Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame^] | 1 | /** @file |
| 2 | * |
| 3 | * Dynamic memory manager |
| 4 | * |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
| 9 | * All rights reserved. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without modification, |
| 12 | * are permitted provided that the following conditions are met: |
| 13 | * |
| 14 | * 1. Redistributions of source code must retain the above copyright notice, |
| 15 | * this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 17 | * this list of conditions and the following disclaimer in the documentation |
| 18 | * and/or other materials provided with the distribution. |
| 19 | * 3. The name of the author may not be used to endorse or promote products |
| 20 | * derived from this software without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 23 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 24 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
| 25 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 26 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
| 27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| 30 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
| 31 | * OF SUCH DAMAGE. |
| 32 | * |
| 33 | * This file is part of the lwIP TCP/IP stack. |
| 34 | * |
| 35 | * Author: Adam Dunkels <adam@sics.se> |
| 36 | * |
| 37 | */ |
| 38 | |
| 39 | #include <string.h> |
| 40 | |
| 41 | #include "lwip/arch.h" |
| 42 | #include "lwip/opt.h" |
| 43 | #include "lwip/def.h" |
| 44 | #include "lwip/mem.h" |
| 45 | |
| 46 | #include "lwip/sys.h" |
| 47 | |
| 48 | #include "lwip/stats.h" |
| 49 | |
| 50 | struct mem { |
| 51 | mem_size_t next, prev; |
| 52 | #if MEM_ALIGNMENT == 1 |
| 53 | u8_t used; |
| 54 | #elif MEM_ALIGNMENT == 2 |
| 55 | u16_t used; |
| 56 | #elif MEM_ALIGNMENT == 4 |
| 57 | u32_t used; |
| 58 | #elif MEM_ALIGNMENT == 8 |
| 59 | u64_t used; |
| 60 | #else |
| 61 | #error "unhandled MEM_ALIGNMENT size" |
| 62 | #endif /* MEM_ALIGNMENT */ |
| 63 | }; |
| 64 | |
| 65 | static struct mem *ram_end; |
| 66 | static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT]; |
| 67 | |
| 68 | #define MIN_SIZE 12 |
| 69 | #if 0 /* this one does not align correctly for some, resulting in crashes */ |
| 70 | #define SIZEOF_STRUCT_MEM (unsigned int)MEM_ALIGN_SIZE(sizeof(struct mem)) |
| 71 | #else |
| 72 | #define SIZEOF_STRUCT_MEM (sizeof(struct mem) + \ |
| 73 | (((sizeof(struct mem) % MEM_ALIGNMENT) == 0)? 0 : \ |
| 74 | (4 - (sizeof(struct mem) % MEM_ALIGNMENT)))) |
| 75 | #endif |
| 76 | |
| 77 | static struct mem *lfree; /* pointer to the lowest free block */ |
| 78 | |
| 79 | static sys_sem_t mem_sem; |
| 80 | |
| 81 | static void |
| 82 | plug_holes(struct mem *mem) |
| 83 | { |
| 84 | struct mem *nmem; |
| 85 | struct mem *pmem; |
| 86 | |
| 87 | LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram); |
| 88 | LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end); |
| 89 | LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0); |
| 90 | |
| 91 | /* plug hole forward */ |
| 92 | LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE", mem->next <= MEM_SIZE); |
| 93 | |
| 94 | nmem = (struct mem *)&ram[mem->next]; |
| 95 | if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) { |
| 96 | if (lfree == nmem) { |
| 97 | lfree = mem; |
| 98 | } |
| 99 | mem->next = nmem->next; |
| 100 | ((struct mem *)&ram[nmem->next])->prev = (u8_t *)mem - ram; |
| 101 | } |
| 102 | |
| 103 | /* plug hole backward */ |
| 104 | pmem = (struct mem *)&ram[mem->prev]; |
| 105 | if (pmem != mem && pmem->used == 0) { |
| 106 | if (lfree == mem) { |
| 107 | lfree = pmem; |
| 108 | } |
| 109 | pmem->next = mem->next; |
| 110 | ((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram; |
| 111 | } |
| 112 | |
| 113 | } |
| 114 | void |
| 115 | mem_init(void) |
| 116 | { |
| 117 | struct mem *mem; |
| 118 | |
| 119 | memset(ram, 0, MEM_SIZE); |
| 120 | mem = (struct mem *)ram; |
| 121 | mem->next = MEM_SIZE; |
| 122 | mem->prev = 0; |
| 123 | mem->used = 0; |
| 124 | ram_end = (struct mem *)&ram[MEM_SIZE]; |
| 125 | ram_end->used = 1; |
| 126 | ram_end->next = MEM_SIZE; |
| 127 | ram_end->prev = MEM_SIZE; |
| 128 | |
| 129 | mem_sem = sys_sem_new(1); |
| 130 | |
| 131 | lfree = (struct mem *)ram; |
| 132 | |
| 133 | #if MEM_STATS |
| 134 | lwip_stats.mem.avail = MEM_SIZE; |
| 135 | #endif /* MEM_STATS */ |
| 136 | } |
| 137 | void |
| 138 | mem_free(void *rmem) |
| 139 | { |
| 140 | struct mem *mem; |
| 141 | |
| 142 | if (rmem == NULL) { |
| 143 | LWIP_DEBUGF(MEM_DEBUG | DBG_TRACE | 2, ("mem_free(p == NULL) was called.\n")); |
| 144 | return; |
| 145 | } |
| 146 | |
| 147 | sys_sem_wait(mem_sem); |
| 148 | |
| 149 | LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram && |
| 150 | (u8_t *)rmem < (u8_t *)ram_end); |
| 151 | |
| 152 | if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { |
| 153 | LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n")); |
| 154 | #if MEM_STATS |
| 155 | ++lwip_stats.mem.err; |
| 156 | #endif /* MEM_STATS */ |
| 157 | sys_sem_signal(mem_sem); |
| 158 | return; |
| 159 | } |
| 160 | mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); |
| 161 | |
| 162 | LWIP_ASSERT("mem_free: mem->used", mem->used); |
| 163 | |
| 164 | mem->used = 0; |
| 165 | |
| 166 | if (mem < lfree) { |
| 167 | lfree = mem; |
| 168 | } |
| 169 | |
| 170 | #if MEM_STATS |
| 171 | lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram); |
| 172 | |
| 173 | #endif /* MEM_STATS */ |
| 174 | plug_holes(mem); |
| 175 | sys_sem_signal(mem_sem); |
| 176 | } |
| 177 | void * |
| 178 | mem_reallocm(void *rmem, mem_size_t newsize) |
| 179 | { |
| 180 | void *nmem; |
| 181 | nmem = mem_malloc(newsize); |
| 182 | if (nmem == NULL) { |
| 183 | return mem_realloc(rmem, newsize); |
| 184 | } |
| 185 | memcpy(nmem, rmem, newsize); |
| 186 | mem_free(rmem); |
| 187 | return nmem; |
| 188 | } |
| 189 | |
| 190 | void * |
| 191 | mem_realloc(void *rmem, mem_size_t newsize) |
| 192 | { |
| 193 | mem_size_t size; |
| 194 | mem_size_t ptr, ptr2; |
| 195 | struct mem *mem, *mem2; |
| 196 | |
| 197 | /* Expand the size of the allocated memory region so that we can |
| 198 | adjust for alignment. */ |
| 199 | if ((newsize % MEM_ALIGNMENT) != 0) { |
| 200 | newsize += MEM_ALIGNMENT - ((newsize + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT); |
| 201 | } |
| 202 | |
| 203 | if (newsize > MEM_SIZE) { |
| 204 | return NULL; |
| 205 | } |
| 206 | |
| 207 | sys_sem_wait(mem_sem); |
| 208 | |
| 209 | LWIP_ASSERT("mem_realloc: legal memory", (u8_t *)rmem >= (u8_t *)ram && |
| 210 | (u8_t *)rmem < (u8_t *)ram_end); |
| 211 | |
| 212 | if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { |
| 213 | LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n")); |
| 214 | return rmem; |
| 215 | } |
| 216 | mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); |
| 217 | |
| 218 | ptr = (u8_t *)mem - ram; |
| 219 | |
| 220 | size = mem->next - ptr - SIZEOF_STRUCT_MEM; |
| 221 | #if MEM_STATS |
| 222 | lwip_stats.mem.used -= (size - newsize); |
| 223 | #endif /* MEM_STATS */ |
| 224 | |
| 225 | if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE < size) { |
| 226 | ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; |
| 227 | mem2 = (struct mem *)&ram[ptr2]; |
| 228 | mem2->used = 0; |
| 229 | mem2->next = mem->next; |
| 230 | mem2->prev = ptr; |
| 231 | mem->next = ptr2; |
| 232 | if (mem2->next != MEM_SIZE) { |
| 233 | ((struct mem *)&ram[mem2->next])->prev = ptr2; |
| 234 | } |
| 235 | |
| 236 | plug_holes(mem2); |
| 237 | } |
| 238 | sys_sem_signal(mem_sem); |
| 239 | return rmem; |
| 240 | } |
| 241 | void * |
| 242 | mem_malloc(mem_size_t size) |
| 243 | { |
| 244 | mem_size_t ptr, ptr2; |
| 245 | struct mem *mem, *mem2; |
| 246 | |
| 247 | if (size == 0) { |
| 248 | return NULL; |
| 249 | } |
| 250 | |
| 251 | /* Expand the size of the allocated memory region so that we can |
| 252 | adjust for alignment. */ |
| 253 | if ((size % MEM_ALIGNMENT) != 0) { |
| 254 | size += MEM_ALIGNMENT - ((size + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT); |
| 255 | } |
| 256 | |
| 257 | if (size > MEM_SIZE) { |
| 258 | return NULL; |
| 259 | } |
| 260 | |
| 261 | sys_sem_wait(mem_sem); |
| 262 | |
| 263 | for (ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE; ptr = ((struct mem *)&ram[ptr])->next) { |
| 264 | mem = (struct mem *)&ram[ptr]; |
| 265 | if (!mem->used && |
| 266 | mem->next - (ptr + SIZEOF_STRUCT_MEM) >= size + SIZEOF_STRUCT_MEM) { |
| 267 | ptr2 = ptr + SIZEOF_STRUCT_MEM + size; |
| 268 | mem2 = (struct mem *)&ram[ptr2]; |
| 269 | |
| 270 | mem2->prev = ptr; |
| 271 | mem2->next = mem->next; |
| 272 | mem->next = ptr2; |
| 273 | if (mem2->next != MEM_SIZE) { |
| 274 | ((struct mem *)&ram[mem2->next])->prev = ptr2; |
| 275 | } |
| 276 | |
| 277 | mem2->used = 0; |
| 278 | mem->used = 1; |
| 279 | #if MEM_STATS |
| 280 | lwip_stats.mem.used += (size + SIZEOF_STRUCT_MEM); |
| 281 | /* if (lwip_stats.mem.max < lwip_stats.mem.used) { |
| 282 | lwip_stats.mem.max = lwip_stats.mem.used; |
| 283 | } */ |
| 284 | if (lwip_stats.mem.max < ptr2) { |
| 285 | lwip_stats.mem.max = ptr2; |
| 286 | } |
| 287 | #endif /* MEM_STATS */ |
| 288 | |
| 289 | if (mem == lfree) { |
| 290 | /* Find next free block after mem */ |
| 291 | while (lfree->used && lfree != ram_end) { |
| 292 | lfree = (struct mem *)&ram[lfree->next]; |
| 293 | } |
| 294 | LWIP_ASSERT("mem_malloc: !lfree->used", !lfree->used); |
| 295 | } |
| 296 | sys_sem_signal(mem_sem); |
| 297 | LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.", |
| 298 | (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end); |
| 299 | LWIP_ASSERT("mem_malloc: allocated memory properly aligned.", |
| 300 | (unsigned long)((u8_t *)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0); |
| 301 | return (u8_t *)mem + SIZEOF_STRUCT_MEM; |
| 302 | } |
| 303 | } |
| 304 | LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size)); |
| 305 | #if MEM_STATS |
| 306 | ++lwip_stats.mem.err; |
| 307 | #endif /* MEM_STATS */ |
| 308 | sys_sem_signal(mem_sem); |
| 309 | return NULL; |
| 310 | } |