debuggers.hg

view tools/memshr/shm.c @ 21067:b4a1832a916f

Update Xen version to 4.0.0-rc6
author Keir Fraser <keir.fraser@citrix.com>
date Tue Mar 09 18:18:05 2010 +0000 (2010-03-09)
parents 47ec2d131c22
children
line source
1 /******************************************************************************
2 *
3 * Copyright (c) 2009 Citrix Systems, Inc. (Grzegorz Milos)
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19 #include <assert.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <fcntl.h>
23 #include <unistd.h>
24 #include <sys/mman.h>
25 #include <sys/stat.h>
26 #include <sys/types.h>
28 #include "memshr-priv.h"
29 #include "bidir-hash.h"
30 #include "shm.h"
32 #define MEMSHR_INFO_SHM_FILE "/memshr-info"
33 #define MEMSHR_INFO_MAGIC 0x15263748
35 #define FGPRT_HASH_SHM_FILE "/blktap-fgprts"
36 #define FGPRT_HASH_PAGES 10000
38 #define BLOCK_HASH_SHM_FILE "/blktap-blks"
39 #define BLOCK_HASH_PAGES 10000
41 typedef struct shm_area {
42 void* base_addr;
43 size_t size;
44 int fd;
45 } shm_area_t;
47 typedef struct {
48 struct shm_area shared_info_area;
49 struct shm_area fgprts_area;
50 struct shm_area blocks_area;
51 } private_shm_info_t;
53 private_shm_info_t shm_info;
57 static int shm_area_open(const char *file, size_t size, int unlink, shm_area_t *shma)
58 {
59 /* TODO: If blktapctrl can be restarted while system is running, this needs
60 * to be cleverer */
61 if(unlink) shm_unlink(file);
63 shma->size = size;
64 shma->fd = shm_open(file,
65 (O_CREAT | O_RDWR),
66 (S_IREAD | S_IWRITE));
68 if(shma->fd < 0) return -1;
70 if(ftruncate(shma->fd, size) < 0) return -2;
72 shma->base_addr = mmap(NULL,
73 size,
74 PROT_READ | PROT_WRITE,
75 MAP_SHARED,
76 shma->fd,
77 0);
79 if(shma->base_addr == MAP_FAILED) return -2;
81 return 0;
82 }
84 static void shm_area_close(shm_area_t *shma)
85 {
86 munmap(shma->base_addr, shma->size);
87 close(shma->fd);
88 }
91 shared_memshr_info_t * shm_shared_info_open(int unlink)
92 {
93 shared_memshr_info_t *shared_info;
94 pthread_mutexattr_t lock_attr;
95 int nr_pages, i;
97 nr_pages = (sizeof(shared_memshr_info_t) >> XC_PAGE_SHIFT) + 1;
98 if(shm_area_open(MEMSHR_INFO_SHM_FILE,
99 nr_pages * XC_PAGE_SIZE,
100 unlink,
101 &(shm_info.shared_info_area)) < 0)
102 {
103 DPRINTF("Failed to open shma for shared info.\n");
104 return NULL;
105 }
106 shared_info = (shared_memshr_info_t *)
107 shm_info.shared_info_area.base_addr;
108 if(unlink)
109 {
110 memset(shared_info, 0, sizeof(shared_memshr_info_t));
111 if(pthread_mutexattr_init(&lock_attr) ||
112 pthread_mutexattr_setpshared(&lock_attr, PTHREAD_PROCESS_SHARED) ||
113 pthread_mutex_init(&shared_info->lock, &lock_attr) ||
114 pthread_mutexattr_destroy(&lock_attr))
115 {
116 DPRINTF("Failed to init shared info lock.\n");
117 return NULL;
118 }
119 strcpy(shared_info->vbd_images[0].file, "list-head");
120 for(i=1; i<MAX_NR_VBD_IMAGES; i++)
121 {
122 shared_info->vbd_images[i].next = i;
123 shared_info->vbd_images[i].prev = i;
124 }
125 shared_info->magic = MEMSHR_INFO_MAGIC;
126 }
127 else
128 if(shared_info->magic != MEMSHR_INFO_MAGIC)
129 {
130 DPRINTF("Incorrect magic in shared info.\n");
131 return NULL;
132 }
134 return shared_info;
135 }
138 struct fgprtshr_hash * shm_fgprtshr_hash_open(int unlink)
139 {
140 struct fgprtshr_hash *h;
141 if(shm_area_open(FGPRT_HASH_SHM_FILE,
142 FGPRT_HASH_PAGES * XC_PAGE_SIZE,
143 unlink,
144 &(shm_info.fgprts_area)) < 0)
145 {
146 DPRINTF("Failed to init shma for fgprtshr_hash.\n");
147 return NULL;
148 }
150 if(unlink)
151 {
152 h = fgprtshr_shm_hash_init(
153 (unsigned long) shm_info.fgprts_area.base_addr,
154 FGPRT_HASH_PAGES * XC_PAGE_SIZE);
155 } else
156 {
157 h = fgprtshr_shm_hash_get(
158 (unsigned long) shm_info.fgprts_area.base_addr);
159 }
161 return h;
162 }
164 struct blockshr_hash * shm_blockshr_hash_open(int unlink)
165 {
166 struct blockshr_hash *h;
167 if(shm_area_open(BLOCK_HASH_SHM_FILE,
168 BLOCK_HASH_PAGES * XC_PAGE_SIZE,
169 unlink,
170 &(shm_info.blocks_area)) < 0)
171 {
172 DPRINTF("Failed to init shma for blockshr_hash.\n");
173 return NULL;
174 }
176 if(unlink)
177 {
178 h = blockshr_shm_hash_init(
179 (unsigned long) shm_info.blocks_area.base_addr,
180 BLOCK_HASH_PAGES * XC_PAGE_SIZE);
181 } else
182 {
183 h = blockshr_shm_hash_get(
184 (unsigned long) shm_info.blocks_area.base_addr);
185 }
187 return h;
188 }
190 uint16_t shm_vbd_image_get(char* file, vbd_image_info_t *vbd_imgs)
191 {
192 vbd_image_info_t *img, *next_img;
193 int i, img_id;
195 /* Try to find the file in the existing list first */
196 img = vbd_imgs;
197 while(img->next != 0)
198 {
199 img = vbd_imgs + img->next;
200 if(strncmp(img->file, file, MAX_NAME_LEN) == 0)
201 {
202 img->ref_cnt++;
203 return (uint16_t)(img - vbd_imgs);
204 }
205 }
207 /* Couldn't find an existing entry. We need to add one. Find empty slot */
208 for(i=1; i<MAX_NR_VBD_IMAGES; i++)
209 {
210 img = vbd_imgs + i;
211 if((img->next == i) && (img->prev == i))
212 break;
213 }
214 /* No entries left! */
215 if(i == MAX_NR_VBD_IMAGES)
216 {
217 DPRINTF("No space in vbds table.\n");
218 return 0;
219 }
220 if(strlen(file) > MAX_NAME_LEN)
221 {
222 DPRINTF("Filename: %s too long (>%d).\n", file, MAX_NAME_LEN);
223 return 0;
224 }
225 /* Init the entry */
226 img_id = (img - vbd_imgs);
227 next_img = vbd_imgs + vbd_imgs[0].next;
228 strcpy(img->file, file);
229 img->ref_cnt = 1;
230 img->next = vbd_imgs[0].next;
231 img->prev = 0;
232 next_img->prev = img_id;
233 vbd_imgs[0].next = img_id;
235 return img_id;
236 }
239 void shm_vbd_image_put(uint16_t memshr_id, vbd_image_info_t *vbd_imgs)
240 {
241 vbd_image_info_t *img, *next_img, *prev_img;
243 img = vbd_imgs + memshr_id;
244 if(img->ref_cnt == 0)
245 {
246 DPRINTF("Incorrect image put.\n");
247 return;
248 }
250 img->ref_cnt--;
252 /* Remove from list if ref_cnt is zero */
253 if(img->ref_cnt == 0)
254 {
255 next_img = vbd_imgs + img->next;
256 prev_img = vbd_imgs + img->prev;
257 prev_img->next = img->next;
258 next_img->prev = img->prev;
259 img->next = img->prev = (img - vbd_imgs);
260 memset(img->file, 0, MAX_NAME_LEN);
261 }
262 }