subr_sbuf.c revision 78092
1/*- 2 * Copyright (c) 2000 Poul-Henning Kamp and Dag-Erling Co�dan Sm�rgrav 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: head/sys/kern/subr_sbuf.c 78092 2001-06-11 18:36:18Z des $ 29 */ 30 31#include <sys/param.h> 32#include <sys/sbuf.h> 33 34#ifdef _KERNEL 35#include <sys/kernel.h> 36#include <sys/malloc.h> 37#include <sys/systm.h> 38#include <machine/stdarg.h> 39#else /* _KERNEL */ 40#include <stdarg.h> 41#endif /* _KERNEL */ 42 43#ifdef _KERNEL 44MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); 45#define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK) 46#define SBFREE(buf) free(buf, M_SBUF) 47#else /* _KERNEL */ 48#define KASSERT(e, m) 49#define SBMALLOC(size) malloc(size) 50#define SBFREE(buf) free(buf) 51#define min(x,y) MIN(x,y) 52#endif /* _KERNEL */ 53 54/* 55 * Predicates 56 */ 57#define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC) 58#define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT) 59#define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED) 60#define SBUF_HASOVERFLOWED(s) ((s)->s_flags & SBUF_OVERFLOWED) 61#define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1) 62 63/* 64 * Set / clear flags 65 */ 66#define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0) 67#define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0) 68 69/* 70 * Debugging support 71 */ 72#if defined(_KERNEL) && defined(INVARIANTS) 73static void 74_assert_sbuf_integrity(char *fun, struct sbuf *s) 75{ 76 KASSERT(s != NULL, 77 ("%s called with a NULL sbuf pointer", fun)); 78 KASSERT(s->s_buf != NULL, 79 ("%s called with unitialized or corrupt sbuf", fun)); 80 KASSERT(s->s_len < s->s_size, 81 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size)); 82} 83 84static void 85_assert_sbuf_state(char *fun, struct sbuf *s, int state) 86{ 87 KASSERT((s->s_flags & SBUF_FINISHED) == state, 88 ("%s called with %sfinished or corrupt sbuf", fun, 89 (state ? "un" : ""))); 90} 91#define assert_sbuf_integrity(s) _assert_sbuf_integrity(__FUNCTION__, (s)) 92#define assert_sbuf_state(s, i) _assert_sbuf_state(__FUNCTION__, (s), (i)) 93#else /* _KERNEL && INVARIANTS */ 94#define assert_sbuf_integrity(s) do { } while (0) 95#define assert_sbuf_state(s, i) do { } while (0) 96#endif /* _KERNEL && INVARIANTS */ 97 98/* 99 * Initialize an sbuf. 100 * If buf is non-NULL, it points to a static or already-allocated string 101 * big enough to hold at least length characters. 102 */ 103struct sbuf * 104sbuf_new(struct sbuf *s, char *buf, int length, int flags) 105{ 106 KASSERT(length >= 0, 107 ("attempt to create an sbuf of negative length (%d)", length)); 108 KASSERT(flags == 0, 109 (__FUNCTION__ " called with non-zero flags")); 110 111 if (s == NULL) { 112 s = (struct sbuf *)SBMALLOC(sizeof *s); 113 if (s == NULL) 114 return (NULL); 115 bzero(s, sizeof *s); 116 SBUF_SETFLAG(s, SBUF_DYNSTRUCT); 117 } else { 118 bzero(s, sizeof *s); 119 } 120 s->s_size = length; 121 if (buf) { 122 s->s_buf = buf; 123 return (s); 124 } 125 s->s_buf = (char *)SBMALLOC(s->s_size); 126 if (s->s_buf == NULL) { 127 if (SBUF_ISDYNSTRUCT(s)) 128 SBFREE(s); 129 return (NULL); 130 } 131 SBUF_SETFLAG(s, SBUF_DYNAMIC); 132 return (s); 133} 134 135/* 136 * Clear an sbuf and reset its position 137 */ 138void 139sbuf_clear(struct sbuf *s) 140{ 141 assert_sbuf_integrity(s); 142 /* don't care if it's finished or not */ 143 144 SBUF_CLEARFLAG(s, SBUF_FINISHED); 145 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED); 146 s->s_len = 0; 147} 148 149/* 150 * Set the sbuf's position to an arbitrary value 151 */ 152int 153sbuf_setpos(struct sbuf *s, int pos) 154{ 155 assert_sbuf_integrity(s); 156 assert_sbuf_state(s, 0); 157 158 KASSERT(pos >= 0, 159 ("attempt to seek to a negative position (%d)", pos)); 160 KASSERT(pos < s->s_size, 161 ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size)); 162 163 if (pos < 0 || pos > s->s_len) 164 return (-1); 165 s->s_len = pos; 166 return (0); 167} 168 169/* 170 * Append a byte string to an sbuf. 171 */ 172int 173sbuf_bcat(struct sbuf *s, const char *str, size_t len) 174{ 175 assert_sbuf_integrity(s); 176 assert_sbuf_state(s, 0); 177 178 if (SBUF_HASOVERFLOWED(s)) 179 return (-1); 180 181 while (len-- && SBUF_HASROOM(s)) 182 s->s_buf[s->s_len++] = *str++; 183 if (len) { 184 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 185 return (-1); 186 } 187 return (0); 188} 189 190#ifdef _KERNEL 191/* 192 * Copy a byte string from userland into an sbuf. 193 */ 194int 195sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len) 196{ 197 assert_sbuf_integrity(s); 198 assert_sbuf_state(s, 0); 199 200 if (SBUF_HASOVERFLOWED(s)) 201 return (-1); 202 203 if (len == 0) 204 return (0); 205 if (len > (s->s_size - s->s_len - 1)) 206 len = s->s_size - s->s_len - 1; 207 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0) 208 return (-1); 209 210 return (0); 211} 212#endif 213 214/* 215 * Copy a byte string into an sbuf. 216 */ 217int 218sbuf_bcpy(struct sbuf *s, const char *str, size_t len) 219{ 220 assert_sbuf_integrity(s); 221 assert_sbuf_state(s, 0); 222 223 sbuf_clear(s); 224 return (sbuf_bcat(s, str, len)); 225} 226 227/* 228 * Append a string to an sbuf. 229 */ 230int 231sbuf_cat(struct sbuf *s, const char *str) 232{ 233 assert_sbuf_integrity(s); 234 assert_sbuf_state(s, 0); 235 236 if (SBUF_HASOVERFLOWED(s)) 237 return (-1); 238 239 while (*str && SBUF_HASROOM(s)) 240 s->s_buf[s->s_len++] = *str++; 241 if (*str) { 242 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 243 return (-1); 244 } 245 return (0); 246} 247 248#ifdef _KERNEL 249/* 250 * Copy a string from userland into an sbuf. 251 */ 252int 253sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len) 254{ 255 size_t done; 256 257 assert_sbuf_integrity(s); 258 assert_sbuf_state(s, 0); 259 260 if (SBUF_HASOVERFLOWED(s)) 261 return (-1); 262 263 if (len == 0 || len > (s->s_size - s->s_len - 1)) 264 len = s->s_size - s->s_len - 1; 265 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) { 266 case ENAMETOOLONG: 267 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 268 /* fall through */ 269 case 0: 270 s->s_len += done - 1; 271 break; 272 default: 273 return (-1); /* XXX */ 274 } 275 276 return (0); 277} 278#endif 279 280/* 281 * Copy a string into an sbuf. 282 */ 283int 284sbuf_cpy(struct sbuf *s, const char *str) 285{ 286 assert_sbuf_integrity(s); 287 assert_sbuf_state(s, 0); 288 289 sbuf_clear(s); 290 return (sbuf_cat(s, str)); 291} 292 293/* 294 * Format the given arguments and append the resulting string to an sbuf. 295 */ 296int 297sbuf_printf(struct sbuf *s, char *fmt, ...) 298{ 299 va_list ap; 300 int len; 301 302 assert_sbuf_integrity(s); 303 assert_sbuf_state(s, 0); 304 305 KASSERT(fmt != NULL, 306 (__FUNCTION__ " called with a NULL format string")); 307 308 if (SBUF_HASOVERFLOWED(s)) 309 return (-1); 310 311 va_start(ap, fmt); 312 len = vsnprintf(&s->s_buf[s->s_len], s->s_size - s->s_len, fmt, ap); 313 va_end(ap); 314 315 /* 316 * s->s_len is the length of the string, without the terminating nul. 317 * When updating s->s_len, we must subtract 1 from the length that 318 * we passed into vsnprintf() because that length includes the 319 * terminating nul. 320 * 321 * vsnprintf() returns the amount that would have been copied, 322 * given sufficient space, hence the min() calculation below. 323 */ 324 s->s_len += min(len, s->s_size - s->s_len - 1); 325 if (!SBUF_HASROOM(s)) 326 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 327 328 KASSERT(s->s_len < s->s_size, 329 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size)); 330 331 if (SBUF_HASOVERFLOWED(s)) 332 return (-1); 333 return (0); 334} 335 336/* 337 * Append a character to an sbuf. 338 */ 339int 340sbuf_putc(struct sbuf *s, int c) 341{ 342 assert_sbuf_integrity(s); 343 assert_sbuf_state(s, 0); 344 345 if (SBUF_HASOVERFLOWED(s)) 346 return (-1); 347 348 if (!SBUF_HASROOM(s)) { 349 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 350 return (-1); 351 } 352 if (c != '\0') 353 s->s_buf[s->s_len++] = c; 354 return (0); 355} 356 357/* 358 * Check if an sbuf overflowed 359 */ 360int 361sbuf_overflowed(struct sbuf *s) 362{ 363 return SBUF_HASOVERFLOWED(s); 364} 365 366/* 367 * Finish off an sbuf. 368 */ 369void 370sbuf_finish(struct sbuf *s) 371{ 372 assert_sbuf_integrity(s); 373 assert_sbuf_state(s, 0); 374 375 s->s_buf[s->s_len] = '\0'; 376 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED); 377 SBUF_SETFLAG(s, SBUF_FINISHED); 378} 379 380/* 381 * Return a pointer to the sbuf data. 382 */ 383char * 384sbuf_data(struct sbuf *s) 385{ 386 assert_sbuf_integrity(s); 387 assert_sbuf_state(s, SBUF_FINISHED); 388 389 return s->s_buf; 390} 391 392/* 393 * Return the length of the sbuf data. 394 */ 395int 396sbuf_len(struct sbuf *s) 397{ 398 assert_sbuf_integrity(s); 399 /* don't care if it's finished or not */ 400 401 if (SBUF_HASOVERFLOWED(s)) 402 return (-1); 403 return s->s_len; 404} 405 406/* 407 * Clear an sbuf, free its buffer if necessary. 408 */ 409void 410sbuf_delete(struct sbuf *s) 411{ 412 assert_sbuf_integrity(s); 413 /* don't care if it's finished or not */ 414 415 if (SBUF_ISDYNAMIC(s)) 416 SBFREE(s->s_buf); 417 bzero(s, sizeof *s); 418 if (SBUF_ISDYNSTRUCT(s)) 419 SBFREE(s); 420} 421