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                         // Setting it to more than 1 breaks poll():
 142                         // it blocks even if there's data. !??
 143                         //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
 144                         /* reads would block only if < 1 char is available */
 145                         tty.c_cc[VMIN] = 1;
 146                         /* no timeout (reads block forever) */
 147                         tty.c_cc[VTIME] = 0;
 148                 }
 149                 if (read_flags & BUILTIN_READ_SILENT) {
 150                         tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
 151                 }
 152                 /* This forces execution of "restoring" tcgetattr later */
 153                 read_flags |= BUILTIN_READ_SILENT;
 154                 /* if tcgetattr failed, tcsetattr will fail too.
 155                  * Ignoring, it's harmless. */
 156                 tcsetattr(fd, TCSANOW, &tty);
 157         }
 158
 159         retval = (const char *)(uintptr_t)0;
 160         startword = 1;
 161         backslash = 0;
 162         if (end_ms) /* NB: end_ms stays nonzero: */
 163                 end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
 164         buffer = NULL;
 165         bufpos = 0;
 166         do {
 167                 char c;
 168                 struct pollfd pfd[1];
 169                 int timeout;
 170
 171                 if ((bufpos & 0xff) == 0)
 172                         buffer = xrealloc(buffer, bufpos + 0x100);
 173
 174                 timeout = -1;
 175                 if (end_ms) {
 176                         timeout = end_ms - (unsigned)monotonic_ms();
 177                         if (timeout <= 0) { /* already late? */
 178                                 retval = (const char *)(uintptr_t)1;
 179                                 goto ret;
 180                         }
 181                 }
 182
 183                 /* We must poll even if timeout is -1:
 184                  * we want to be interrupted if signal arrives,
 185                  * regardless of SA_RESTART-ness of that signal!
 186                  */
 187                 errno = 0;
 188                 pfd[0].fd = fd;
 189                 pfd[0].events = POLLIN;
 190                 if (poll(pfd, 1, timeout) != 1) {
 191                         /* timed out, or EINTR */
 192                         err = errno;
 193                         retval = (const char *)(uintptr_t)1;
 194                         goto ret;
 195                 }
 196                 if (read(fd, &buffer[bufpos], 1) != 1) {
 197                         err = errno;
 198                         retval = (const char *)(uintptr_t)1;
 199                         break;
 200                 }
 201
 202                 c = buffer[bufpos];
 203                 if (c == '\0')
 204                         continue;
 205                 if (backslash) {
 206                         backslash = 0;
 207                         if (c != '\n')
 208                                 goto put;
 209                         continue;
 210                 }
 211                 if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
 212                         backslash = 1;
 213                         continue;
 214                 }
 215                 if (c == '\n')
 216                         break;
 217
 218                 /* $IFS splitting. NOT done if we run "read"
 219                  * without variable names (bash compat).
 220                  * Thus, "read" and "read REPLY" are not the same.
 221                  */
 222                 if (argv[0]) {
 223 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
 224                         const char *is_ifs = strchr(ifs, c);
 225                         if (startword && is_ifs) {
 226                                 if (isspace(c))
 227                                         continue;
 228                                 /* it is a non-space ifs char */
 229                                 startword--;
 230                                 if (startword == 1) /* first one? */
 231                                         continue; /* yes, it is not next word yet */
 232                         }
 233                         startword = 0;
 234                         if (argv[1] != NULL && is_ifs) {
 235                                 buffer[bufpos] = '\0';
 236                                 bufpos = 0;
 237                                 setvar(*argv, buffer);
 238                                 argv++;
 239                                 /* can we skip one non-space ifs char? (2: yes) */
 240                                 startword = isspace(c) ? 2 : 1;
 241                                 continue;
 242                         }
 243                 }
 244  put:
 245                 bufpos++;
 246         } while (--nchars);
 247
 248         if (argv[0]) {
 249                 /* Remove trailing space $IFS chars */
 250                 while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
 251                         continue;
 252                 buffer[bufpos + 1] = '\0';
 253                 /* Use the remainder as a value for the next variable */
 254                 setvar(*argv, buffer);
 255                 /* Set the rest to "" */
 256                 while (*++argv)
 257                         setvar(*argv, "");
 258         } else {
 259                 /* Note: no $IFS removal */
 260                 buffer[bufpos] = '\0';
 261                 setvar("REPLY", buffer);
 262         }
 263
 264  ret:
 265         free(buffer);
 266         if (read_flags & BUILTIN_READ_SILENT)
 267                 tcsetattr(fd, TCSANOW, &old_tty);
 268
 269         errno = err;
 270         return retval;
 271 }
 272
 273 /* ulimit builtin */
 274
 275 struct limits {
 276         uint8_t cmd;            /* RLIMIT_xxx fit into it */
 277         uint8_t factor_shift;   /* shift by to get rlim_{cur,max} values */
 278         char option;
 279         const char *name;
 280 };
 281
 282 static const struct limits limits_tbl[] = {
 283 #ifdef RLIMIT_FSIZE
 284         { RLIMIT_FSIZE,         9,      'f',    "file size (blocks)" },
 285 #endif
 286 #ifdef RLIMIT_CPU
 287         { RLIMIT_CPU,           0,      't',    "cpu time (seconds)" },
 288 #endif
 289 #ifdef RLIMIT_DATA
 290         { RLIMIT_DATA,          10,     'd',    "data seg size (kb)" },
 291 #endif
 292 #ifdef RLIMIT_STACK
 293         { RLIMIT_STACK,         10,     's',    "stack size (kb)" },
 294 #endif
 295 #ifdef RLIMIT_CORE
 296         { RLIMIT_CORE,          9,      'c',    "core file size (blocks)" },
 297 #endif
 298 #ifdef RLIMIT_RSS
 299         { RLIMIT_RSS,           10,     'm',    "resident set size (kb)" },
 300 #endif
 301 #ifdef RLIMIT_MEMLOCK
 302         { RLIMIT_MEMLOCK,       10,     'l',    "locked memory (kb)" },
 303 #endif
 304 #ifdef RLIMIT_NPROC
 305         { RLIMIT_NPROC,         0,      'p',    "processes" },
 306 #endif
 307 #ifdef RLIMIT_NOFILE
 308         { RLIMIT_NOFILE,        0,      'n',    "file descriptors" },
 309 #endif
 310 #ifdef RLIMIT_AS
 311         { RLIMIT_AS,            10,     'v',    "address space (kb)" },
 312 #endif
 313 #ifdef RLIMIT_LOCKS
 314         { RLIMIT_LOCKS,         0,      'w',    "locks" },
 315 #endif
 316 #ifdef RLIMIT_NICE
 317         { RLIMIT_NICE,          0,      'e',    "scheduling priority" },
 318 #endif
 319 #ifdef RLIMIT_RTPRIO
 320         { RLIMIT_RTPRIO,        0,      'r',    "real-time priority" },
 321 #endif
 322 };
 323
 324 enum {
 325         OPT_hard = (1 << 0),
 326         OPT_soft = (1 << 1),
 327 };
 328
 329 /* "-": treat args as parameters of option with ASCII code 1 */
 330 static const char ulimit_opt_string[] = "-HSa"
 331 #ifdef RLIMIT_FSIZE
 332                         "f::"
 333 #endif
 334 #ifdef RLIMIT_CPU
 335                         "t::"
 336 #endif
 337 #ifdef RLIMIT_DATA
 338                         "d::"
 339 #endif
 340 #ifdef RLIMIT_STACK
 341                         "s::"
 342 #endif
 343 #ifdef RLIMIT_CORE
 344                         "c::"
 345 #endif
 346 #ifdef RLIMIT_RSS
 347                         "m::"
 348 #endif
 349 #ifdef RLIMIT_MEMLOCK
 350                         "l::"
 351 #endif
 352 #ifdef RLIMIT_NPROC
 353                         "p::"
 354 #endif
 355 #ifdef RLIMIT_NOFILE
 356                         "n::"
 357 #endif
 358 #ifdef RLIMIT_AS
 359                         "v::"
 360 #endif
 361 #ifdef RLIMIT_LOCKS
 362                         "w::"
 363 #endif
 364 #ifdef RLIMIT_NICE
 365                         "e::"
 366 #endif
 367 #ifdef RLIMIT_RTPRIO
 368                         "r::"
 369 #endif
 370                         ;
 371
 372 static void printlim(unsigned opts, const struct rlimit *limit,
 373                         const struct limits *l)
 374 {
 375         rlim_t val;
 376
 377         val = limit->rlim_max;
 378         if (!(opts & OPT_hard))
 379                 val = limit->rlim_cur;
 380
 381         if (val == RLIM_INFINITY)
 382                 printf("unlimited\n");
 383         else {
 384                 val >>= l->factor_shift;
 385                 printf("%llu\n", (long long) val);
 386         }
 387 }
 388
 389 int FAST_FUNC
 390 shell_builtin_ulimit(char **argv)
 391 {
 392         unsigned opts;
 393         unsigned argc;
 394
 395         /* We can't use getopt32: need to handle commands like
 396          * ulimit 123 -c2 -l 456
 397          */
 398
 399         /* In case getopt was already called:
 400          * reset the libc getopt() function, which keeps internal state.
 401          */
 402 #ifdef __GLIBC__
 403         optind = 0;
 404 #else /* BSD style */
 405         optind = 1;
 406         /* optreset = 1; */
 407 #endif
 408         /* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */
 409
 410         argc = 1;
 411         while (argv[argc])
 412                 argc++;
 413
 414         opts = 0;
 415         while (1) {
 416                 struct rlimit limit;
 417                 const struct limits *l;
 418                 int opt_char = getopt(argc, argv, ulimit_opt_string);
 419
 420                 if (opt_char == -1)
 421                         break;
 422                 if (opt_char == 'H') {
 423                         opts |= OPT_hard;
 424                         continue;
 425                 }
 426                 if (opt_char == 'S') {
 427                         opts |= OPT_soft;
 428                         continue;
 429                 }
 430
 431                 if (opt_char == 'a') {
 432                         for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
 433                                 getrlimit(l->cmd, &limit);
 434                                 printf("-%c: %-30s ", l->option, l->name);
 435                                 printlim(opts, &limit, l);
 436                         }
 437                         continue;
 438                 }
 439
 440                 if (opt_char == 1)
 441                         opt_char = 'f';
 442                 for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
 443                         if (opt_char == l->option) {
 444                                 char *val_str;
 445
 446                                 getrlimit(l->cmd, &limit);
 447
 448                                 val_str = optarg;
 449                                 if (!val_str && argv[optind] && argv[optind][0] != '-')
 450                                         val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
 451                                 if (val_str) {
 452                                         rlim_t val;
 453
 454                                         if (strcmp(val_str, "unlimited") == 0)
 455                                                 val = RLIM_INFINITY;
 456                                         else {
 457                                                 if (sizeof(val) == sizeof(int))
 458                                                         val = bb_strtou(val_str, NULL, 10);
 459                                                 else if (sizeof(val) == sizeof(long))
 460                                                         val = bb_strtoul(val_str, NULL, 10);
 461                                                 else
 462                                                         val = bb_strtoull(val_str, NULL, 10);
 463                                                 if (errno) {
 464                                                         bb_error_msg("invalid number '%s'", val_str);
 465                                                         return EXIT_FAILURE;
 466                                                 }
 467                                                 val <<= l->factor_shift;
 468                                         }
 469 //bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
 470                                         /* from man bash: "If neither -H nor -S
 471                                          * is specified, both the soft and hard
 472                                          * limits are set. */
 473                                         if (!opts)
 474                                                 opts = OPT_hard + OPT_soft;
 475                                         if (opts & OPT_hard)
 476                                                 limit.rlim_max = val;
 477                                         if (opts & OPT_soft)
 478                                                 limit.rlim_cur = val;
 479 //bb_error_msg("setrlimit(%d, %lld, %lld)", l->cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
 480                                         if (setrlimit(l->cmd, &limit) < 0) {
 481                                                 bb_perror_msg("error setting limit");
 482                                                 return EXIT_FAILURE;
 483                                         }
 484                                 } else {
 485                                         printlim(opts, &limit, l);
 486                                 }
 487                                 break;
 488                         }
 489                 } /* for (every possible opt) */
 490
 491                 if (l == &limits_tbl[ARRAY_SIZE(limits_tbl)]) {
 492                         /* bad option. getopt already complained. */
 493                         break;
 494                 }
 495
 496         } /* while (there are options) */
 497
 498         return 0;
 499 }