shell/shell_common.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Adapted from ash applet code
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Copyright (c) 1989, 1991, 1993, 1994
   9  *      The Regents of the University of California.  All rights reserved.
  10  *
  11  * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
  12  * was re-ported from NetBSD and debianized.
  13  *
  14  * Copyright (c) 2010 Denys Vlasenko
  15  * Split from ash.c
  16  *
  17  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  18  */
  19 #include "libbb.h"
  20 #include "shell_common.h"
  21
  22 const char defifsvar[] ALIGN1 = "IFS= \t\n";
  23
  24
  25 int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
  26 {
  27         if (!s || !(isalpha(*s) || *s == '_'))
  28                 return 0;
  29
  30         do
  31                 s++;
  32         while (isalnum(*s) || *s == '_');
  33
  34         return *s == terminator;
  35 }
  36
  37 /* read builtin */
  38
  39 /* Needs to be interruptible: shell mush handle traps and shell-special signals
  40  * while inside read. To implement this, be sure to not loop on EINTR
  41  * and return errno == EINTR reliably.
  42  */
  43 //TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
  44 //string. hush naturally has it, and ash has setvareq().
  45 //Here we can simply store "VAR=" at buffer start and store read data directly
  46 //after "=", then pass buffer to setvar() to consume.
  47 const char* FAST_FUNC
  48 shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
  49         char       **argv,
  50         const char *ifs,
  51         int        read_flags,
  52         const char *opt_n,
  53         const char *opt_p,
  54         const char *opt_t,
  55         const char *opt_u
  56 )
  57 {
  58         unsigned err;
  59         unsigned end_ms; /* -t TIMEOUT */
  60         int fd; /* -u FD */
  61         int nchars; /* -n NUM */
  62         char **pp;
  63         char *buffer;
  64         struct termios tty, old_tty;
  65         const char *retval;
  66         int bufpos; /* need to be able to hold -1 */
  67         int startword;
  68         smallint backslash;
  69
  70         errno = err = 0;
  71
  72         pp = argv;
  73         while (*pp) {
  74                 if (!is_well_formed_var_name(*pp, '\0')) {
  75                         /* Mimic bash message */
  76                         bb_error_msg("read: '%s': not a valid identifier", *pp);
  77                         return (const char *)(uintptr_t)1;
  78                 }
  79                 pp++;
  80         }
  81
  82         nchars = 0; /* if != 0, -n is in effect */
  83         if (opt_n) {
  84                 nchars = bb_strtou(opt_n, NULL, 10);
  85                 if (nchars < 0 || errno)
  86                         return "invalid count";
  87                 /* note: "-n 0": off (bash 3.2 does this too) */
  88         }
  89         end_ms = 0;
  90         if (opt_t) {
  91                 end_ms = bb_strtou(opt_t, NULL, 10);
  92                 if (errno || end_ms > UINT_MAX / 2048)
  93                         return "invalid timeout";
  94                 end_ms *= 1000;
  95 #if 0 /* even bash has no -t N.NNN support */
  96                 ts.tv_sec = bb_strtou(opt_t, &p, 10);
  97                 ts.tv_usec = 0;
  98                 /* EINVAL means number is ok, but not terminated by NUL */
  99                 if (*p == '.' && errno == EINVAL) {
 100                         char *p2;
 101                         if (*++p) {
 102                                 int scale;
 103                                 ts.tv_usec = bb_strtou(p, &p2, 10);
 104                                 if (errno)
 105                                         return "invalid timeout";
 106                                 scale = p2 - p;
 107                                 /* normalize to usec */
 108                                 if (scale > 6)
 109                                         return "invalid timeout";
 110                                 while (scale++ < 6)
 111                                         ts.tv_usec *= 10;
 112                         }
 113                 } else if (ts.tv_sec < 0 || errno) {
 114                         return "invalid timeout";
 115                 }
 116                 if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
 117                         return "invalid timeout";
 118                 }
 119 #endif /* if 0 */
 120         }
 121         fd = STDIN_FILENO;
 122         if (opt_u) {
 123                 fd = bb_strtou(opt_u, NULL, 10);
 124                 if (fd < 0 || errno)
 125                         return "invalid file descriptor";
 126         }
 127
 128         if (opt_p && isatty(fd)) {
 129                 fputs(opt_p, stderr);
 130                 fflush_all();
 131         }
 132
 133         if (ifs == NULL)
 134                 ifs = defifs;
 135
 136         if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
 137                 tcgetattr(fd, &tty);
 138                 old_tty = tty;
 139                 if (nchars) {
 140                         tty.c_lflag &= ~ICANON;
 141                         tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
 142                 }
 143                 if (read_flags & BUILTIN_READ_SILENT) {
 144                         tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
 145                 }
 146                 /* This forces execution of "restoring" tcgetattr later */
 147                 read_flags |= BUILTIN_READ_SILENT;
 148                 /* if tcgetattr failed, tcsetattr will fail too.
 149                  * Ignoring, it's harmless. */
 150                 tcsetattr(fd, TCSANOW, &tty);
 151         }
 152
 153         retval = (const char *)(uintptr_t)0;
 154         startword = 1;
 155         backslash = 0;
 156         if (end_ms) /* NB: end_ms stays nonzero: */
 157                 end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
 158         buffer = NULL;
 159         bufpos = 0;
 160         do {
 161                 char c;
 162                 struct pollfd pfd[1];
 163                 int timeout;
 164
 165                 if ((bufpos & 0xff) == 0)
 166                         buffer = xrealloc(buffer, bufpos + 0x100);
 167
 168                 timeout = -1;
 169                 if (end_ms) {
 170                         timeout = end_ms - (unsigned)monotonic_ms();
 171                         if (timeout <= 0) { /* already late? */
 172                                 retval = (const char *)(uintptr_t)1;
 173                                 goto ret;
 174                         }
 175                 }
 176
 177                 /* We must poll even if timeout is -1:
 178                  * we want to be interrupted if signal arrives,
 179                  * regardless of SA_RESTART-ness of that signal!
 180                  */
 181                 errno = 0;
 182                 pfd[0].fd = fd;
 183                 pfd[0].events = POLLIN;
 184                 if (poll(pfd, 1, timeout) != 1) {
 185                         /* timed out, or EINTR */
 186                         err = errno;
 187                         retval = (const char *)(uintptr_t)1;
 188                         goto ret;
 189                 }
 190                 if (read(fd, &buffer[bufpos], 1) != 1) {
 191                         err = errno;
 192                         retval = (const char *)(uintptr_t)1;
 193                         break;
 194                 }
 195
 196                 c = buffer[bufpos];
 197                 if (c == '\0')
 198                         continue;
 199                 if (backslash) {
 200                         backslash = 0;
 201                         if (c != '\n')
 202                                 goto put;
 203                         continue;
 204                 }
 205                 if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
 206                         backslash = 1;
 207                         continue;
 208                 }
 209                 if (c == '\n')
 210                         break;
 211
 212                 /* $IFS splitting. NOT done if we run "read"
 213                  * without variable names (bash compat).
 214                  * Thus, "read" and "read REPLY" are not the same.
 215                  */
 216                 if (argv[0]) {
 217 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
 218                         const char *is_ifs = strchr(ifs, c);
 219                         if (startword && is_ifs) {
 220                                 if (isspace(c))
 221                                         continue;
 222                                 /* it is a non-space ifs char */
 223                                 startword--;
 224                                 if (startword == 1) /* first one? */
 225                                         continue; /* yes, it is not next word yet */
 226                         }
 227                         startword = 0;
 228                         if (argv[1] != NULL && is_ifs) {
 229                                 buffer[bufpos] = '\0';
 230                                 bufpos = 0;
 231                                 setvar(*argv, buffer);
 232                                 argv++;
 233                                 /* can we skip one non-space ifs char? (2: yes) */
 234                                 startword = isspace(c) ? 2 : 1;
 235                                 continue;
 236                         }
 237                 }
 238  put:
 239                 bufpos++;
 240         } while (--nchars);
 241
 242         if (argv[0]) {
 243                 /* Remove trailing space $IFS chars */
 244                 while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
 245                         continue;
 246                 buffer[bufpos + 1] = '\0';
 247                 /* Use the remainder as a value for the next variable */
 248                 setvar(*argv, buffer);
 249                 /* Set the rest to "" */
 250                 while (*++argv)
 251                         setvar(*argv, "");
 252         } else {
 253                 /* Note: no $IFS removal */
 254                 buffer[bufpos] = '\0';
 255                 setvar("REPLY", buffer);
 256         }
 257
 258  ret:
 259         free(buffer);
 260         if (read_flags & BUILTIN_READ_SILENT)
 261                 tcsetattr(fd, TCSANOW, &old_tty);
 262
 263         errno = err;
 264         return retval;
 265 }
 266
 267 /* ulimit builtin */
 268
 269 struct limits {
 270         uint8_t cmd;            /* RLIMIT_xxx fit into it */
 271         uint8_t factor_shift;   /* shift by to get rlim_{cur,max} values */
 272         char option;
 273         const char *name;
 274 };
 275
 276 static const struct limits limits_tbl[] = {
 277 #ifdef RLIMIT_FSIZE
 278         { RLIMIT_FSIZE,         9,      'f',    "file size (blocks)" },
 279 #endif
 280 #ifdef RLIMIT_CPU
 281         { RLIMIT_CPU,           0,      't',    "cpu time (seconds)" },
 282 #endif
 283 #ifdef RLIMIT_DATA
 284         { RLIMIT_DATA,          10,     'd',    "data seg size (kb)" },
 285 #endif
 286 #ifdef RLIMIT_STACK
 287         { RLIMIT_STACK,         10,     's',    "stack size (kb)" },
 288 #endif
 289 #ifdef RLIMIT_CORE
 290         { RLIMIT_CORE,          9,      'c',    "core file size (blocks)" },
 291 #endif
 292 #ifdef RLIMIT_RSS
 293         { RLIMIT_RSS,           10,     'm',    "resident set size (kb)" },
 294 #endif
 295 #ifdef RLIMIT_MEMLOCK
 296         { RLIMIT_MEMLOCK,       10,     'l',    "locked memory (kb)" },
 297 #endif
 298 #ifdef RLIMIT_NPROC
 299         { RLIMIT_NPROC,         0,      'p',    "processes" },
 300 #endif
 301 #ifdef RLIMIT_NOFILE
 302         { RLIMIT_NOFILE,        0,      'n',    "file descriptors" },
 303 #endif
 304 #ifdef RLIMIT_AS
 305         { RLIMIT_AS,            10,     'v',    "address space (kb)" },
 306 #endif
 307 #ifdef RLIMIT_LOCKS
 308         { RLIMIT_LOCKS,         0,      'w',    "locks" },
 309 #endif
 310 #ifdef RLIMIT_NICE
 311         { RLIMIT_NICE,          0,      'e',    "scheduling priority" },
 312 #endif
 313 #ifdef RLIMIT_RTPRIO
 314         { RLIMIT_RTPRIO,        0,      'r',    "real-time priority" },
 315 #endif
 316 };
 317
 318 enum {
 319         OPT_hard = (1 << 0),
 320         OPT_soft = (1 << 1),
 321 };
 322
 323 /* "-": treat args as parameters of option with ASCII code 1 */
 324 static const char ulimit_opt_string[] = "-HSa"
 325 #ifdef RLIMIT_FSIZE
 326                         "f::"
 327 #endif
 328 #ifdef RLIMIT_CPU
 329                         "t::"
 330 #endif
 331 #ifdef RLIMIT_DATA
 332                         "d::"
 333 #endif
 334 #ifdef RLIMIT_STACK
 335                         "s::"
 336 #endif
 337 #ifdef RLIMIT_CORE
 338                         "c::"
 339 #endif
 340 #ifdef RLIMIT_RSS
 341                         "m::"
 342 #endif
 343 #ifdef RLIMIT_MEMLOCK
 344                         "l::"
 345 #endif
 346 #ifdef RLIMIT_NPROC
 347                         "p::"
 348 #endif
 349 #ifdef RLIMIT_NOFILE
 350                         "n::"
 351 #endif
 352 #ifdef RLIMIT_AS
 353                         "v::"
 354 #endif
 355 #ifdef RLIMIT_LOCKS
 356                         "w::"
 357 #endif
 358 #ifdef RLIMIT_NICE
 359                         "e::"
 360 #endif
 361 #ifdef RLIMIT_RTPRIO
 362                         "r::"
 363 #endif
 364                         ;
 365
 366 static void printlim(unsigned opts, const struct rlimit *limit,
 367                         const struct limits *l)
 368 {
 369         rlim_t val;
 370
 371         val = limit->rlim_max;
 372         if (!(opts & OPT_hard))
 373                 val = limit->rlim_cur;
 374
 375         if (val == RLIM_INFINITY)
 376                 printf("unlimited\n");
 377         else {
 378                 val >>= l->factor_shift;
 379                 printf("%llu\n", (long long) val);
 380         }
 381 }
 382
 383 int FAST_FUNC
 384 shell_builtin_ulimit(char **argv)
 385 {
 386         unsigned opts;
 387         unsigned argc;
 388
 389         /* We can't use getopt32: need to handle commands like
 390          * ulimit 123 -c2 -l 456
 391          */
 392
 393         /* In case getopt was already called:
 394          * reset the libc getopt() function, which keeps internal state.
 395          */
 396 #ifdef __GLIBC__
 397         optind = 0;
 398 #else /* BSD style */
 399         optind = 1;
 400         /* optreset = 1; */
 401 #endif
 402         /* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */
 403
 404         argc = 1;
 405         while (argv[argc])
 406                 argc++;
 407
 408         opts = 0;
 409         while (1) {
 410                 struct rlimit limit;
 411                 const struct limits *l;
 412                 int opt_char = getopt(argc, argv, ulimit_opt_string);
 413
 414                 if (opt_char == -1)
 415                         break;
 416                 if (opt_char == 'H') {
 417                         opts |= OPT_hard;
 418                         continue;
 419                 }
 420                 if (opt_char == 'S') {
 421                         opts |= OPT_soft;
 422                         continue;
 423                 }
 424
 425                 if (opt_char == 'a') {
 426                         for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
 427                                 getrlimit(l->cmd, &limit);
 428                                 printf("-%c: %-30s ", l->option, l->name);
 429                                 printlim(opts, &limit, l);
 430                         }
 431                         continue;
 432                 }
 433
 434                 if (opt_char == 1)
 435                         opt_char = 'f';
 436                 for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
 437                         if (opt_char == l->option) {
 438                                 char *val_str;
 439
 440                                 getrlimit(l->cmd, &limit);
 441
 442                                 val_str = optarg;
 443                                 if (!val_str && argv[optind] && argv[optind][0] != '-')
 444                                         val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
 445                                 if (val_str) {
 446                                         rlim_t val;
 447
 448                                         if (strcmp(val_str, "unlimited") == 0)
 449                                                 val = RLIM_INFINITY;
 450                                         else {
 451                                                 if (sizeof(val) == sizeof(int))
 452                                                         val = bb_strtou(val_str, NULL, 10);
 453                                                 else if (sizeof(val) == sizeof(long))
 454                                                         val = bb_strtoul(val_str, NULL, 10);
 455                                                 else
 456                                                         val = bb_strtoull(val_str, NULL, 10);
 457                                                 if (errno) {
 458                                                         bb_error_msg("invalid number '%s'", val_str);
 459                                                         return EXIT_FAILURE;
 460                                                 }
 461                                                 val <<= l->factor_shift;
 462                                         }
 463 //bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
 464                                         /* from man bash: "If neither -H nor -S
 465                                          * is specified, both the soft and hard
 466                                          * limits are set. */
 467                                         if (!opts)
 468                                                 opts = OPT_hard + OPT_soft;
 469                                         if (opts & OPT_hard)
 470                                                 limit.rlim_max = val;
 471                                         if (opts & OPT_soft)
 472                                                 limit.rlim_cur = val;
 473 //bb_error_msg("setrlimit(%d, %lld, %lld)", l->cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
 474                                         if (setrlimit(l->cmd, &limit) < 0) {
 475                                                 bb_perror_msg("error setting limit");
 476                                                 return EXIT_FAILURE;
 477                                         }
 478                                 } else {
 479                                         printlim(opts, &limit, l);
 480                                 }
 481                                 break;
 482                         }
 483                 } /* for (every possible opt) */
 484
 485                 if (l == &limits_tbl[ARRAY_SIZE(limits_tbl)]) {
 486                         /* bad option. getopt already complained. */
 487                         break;
 488                 }
 489
 490         } /* while (there are options) */
 491
 492         return 0;
 493 }