lib/libc/upmap/upmap.c

   1 /*
   2  * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "namespace.h"
  36 #include <sys/cdefs.h>
  37 #include <sys/types.h>
  38 #include <sys/syscall.h>
  39 #include <sys/upmap.h>
  40 #include <sys/time.h>
  41 #include <sys/mman.h>
  42 #include <sys/fcntl.h>
  43 #include <errno.h>
  44 #include <stdio.h>
  45 #include <unistd.h>
  46 #include <time.h>
  47 #include <pthread.h>
  48 #include "un-namespace.h"
  49 #include "libc_private.h"
  50 #include "upmap.h"
  51
  52 static pthread_mutex_t ukpmap_lock;
  53 static ukpheader_t *kpmap_headers;
  54 static ukpheader_t *upmap_headers;
  55 static int kpmap_ok;
  56 static int upmap_ok;
  57
  58 /*
  59  * Map the requested data item from the user-kernel global shared mmap
  60  *
  61  * *state is set to -1 on failure, else it is left alone.
  62  * *datap is set to a pointer to the item on success, else it is left alone.
  63  * If type == 0 this function finalizes state, setting it to 1 if it is 0.
  64  */
  65 void
  66 __kpmap_map(void *datap, int *state, uint16_t type)
  67 {
  68         ukpheader_t *head;
  69
  70         if (__isthreaded)
  71                 _pthread_mutex_lock(&ukpmap_lock);
  72
  73         if (kpmap_ok <= 0) {
  74                 int fd;
  75
  76                 if (kpmap_ok < 0)
  77                         goto failed;
  78                 fd = _open("/dev/kpmap", O_RDONLY);
  79                 if (fd < 0) {
  80                         kpmap_ok = -1;
  81                         goto failed;
  82                 }
  83                 kpmap_headers = mmap(NULL, KPMAP_MAPSIZE,
  84                                      PROT_READ, MAP_SHARED,
  85                                      fd, 0);
  86                 _close(fd);
  87                 if ((void *)kpmap_headers == MAP_FAILED) {
  88                         kpmap_ok = -1;
  89                         goto failed;
  90                 }
  91                 kpmap_ok = 1;
  92         }
  93
  94         /*
  95          * Special case to finalize state
  96          */
  97         if (type == 0) {
  98                 if (*state == 0)
  99                         *state = 1;
 100                 if (__isthreaded)
 101                         _pthread_mutex_unlock(&ukpmap_lock);
 102                 return;
 103         }
 104
 105         /*
 106          * Look for type.
 107          */
 108         for (head = kpmap_headers; head->type; ++head) {
 109                 if (head->type == type) {
 110                         *(void **)datap = (char *)kpmap_headers + head->offset;
 111                         if (__isthreaded)
 112                                 _pthread_mutex_unlock(&ukpmap_lock);
 113                         return;
 114                 }
 115         }
 116 failed:
 117         *state = -1;
 118         if (__isthreaded)
 119                 _pthread_mutex_unlock(&ukpmap_lock);
 120 }
 121
 122 /*
 123  * Map the requested data item from the user-kernel per-process shared mmap
 124  *
 125  * *state is set to -1 on failure, else it is left alone.
 126  * *datap is set to a pointer to the item on success, else it is left alone.
 127  * If type == 0 this function finalizes state, setting it to 1 if it is 0.
 128  */
 129 void
 130 __upmap_map(void *datap, int *state, uint16_t type)
 131 {
 132         ukpheader_t *head;
 133
 134         if (__isthreaded)
 135                 _pthread_mutex_lock(&ukpmap_lock);
 136
 137         if (upmap_ok <= 0) {
 138                 int fd;
 139
 140                 if (upmap_ok < 0)
 141                         goto failed;
 142                 fd = _open("/dev/upmap", O_RDWR);
 143                 if (fd < 0) {
 144                         upmap_ok = -1;
 145                         goto failed;
 146                 }
 147                 upmap_headers = mmap(NULL, UPMAP_MAPSIZE,
 148                                      PROT_READ | PROT_WRITE, MAP_SHARED,
 149                                      fd, 0);
 150                 _close(fd);
 151                 if ((void *)upmap_headers == MAP_FAILED) {
 152                         upmap_ok = -1;
 153                         goto failed;
 154                 }
 155                 upmap_ok = 1;
 156         }
 157
 158         /*
 159          * Special case to finalize state
 160          */
 161         if (type == 0) {
 162                 if (*state == 0)
 163                         *state = 1;
 164                 if (__isthreaded)
 165                         _pthread_mutex_unlock(&ukpmap_lock);
 166                 return;
 167         }
 168
 169         /*
 170          * Look for type.
 171          */
 172         for (head = upmap_headers; head->type; ++head) {
 173                 if (head->type == type) {
 174                         *(void **)datap = (char *)upmap_headers + head->offset;
 175                         if (__isthreaded)
 176                                 _pthread_mutex_unlock(&ukpmap_lock);
 177                         return;
 178                 }
 179         }
 180 failed:
 181         *state = -1;
 182         if (__isthreaded)
 183                 _pthread_mutex_unlock(&ukpmap_lock);
 184 }