1 /* 2 * ***************************************************************************** 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (c) 2018-2021 Gavin D. Howard and contributors. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions are met: 10 * 11 * * Redistributions of source code must retain the above copyright notice, this 12 * list of conditions and the following disclaimer. 13 * 14 * * Redistributions in binary form must reproduce the above copyright notice, 15 * this list of conditions and the following disclaimer in the documentation 16 * and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 * 30 * ***************************************************************************** 31 * 32 * Code for implementing buffered I/O on my own terms. 33 * 34 */ 35 36 #include <assert.h> 37 #include <errno.h> 38 #include <string.h> 39 40 #ifndef _WIN32 41 #include <unistd.h> 42 #endif // _WIN32 43 44 #include <file.h> 45 #include <vm.h> 46 47 /** 48 * Translates an integer into a string. 49 * @param val The value to translate. 50 * @param buf The return parameter. 51 */ 52 static void bc_file_ultoa(unsigned long long val, char buf[BC_FILE_ULL_LENGTH]) 53 { 54 char buf2[BC_FILE_ULL_LENGTH]; 55 size_t i, len; 56 57 // We need to make sure the entire thing is zeroed. 58 memset(buf2, 0, BC_FILE_ULL_LENGTH); 59 60 // The i = 1 is to ensure that there is a null byte at the end. 61 for (i = 1; val; ++i) { 62 63 unsigned long long mod = val % 10; 64 65 buf2[i] = ((char) mod) + '0'; 66 val /= 10; 67 } 68 69 len = i; 70 71 // Since buf2 is reversed, reverse it into buf. 72 for (i = 0; i < len; ++i) buf[i] = buf2[len - i - 1]; 73 } 74 75 /** 76 * Output to the file directly. 77 * @param fd The file descriptor. 78 * @param buf The buffer of data to output. 79 * @param n The number of bytes to output. 80 * @return A status indicating error or success. We could have a fatal I/O 81 * error or EOF. 82 */ 83 static BcStatus bc_file_output(int fd, const char *buf, size_t n) { 84 85 size_t bytes = 0; 86 sig_atomic_t lock; 87 88 BC_SIG_TRYLOCK(lock); 89 90 // While the number of bytes written is less than intended... 91 while (bytes < n) { 92 93 // Write. 94 ssize_t written = write(fd, buf + bytes, n - bytes); 95 96 // Check for error and return, if any. 97 if (BC_ERR(written == -1)) { 98 99 BC_SIG_TRYUNLOCK(lock); 100 101 return errno == EPIPE ? BC_STATUS_EOF : BC_STATUS_ERROR_FATAL; 102 } 103 104 bytes += (size_t) written; 105 } 106 107 BC_SIG_TRYUNLOCK(lock); 108 109 return BC_STATUS_SUCCESS; 110 } 111 112 BcStatus bc_file_flushErr(BcFile *restrict f, BcFlushType type) 113 { 114 BcStatus s; 115 116 BC_SIG_ASSERT_LOCKED; 117 118 // If there is stuff to output... 119 if (f->len) { 120 121 #if BC_ENABLE_HISTORY 122 123 // If history is enabled... 124 if (BC_TTY) { 125 126 // If we have been told to save the extras, and there *are* 127 // extras... 128 if (f->buf[f->len - 1] != '\n' && 129 (type == BC_FLUSH_SAVE_EXTRAS_CLEAR || 130 type == BC_FLUSH_SAVE_EXTRAS_NO_CLEAR)) 131 { 132 size_t i; 133 134 // Look for the last newline. 135 for (i = f->len - 2; i < f->len && f->buf[i] != '\n'; --i); 136 137 i += 1; 138 139 // Save the extras. 140 bc_vec_string(&vm.history.extras, f->len - i, f->buf + i); 141 } 142 // Else clear the extras if told to. 143 else if (type >= BC_FLUSH_NO_EXTRAS_CLEAR) { 144 bc_vec_popAll(&vm.history.extras); 145 } 146 } 147 #endif // BC_ENABLE_HISTORY 148 149 // Actually output. 150 s = bc_file_output(f->fd, f->buf, f->len); 151 f->len = 0; 152 } 153 else s = BC_STATUS_SUCCESS; 154 155 return s; 156 } 157 158 void bc_file_flush(BcFile *restrict f, BcFlushType type) { 159 160 BcStatus s; 161 sig_atomic_t lock; 162 163 BC_SIG_TRYLOCK(lock); 164 165 s = bc_file_flushErr(f, type); 166 167 // If we have an error... 168 if (BC_ERR(s)) { 169 170 // For EOF, set it and jump. 171 if (s == BC_STATUS_EOF) { 172 vm.status = (sig_atomic_t) s; 173 BC_SIG_TRYUNLOCK(lock); 174 BC_JMP; 175 } 176 // Blow up on fatal error. Okay, not blow up, just quit. 177 else bc_vm_fatalError(BC_ERR_FATAL_IO_ERR); 178 } 179 180 BC_SIG_TRYUNLOCK(lock); 181 } 182 183 void bc_file_write(BcFile *restrict f, BcFlushType type, 184 const char *buf, size_t n) 185 { 186 sig_atomic_t lock; 187 188 BC_SIG_TRYLOCK(lock); 189 190 // If we have enough to flush, do it. 191 if (n > f->cap - f->len) { 192 bc_file_flush(f, type); 193 assert(!f->len); 194 } 195 196 // If the output is large enough to flush by itself, just output it. 197 // Otherwise, put it into the buffer. 198 if (BC_UNLIKELY(n > f->cap - f->len)) bc_file_output(f->fd, buf, n); 199 else { 200 memcpy(f->buf + f->len, buf, n); 201 f->len += n; 202 } 203 204 BC_SIG_TRYUNLOCK(lock); 205 } 206 207 void bc_file_printf(BcFile *restrict f, const char *fmt, ...) 208 { 209 va_list args; 210 sig_atomic_t lock; 211 212 BC_SIG_TRYLOCK(lock); 213 214 va_start(args, fmt); 215 bc_file_vprintf(f, fmt, args); 216 va_end(args); 217 218 BC_SIG_TRYUNLOCK(lock); 219 } 220 221 void bc_file_vprintf(BcFile *restrict f, const char *fmt, va_list args) { 222 223 char *percent; 224 const char *ptr = fmt; 225 char buf[BC_FILE_ULL_LENGTH]; 226 227 BC_SIG_ASSERT_LOCKED; 228 229 // This is a poor man's printf(). While I could look up algorithms to make 230 // it as fast as possible, and should when I write the standard library for 231 // a new language, for bc, outputting is not the bottleneck. So we cheese it 232 // for now. 233 234 // Find each percent sign. 235 while ((percent = strchr(ptr, '%')) != NULL) { 236 237 char c; 238 239 // If the percent sign is not where we are, write what's inbetween to 240 // the buffer. 241 if (percent != ptr) { 242 size_t len = (size_t) (percent - ptr); 243 bc_file_write(f, bc_flush_none, ptr, len); 244 } 245 246 c = percent[1]; 247 248 // We only parse some format specifiers, the ones bc uses. If you add 249 // more, you need to make sure to add them here. 250 if (c == 'c') { 251 252 uchar uc = (uchar) va_arg(args, int); 253 254 bc_file_putchar(f, bc_flush_none, uc); 255 } 256 else if (c == 's') { 257 258 char *s = va_arg(args, char*); 259 260 bc_file_puts(f, bc_flush_none, s); 261 } 262 #if BC_DEBUG_CODE 263 // We only print signed integers in debug code. 264 else if (c == 'd') { 265 266 int d = va_arg(args, int); 267 268 // Take care of negative. Let's not worry about overflow. 269 if (d < 0) { 270 bc_file_putchar(f, bc_flush_none, '-'); 271 d = -d; 272 } 273 274 // Either print 0 or translate and print. 275 if (!d) bc_file_putchar(f, bc_flush_none, '0'); 276 else { 277 bc_file_ultoa((unsigned long long) d, buf); 278 bc_file_puts(f, bc_flush_none, buf); 279 } 280 } 281 #endif // BC_DEBUG_CODE 282 else { 283 284 unsigned long long ull; 285 286 // These are the ones that it expects from here. Fortunately, all of 287 // these are unsigned types, so they can use the same code, more or 288 // less. 289 assert((c == 'l' || c == 'z') && percent[2] == 'u'); 290 291 if (c == 'z') ull = (unsigned long long) va_arg(args, size_t); 292 else ull = (unsigned long long) va_arg(args, unsigned long); 293 294 // Either print 0 or translate and print. 295 if (!ull) bc_file_putchar(f, bc_flush_none, '0'); 296 else { 297 bc_file_ultoa(ull, buf); 298 bc_file_puts(f, bc_flush_none, buf); 299 } 300 } 301 302 // Increment to the next spot after the specifier. 303 ptr = percent + 2 + (c == 'l' || c == 'z'); 304 } 305 306 // If we get here, there are no more percent signs, so we just output 307 // whatever is left. 308 if (ptr[0]) bc_file_puts(f, bc_flush_none, ptr); 309 } 310 311 void bc_file_puts(BcFile *restrict f, BcFlushType type, const char *str) { 312 bc_file_write(f, type, str, strlen(str)); 313 } 314 315 void bc_file_putchar(BcFile *restrict f, BcFlushType type, uchar c) { 316 317 sig_atomic_t lock; 318 319 BC_SIG_TRYLOCK(lock); 320 321 if (f->len == f->cap) bc_file_flush(f, type); 322 323 assert(f->len < f->cap); 324 325 f->buf[f->len] = (char) c; 326 f->len += 1; 327 328 BC_SIG_TRYUNLOCK(lock); 329 } 330 331 void bc_file_init(BcFile *f, int fd, char *buf, size_t cap) { 332 333 BC_SIG_ASSERT_LOCKED; 334 335 f->fd = fd; 336 f->buf = buf; 337 f->len = 0; 338 f->cap = cap; 339 } 340 341 void bc_file_free(BcFile *f) { 342 BC_SIG_ASSERT_LOCKED; 343 bc_file_flush(f, bc_flush_none); 344 } 345