  svm_region_init_internal (a);
+}
+
+void
+svm_region_init_args (svm_map_region_args_t * a)
+{
+  svm_region_init_internal (a);
+}
+
+void *
+svm_region_find_or_create (svm_map_region_args_t * a)
+{
+  svm_main_region_t *mp;
+  svm_region_t *rp;
+  uword need_nbits;
+  int index, i;
+  void *oldheap;
+  uword *p;
+  u8 *name;
+  svm_subregion_t *subp;
+
+  ASSERT (root_rp);
+
+  a->size += MMAP_PAGESIZE +
+    ((a->pvt_heap_size != 0) ? a->pvt_heap_size : SVM_PVT_MHEAP_SIZE);
+  a->size = rnd_pagesize (a->size);
+
+  region_lock (root_rp, 4);
+  oldheap = svm_push_pvt_heap (root_rp);
+  mp = root_rp->data_base;
+
+  ASSERT (mp);
+
+  /* Map the named region from the correct chroot environment */
+  a->root_path = (char *) mp->root_path;
+
+  /*
+   * See if this region is already known. If it is, we're
+   * almost done...
+   */
+  p = hash_get_mem (mp->name_hash, a->name);
+
+  if (p)
+    {
+      rp = svm_map_region (a);
+      region_unlock (root_rp);
+      svm_pop_heap (oldheap);
+      return rp;
+    }
+
+  /* Create the region. */
+  ASSERT ((a->size & ~(MMAP_PAGESIZE - 1)) == a->size);
+
+  need_nbits = a->size / MMAP_PAGESIZE;
+
+  index = 1;			/* $$$ fixme, figure out how many bit to really skip */
+
+  /*
+   * Scan the virtual space allocation bitmap, looking for a large
+   * enough chunk
+   */
+  do
+    {
+      if (clib_bitmap_get_no_check (root_rp->bitmap, index) == 0)
+	{
+	  for (i = 0; i < (need_nbits - 1); i++)
+	    {
+	      if (clib_bitmap_get_no_check (root_rp->bitmap, index + i) == 1)
+		{
+		  index = index + i;
+		  goto next;
+		}
+	    }
+	  break;
+	}
+      index++;
+    next:;
+    }
+  while (index < root_rp->bitmap_size);
+
+  /* Completely out of VM? */
+  if (index >= root_rp->bitmap_size)
+    {
+      clib_warning ("region %s: not enough VM to allocate 0x%llx (%lld)",
+		    root_rp->region_name, a->size, a->size);
+      svm_pop_heap (oldheap);
+      region_unlock (root_rp);
+      return 0;
+    }
+
+  /*
+   * Mark virtual space allocated
+   */
+#if CLIB_DEBUG > 1
+  clib_warning ("set %d bits at index %d", need_nbits, index);
+#endif
+
+  for (i = 0; i < need_nbits; i++)
+    {
+      clib_bitmap_set_no_check (root_rp->bitmap, index + i, 1);
+    }
+
+  /* Place this region where it goes... */
+  a->baseva = root_rp->virtual_base + index * MMAP_PAGESIZE;
+
+  rp = svm_map_region (a);
+
+  pool_get (mp->subregions, subp);
+  name = format (0, "%s%c", a->name, 0);
+  subp->subregion_name = name;
+
+  hash_set_mem (mp->name_hash, name, subp - mp->subregions);
+
+  svm_pop_heap (oldheap);
+
+  region_unlock (root_rp);
+
+  return (rp);
+}
+
+/*
+ * svm_region_unmap
+ *
+ * Let go of the indicated region. If the calling process
+ * is the last customer, throw it away completely.
+ * The root region mutex guarantees atomicity with respect to
+ * a new region client showing up at the wrong moment.
+ */
+void
+svm_region_unmap (void *rp_arg)
+{
+  int i, mypid = getpid ();
+  int nclients_left;
+  void *oldheap;
+  uword virtual_base, virtual_size;
+  svm_region_t *rp = rp_arg;
+  char *name;
+
+  /*
+   * If we take a signal while holding one or more shared-memory
+   * mutexes, we may end up back here from an otherwise
+   * benign exit handler. Bail out to avoid a recursive
+   * mutex screw-up.
+   */
+  if (nheld)
+    return;
+
+  ASSERT (rp);
+  ASSERT (root_rp);
+
+  if (CLIB_DEBUG > 1)
+    clib_warning ("[%d] unmap region %s", getpid (), rp->region_name);
+
+  region_lock (root_rp, 5);
+  region_lock (rp, 6);
+
+  oldheap = svm_push_pvt_heap (rp);	/* nb vec_delete() in the loop */
+
+  /* Remove the caller from the list of mappers */
+  for (i = 0; i < vec_len (rp->client_pids); i++)
+    {
+      if (rp->client_pids[i] == mypid)
+	{
+	  vec_delete (rp->client_pids, 1, i);
+	  goto found;
+	}
+    }
+  clib_warning ("pid %d AWOL", mypid);
+
+found:
+
+  svm_pop_heap (oldheap);
+
+  nclients_left = vec_len (rp->client_pids);
+  virtual_base = rp->virtual_base;
+  virtual_size = rp->virtual_size;
+
+  if (nclients_left == 0)
+    {
+      int index, nbits, i;
+      svm_main_region_t *mp;
+      uword *p;
+      svm_subregion_t *subp;
+
+      /* Kill the region, last guy on his way out */
+
+      oldheap = svm_push_pvt_heap (root_rp);
+      name = vec_dup (rp->region_name);
+
+      virtual_base = rp->virtual_base;
+      virtual_size = rp->virtual_size;
+
+      /* Figure out which bits to clear in the root region bitmap */
+      index = (virtual_base - root_rp->virtual_base) / MMAP_PAGESIZE;
+
+      nbits = (virtual_size + MMAP_PAGESIZE - 1) / MMAP_PAGESIZE;
+
+#if CLIB_DEBUG > 1
+      clib_warning ("clear %d bits at index %d", nbits, index);
+#endif
+      /* Give back the allocated VM */
+      for (i = 0; i < nbits; i++)
+	{
+	  clib_bitmap_set_no_check (root_rp->bitmap, index + i, 0);
+	}
+
+      mp = root_rp->data_base;
+
+      p = hash_get_mem (mp->name_hash, name);
+
+      /* Better never happen ... */
+      if (p == NULL)
+	{
+	  region_unlock (rp);
+	  region_unlock (root_rp);
+	  svm_pop_heap (oldheap);
+	  clib_warning ("Region name '%s' not found?", name);
+	  return;
+	}
+
+      /* Remove from the root region subregion pool */
+      subp = mp->subregions + p[0];
+      pool_put (mp->subregions, subp);
+
+      hash_unset_mem (mp->name_hash, name);
+
+      vec_free (name);
+
+      region_unlock (rp);
+      shm_unlink (rp->region_name);
+      munmap ((void *) virtual_base, virtual_size);
+      region_unlock (root_rp);
+      svm_pop_heap (oldheap);
+      return;
+    }
+
+  region_unlock (rp);
+  region_unlock (root_rp);
+
+  munmap ((void *) virtual_base, virtual_size);
+}
+
+/*
+ * svm_region_exit
+ * There is no clean way to unlink the
+ * root region when all clients go away,
+ * so remove the pid entry and call it a day.
+ */
+void
+svm_region_exit ()
+{
+  void *oldheap;
+  int i, mypid = getpid ();
+  uword virtual_base, virtual_size;
+
+  /* It felt so nice we did it twice... */
+  if (root_rp == 0)
+    return;
+
+  if (--root_rp_refcount > 0)
+    return;
+
+  /*
+   * If we take a signal while holding one or more shared-memory
+   * mutexes, we may end up back here from an otherwise
+   * benign exit handler. Bail out to avoid a recursive
+   * mutex screw-up.
+   */
+  if (nheld)
+    return;
+
+  region_lock (root_rp, 7);
+  oldheap = svm_push_pvt_heap (root_rp);
+
+  virtual_base = root_rp->virtual_base;
+  virtual_size = root_rp->virtual_size;
+
+  for (i = 0; i < vec_len (root_rp->client_pids); i++)
+    {
+      if (root_rp->client_pids[i] == mypid)
+	{
+	  vec_delete (root_rp->client_pids, 1, i);
+	  goto found;
+	}
+    }
+  clib_warning ("pid %d AWOL", mypid);
+
+found:
+
+  region_unlock (root_rp);
+  svm_pop_heap (oldheap);
+
+  root_rp = 0;
+  munmap ((void *) virtual_base, virtual_size);
+}
+
+void
+svm_client_scan_this_region_nolock (svm_region_t * rp)
+{
+  int j;
+  int mypid = getpid ();
+  void *oldheap;
+
+  for (j = 0; j < vec_len (rp->client_pids); j++)
+    {
+      if (mypid == rp->client_pids[j])
+	continue;
+      if (rp->client_pids[j] && (kill (rp->client_pids[j], 0) < 0))
+	{
+	  clib_warning ("%s: cleanup ghost pid %d",
+			rp->region_name, rp->client_pids[j]);
+	  /* nb: client vec in rp->region_heap */
+	  oldheap = svm_push_pvt_heap (rp);
+	  vec_delete (rp->client_pids, 1, j);
+	  j--;
+	  svm_pop_heap (oldheap);
+	}
+    }
+}
+
+
+/*
+ * Scan svm regions for dead clients
+ */
+void
+svm_client_scan (char *root_path)
+{
+  int i, j;
+  svm_main_region_t *mp;
+  svm_map_region_args_t *a = 0;
+  svm_region_t *root_rp;
+  svm_region_t *rp;
+  svm_subregion_t *subp;
+  u8 *name = 0;
+  u8 **svm_names = 0;
+  void *oldheap;
+  int mypid = getpid ();
+
+  vec_validate (a, 0);
+
+  svm_region_init_chroot (root_path);
+
+  root_rp = svm_get_root_rp ();
+
+  pthread_mutex_lock (&root_rp->mutex);
+
+  mp = root_rp->data_base;
+
+  for (j = 0; j < vec_len (root_rp->client_pids); j++)
+    {
+      if (mypid == root_rp->client_pids[j])
+	continue;
+      if (root_rp->client_pids[j] && (kill (root_rp->client_pids[j], 0) < 0))
+	{
+	  clib_warning ("%s: cleanup ghost pid %d",
+			root_rp->region_name, root_rp->client_pids[j]);
+	  /* nb: client vec in root_rp->region_heap */
+	  oldheap = svm_push_pvt_heap (root_rp);
+	  vec_delete (root_rp->client_pids, 1, j);
+	  j--;
+	  svm_pop_heap (oldheap);
+	}
+    }
+
+  /*
+   * Snapshoot names, can't hold root rp mutex across
+   * find_or_create.
+   */
+  /* *INDENT-OFF* */
+  pool_foreach (subp, mp->subregions, ({
+        name = vec_dup (subp->subregion_name);
+        vec_add1(svm_names, name);
+      }));
+  /* *INDENT-ON* */
+
+  pthread_mutex_unlock (&root_rp->mutex);
+
+  for (i = 0; i < vec_len (svm_names); i++)
+    {
+      vec_validate (a, 0);
+      a->root_path = root_path;
+      a->name = (char *) svm_names[i];
+      rp = svm_region_find_or_create (a);
+      if (rp)
+	{
+	  pthread_mutex_lock (&rp->mutex);
+
+	  svm_client_scan_this_region_nolock (rp);
+
+	  pthread_mutex_unlock (&rp->mutex);
+	  svm_region_unmap (rp);
+	  vec_free (svm_names[i]);
+	}
+      vec_free (a);
+    }
+  vec_free (svm_names);
+
+  svm_region_exit ();
+
+  vec_free (a);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */