LXR 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/* We need to have separate xfuncs.c and xfuncs_printf.c because
  12 * with current linkers, even with section garbage collection,
  13 * if *.o module references any of XXXprintf functions, you pull in
  14 * entire printf machinery. Even if you do not use the function
  15 * which uses XXXprintf.
  16 *
  17 * xfuncs.c contains functions (not necessarily xfuncs)
  18 * which do not pull in printf, directly or indirectly.
  19 * xfunc_printf.c contains those which do.
  20 *
  21 * TODO: move xmalloc() and xatonum() here.
  22 */
  23#include "libbb.h"
  24
  25/* Turn on nonblocking I/O on a fd */
  26int FAST_FUNC ndelay_on(int fd)
  27{
  28        int flags = fcntl(fd, F_GETFL);
  29        if (flags & O_NONBLOCK)
  30                return flags;
  31        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  32        return flags;
  33}
  34
  35int FAST_FUNC ndelay_off(int fd)
  36{
  37        int flags = fcntl(fd, F_GETFL);
  38        if (!(flags & O_NONBLOCK))
  39                return flags;
  40        fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
  41        return flags;
  42}
  43
  44void FAST_FUNC close_on_exec_on(int fd)
  45{
  46        fcntl(fd, F_SETFD, FD_CLOEXEC);
  47}
  48
  49char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
  50{
  51#ifndef IFNAMSIZ
  52        enum { IFNAMSIZ = 16 };
  53#endif
  54        return strncpy(dst, src, IFNAMSIZ);
  55}
  56
  57
  58/* Convert unsigned integer to ascii, writing into supplied buffer.
  59 * A truncated result contains the first few digits of the result ala strncpy.
  60 * Returns a pointer past last generated digit, does _not_ store NUL.
  61 */
  62char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
  63{
  64        unsigned i, out, res;
  65
  66        if (buflen) {
  67                out = 0;
  68
  69                BUILD_BUG_ON(sizeof(n) != 4 && sizeof(n) != 8);
  70                if (sizeof(n) == 4)
  71                // 2^32-1 = 4294967295
  72                        i = 1000000000;
  73#if UINT_MAX > 0xffffffff /* prevents warning about "const too large" */
  74                else
  75                if (sizeof(n) == 8)
  76                // 2^64-1 = 18446744073709551615
  77                        i = 10000000000000000000;
  78#endif
  79                for (; i; i /= 10) {
  80                        res = n / i;
  81                        n = n % i;
  82                        if (res || out || i == 1) {
  83                                if (--buflen == 0)
  84                                        break;
  85                                out++;
  86                                *buf++ = '0' + res;
  87                        }
  88                }
  89        }
  90        return buf;
  91}
  92
  93/* Convert signed integer to ascii, like utoa_to_buf() */
  94char* FAST_FUNC itoa_to_buf(int n, char *buf, unsigned buflen)
  95{
  96        if (!buflen)
  97                return buf;
  98        if (n < 0) {
  99                n = -n;
 100                *buf++ = '-';
 101                buflen--;
 102        }
 103        return utoa_to_buf((unsigned)n, buf, buflen);
 104}
 105
 106// The following two functions use a static buffer, so calling either one a
 107// second time will overwrite previous results.
 108//
 109// The largest 32 bit integer is -2 billion plus NUL, or 1+10+1=12 bytes.
 110// It so happens that sizeof(int) * 3 is enough for 32+ bit ints.
 111// (sizeof(int) * 3 + 2 is correct for any width, even 8-bit)
 112
 113static char local_buf[sizeof(int) * 3];
 114
 115/* Convert unsigned integer to ascii using a static buffer (returned). */
 116char* FAST_FUNC utoa(unsigned n)
 117{
 118        *(utoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
 119
 120        return local_buf;
 121}
 122
 123/* Convert signed integer to ascii using a static buffer (returned). */
 124char* FAST_FUNC itoa(int n)
 125{
 126        *(itoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
 127
 128        return local_buf;
 129}
 130
 131/* Emit a string of hex representation of bytes */
 132char* FAST_FUNC bin2hex(char *p, const char *cp, int count)
 133{
 134        while (count) {
 135                unsigned char c = *cp++;
 136                /* put lowercase hex digits */
 137                *p++ = 0x20 | bb_hexdigits_upcase[c >> 4];
 138                *p++ = 0x20 | bb_hexdigits_upcase[c & 0xf];
 139                count--;
 140        }
 141        return p;
 142}
 143
 144/* Convert "[x]x[:][x]x[:][x]x[:][x]x" hex string to binary, no more than COUNT bytes */
 145char* FAST_FUNC hex2bin(char *dst, const char *str, int count)
 146{
 147        errno = EINVAL;
 148        while (*str && count) {
 149                uint8_t val;
 150                uint8_t c = *str++;
 151                if (isdigit(c))
 152                        val = c - '0';
 153                else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
 154                        val = (c|0x20) - ('a' - 10);
 155                else
 156                        return NULL;
 157                val <<= 4;
 158                c = *str;
 159                if (isdigit(c))
 160                        val |= c - '0';
 161                else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
 162                        val |= (c|0x20) - ('a' - 10);
 163                else if (c == ':' || c == '\0')
 164                        val >>= 4;
 165                else
 166                        return NULL;
 167
 168                *dst++ = val;
 169                if (c != '\0')
 170                        str++;
 171                if (*str == ':')
 172                        str++;
 173                count--;
 174        }
 175        errno = (*str ? ERANGE : 0);
 176        return dst;
 177}
 178
 179/* Return how long the file at fd is, if there's any way to determine it. */
 180#ifdef UNUSED
 181off_t FAST_FUNC fdlength(int fd)
 182{
 183        off_t bottom = 0, top = 0, pos;
 184        long size;
 185
 186        // If the ioctl works for this, return it.
 187
 188        if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
 189
 190        // FIXME: explain why lseek(SEEK_END) is not used here!
 191
 192        // If not, do a binary search for the last location we can read.  (Some
 193        // block devices don't do BLKGETSIZE right.)
 194
 195        do {
 196                char temp;
 197
 198                pos = bottom + (top - bottom) / 2;
 199
 200                // If we can read from the current location, it's bigger.
 201
 202                if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
 203                        if (bottom == top) bottom = top = (top+1) * 2;
 204                        else bottom = pos;
 205
 206                // If we can't, it's smaller.
 207                } else {
 208                        if (bottom == top) {
 209                                if (!top) return 0;
 210                                bottom = top/2;
 211                        }
 212                        else top = pos;
 213                }
 214        } while (bottom + 1 != top);
 215
 216        return pos + 1;
 217}
 218#endif
 219
 220int FAST_FUNC bb_putchar_stderr(char ch)
 221{
 222        return write(STDERR_FILENO, &ch, 1);
 223}
 224
 225ssize_t FAST_FUNC full_write1_str(const char *str)
 226{
 227        return full_write(STDOUT_FILENO, str, strlen(str));
 228}
 229
 230ssize_t FAST_FUNC full_write2_str(const char *str)
 231{
 232        return full_write(STDERR_FILENO, str, strlen(str));
 233}
 234
 235static int wh_helper(int value, int def_val, const char *env_name, int *err)
 236{
 237        /* Envvars override even if "value" from ioctl is valid (>0).
 238         * Rationale: it's impossible to guess what user wants.
 239         * For example: "man CMD | ...": should "man" format output
 240         * to stdout's width? stdin's width? /dev/tty's width? 80 chars?
 241         * We _cant_ know it. If "..." saves text for e.g. email,
 242         * then it's probably 80 chars.
 243         * If "..." is, say, "grep -v DISCARD | $PAGER", then user
 244         * would prefer his tty's width to be used!
 245         *
 246         * Since we don't know, at least allow user to do this:
 247         * "COLUMNS=80 man CMD | ..."
 248         */
 249        char *s = getenv(env_name);
 250        if (s) {
 251                value = atoi(s);
 252                /* If LINES/COLUMNS are set, pretend that there is
 253                 * no error getting w/h, this prevents some ugly
 254                 * cursor tricks by our callers */
 255                *err = 0;
 256        }
 257
 258        if (value <= 1 || value >= 30000)
 259                value = def_val;
 260        return value;
 261}
 262
 263/* It is perfectly ok to pass in a NULL for either width or for
 264 * height, in which case that value will not be set.  */
 265int FAST_FUNC get_terminal_width_height(int fd, unsigned *width, unsigned *height)
 266{
 267        struct winsize win;
 268        int err;
 269        int close_me = -1;
 270
 271        if (fd == -1) {
 272                if (isatty(STDOUT_FILENO))
 273                        fd = STDOUT_FILENO;
 274                else
 275                if (isatty(STDERR_FILENO))
 276                        fd = STDERR_FILENO;
 277                else
 278                if (isatty(STDIN_FILENO))
 279                        fd = STDIN_FILENO;
 280                else
 281                        close_me = fd = open("/dev/tty", O_RDONLY);
 282        }
 283
 284        win.ws_row = 0;
 285        win.ws_col = 0;
 286        /* I've seen ioctl returning 0, but row/col is (still?) 0.
 287         * We treat that as an error too.  */
 288        err = ioctl(fd, TIOCGWINSZ, &win) != 0 || win.ws_row == 0;
 289        if (height)
 290                *height = wh_helper(win.ws_row, 24, "LINES", &err);
 291        if (width)
 292                *width = wh_helper(win.ws_col, 80, "COLUMNS", &err);
 293
 294        if (close_me >= 0)
 295                close(close_me);
 296
 297        return err;
 298}
 299int FAST_FUNC get_terminal_width(int fd)
 300{
 301        unsigned width;
 302        get_terminal_width_height(fd, &width, NULL);
 303        return width;
 304}
 305
 306int FAST_FUNC is_TERM_dumb(void)
 307{
 308        char *term = getenv("TERM");
 309        return term && strcmp(term, "dumb") == 0;
 310}
 311
 312int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
 313{
 314        return tcsetattr(STDIN_FILENO, TCSANOW, tp);
 315}
 316
 317int FAST_FUNC get_termios_and_make_raw(int fd, struct termios *newterm, struct termios *oldterm, int flags)
 318{
 319//TODO: slattach, shell read might be adapted to use this too: grep for "tcsetattr", "[VTIME] = 0"
 320        int r;
 321
 322        memset(oldterm, 0, sizeof(*oldterm)); /* paranoia */
 323        r = tcgetattr(fd, oldterm);
 324        *newterm = *oldterm;
 325
 326        /* Turn off buffered input (ICANON)
 327         * Turn off echoing (ECHO)
 328         * and separate echoing of newline (ECHONL, normally off anyway)
 329         */
 330        newterm->c_lflag &= ~(ICANON | ECHO | ECHONL);
 331        if (flags & TERMIOS_CLEAR_ISIG) {
 332                /* dont recognize INT/QUIT/SUSP chars */
 333                newterm->c_lflag &= ~ISIG;
 334        }
 335        /* reads will block only if < 1 char is available */
 336        newterm->c_cc[VMIN] = 1;
 337        /* no timeout (reads block forever) */
 338        newterm->c_cc[VTIME] = 0;
 339/* IXON, IXOFF, and IXANY:
 340 * IXOFF=1: sw flow control is enabled on input queue:
 341 * tty transmits a STOP char when input queue is close to full
 342 * and transmits a START char when input queue is nearly empty.
 343 * IXON=1: sw flow control is enabled on output queue:
 344 * tty will stop sending if STOP char is received,
 345 * and resume sending if START is received, or if any char
 346 * is received and IXANY=1.
 347 */
 348        if (flags & TERMIOS_RAW_CRNL_INPUT) {
 349                /* IXON=0: XON/XOFF chars are treated as normal chars (why we do this?) */
 350                /* dont convert CR to NL on input */
 351                newterm->c_iflag &= ~(IXON | ICRNL);
 352        }
 353        if (flags & TERMIOS_RAW_CRNL_OUTPUT) {
 354                /* dont convert NL to CR+NL on output */
 355                newterm->c_oflag &= ~(ONLCR);
 356                /* Maybe clear more c_oflag bits? Usually, only OPOST and ONLCR are set.
 357                 * OPOST  Enable output processing (reqd for OLCUC and *NL* bits to work)
 358                 * OLCUC  Map lowercase characters to uppercase on output.
 359                 * OCRNL  Map CR to NL on output.
 360                 * ONOCR  Don't output CR at column 0.
 361                 * ONLRET Don't output CR.
 362                 */
 363        }
 364        if (flags & TERMIOS_RAW_INPUT) {
 365#ifndef IMAXBEL
 366# define IMAXBEL 0
 367#endif
 368#ifndef IUCLC
 369# define IUCLC 0
 370#endif
 371#ifndef IXANY
 372# define IXANY 0
 373#endif
 374                /* IXOFF=0: disable sending XON/XOFF if input buf is full
 375                 * IXON=0: input XON/XOFF chars are not special
 376                 * BRKINT=0: dont send SIGINT on break
 377                 * IMAXBEL=0: dont echo BEL on input line too long
 378                 * INLCR,ICRNL,IUCLC: dont convert anything on input
 379                 */
 380                newterm->c_iflag &= ~(IXOFF|IXON|IXANY|BRKINT|INLCR|ICRNL|IUCLC|IMAXBEL);
 381        }
 382        return r;
 383}
 384
 385int FAST_FUNC set_termios_to_raw(int fd, struct termios *oldterm, int flags)
 386{
 387        struct termios newterm;
 388
 389        get_termios_and_make_raw(fd, &newterm, oldterm, flags);
 390        return tcsetattr(fd, TCSANOW, &newterm);
 391}
 392
 393pid_t FAST_FUNC safe_waitpid(pid_t pid, int *wstat, int options)
 394{
 395        pid_t r;
 396
 397        do
 398                r = waitpid(pid, wstat, options);
 399        while ((r == -1) && (errno == EINTR));
 400        return r;
 401}
 402
 403pid_t FAST_FUNC wait_any_nohang(int *wstat)
 404{
 405        return safe_waitpid(-1, wstat, WNOHANG);
 406}
 407
 408// Wait for the specified child PID to exit, returning child's error return.
 409int FAST_FUNC wait4pid(pid_t pid)
 410{
 411        int status;
 412
 413        if (pid <= 0) {
 414                /*errno = ECHILD; -- wrong. */
 415                /* we expect errno to be already set from failed [v]fork/exec */
 416                return -1;
 417        }
 418        if (safe_waitpid(pid, &status, 0) == -1)
 419                return -1;
 420        if (WIFEXITED(status))
 421                return WEXITSTATUS(status);
 422        if (WIFSIGNALED(status))
 423                return WTERMSIG(status) + 0x180;
 424        return 0;
 425}
 426