subr_sbuf.c revision 79162
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 79162 2001-07-03 21:46:43Z 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#include <stdlib.h> 42#endif /* _KERNEL */ 43 44#ifdef _KERNEL 45MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); 46#define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK) 47#define SBFREE(buf) free(buf, M_SBUF) 48#else /* _KERNEL */ 49#define KASSERT(e, m) 50#define SBMALLOC(size) malloc(size) 51#define SBFREE(buf) free(buf) 52#define min(x,y) MIN(x,y) 53#endif /* _KERNEL */ 54 55/* 56 * Predicates 57 */ 58#define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC) 59#define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT) 60#define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED) 61#define SBUF_HASOVERFLOWED(s) ((s)->s_flags & SBUF_OVERFLOWED) 62#define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1) 63 64/* 65 * Set / clear flags 66 */ 67#define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0) 68#define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0) 69 70/* 71 * Debugging support 72 */ 73#if defined(_KERNEL) && defined(INVARIANTS) 74static void 75_assert_sbuf_integrity(char *fun, struct sbuf *s) 76{ 77 KASSERT(s != NULL, 78 ("%s called with a NULL sbuf pointer", fun)); 79 KASSERT(s->s_buf != NULL, 80 ("%s called with unitialized or corrupt sbuf", fun)); 81 KASSERT(s->s_len < s->s_size, 82 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size)); 83} 84 85static void 86_assert_sbuf_state(char *fun, struct sbuf *s, int state) 87{ 88 KASSERT((s->s_flags & SBUF_FINISHED) == state, 89 ("%s called with %sfinished or corrupt sbuf", fun, 90 (state ? "un" : ""))); 91} 92#define assert_sbuf_integrity(s) _assert_sbuf_integrity(__FUNCTION__, (s)) 93#define assert_sbuf_state(s, i) _assert_sbuf_state(__FUNCTION__, (s), (i)) 94#else /* _KERNEL && INVARIANTS */ 95#define assert_sbuf_integrity(s) do { } while (0) 96#define assert_sbuf_state(s, i) do { } while (0) 97#endif /* _KERNEL && INVARIANTS */ 98 99/* 100 * Initialize an sbuf. 101 * If buf is non-NULL, it points to a static or already-allocated string 102 * big enough to hold at least length characters. 103 */ 104struct sbuf * 105sbuf_new(struct sbuf *s, char *buf, int length, int flags) 106{ 107 KASSERT(length >= 0, 108 ("attempt to create an sbuf of negative length (%d)", length)); 109 KASSERT(flags == 0, 110 (__FUNCTION__ " called with non-zero flags")); 111 112 if (s == NULL) { 113 s = (struct sbuf *)SBMALLOC(sizeof *s); 114 if (s == NULL) 115 return (NULL); 116 bzero(s, sizeof *s); 117 SBUF_SETFLAG(s, SBUF_DYNSTRUCT); 118 } else { 119 bzero(s, sizeof *s); 120 } 121 s->s_size = length; 122 if (buf) { 123 s->s_buf = buf; 124 return (s); 125 } 126 s->s_buf = (char *)SBMALLOC(s->s_size); 127 if (s->s_buf == NULL) { 128 if (SBUF_ISDYNSTRUCT(s)) 129 SBFREE(s); 130 return (NULL); 131 } 132 SBUF_SETFLAG(s, SBUF_DYNAMIC); 133 return (s); 134} 135 136/* 137 * Clear an sbuf and reset its position 138 */ 139void 140sbuf_clear(struct sbuf *s) 141{ 142 assert_sbuf_integrity(s); 143 /* don't care if it's finished or not */ 144 145 SBUF_CLEARFLAG(s, SBUF_FINISHED); 146 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED); 147 s->s_len = 0; 148} 149 150/* 151 * Set the sbuf's position to an arbitrary value 152 */ 153int 154sbuf_setpos(struct sbuf *s, int pos) 155{ 156 assert_sbuf_integrity(s); 157 assert_sbuf_state(s, 0); 158 159 KASSERT(pos >= 0, 160 ("attempt to seek to a negative position (%d)", pos)); 161 KASSERT(pos < s->s_size, 162 ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size)); 163 164 if (pos < 0 || pos > s->s_len) 165 return (-1); 166 s->s_len = pos; 167 return (0); 168} 169 170/* 171 * Append a byte string to an sbuf. 172 */ 173int 174sbuf_bcat(struct sbuf *s, const char *str, size_t len) 175{ 176 assert_sbuf_integrity(s); 177 assert_sbuf_state(s, 0); 178 179 if (SBUF_HASOVERFLOWED(s)) 180 return (-1); 181 182 while (len-- && SBUF_HASROOM(s)) 183 s->s_buf[s->s_len++] = *str++; 184 if (len) { 185 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 186 return (-1); 187 } 188 return (0); 189} 190 191#ifdef _KERNEL 192/* 193 * Copy a byte string from userland into an sbuf. 194 */ 195int 196sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len) 197{ 198 assert_sbuf_integrity(s); 199 assert_sbuf_state(s, 0); 200 201 if (SBUF_HASOVERFLOWED(s)) 202 return (-1); 203 204 if (len == 0) 205 return (0); 206 if (len > (s->s_size - s->s_len - 1)) 207 len = s->s_size - s->s_len - 1; 208 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0) 209 return (-1); 210 s->s_len += len; 211 212 return (0); 213} 214#endif 215 216/* 217 * Copy a byte string into an sbuf. 218 */ 219int 220sbuf_bcpy(struct sbuf *s, const char *str, size_t len) 221{ 222 assert_sbuf_integrity(s); 223 assert_sbuf_state(s, 0); 224 225 sbuf_clear(s); 226 return (sbuf_bcat(s, str, len)); 227} 228 229/* 230 * Append a string to an sbuf. 231 */ 232int 233sbuf_cat(struct sbuf *s, const char *str) 234{ 235 assert_sbuf_integrity(s); 236 assert_sbuf_state(s, 0); 237 238 if (SBUF_HASOVERFLOWED(s)) 239 return (-1); 240 241 while (*str && SBUF_HASROOM(s)) 242 s->s_buf[s->s_len++] = *str++; 243 if (*str) { 244 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 245 return (-1); 246 } 247 return (0); 248} 249 250#ifdef _KERNEL 251/* 252 * Copy a string from userland into an sbuf. 253 */ 254int 255sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len) 256{ 257 size_t done; 258 259 assert_sbuf_integrity(s); 260 assert_sbuf_state(s, 0); 261 262 if (SBUF_HASOVERFLOWED(s)) 263 return (-1); 264 265 if (len == 0 || len > (s->s_size - s->s_len - 1)) 266 len = s->s_size - s->s_len - 1; 267 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) { 268 case ENAMETOOLONG: 269 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 270 /* fall through */ 271 case 0: 272 s->s_len += done - 1; 273 break; 274 default: 275 return (-1); /* XXX */ 276 } 277 278 return (0); 279} 280#endif 281 282/* 283 * Copy a string into an sbuf. 284 */ 285int 286sbuf_cpy(struct sbuf *s, const char *str) 287{ 288 assert_sbuf_integrity(s); 289 assert_sbuf_state(s, 0); 290 291 sbuf_clear(s); 292 return (sbuf_cat(s, str)); 293} 294 295/* 296 * Format the given arguments and append the resulting string to an sbuf. 297 */ 298int 299sbuf_printf(struct sbuf *s, const char *fmt, ...) 300{ 301 va_list ap; 302 int len; 303 304 assert_sbuf_integrity(s); 305 assert_sbuf_state(s, 0); 306 307 KASSERT(fmt != NULL, 308 (__FUNCTION__ " called with a NULL format string")); 309 310 if (SBUF_HASOVERFLOWED(s)) 311 return (-1); 312 313 va_start(ap, fmt); 314 len = vsnprintf(&s->s_buf[s->s_len], s->s_size - s->s_len, fmt, ap); 315 va_end(ap); 316 317 /* 318 * s->s_len is the length of the string, without the terminating nul. 319 * When updating s->s_len, we must subtract 1 from the length that 320 * we passed into vsnprintf() because that length includes the 321 * terminating nul. 322 * 323 * vsnprintf() returns the amount that would have been copied, 324 * given sufficient space, hence the min() calculation below. 325 */ 326 s->s_len += min(len, s->s_size - s->s_len - 1); 327 if (!SBUF_HASROOM(s)) 328 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 329 330 KASSERT(s->s_len < s->s_size, 331 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size)); 332 333 if (SBUF_HASOVERFLOWED(s)) 334 return (-1); 335 return (0); 336} 337 338/* 339 * Append a character to an sbuf. 340 */ 341int 342sbuf_putc(struct sbuf *s, int c) 343{ 344 assert_sbuf_integrity(s); 345 assert_sbuf_state(s, 0); 346 347 if (SBUF_HASOVERFLOWED(s)) 348 return (-1); 349 350 if (!SBUF_HASROOM(s)) { 351 SBUF_SETFLAG(s, SBUF_OVERFLOWED); 352 return (-1); 353 } 354 if (c != '\0') 355 s->s_buf[s->s_len++] = c; 356 return (0); 357} 358 359/* 360 * Check if an sbuf overflowed 361 */ 362int 363sbuf_overflowed(struct sbuf *s) 364{ 365 return SBUF_HASOVERFLOWED(s); 366} 367 368/* 369 * Finish off an sbuf. 370 */ 371void 372sbuf_finish(struct sbuf *s) 373{ 374 assert_sbuf_integrity(s); 375 assert_sbuf_state(s, 0); 376 377 s->s_buf[s->s_len] = '\0'; 378 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED); 379 SBUF_SETFLAG(s, SBUF_FINISHED); 380} 381 382/* 383 * Return a pointer to the sbuf data. 384 */ 385char * 386sbuf_data(struct sbuf *s) 387{ 388 assert_sbuf_integrity(s); 389 assert_sbuf_state(s, SBUF_FINISHED); 390 391 return s->s_buf; 392} 393 394/* 395 * Return the length of the sbuf data. 396 */ 397int 398sbuf_len(struct sbuf *s) 399{ 400 assert_sbuf_integrity(s); 401 /* don't care if it's finished or not */ 402 403 if (SBUF_HASOVERFLOWED(s)) 404 return (-1); 405 return s->s_len; 406} 407 408/* 409 * Clear an sbuf, free its buffer if necessary. 410 */ 411void 412sbuf_delete(struct sbuf *s) 413{ 414 assert_sbuf_integrity(s); 415 /* don't care if it's finished or not */ 416 417 if (SBUF_ISDYNAMIC(s)) 418 SBFREE(s->s_buf); 419 bzero(s, sizeof *s); 420 if (SBUF_ISDYNSTRUCT(s)) 421 SBFREE(s); 422} 423