lib/printf.c

   1 /*
   2  *      BIRD Library -- Formatted Output
   3  *
   4  *      (c) 1991, 1992 Lars Wirzenius & Linus Torvalds
   5  *
   6  *      Hacked up for BIRD by Martin Mares <mj@ucw.cz>
   7  *      Buffer size limitation implemented by Martin Mares.
   8  */
   9
  10 #include "nest/bird.h"
  11 #include "string.h"
  12
  13 #include <errno.h>
  14
  15 #include "nest/iface.h"
  16
  17 /* we use this so that we can do without the ctype library */
  18 #define is_digit(c)     ((c) >= '0' && (c) <= '9')
  19
  20 static int skip_atoi(const char **s)
  21 {
  22         int i=0;
  23
  24         while (is_digit(**s))
  25                 i = i*10 + *((*s)++) - '0';
  26         return i;
  27 }
  28
  29 #define ZEROPAD 1               /* pad with zero */
  30 #define SIGN    2               /* unsigned/signed long */
  31 #define PLUS    4               /* show plus */
  32 #define SPACE   8               /* space if plus */
  33 #define LEFT    16              /* left justified */
  34 #define SPECIAL 32              /* 0x */
  35 #define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
  36
  37 #define do_div(n,base) ({ \
  38 int __res; \
  39 __res = ((unsigned long) n) % (unsigned) base; \
  40 n = ((unsigned long) n) / (unsigned) base; \
  41 __res; })
  42
  43 static char * number(char * str, long num, int base, int size, int precision,
  44         int type, int remains)
  45 {
  46         char c,sign,tmp[66];
  47         const char *digits="0123456789abcdefghijklmnopqrstuvwxyz";
  48         int i;
  49
  50         if (size >= 0 && (remains -= size) < 0)
  51                 return NULL;
  52         if (type & LARGE)
  53                 digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  54         if (type & LEFT)
  55                 type &= ~ZEROPAD;
  56         if (base < 2 || base > 36)
  57                 return 0;
  58         c = (type & ZEROPAD) ? '0' : ' ';
  59         sign = 0;
  60         if (type & SIGN) {
  61                 if (num < 0) {
  62                         sign = '-';
  63                         num = -num;
  64                         size--;
  65                 } else if (type & PLUS) {
  66                         sign = '+';
  67                         size--;
  68                 } else if (type & SPACE) {
  69                         sign = ' ';
  70                         size--;
  71                 }
  72         }
  73         if (type & SPECIAL) {
  74                 if (base == 16)
  75                         size -= 2;
  76                 else if (base == 8)
  77                         size--;
  78         }
  79         i = 0;
  80         if (num == 0)
  81                 tmp[i++]='0';
  82         else while (num != 0)
  83                 tmp[i++] = digits[do_div(num,base)];
  84         if (i > precision)
  85                 precision = i;
  86         size -= precision;
  87         if (size < 0 && -size > remains)
  88                 return NULL;
  89         if (!(type&(ZEROPAD+LEFT)))
  90                 while(size-->0)
  91                         *str++ = ' ';
  92         if (sign)
  93                 *str++ = sign;
  94         if (type & SPECIAL) {
  95                 if (base==8)
  96                         *str++ = '0';
  97                 else if (base==16) {
  98                         *str++ = '0';
  99                         *str++ = digits[33];
 100                 }
 101         }
 102         if (!(type & LEFT))
 103                 while (size-- > 0)
 104                         *str++ = c;
 105         while (i < precision--)
 106                 *str++ = '0';
 107         while (i-- > 0)
 108                 *str++ = tmp[i];
 109         while (size-- > 0)
 110                 *str++ = ' ';
 111         return str;
 112 }
 113
 114 /**
 115  * bvsnprintf - BIRD's vsnprintf()
 116  * @buf: destination buffer
 117  * @size: size of the buffer
 118  * @fmt: format string
 119  * @args: a list of arguments to be formatted
 120  *
 121  * This functions acts like ordinary sprintf() except that it checks
 122  * available space to avoid buffer overflows and it allows some more
 123  * format specifiers: |%I| for formatting of IP addresses (any non-zero
 124  * width is automatically replaced by standard IP address width which
 125  * depends on whether we use IPv4 or IPv6; |%#I| gives hexadecimal format),
 126  * |%R| for Router / Network ID (u32 value printed as IPv4 address)
 127  * and |%m| resp. |%M| for error messages (uses strerror() to translate @errno code to
 128  * message text). On the other hand, it doesn't support floating
 129  * point numbers.
 130  *
 131  * Result: number of characters of the output string or -1 if
 132  * the buffer space was insufficient.
 133  */
 134 int bvsnprintf(char *buf, int size, const char *fmt, va_list args)
 135 {
 136         int len;
 137         unsigned long num;
 138         int i, base;
 139         u32 x;
 140         char *str, *start;
 141         const char *s;
 142         char ipbuf[STD_ADDRESS_P_LENGTH+1];
 143         struct iface *iface;
 144
 145         int flags;              /* flags to number() */
 146
 147         int field_width;        /* width of output field */
 148         int precision;          /* min. # of digits for integers; max
 149                                    number of chars for from string */
 150         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 151
 152         for (start=str=buf ; *fmt ; ++fmt, size-=(str-start), start=str) {
 153                 if (*fmt != '%') {
 154                         if (!size)
 155                                 return -1;
 156                         *str++ = *fmt;
 157                         continue;
 158                 }
 159
 160                 /* process flags */
 161                 flags = 0;
 162                 repeat:
 163                         ++fmt;          /* this also skips first '%' */
 164                         switch (*fmt) {
 165                                 case '-': flags |= LEFT; goto repeat;
 166                                 case '+': flags |= PLUS; goto repeat;
 167                                 case ' ': flags |= SPACE; goto repeat;
 168                                 case '#': flags |= SPECIAL; goto repeat;
 169                                 case '0': flags |= ZEROPAD; goto repeat;
 170                                 }
 171
 172                 /* get field width */
 173                 field_width = -1;
 174                 if (is_digit(*fmt))
 175                         field_width = skip_atoi(&fmt);
 176                 else if (*fmt == '*') {
 177                         ++fmt;
 178                         /* it's the next argument */
 179                         field_width = va_arg(args, int);
 180                         if (field_width < 0) {
 181                                 field_width = -field_width;
 182                                 flags |= LEFT;
 183                         }
 184                 }
 185
 186                 /* get the precision */
 187                 precision = -1;
 188                 if (*fmt == '.') {
 189                         ++fmt;
 190                         if (is_digit(*fmt))
 191                                 precision = skip_atoi(&fmt);
 192                         else if (*fmt == '*') {
 193                                 ++fmt;
 194                                 /* it's the next argument */
 195                                 precision = va_arg(args, int);
 196                         }
 197                         if (precision < 0)
 198                                 precision = 0;
 199                 }
 200
 201                 /* get the conversion qualifier */
 202                 qualifier = -1;
 203                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
 204                         qualifier = *fmt;
 205                         ++fmt;
 206                 }
 207
 208                 /* default base */
 209                 base = 10;
 210
 211                 if (field_width > size)
 212                         return -1;
 213                 switch (*fmt) {
 214                 case 'c':
 215                         if (!(flags & LEFT))
 216                                 while (--field_width > 0)
 217                                         *str++ = ' ';
 218                         *str++ = (unsigned char) va_arg(args, int);
 219                         while (--field_width > 0)
 220                                 *str++ = ' ';
 221                         continue;
 222
 223                 case 'm':
 224                         if (flags & SPECIAL) {
 225                                 if (!errno)
 226                                         continue;
 227                                 if (size < 2)
 228                                         return -1;
 229                                 *str++ = ':';
 230                                 *str++ = ' ';
 231                                 start += 2;
 232                                 size -= 2;
 233                         }
 234                         s = strerror(errno);
 235                         goto str;
 236                 case 'M':
 237                         s = strerror(va_arg(args, int));
 238                         goto str;
 239                 case 's':
 240                         s = va_arg(args, char *);
 241                         if (!s)
 242                                 s = "<NULL>";
 243
 244                 str:
 245                         len = strlen(s);
 246                         if (precision >= 0 && len > precision)
 247                                 len = precision;
 248                         if (len > size)
 249                                 return -1;
 250
 251                         if (!(flags & LEFT))
 252                                 while (len < field_width--)
 253                                         *str++ = ' ';
 254                         for (i = 0; i < len; ++i)
 255                                 *str++ = *s++;
 256                         while (len < field_width--)
 257                                 *str++ = ' ';
 258                         continue;
 259
 260                 case 'p':
 261                         if (field_width == -1) {
 262                                 field_width = 2*sizeof(void *);
 263                                 flags |= ZEROPAD;
 264                         }
 265                         str = number(str,
 266                                 (unsigned long) va_arg(args, void *), 16,
 267                                 field_width, precision, flags, size);
 268                         if (!str)
 269                                 return -1;
 270                         continue;
 271
 272
 273                 case 'n':
 274                         if (qualifier == 'l') {
 275                                 long * ip = va_arg(args, long *);
 276                                 *ip = (str - buf);
 277                         } else {
 278                                 int * ip = va_arg(args, int *);
 279                                 *ip = (str - buf);
 280                         }
 281                         continue;
 282
 283                 /* IP address */
 284                 case 'I':
 285                         if (flags & SPECIAL)
 286                                 ipa_ntox(va_arg(args, ip_addr), ipbuf);
 287                         else {
 288                                 ipa_ntop(va_arg(args, ip_addr), ipbuf);
 289                                 if (field_width == 1)
 290                                         field_width = STD_ADDRESS_P_LENGTH;
 291                         }
 292                         s = ipbuf;
 293                         goto str;
 294
 295                 /* Interface scope after link-local IP address */
 296                 case 'J':
 297                         iface = va_arg(args, struct iface *);
 298                         if (!iface)
 299                                 continue;
 300                         if (!size)
 301                                 return -1;
 302
 303                         *str++ = '%';
 304                         start++;
 305                         size--;
 306
 307                         s = iface->name;
 308                         goto str;
 309
 310                 /* Router/Network ID - essentially IPv4 address in u32 value */
 311                 case 'R':
 312                         x = va_arg(args, u32);
 313                         bsprintf(ipbuf, "%d.%d.%d.%d",
 314                                  ((x >> 24) & 0xff),
 315                                  ((x >> 16) & 0xff),
 316                                  ((x >> 8) & 0xff),
 317                                  (x & 0xff));
 318                         s = ipbuf;
 319                         goto str;
 320
 321                 /* integer number formats - set up the flags and "break" */
 322                 case 'o':
 323                         base = 8;
 324                         break;
 325
 326                 case 'X':
 327                         flags |= LARGE;
 328                 case 'x':
 329                         base = 16;
 330                         break;
 331
 332                 case 'd':
 333                 case 'i':
 334                         flags |= SIGN;
 335                 case 'u':
 336                         break;
 337
 338                 default:
 339                         if (size < 2)
 340                                 return -1;
 341                         if (*fmt != '%')
 342                                 *str++ = '%';
 343                         if (*fmt)
 344                                 *str++ = *fmt;
 345                         else
 346                                 --fmt;
 347                         continue;
 348                 }
 349                 if (qualifier == 'l')
 350                         num = va_arg(args, unsigned long);
 351                 else if (qualifier == 'h') {
 352                         num = (unsigned short) va_arg(args, int);
 353                         if (flags & SIGN)
 354                                 num = (short) num;
 355                 } else if (flags & SIGN)
 356                         num = va_arg(args, int);
 357                 else
 358                         num = va_arg(args, unsigned int);
 359                 str = number(str, num, base, field_width, precision, flags, size);
 360                 if (!str)
 361                         return -1;
 362         }
 363         if (!size)
 364                 return -1;
 365         *str = '\0';
 366         return str-buf;
 367 }
 368
 369 /**
 370  * bvsprintf - BIRD's vsprintf()
 371  * @buf: buffer
 372  * @fmt: format string
 373  * @args: a list of arguments to be formatted
 374  *
 375  * This function is equivalent to bvsnprintf() with an infinite
 376  * buffer size. Please use carefully only when you are absolutely
 377  * sure the buffer won't overflow.
 378  */
 379 int bvsprintf(char *buf, const char *fmt, va_list args)
 380 {
 381   return bvsnprintf(buf, 1000000000, fmt, args);
 382 }
 383
 384 /**
 385  * bsprintf - BIRD's sprintf()
 386  * @buf: buffer
 387  * @fmt: format string
 388  *
 389  * This function is equivalent to bvsnprintf() with an infinite
 390  * buffer size and variable arguments instead of a &va_list.
 391  * Please use carefully only when you are absolutely
 392  * sure the buffer won't overflow.
 393  */
 394 int bsprintf(char * buf, const char *fmt, ...)
 395 {
 396   va_list args;
 397   int i;
 398
 399   va_start(args, fmt);
 400   i=bvsnprintf(buf, 1000000000, fmt, args);
 401   va_end(args);
 402   return i;
 403 }
 404
 405 /**
 406  * bsnprintf - BIRD's snprintf()
 407  * @buf: buffer
 408  * @size: buffer size
 409  * @fmt: format string
 410  *
 411  * This function is equivalent to bsnprintf() with variable arguments instead of a &va_list.
 412  */
 413 int bsnprintf(char * buf, int size, const char *fmt, ...)
 414 {
 415   va_list args;
 416   int i;
 417
 418   va_start(args, fmt);
 419   i=bvsnprintf(buf, size, fmt, args);
 420   va_end(args);
 421   return i;
 422 }
 423
 424 int
 425 buffer_vprint(buffer *buf, const char *fmt, va_list args)
 426 {
 427   int i = bvsnprintf((char *) buf->pos, buf->end - buf->pos, fmt, args);
 428   buf->pos = (i >= 0) ? (buf->pos + i) : buf->end;
 429   return i;
 430 }
 431
 432 int
 433 buffer_print(buffer *buf, const char *fmt, ...)
 434 {
 435   va_list args;
 436   int i;
 437
 438   va_start(args, fmt);
 439   i=bvsnprintf((char *) buf->pos, buf->end - buf->pos, fmt, args);
 440   va_end(args);
 441
 442   buf->pos = (i >= 0) ? (buf->pos + i) : buf->end;
 443   return i;
 444 }
 445
 446 void
 447 buffer_puts(buffer *buf, const char *str)
 448 {
 449   byte *bp = buf->pos;
 450   byte *be = buf->end;
 451
 452   while (bp < be && *str)
 453     *bp++ = *str++;
 454
 455   if (bp < be)
 456     *bp = 0;
 457
 458   buf->pos = bp;
 459 }