/* vi: set sw=4 ts=4: */ /* * Adapted from ash applet code * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Copyright (c) 1989, 1991, 1993, 1994 * The Regents of the University of California. All rights reserved. * * Copyright (c) 1997-2005 Herbert Xu * was re-ported from NetBSD and debianized. * * Copyright (c) 2010 Denys Vlasenko * Split from ash.c * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" #include "shell_common.h" const char defifsvar[] ALIGN1 = "IFS= \t\n"; const char defoptindvar[] ALIGN1 = "OPTIND=1"; /* Compare two strings up to the first '=' or '\0'. */ int FAST_FUNC varcmp(const char *p, const char *q) { int c, d; while ((c = *p) == (d = *q)) { if (c == '\0' || c == '=') goto out; p++; q++; } if (c == '=') c = '\0'; if (d == '=') d = '\0'; out: return c - d; } /* read builtin */ /* Needs to be interruptible: shell must handle traps and shell-special signals * while inside read. To implement this, be sure to not loop on EINTR * and return errno == EINTR reliably. */ //TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL" //string. hush naturally has it, and ash has setvareq(). //Here we can simply store "VAR=" at buffer start and store read data directly //after "=", then pass buffer to setvar() to consume. const char* FAST_FUNC shell_builtin_read(struct builtin_read_params *params) { struct pollfd pfd[1]; #define fd (pfd[0].fd) /* -u FD */ unsigned err; unsigned end_ms; /* -t TIMEOUT */ int nchars; /* -n NUM */ char **pp; char *buffer; char delim; struct termios tty, old_tty; const char *retval; int bufpos; /* need to be able to hold -1 */ int startword; smallint backslash; char **argv; const char *ifs; int read_flags; errno = err = 0; argv = params->argv; pp = argv; while (*pp) { if (!*pp[0] || endofname(*pp)[0] != '\0') { /* Mimic bash message */ bb_error_msg("read: '%s': bad variable name", *pp); return (const char *)(uintptr_t)1; } pp++; } nchars = 0; /* if != 0, -n is in effect */ if (params->opt_n) { nchars = bb_strtou(params->opt_n, NULL, 10); if (nchars < 0 || errno) return "invalid count"; /* note: "-n 0": off (bash 3.2 does this too) */ } end_ms = 0; if (params->opt_t && !ENABLE_FEATURE_SH_READ_FRAC) { end_ms = bb_strtou(params->opt_t, NULL, 10); if (errno) return "invalid timeout"; if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */ end_ms = UINT_MAX / 2048; end_ms *= 1000; } if (params->opt_t && ENABLE_FEATURE_SH_READ_FRAC) { /* bash 4.3 (maybe earlier) supports -t N.NNNNNN */ char *p; /* Eat up to three fractional digits */ int frac_digits = 3 + 1; end_ms = bb_strtou(params->opt_t, &p, 10); if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */ end_ms = UINT_MAX / 2048; if (errno) { /* EINVAL = number is ok, but not NUL terminated */ if (errno != EINVAL || *p != '.') return "invalid timeout"; /* Do not check the rest: bash allows "0.123456xyz" */ while (*++p && --frac_digits) { end_ms *= 10; end_ms += (*p - '0'); if ((unsigned char)(*p - '0') > 9) return "invalid timeout"; } } while (--frac_digits > 0) { end_ms *= 10; } } fd = STDIN_FILENO; if (params->opt_u) { fd = bb_strtou(params->opt_u, NULL, 10); if (fd < 0 || errno) return "invalid file descriptor"; } if (params->opt_t && end_ms == 0) { /* "If timeout is 0, read returns immediately, without trying * to read any data. The exit status is 0 if input is available * on the specified file descriptor, non-zero otherwise." * bash seems to ignore -p PROMPT for this use case. */ int r; pfd[0].events = POLLIN; r = poll(pfd, 1, /*timeout:*/ 0); /* Return 0 only if poll returns 1 ("one fd ready"), else return 1: */ return (const char *)(uintptr_t)(r <= 0); } if (params->opt_p && isatty(fd)) { fputs(params->opt_p, stderr); fflush_all(); } ifs = params->ifs; if (ifs == NULL) ifs = defifs; read_flags = params->read_flags; if (nchars || (read_flags & BUILTIN_READ_SILENT)) { tcgetattr(fd, &tty); old_tty = tty; if (nchars) { tty.c_lflag &= ~ICANON; // Setting it to more than 1 breaks poll(): // it blocks even if there's data. !?? //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255; /* reads will block only if < 1 char is available */ tty.c_cc[VMIN] = 1; /* no timeout (reads block forever) */ tty.c_cc[VTIME] = 0; } if (read_flags & BUILTIN_READ_SILENT) { tty.c_lflag &= ~(ECHO | ECHOK | ECHONL); } /* This forces execution of "restoring" tcgetattr later */ read_flags |= BUILTIN_READ_SILENT; /* if tcgetattr failed, tcsetattr will fail too. * Ignoring, it's harmless. */ tcsetattr(fd, TCSANOW, &tty); } retval = (const char *)(uintptr_t)0; startword = 1; backslash = 0; if (params->opt_t) end_ms += (unsigned)monotonic_ms(); buffer = NULL; bufpos = 0; delim = params->opt_d ? params->opt_d[0] : '\n'; do { char c; int timeout; if ((bufpos & 0xff) == 0) buffer = xrealloc(buffer, bufpos + 0x101); timeout = -1; if (params->opt_t) { timeout = end_ms - (unsigned)monotonic_ms(); /* ^^^^^^^^^^^^^ all values are unsigned, * wrapping math is used here, good even if * 32-bit unix time wrapped (year 2038+). */ if (timeout <= 0) { /* already late? */ retval = (const char *)(uintptr_t)1; goto ret; } } /* We must poll even if timeout is -1: * we want to be interrupted if signal arrives, * regardless of SA_RESTART-ness of that signal! */ errno = 0; pfd[0].events = POLLIN; //TODO race with a signal arriving just before the poll! if (poll(pfd, 1, timeout) <= 0) { /* timed out, or EINTR */ err = errno; retval = (const char *)(uintptr_t)1; goto ret; } if (read(fd, &buffer[bufpos], 1) != 1) { err = errno; retval = (const char *)(uintptr_t)1; break; } c = buffer[bufpos]; if (!(read_flags & BUILTIN_READ_RAW)) { if (backslash) { backslash = 0; if (c != '\n') goto put; continue; } if (c == '\\') { backslash = 1; continue; } } if (c == delim) /* '\n' or -d CHAR */ break; if (c == '\0') continue; /* $IFS splitting. NOT done if we run "read" * without variable names (bash compat). * Thus, "read" and "read REPLY" are not the same. */ if (argv[0]) { /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */ const char *is_ifs = strchr(ifs, c); if (startword && is_ifs) { if (isspace(c)) continue; /* it is a non-space ifs char */ startword--; if (startword == 1) /* first one? */ continue; /* yes, it is not next word yet */ } startword = 0; if (argv[1] != NULL && is_ifs) { buffer[bufpos] = '\0'; bufpos = 0; params->setvar(*argv, buffer); argv++; /* can we skip one non-space ifs char? (2: yes) */ startword = isspace(c) ? 2 : 1; continue; } } put: bufpos++; } while (--nchars); if (argv[0]) { /* Remove trailing space $IFS chars */ while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL ) { continue; } buffer[bufpos + 1] = '\0'; /* Last variable takes the entire remainder with delimiters * (sans trailing whitespace $IFS), * but ***only "if there are fewer vars than fields"(c)***! * The "X:Y:" case below: there are two fields, * and therefore last delimiter (:) is eaten: * IFS=": " * echo "X:Y:Z:" | (read x y; echo "|$x|$y|") # |X|Y:Z:| * echo "X:Y:Z" | (read x y; echo "|$x|$y|") # |X|Y:Z| * echo "X:Y:" | (read x y; echo "|$x|$y|") # |X|Y|, not |X|Y:| * echo "X:Y : " | (read x y; echo "|$x|$y|") # |X|Y| */ if (bufpos >= 0 && strchr(ifs, buffer[bufpos]) != NULL ) { /* There _is_ a non-whitespace IFS char */ /* Skip whitespace IFS char before it */ while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL ) { continue; } /* Are there $IFS chars? */ if (strcspn(buffer, ifs) >= ++bufpos) { /* No: last var takes one field, not more */ /* So, drop trailing IFS delims */ buffer[bufpos] = '\0'; } } /* Use the remainder as a value for the next variable */ params->setvar(*argv, buffer); /* Set the rest to "" */ while (*++argv) params->setvar(*argv, ""); } else { /* Note: no $IFS removal */ buffer[bufpos] = '\0'; params->setvar("REPLY", buffer); } ret: free(buffer); if (read_flags & BUILTIN_READ_SILENT) tcsetattr(fd, TCSANOW, &old_tty); errno = err; return retval; #undef fd } /* ulimit builtin */ struct limits { uint8_t cmd; /* RLIMIT_xxx fit into it */ uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */ }; /* Order of entries matches order in which bash prints "ulimit -a" */ static const struct limits limits_tbl[] ALIGN2 = { { RLIMIT_CORE, 9, }, // -c { RLIMIT_DATA, 10, }, // -d #ifdef RLIMIT_NICE { RLIMIT_NICE, 0, }, // -e #define LIMIT_F_IDX 3 #else /* for example, Hurd */ #define LIMIT_F_IDX 2 #endif { RLIMIT_FSIZE, 9, }, // -f #ifdef RLIMIT_SIGPENDING { RLIMIT_SIGPENDING, 0, }, // -i #endif #ifdef RLIMIT_MEMLOCK { RLIMIT_MEMLOCK, 10, }, // -l #endif #ifdef RLIMIT_RSS { RLIMIT_RSS, 10, }, // -m #endif #ifdef RLIMIT_NOFILE { RLIMIT_NOFILE, 0, }, // -n #endif #ifdef RLIMIT_MSGQUEUE { RLIMIT_MSGQUEUE, 0, }, // -q #endif #ifdef RLIMIT_RTPRIO { RLIMIT_RTPRIO, 0, }, // -r #endif #ifdef RLIMIT_STACK { RLIMIT_STACK, 10, }, // -s #endif #ifdef RLIMIT_CPU { RLIMIT_CPU, 0, }, // -t #endif #ifdef RLIMIT_NPROC { RLIMIT_NPROC, 0, }, // -u #endif #ifdef RLIMIT_AS { RLIMIT_AS, 10, }, // -v #endif #ifdef RLIMIT_LOCKS { RLIMIT_LOCKS, 0, }, // -x #endif }; // 1) bash also shows: //pipe size (512 bytes, -p) 8 // 2) RLIMIT_RTTIME ("timeout for RT tasks in us") is not in the table static const char limits_help[] ALIGN1 = "core file size (blocks)" // -c "\0""data seg size (kb)" // -d #ifdef RLIMIT_NICE "\0""scheduling priority" // -e #endif "\0""file size (blocks)" // -f #ifdef RLIMIT_SIGPENDING "\0""pending signals" // -i #endif #ifdef RLIMIT_MEMLOCK "\0""max locked memory (kb)" // -l #endif #ifdef RLIMIT_RSS "\0""max memory size (kb)" // -m #endif #ifdef RLIMIT_NOFILE "\0""open files" // -n #endif #ifdef RLIMIT_MSGQUEUE "\0""POSIX message queues (bytes)" // -q #endif #ifdef RLIMIT_RTPRIO "\0""real-time priority" // -r #endif #ifdef RLIMIT_STACK "\0""stack size (kb)" // -s #endif #ifdef RLIMIT_CPU "\0""cpu time (seconds)" // -t #endif #ifdef RLIMIT_NPROC "\0""max user processes" // -u #endif #ifdef RLIMIT_AS "\0""virtual memory (kb)" // -v #endif #ifdef RLIMIT_LOCKS "\0""file locks" // -x #endif ; static const char limit_chars[] ALIGN1 = "c" "d" #ifdef RLIMIT_NICE "e" #endif "f" #ifdef RLIMIT_SIGPENDING "i" #endif #ifdef RLIMIT_MEMLOCK "l" #endif #ifdef RLIMIT_RSS "m" #endif #ifdef RLIMIT_NOFILE "n" #endif #ifdef RLIMIT_MSGQUEUE "q" #endif #ifdef RLIMIT_RTPRIO "r" #endif #ifdef RLIMIT_STACK "s" #endif #ifdef RLIMIT_CPU "t" #endif #ifdef RLIMIT_NPROC "u" #endif #ifdef RLIMIT_AS "v" #endif #ifdef RLIMIT_LOCKS "x" #endif ; /* "-": treat args as parameters of option with ASCII code 1 */ static const char ulimit_opt_string[] ALIGN1 = "-HSa" "c::" "d::" #ifdef RLIMIT_NICE "e::" #endif "f::" #ifdef RLIMIT_SIGPENDING "i::" #endif #ifdef RLIMIT_MEMLOCK "l::" #endif #ifdef RLIMIT_RSS "m::" #endif #ifdef RLIMIT_NOFILE "n::" #endif #ifdef RLIMIT_MSGQUEUE "q::" #endif #ifdef RLIMIT_RTPRIO "r::" #endif #ifdef RLIMIT_STACK "s::" #endif #ifdef RLIMIT_CPU "t::" #endif #ifdef RLIMIT_NPROC "u::" #endif #ifdef RLIMIT_AS "v::" #endif #ifdef RLIMIT_LOCKS "x::" #endif ; enum { OPT_hard = (1 << 0), OPT_soft = (1 << 1), OPT_all = (1 << 2), }; static void printlim(unsigned opts, const struct rlimit *limit, const struct limits *l) { rlim_t val; val = limit->rlim_max; if (opts & OPT_soft) val = limit->rlim_cur; if (val == RLIM_INFINITY) puts("unlimited"); else { val >>= l->factor_shift; printf("%llu\n", (long long) val); } } int FAST_FUNC shell_builtin_ulimit(char **argv) { struct rlimit limit; unsigned opt_cnt; unsigned opts; unsigned argc; unsigned i; /* We can't use getopt32: need to handle commands like * ulimit 123 -c2 -l 456 */ /* In case getopt() was already called: * reset libc getopt() internal state. */ GETOPT_RESET(); // bash 4.4.23: // // -H and/or -S change meaning even of options *before* them: ulimit -f 2000 -H // sets hard limit, ulimit -a -H prints hard limits. // // -a is equivalent for requesting all limits to be shown. // // If -a is specified, attempts to set limits are ignored: // ulimit -m 1000; ulimit -m 2000 -a // shows 1000, not 2000. HOWEVER, *implicit* -f form "ulimit 2000 -a" // DOES set -f limit [we don't implement this quirk], "ulimit -a 2000" does not. // Options are still parsed: ulimit -az complains about unknown -z opt. // // -a is not cumulative: "ulimit -a -a" = "ulimit -a -f -m" = "ulimit -a" // // -HSa can be combined in one argument and with one other option (example: -Sm), // but other options can't: limit value is an optional argument, // thus "-mf" means "-m f", f is the parameter of -m. // // Limit can be set and then printed: ulimit -m 2000 -m // If set more than once, they are set and printed in order: // try ulimit -m -m 1000 -m -m 2000 -m -m 3000 -m // // Limits are shown in the order of options given: // ulimit -m -f is not the same as ulimit -f -m. // // If both -S and -H are given, show soft limit. // // Short printout (limit value only) is printed only if just one option // is given: ulimit -m. ulimit -f -m prints verbose lines. // ulimit -f -f prints same verbose line twice. // ulimit -m 10000 -f prints verbose line for -f. argc = string_array_len(argv); /* First pass over options: detect -H/-S/-a status, * and "bare ulimit" and "only one option" cases * by counting other opts. */ opt_cnt = 0; opts = 0; while (1) { int opt_char = getopt(argc, argv, ulimit_opt_string); if (opt_char == -1) break; if (opt_char == 'H') { opts |= OPT_hard; continue; } if (opt_char == 'S') { opts |= OPT_soft; continue; } if (opt_char == 'a') { opts |= OPT_all; continue; } if (opt_char == '?') { /* bad option. getopt already complained. */ return EXIT_FAILURE; } opt_cnt++; } /* while (there are options) */ if (!(opts & (OPT_hard | OPT_soft))) opts |= (OPT_hard | OPT_soft); if (opts & OPT_all) { const char *help = limits_help; for (i = 0; i < ARRAY_SIZE(limits_tbl); i++) { getrlimit(limits_tbl[i].cmd, &limit); printf("%-32s(-%c) ", help, limit_chars[i]); printlim(opts, &limit, &limits_tbl[i]); help += strlen(help) + 1; } return EXIT_SUCCESS; } /* Second pass: set or print limits, in order */ GETOPT_RESET(); while (1) { char *val_str; int opt_char = getopt(argc, argv, ulimit_opt_string); if (opt_char == -1) break; if (opt_char == 'H') continue; if (opt_char == 'S') continue; //if (opt_char == 'a') - impossible if (opt_char == 1) /* if "ulimit NNN", -f is assumed */ opt_char = 'f'; i = strchrnul(limit_chars, opt_char) - limit_chars; //if (i >= ARRAY_SIZE(limits_tbl)) - bad option, impossible val_str = optarg; if (!val_str && argv[optind] && argv[optind][0] != '-') val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */ getrlimit(limits_tbl[i].cmd, &limit); if (!val_str) { if (opt_cnt > 1) printf("%-32s(-%c) ", nth_string(limits_help, i), limit_chars[i]); printlim(opts, &limit, &limits_tbl[i]); } else { rlim_t val = RLIM_INFINITY; if (strcmp(val_str, "unlimited") != 0) { if (sizeof(val) == sizeof(int)) val = bb_strtou(val_str, NULL, 10); else if (sizeof(val) == sizeof(long)) val = bb_strtoul(val_str, NULL, 10); else val = bb_strtoull(val_str, NULL, 10); if (errno) { bb_error_msg("invalid number '%s'", val_str); return EXIT_FAILURE; } val <<= limits_tbl[i].factor_shift; } //bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val); /* from man bash: "If neither -H nor -S * is specified, both the soft and hard * limits are set. */ if (opts & OPT_hard) limit.rlim_max = val; if (opts & OPT_soft) limit.rlim_cur = val; //bb_error_msg("setrlimit(%d, %lld, %lld)", limits_tbl[i].cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max); if (setrlimit(limits_tbl[i].cmd, &limit) < 0) { bb_simple_perror_msg("error setting limit"); return EXIT_FAILURE; } } } /* while (there are options) */ if (opt_cnt == 0) { /* "bare ulimit": treat it as if it was -f */ getrlimit(RLIMIT_FSIZE, &limit); printlim(opts, &limit, &limits_tbl[LIMIT_F_IDX]); } return EXIT_SUCCESS; }