| 1 | #include <windows.h> |
| 2 | #include <stdio.h> |
| 3 | #include <stdlib.h> |
| 4 | #include "putty.h" |
| 5 | |
| 6 | /* |
| 7 | * My own versions of malloc, realloc and free. Because I want |
| 8 | * malloc and realloc to bomb out and exit the program if they run |
| 9 | * out of memory, realloc to reliably call malloc if passed a NULL |
| 10 | * pointer, and free to reliably do nothing if passed a NULL |
| 11 | * pointer. We can also put trace printouts in, if we need to; and |
| 12 | * we can also replace the allocator with an ElectricFence-like |
| 13 | * one. |
| 14 | */ |
| 15 | |
| 16 | #ifdef MINEFIELD |
| 17 | /* |
| 18 | * Minefield - a Windows equivalent for Electric Fence |
| 19 | */ |
| 20 | |
| 21 | #define PAGESIZE 4096 |
| 22 | |
| 23 | /* |
| 24 | * Design: |
| 25 | * |
| 26 | * We start by reserving as much virtual address space as Windows |
| 27 | * will sensibly (or not sensibly) let us have. We flag it all as |
| 28 | * invalid memory. |
| 29 | * |
| 30 | * Any allocation attempt is satisfied by committing one or more |
| 31 | * pages, with an uncommitted page on either side. The returned |
| 32 | * memory region is jammed up against the _end_ of the pages. |
| 33 | * |
| 34 | * Freeing anything causes instantaneous decommitment of the pages |
| 35 | * involved, so stale pointers are caught as soon as possible. |
| 36 | */ |
| 37 | |
| 38 | static int minefield_initialised = 0; |
| 39 | static void *minefield_region = NULL; |
| 40 | static long minefield_size = 0; |
| 41 | static long minefield_npages = 0; |
| 42 | static long minefield_curpos = 0; |
| 43 | static unsigned short *minefield_admin = NULL; |
| 44 | static void *minefield_pages = NULL; |
| 45 | |
| 46 | static void minefield_admin_hide(int hide) { |
| 47 | int access = hide ? PAGE_NOACCESS : PAGE_READWRITE; |
| 48 | VirtualProtect(minefield_admin, minefield_npages*2, access, NULL); |
| 49 | } |
| 50 | |
| 51 | static void minefield_init(void) { |
| 52 | int size; |
| 53 | int admin_size; |
| 54 | int i; |
| 55 | |
| 56 | for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) &~ 0xFFF) { |
| 57 | minefield_region = VirtualAlloc(NULL, size, |
| 58 | MEM_RESERVE, PAGE_NOACCESS); |
| 59 | if (minefield_region) |
| 60 | break; |
| 61 | } |
| 62 | minefield_size = size; |
| 63 | |
| 64 | /* |
| 65 | * Firstly, allocate a section of that to be the admin block. |
| 66 | * We'll need a two-byte field for each page. |
| 67 | */ |
| 68 | minefield_admin = minefield_region; |
| 69 | minefield_npages = minefield_size / PAGESIZE; |
| 70 | admin_size = (minefield_npages * 2 + PAGESIZE-1) &~ (PAGESIZE-1); |
| 71 | minefield_npages = (minefield_size - admin_size) / PAGESIZE; |
| 72 | minefield_pages = (char *)minefield_region + admin_size; |
| 73 | |
| 74 | /* |
| 75 | * Commit the admin region. |
| 76 | */ |
| 77 | VirtualAlloc(minefield_admin, minefield_npages * 2, |
| 78 | MEM_COMMIT, PAGE_READWRITE); |
| 79 | |
| 80 | /* |
| 81 | * Mark all pages as unused (0xFFFF). |
| 82 | */ |
| 83 | for (i = 0; i < minefield_npages; i++) |
| 84 | minefield_admin[i] = 0xFFFF; |
| 85 | |
| 86 | /* |
| 87 | * Hide the admin region. |
| 88 | */ |
| 89 | minefield_admin_hide(1); |
| 90 | |
| 91 | minefield_initialised = 1; |
| 92 | } |
| 93 | |
| 94 | static void minefield_bomb(void) { |
| 95 | div(1, *(int*)minefield_pages); |
| 96 | } |
| 97 | |
| 98 | static void *minefield_alloc(int size) { |
| 99 | int npages; |
| 100 | int pos, lim, region_end, region_start; |
| 101 | int start; |
| 102 | int i; |
| 103 | |
| 104 | npages = (size + PAGESIZE-1) / PAGESIZE; |
| 105 | |
| 106 | minefield_admin_hide(0); |
| 107 | |
| 108 | /* |
| 109 | * Search from current position until we find a contiguous |
| 110 | * bunch of npages+2 unused pages. |
| 111 | */ |
| 112 | pos = minefield_curpos; |
| 113 | lim = minefield_npages; |
| 114 | while (1) { |
| 115 | /* Skip over used pages. */ |
| 116 | while (pos < lim && minefield_admin[pos] != 0xFFFF) |
| 117 | pos++; |
| 118 | /* Count unused pages. */ |
| 119 | start = pos; |
| 120 | while (pos < lim && pos - start < npages+2 && |
| 121 | minefield_admin[pos] == 0xFFFF) |
| 122 | pos++; |
| 123 | if (pos - start == npages+2) |
| 124 | break; |
| 125 | /* If we've reached the limit, reset the limit or stop. */ |
| 126 | if (pos >= lim) { |
| 127 | if (lim == minefield_npages) { |
| 128 | /* go round and start again at zero */ |
| 129 | lim = minefield_curpos; |
| 130 | pos = 0; |
| 131 | } else { |
| 132 | minefield_admin_hide(1); |
| 133 | return NULL; |
| 134 | } |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | minefield_curpos = pos-1; |
| 139 | |
| 140 | /* |
| 141 | * We have npages+2 unused pages starting at start. We leave |
| 142 | * the first and last of these alone and use the rest. |
| 143 | */ |
| 144 | region_end = (start + npages+1) * PAGESIZE; |
| 145 | region_start = region_end - size; |
| 146 | /* FIXME: could align here if we wanted */ |
| 147 | |
| 148 | /* |
| 149 | * Update the admin region. |
| 150 | */ |
| 151 | for (i = start + 2; i < start + npages-1; i++) |
| 152 | minefield_admin[i] = 0xFFFE; /* used but no region starts here */ |
| 153 | minefield_admin[start+1] = region_start % PAGESIZE; |
| 154 | |
| 155 | minefield_admin_hide(1); |
| 156 | |
| 157 | VirtualAlloc((char *)minefield_pages + region_start, size, |
| 158 | MEM_COMMIT, PAGE_READWRITE); |
| 159 | return (char *)minefield_pages + region_start; |
| 160 | } |
| 161 | |
| 162 | static void minefield_free(void *ptr) { |
| 163 | int region_start, i, j; |
| 164 | |
| 165 | minefield_admin_hide(0); |
| 166 | |
| 167 | region_start = (char *)ptr - (char *)minefield_pages; |
| 168 | i = region_start / PAGESIZE; |
| 169 | if (i < 0 || i >= minefield_npages || |
| 170 | minefield_admin[i] != region_start % PAGESIZE) |
| 171 | minefield_bomb(); |
| 172 | for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) { |
| 173 | minefield_admin[j] = 0xFFFF; |
| 174 | } |
| 175 | |
| 176 | VirtualFree(ptr, j*PAGESIZE - region_start, MEM_DECOMMIT); |
| 177 | |
| 178 | minefield_admin_hide(1); |
| 179 | } |
| 180 | |
| 181 | static int minefield_get_size(void *ptr) { |
| 182 | int region_start, i, j; |
| 183 | |
| 184 | minefield_admin_hide(0); |
| 185 | |
| 186 | region_start = (char *)ptr - (char *)minefield_pages; |
| 187 | i = region_start / PAGESIZE; |
| 188 | if (i < 0 || i >= minefield_npages || |
| 189 | minefield_admin[i] != region_start % PAGESIZE) |
| 190 | minefield_bomb(); |
| 191 | for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++); |
| 192 | |
| 193 | minefield_admin_hide(1); |
| 194 | |
| 195 | return j*PAGESIZE - region_start; |
| 196 | } |
| 197 | |
| 198 | static void *minefield_c_malloc(size_t size) { |
| 199 | if (!minefield_initialised) minefield_init(); |
| 200 | return minefield_alloc(size); |
| 201 | } |
| 202 | |
| 203 | static void minefield_c_free(void *p) { |
| 204 | if (!minefield_initialised) minefield_init(); |
| 205 | minefield_free(p); |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * realloc _always_ moves the chunk, for rapid detection of code |
| 210 | * that assumes it won't. |
| 211 | */ |
| 212 | static void *minefield_c_realloc(void *p, size_t size) { |
| 213 | size_t oldsize; |
| 214 | void *q; |
| 215 | if (!minefield_initialised) minefield_init(); |
| 216 | q = minefield_alloc(size); |
| 217 | oldsize = minefield_get_size(p); |
| 218 | memcpy(q, p, (oldsize < size ? oldsize : size)); |
| 219 | minefield_free(p); |
| 220 | return q; |
| 221 | } |
| 222 | |
| 223 | #endif /* MINEFIELD */ |
| 224 | |
| 225 | #ifdef MALLOC_LOG |
| 226 | static FILE *fp = NULL; |
| 227 | |
| 228 | void mlog(char *file, int line) { |
| 229 | if (!fp) { |
| 230 | fp = fopen("putty_mem.log", "w"); |
| 231 | setvbuf(fp, NULL, _IONBF, BUFSIZ); |
| 232 | } |
| 233 | if (fp) |
| 234 | fprintf (fp, "%s:%d: ", file, line); |
| 235 | } |
| 236 | #endif |
| 237 | |
| 238 | void *safemalloc(size_t size) { |
| 239 | void *p; |
| 240 | #ifdef MINEFIELD |
| 241 | p = minefield_c_malloc (size); |
| 242 | #else |
| 243 | p = malloc (size); |
| 244 | #endif |
| 245 | if (!p) { |
| 246 | MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error", |
| 247 | MB_SYSTEMMODAL | MB_ICONERROR | MB_OK); |
| 248 | exit(1); |
| 249 | } |
| 250 | #ifdef MALLOC_LOG |
| 251 | if (fp) |
| 252 | fprintf(fp, "malloc(%d) returns %p\n", size, p); |
| 253 | #endif |
| 254 | return p; |
| 255 | } |
| 256 | |
| 257 | void *saferealloc(void *ptr, size_t size) { |
| 258 | void *p; |
| 259 | if (!ptr) { |
| 260 | #ifdef MINEFIELD |
| 261 | p = minefield_c_malloc (size); |
| 262 | #else |
| 263 | p = malloc (size); |
| 264 | #endif |
| 265 | } else { |
| 266 | #ifdef MINEFIELD |
| 267 | p = minefield_c_realloc (ptr, size); |
| 268 | #else |
| 269 | p = realloc (ptr, size); |
| 270 | #endif |
| 271 | } |
| 272 | if (!p) { |
| 273 | MessageBox(NULL, "Out of memory!", "PuTTY Fatal Error", |
| 274 | MB_SYSTEMMODAL | MB_ICONERROR | MB_OK); |
| 275 | exit(1); |
| 276 | } |
| 277 | #ifdef MALLOC_LOG |
| 278 | if (fp) |
| 279 | fprintf(fp, "realloc(%p,%d) returns %p\n", ptr, size, p); |
| 280 | #endif |
| 281 | return p; |
| 282 | } |
| 283 | |
| 284 | void safefree(void *ptr) { |
| 285 | if (ptr) { |
| 286 | #ifdef MALLOC_LOG |
| 287 | if (fp) |
| 288 | fprintf(fp, "free(%p)\n", ptr); |
| 289 | #endif |
| 290 | #ifdef MINEFIELD |
| 291 | minefield_c_free (ptr); |
| 292 | #else |
| 293 | free (ptr); |
| 294 | #endif |
| 295 | } |
| 296 | #ifdef MALLOC_LOG |
| 297 | else if (fp) |
| 298 | fprintf(fp, "freeing null pointer - no action taken\n"); |
| 299 | #endif |
| 300 | } |
| 301 | |
| 302 | #ifdef DEBUG |
| 303 | static FILE *debug_fp = NULL; |
| 304 | static int debug_got_console = 0; |
| 305 | |
| 306 | void dprintf(char *fmt, ...) { |
| 307 | char buf[2048]; |
| 308 | DWORD dw; |
| 309 | va_list ap; |
| 310 | |
| 311 | if (!debug_got_console) { |
| 312 | AllocConsole(); |
| 313 | debug_got_console = 1; |
| 314 | } |
| 315 | if (!debug_fp) { |
| 316 | debug_fp = fopen("debug.log", "w"); |
| 317 | } |
| 318 | |
| 319 | va_start(ap, fmt); |
| 320 | vsprintf(buf, fmt, ap); |
| 321 | WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), buf, strlen(buf), &dw, NULL); |
| 322 | fputs(buf, debug_fp); |
| 323 | fflush(debug_fp); |
| 324 | va_end(ap); |
| 325 | } |
| 326 | #endif |