release/src/router/busybox/libbb/xfuncs.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  * Copyright (C) 2006 Rob Landley
   7  * Copyright (C) 2006 Denys Vlasenko
   8  *
   9  * Licensed under GPLv2, see file LICENSE in this source tree.
  10  */
  11
  12 /* We need to have separate xfuncs.c and xfuncs_printf.c because
  13  * with current linkers, even with section garbage collection,
  14  * if *.o module references any of XXXprintf functions, you pull in
  15  * entire printf machinery. Even if you do not use the function
  16  * which uses XXXprintf.
  17  *
  18  * xfuncs.c contains functions (not necessarily xfuncs)
  19  * which do not pull in printf, directly or indirectly.
  20  * xfunc_printf.c contains those which do.
  21  *
  22  * TODO: move xmalloc() and xatonum() here.
  23  */
  24
  25 #include "libbb.h"
  26
  27 /* Turn on nonblocking I/O on a fd */
  28 int FAST_FUNC ndelay_on(int fd)
  29 {
  30         int flags = fcntl(fd, F_GETFL);
  31         if (flags & O_NONBLOCK)
  32                 return flags;
  33         fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  34         return flags;
  35 }
  36
  37 int FAST_FUNC ndelay_off(int fd)
  38 {
  39         int flags = fcntl(fd, F_GETFL);
  40         if (!(flags & O_NONBLOCK))
  41                 return flags;
  42         fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
  43         return flags;
  44 }
  45
  46 void FAST_FUNC close_on_exec_on(int fd)
  47 {
  48         fcntl(fd, F_SETFD, FD_CLOEXEC);
  49 }
  50
  51 char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
  52 {
  53 #ifndef IFNAMSIZ
  54         enum { IFNAMSIZ = 16 };
  55 #endif
  56         return strncpy(dst, src, IFNAMSIZ);
  57 }
  58
  59
  60 /* Convert unsigned integer to ascii, writing into supplied buffer.
  61  * A truncated result contains the first few digits of the result ala strncpy.
  62  * Returns a pointer past last generated digit, does _not_ store NUL.
  63  */
  64 void BUG_sizeof(void);
  65 char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
  66 {
  67         unsigned i, out, res;
  68
  69         if (buflen) {
  70                 out = 0;
  71                 if (sizeof(n) == 4)
  72                 // 2^32-1 = 4294967295
  73                         i = 1000000000;
  74 #if UINT_MAX > 4294967295 /* prevents warning about "const too large" */
  75                 else
  76                 if (sizeof(n) == 8)
  77                 // 2^64-1 = 18446744073709551615
  78                         i = 10000000000000000000;
  79 #endif
  80                 else
  81                         BUG_sizeof();
  82                 for (; i; i /= 10) {
  83                         res = n / i;
  84                         n = n % i;
  85                         if (res || out || i == 1) {
  86                                 if (--buflen == 0)
  87                                         break;
  88                                 out++;
  89                                 *buf++ = '0' + res;
  90                         }
  91                 }
  92         }
  93         return buf;
  94 }
  95
  96 /* Convert signed integer to ascii, like utoa_to_buf() */
  97 char* FAST_FUNC itoa_to_buf(int n, char *buf, unsigned buflen)
  98 {
  99         if (!buflen)
 100                 return buf;
 101         if (n < 0) {
 102                 n = -n;
 103                 *buf++ = '-';
 104                 buflen--;
 105         }
 106         return utoa_to_buf((unsigned)n, buf, buflen);
 107 }
 108
 109 // The following two functions use a static buffer, so calling either one a
 110 // second time will overwrite previous results.
 111 //
 112 // The largest 32 bit integer is -2 billion plus NUL, or 1+10+1=12 bytes.
 113 // It so happens that sizeof(int) * 3 is enough for 32+ bit ints.
 114 // (sizeof(int) * 3 + 2 is correct for any width, even 8-bit)
 115
 116 static char local_buf[sizeof(int) * 3];
 117
 118 /* Convert unsigned integer to ascii using a static buffer (returned). */
 119 char* FAST_FUNC utoa(unsigned n)
 120 {
 121         *(utoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
 122
 123         return local_buf;
 124 }
 125
 126 /* Convert signed integer to ascii using a static buffer (returned). */
 127 char* FAST_FUNC itoa(int n)
 128 {
 129         *(itoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
 130
 131         return local_buf;
 132 }
 133
 134 /* Emit a string of hex representation of bytes */
 135 char* FAST_FUNC bin2hex(char *p, const char *cp, int count)
 136 {
 137         while (count) {
 138                 unsigned char c = *cp++;
 139                 /* put lowercase hex digits */
 140                 *p++ = 0x20 | bb_hexdigits_upcase[c >> 4];
 141                 *p++ = 0x20 | bb_hexdigits_upcase[c & 0xf];
 142                 count--;
 143         }
 144         return p;
 145 }
 146
 147 /* Convert "[x]x[:][x]x[:][x]x[:][x]x" hex string to binary, no more than COUNT bytes */
 148 char* FAST_FUNC hex2bin(char *dst, const char *str, int count)
 149 {
 150         errno = EINVAL;
 151         while (*str && count) {
 152                 uint8_t val;
 153                 uint8_t c = *str++;
 154                 if (isdigit(c))
 155                         val = c - '0';
 156                 else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
 157                         val = (c|0x20) - ('a' - 10);
 158                 else
 159                         return NULL;
 160                 val <<= 4;
 161                 c = *str;
 162                 if (isdigit(c))
 163                         val |= c - '0';
 164                 else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
 165                         val |= (c|0x20) - ('a' - 10);
 166                 else if (c == ':' || c == '\0')
 167                         val >>= 4;
 168                 else
 169                         return NULL;
 170
 171                 *dst++ = val;
 172                 if (c != '\0')
 173                         str++;
 174                 if (*str == ':')
 175                         str++;
 176                 count--;
 177         }
 178         errno = (*str ? ERANGE : 0);
 179         return dst;
 180 }
 181
 182 /* Return how long the file at fd is, if there's any way to determine it. */
 183 #ifdef UNUSED
 184 off_t FAST_FUNC fdlength(int fd)
 185 {
 186         off_t bottom = 0, top = 0, pos;
 187         long size;
 188
 189         // If the ioctl works for this, return it.
 190
 191         if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
 192
 193         // FIXME: explain why lseek(SEEK_END) is not used here!
 194
 195         // If not, do a binary search for the last location we can read.  (Some
 196         // block devices don't do BLKGETSIZE right.)
 197
 198         do {
 199                 char temp;
 200
 201                 pos = bottom + (top - bottom) / 2;
 202
 203                 // If we can read from the current location, it's bigger.
 204
 205                 if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
 206                         if (bottom == top) bottom = top = (top+1) * 2;
 207                         else bottom = pos;
 208
 209                 // If we can't, it's smaller.
 210                 } else {
 211                         if (bottom == top) {
 212                                 if (!top) return 0;
 213                                 bottom = top/2;
 214                         }
 215                         else top = pos;
 216                 }
 217         } while (bottom + 1 != top);
 218
 219         return pos + 1;
 220 }
 221 #endif
 222
 223 int FAST_FUNC bb_putchar_stderr(char ch)
 224 {
 225         return write(STDERR_FILENO, &ch, 1);
 226 }
 227
 228 ssize_t FAST_FUNC full_write1_str(const char *str)
 229 {
 230         return full_write(STDOUT_FILENO, str, strlen(str));
 231 }
 232
 233 ssize_t FAST_FUNC full_write2_str(const char *str)
 234 {
 235         return full_write(STDERR_FILENO, str, strlen(str));
 236 }
 237
 238 static int wh_helper(int value, int def_val, const char *env_name, int *err)
 239 {
 240         if (value == 0) {
 241                 char *s = getenv(env_name);
 242                 if (s) {
 243                         value = atoi(s);
 244                         /* If LINES/COLUMNS are set, pretend that there is
 245                          * no error getting w/h, this prevents some ugly
 246                          * cursor tricks by our callers */
 247                         *err = 0;
 248                 }
 249         }
 250         if (value <= 1 || value >= 30000)
 251                 value = def_val;
 252         return value;
 253 }
 254
 255 /* It is perfectly ok to pass in a NULL for either width or for
 256  * height, in which case that value will not be set.  */
 257 int FAST_FUNC get_terminal_width_height(int fd, unsigned *width, unsigned *height)
 258 {
 259         struct winsize win;
 260         int err;
 261
 262         win.ws_row = 0;
 263         win.ws_col = 0;
 264         /* I've seen ioctl returning 0, but row/col is (still?) 0.
 265          * We treat that as an error too.  */
 266         err = ioctl(fd, TIOCGWINSZ, &win) != 0 || win.ws_row == 0;
 267         if (height)
 268                 *height = wh_helper(win.ws_row, 24, "LINES", &err);
 269         if (width)
 270                 *width = wh_helper(win.ws_col, 80, "COLUMNS", &err);
 271         return err;
 272 }
 273 int FAST_FUNC get_terminal_width(int fd)
 274 {
 275         unsigned width;
 276         get_terminal_width_height(fd, &width, NULL);
 277         return width;
 278 }
 279
 280 int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
 281 {
 282         return tcsetattr(STDIN_FILENO, TCSANOW, tp);
 283 }
 284
 285 pid_t FAST_FUNC safe_waitpid(pid_t pid, int *wstat, int options)
 286 {
 287         pid_t r;
 288
 289         do
 290                 r = waitpid(pid, wstat, options);
 291         while ((r == -1) && (errno == EINTR));
 292         return r;
 293 }
 294
 295 pid_t FAST_FUNC wait_any_nohang(int *wstat)
 296 {
 297         return safe_waitpid(-1, wstat, WNOHANG);
 298 }
 299
 300 // Wait for the specified child PID to exit, returning child's error return.
 301 int FAST_FUNC wait4pid(pid_t pid)
 302 {
 303         int status;
 304
 305         if (pid <= 0) {
 306                 /*errno = ECHILD; -- wrong. */
 307                 /* we expect errno to be already set from failed [v]fork/exec */
 308                 return -1;
 309         }
 310         if (safe_waitpid(pid, &status, 0) == -1)
 311                 return -1;
 312         if (WIFEXITED(status))
 313                 return WEXITSTATUS(status);
 314         if (WIFSIGNALED(status))
 315                 return WTERMSIG(status) + 0x180;
 316         return 0;
 317 }
 318
 319 // Useful when we do know that pid is valid, and we just want to wait
 320 // for it to exit. Not existing pid is fatal. waitpid() status is not returned.
 321 int FAST_FUNC wait_for_exitstatus(pid_t pid)
 322 {
 323         int exit_status, n;
 324
 325         n = safe_waitpid(pid, &exit_status, 0);
 326         if (n < 0)
 327                 bb_perror_msg_and_die("waitpid");
 328         return exit_status;
 329 }
 330
 331 char * FAST_FUNC unparse_uuid(const uint8_t *uu, char *out)
 332 {
 333         char uuid_string[32];
 334
 335         bin2hex(uuid_string, (char *)uu, 16);
 336         /* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
 337         sprintf(out, "%.8s-%.4s-%.4s-%.4s-%.12s",
 338                 uuid_string,
 339                 uuid_string+8,
 340                 uuid_string+8+4,
 341                 uuid_string+8+4+4,
 342                 uuid_string+8+4+4+4
 343         );
 344         return out;
 345 }
 346
 347 static unsigned char fromhex(char c)
 348 {
 349         if (isdigit(c))
 350                 return (c - '0');
 351         return ((c|0x20) - 'a' + 10);
 352 }
 353
 354 /* Parse & verify UUID string */
 355 int FAST_FUNC parse_uuid(const char *s, uint8_t *uuid)
 356 {
 357         int i;
 358
 359         if (strlen(s) != 36 || s[8] != '-' || s[13] != '-'
 360          || s[18] != '-' || s[23] != '-'
 361         ) {
 362                 return -1;
 363         }
 364         for (i = 0; i < 16; i++) {
 365                 if (*s == '-')
 366                         s++;
 367                 if (!isxdigit(s[0]) || !isxdigit(s[1]))
 368                         return -2;
 369                 uuid[i] = ((fromhex(s[0]) << 4) | fromhex(s[1]));
 370                 s += 2;
 371         }
 372
 373         return 0;
 374 }
 375