1 This file is read.def, from which is created read.c.
2 It implements the builtin "read" in Bash.
4 Copyright (C) 1987-2012 Free Software Foundation, Inc.
6 This file is part of GNU Bash, the Bourne Again SHell.
8 Bash is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
13 Bash is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with Bash. If not, see <http://www.gnu.org/licenses/>.
24 $FUNCTION read_builtin
25 $SHORT_DOC read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...]
26 Read a line from the standard input and split it into fields.
28 Reads a single line from the standard input, or from file descriptor FD
29 if the -u option is supplied. The line is split into fields as with word
30 splitting, and the first word is assigned to the first NAME, the second
31 word to the second NAME, and so on, with any leftover words assigned to
32 the last NAME. Only the characters found in $IFS are recognized as word
35 If no NAMEs are supplied, the line read is stored in the REPLY variable.
38 -a array assign the words read to sequential indices of the array
39 variable ARRAY, starting at zero
40 -d delim continue until the first character of DELIM is read, rather
42 -e use Readline to obtain the line in an interactive shell
43 -i text Use TEXT as the initial text for Readline
44 -n nchars return after reading NCHARS characters rather than waiting
45 for a newline, but honor a delimiter if fewer than NCHARS
46 characters are read before the delimiter
47 -N nchars return only after reading exactly NCHARS characters, unless
48 EOF is encountered or read times out, ignoring any delimiter
49 -p prompt output the string PROMPT without a trailing newline before
51 -r do not allow backslashes to escape any characters
52 -s do not echo input coming from a terminal
53 -t timeout time out and return failure if a complete line of input is
54 not read within TIMEOUT seconds. The value of the TMOUT
55 variable is the default timeout. TIMEOUT may be a
56 fractional number. If TIMEOUT is 0, read returns immediately,
57 without trying to read any data, returning success only if
58 input is available on the specified file descriptor. The
59 exit status is greater than 128 if the timeout is exceeded
60 -u fd read from file descriptor FD instead of the standard input
63 The return code is zero, unless end-of-file is encountered, read times out
64 (in which case it's greater than 128), a variable assignment error occurs,
65 or an invalid file descriptor is supplied as the argument to -u.
70 #include "bashtypes.h"
71 #include "posixstat.h"
77 #if defined (HAVE_UNISTD_H)
89 #include "../bashintl.h"
93 #include "bashgetopt.h"
97 #if defined (READLINE)
98 #include "../bashline.h"
99 #include <readline/readline.h>
102 #if defined (BUFFERED_INPUT)
106 #include "shmbutil.h"
112 extern void run_pending_traps __P((void));
114 extern int posixly_correct;
115 extern int trapped_signal_received;
123 #if defined (READLINE)
124 static void reset_attempted_completion_function __P((char *));
125 static int set_itext __P((void));
126 static char *edit_line __P((char *, char *));
127 static void set_eol_delim __P((int));
128 static void reset_eol_delim __P((char *));
130 static SHELL_VAR *bind_read_variable __P((char *, char *));
131 #if defined (HANDLE_MULTIBYTE)
132 static int read_mbchar __P((int, char *, int, int, int));
134 static void ttyrestore __P((struct ttsave *));
136 static sighandler sigalrm __P((int));
137 static void reset_alarm __P((void));
139 /* Try this to see what the rest of the shell can do with the information. */
144 static SigHandler *old_alrm;
145 static unsigned char delim;
147 /* In all cases, SIGALRM just sets a flag that we check periodically. This
148 avoids problems with the semi-tricky stuff we do with the xfree of
149 input_string at the top of the unwind-protect list (see below). */
151 /* Set a flag that CHECK_ALRM can check. This relies on zread calling
152 trap.c:check_signals_and_traps(), which knows about sigalrm_seen and
164 set_signal_handler (SIGALRM, old_alrm);
168 /* Read the value of the shell variables whose names follow.
169 The reading is done from the current input stream, whatever
170 that may be. Successive words of the input line are assigned
171 to the variables mentioned in LIST. The last variable in LIST
172 gets the remainder of the words on the line. If no variables
173 are mentioned in LIST, then the default variable is $REPLY. */
178 register char *varname;
179 int size, i, nr, pass_next, saw_escape, eof, opt, retval, code, print_ps2;
180 int input_is_tty, input_is_pipe, unbuffered_read, skip_ctlesc, skip_ctlnul;
181 int raw, edit, nchars, silent, have_timeout, ignore_delim, fd, lastsig, t_errno;
182 unsigned int tmsec, tmusec;
186 char *input_string, *orig_input_string, *ifs_chars, *prompt, *arrayname;
187 char *e, *t, *t1, *ps2, *tofree;
190 TTYSTRUCT ttattrs, ttset;
191 struct ttsave termsave;
192 #if defined (ARRAY_VARS)
195 #if defined (READLINE)
205 USE_VAR(input_is_pipe);
215 #if defined (READLINE)
224 sigalrm_seen = reading = 0;
226 i = 0; /* Index into the string that we are reading. */
227 raw = edit = 0; /* Not reading raw input by default. */
229 arrayname = prompt = (char *)NULL;
230 fd = 0; /* file descriptor to read from */
232 #if defined (READLINE)
233 rlbuf = itext = (char *)0;
237 tmsec = tmusec = 0; /* no timeout */
238 nr = nchars = input_is_tty = input_is_pipe = unbuffered_read = have_timeout = 0;
239 delim = '\n'; /* read until newline */
242 reset_internal_getopt ();
243 while ((opt = internal_getopt (list, "ersa:d:i:n:p:t:u:N:")) != -1)
251 prompt = list_optarg;
257 #if defined (READLINE)
262 #if defined (READLINE)
266 #if defined (ARRAY_VARS)
268 arrayname = list_optarg;
272 code = uconvert (list_optarg, &ival, &uval);
273 if (code == 0 || ival < 0 || uval < 0)
275 builtin_error (_("%s: invalid timeout specification"), list_optarg);
276 return (EXECUTION_FAILURE);
289 code = legal_number (list_optarg, &intval);
290 if (code == 0 || intval < 0 || intval != (int)intval)
292 sh_invalidnum (list_optarg);
293 return (EXECUTION_FAILURE);
299 code = legal_number (list_optarg, &intval);
300 if (code == 0 || intval < 0 || intval != (int)intval)
302 builtin_error (_("%s: invalid file descriptor specification"), list_optarg);
303 return (EXECUTION_FAILURE);
307 if (sh_validfd (fd) == 0)
309 builtin_error (_("%d: invalid file descriptor: %s"), fd, strerror (errno));
310 return (EXECUTION_FAILURE);
314 delim = *list_optarg;
323 /* `read -t 0 var' tests whether input is available with select/FIONREAD,
324 and fails if those are unavailable */
325 if (have_timeout && tmsec == 0 && tmusec == 0)
327 return (EXECUTION_FAILURE);
329 return (input_avail (fd) ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
332 /* Convenience: check early whether or not the first of possibly several
333 variable names is a valid identifier, and bail early if so. */
334 #if defined (ARRAY_VARS)
335 if (list && legal_identifier (list->word->word) == 0 && valid_array_reference (list->word->word) == 0)
337 if (list && legal_identifier (list->word->word) == 0)
340 sh_invalidid (list->word->word);
341 return (EXECUTION_FAILURE);
344 /* If we're asked to ignore the delimiter, make sure we do. */
348 /* IF IFS is unset, we use the default of " \t\n". */
349 ifs_chars = getifs ();
350 if (ifs_chars == 0) /* XXX - shouldn't happen */
352 /* If we want to read exactly NCHARS chars, don't split on IFS */
355 for (skip_ctlesc = skip_ctlnul = 0, e = ifs_chars; *e; e++)
356 skip_ctlesc |= *e == CTLESC, skip_ctlnul |= *e == CTLNUL;
358 input_string = (char *)xmalloc (size = 112); /* XXX was 128 */
359 input_string[0] = '\0';
361 /* $TMOUT, if set, is the default timeout for read. */
362 if (have_timeout == 0 && (e = get_string_value ("TMOUT")))
364 code = uconvert (e, &ival, &uval);
365 if (code == 0 || ival < 0 || uval < 0)
374 begin_unwind_frame ("read_builtin");
376 #if defined (BUFFERED_INPUT)
377 if (interactive == 0 && default_buffered_input >= 0 && fd_is_bash_input (fd))
378 sync_buffered_stream (default_buffered_input);
381 input_is_tty = isatty (fd);
382 if (input_is_tty == 0)
384 input_is_pipe = (lseek (fd, 0L, SEEK_CUR) < 0) && (errno == ESPIPE);
389 /* If the -p, -e or -s flags were given, but input is not coming from the
390 terminal, turn them off. */
391 if ((prompt || edit || silent) && input_is_tty == 0)
393 prompt = (char *)NULL;
394 #if defined (READLINE)
395 itext = (char *)NULL;
400 #if defined (READLINE)
402 add_unwind_protect (xfree, rlbuf);
405 pass_next = 0; /* Non-zero signifies last char was backslash. */
406 saw_escape = 0; /* Non-zero signifies that we saw an escape char */
408 if (tmsec > 0 || tmusec > 0)
410 /* Turn off the timeout if stdin is a regular file (e.g. from
411 input redirection). */
412 if ((fstat (fd, &tsb) < 0) || S_ISREG (tsb.st_mode))
416 if (tmsec > 0 || tmusec > 0)
418 code = setjmp_nosigs (alrmbuf);
422 /* Tricky. The top of the unwind-protect stack is the free of
423 input_string. We want to run all the rest and use input_string,
424 so we have to save input_string temporarily, run the unwind-
425 protects, then restore input_string so we can use it later */
426 orig_input_string = 0;
427 input_string[i] = '\0'; /* make sure it's terminated */
430 t = (char *)xmalloc (1);
434 t = savestring (input_string);
436 run_unwind_frame ("read_builtin");
438 retval = 128+SIGALRM;
441 old_alrm = set_signal_handler (SIGALRM, sigalrm);
442 add_unwind_protect (reset_alarm, (char *)NULL);
443 #if defined (READLINE)
446 add_unwind_protect (reset_attempted_completion_function, (char *)NULL);
447 add_unwind_protect (bashline_reset_event_hook, (char *)NULL);
450 falarm (tmsec, tmusec);
453 /* If we've been asked to read only NCHARS chars, or we're using some
454 character other than newline to terminate the line, do the right
455 thing to readline or the tty. */
456 if (nchars > 0 || delim != '\n')
458 #if defined (READLINE)
463 unwind_protect_int (rl_num_chars_to_read);
464 rl_num_chars_to_read = nchars;
468 set_eol_delim (delim);
469 add_unwind_protect (reset_eol_delim, (char *)NULL);
478 ttgetattr (fd, &ttattrs);
479 termsave.attrs = &ttattrs;
482 i = silent ? ttfd_cbreak (fd, &ttset) : ttfd_onechar (fd, &ttset);
485 add_unwind_protect ((Function *)ttyrestore, (char *)&termsave);
488 else if (silent) /* turn off echo but leave term in canonical mode */
492 ttgetattr (fd, &ttattrs);
493 termsave.attrs = &ttattrs;
496 i = ttfd_noecho (fd, &ttset); /* ttnoecho (); */
500 add_unwind_protect ((Function *)ttyrestore, (char *)&termsave);
503 /* This *must* be the top unwind-protect on the stack, so the manipulation
504 of the unwind-protect stack after the realloc() works right. */
505 add_unwind_protect (xfree, input_string);
508 if ((nchars > 0) && (input_is_tty == 0) && ignore_delim) /* read -N */
510 else if ((nchars > 0) || (delim != '\n') || input_is_pipe)
513 if (prompt && edit == 0)
515 fprintf (stderr, "%s", prompt);
519 #if defined (__CYGWIN__) && defined (O_TEXT)
524 for (print_ps2 = eof = retval = 0;;)
528 #if defined (READLINE)
531 if (rlbuf && rlbuf[rlind] == '\0')
539 rlbuf = edit_line (prompt ? prompt : "", itext);
557 ps2 = get_string_value ("PS2");
558 fprintf (stderr, "%s", ps2 ? ps2 : "");
564 if (posixly_correct == 0)
565 interrupt_immediately++;
568 if (unbuffered_read == 2)
569 retval = posixly_correct ? zreadintr (fd, &c, 1) : zreadn (fd, &c, nchars - nr);
570 else if (unbuffered_read)
571 retval = posixly_correct ? zreadintr (fd, &c, 1) : zread (fd, &c, 1);
573 retval = posixly_correct ? zreadcintr (fd, &c) : zreadc (fd, &c);
576 if (posixly_correct == 0)
577 interrupt_immediately--;
582 if (retval < 0 && errno == EINTR)
586 lastsig = trapped_signal_received;
587 run_pending_traps (); /* because interrupt_immediately is not set */
598 #if defined (READLINE)
603 if (i + 4 >= size) /* XXX was i + 2; use i + 4 for multibyte/read_mbchar */
606 t = (char *)xrealloc (input_string, size += 128);
608 /* Only need to change unwind-protect if input_string changes */
609 if (t != input_string)
612 remove_unwind_protect ();
613 add_unwind_protect (xfree, input_string);
617 /* If the next character is to be accepted verbatim, a backslash
618 newline pair still disappears from the input. */
624 i--; /* back up over the CTLESC */
625 if (interactive && input_is_tty && raw == 0)
633 /* This may cause problems if IFS contains CTLESC */
634 if (c == '\\' && raw == 0)
637 if (skip_ctlesc == 0)
640 input_string[i++] = CTLESC;
645 if (ignore_delim == 0 && (unsigned char)c == delim)
648 if (c == '\0' && delim != '\0')
649 continue; /* skip NUL bytes in input */
651 if ((skip_ctlesc == 0 && c == CTLESC) || (skip_ctlnul == 0 && c == CTLNUL))
654 input_string[i++] = CTLESC;
658 input_string[i++] = c;
661 #if defined (HANDLE_MULTIBYTE)
662 if (nchars > 0 && MB_CUR_MAX > 1 && is_basic (c) == 0)
664 input_string[i] = '\0'; /* for simplicity and debugging */
665 i += read_mbchar (fd, input_string, i, c, unbuffered_read);
671 if (nchars > 0 && nr >= nchars)
674 input_string[i] = '\0';
681 builtin_error (_("read error: %d: %s"), fd, strerror (errno));
682 run_unwind_frame ("read_builtin");
683 return ((t_errno != EINTR) ? EXECUTION_FAILURE : 128+lastsig);
686 if (tmsec > 0 || tmusec > 0)
689 if (nchars > 0 || delim != '\n')
691 #if defined (READLINE)
695 rl_num_chars_to_read = 0;
697 reset_eol_delim ((char *)NULL);
702 ttyrestore (&termsave);
705 ttyrestore (&termsave);
707 if (unbuffered_read == 0)
710 discard_unwind_frame ("read_builtin");
712 retval = eof ? EXECUTION_FAILURE : EXECUTION_SUCCESS;
716 #if defined (ARRAY_VARS)
717 /* If -a was given, take the string read, break it into a list of words,
718 an assign them to `arrayname' in turn. */
721 if (legal_identifier (arrayname) == 0)
723 sh_invalidid (arrayname);
724 xfree (input_string);
725 return (EXECUTION_FAILURE);
728 var = find_or_make_array_variable (arrayname, 1);
731 xfree (input_string);
732 return EXECUTION_FAILURE; /* readonly or noassign */
736 builtin_error (_("%s: cannot convert associative to indexed array"), arrayname);
737 xfree (input_string);
738 return EXECUTION_FAILURE; /* existing associative array */
740 else if (invisible_p (var))
741 VUNSETATTR (var, att_invisible);
742 array_flush (array_cell (var));
744 alist = list_string (input_string, ifs_chars, 0);
748 dequote_list (alist);
750 word_list_remove_quoted_nulls (alist);
751 assign_array_var_from_word_list (var, alist, 0);
752 dispose_words (alist);
754 xfree (input_string);
757 #endif /* ARRAY_VARS */
759 /* If there are no variables, save the text of the line read to the
760 variable $REPLY. ksh93 strips leading and trailing IFS whitespace,
761 so that `read x ; echo "$x"' and `read ; echo "$REPLY"' behave the
762 same way, but I believe that the difference in behaviors is useful
763 enough to not do it. Without the bash behavior, there is no way
764 to read a line completely without interpretation or modification
765 unless you mess with $IFS (e.g., setting it to the empty string).
766 If you disagree, change the occurrences of `#if 0' to `#if 1' below. */
770 orig_input_string = input_string;
771 for (t = input_string; ifs_chars && *ifs_chars && spctabnl(*t) && isifs(*t); t++)
774 input_string = strip_trailing_ifs_whitespace (input_string, ifs_chars, saw_escape);
779 t = dequote_string (input_string);
780 var = bind_variable ("REPLY", t, 0);
784 var = bind_variable ("REPLY", input_string, 0);
785 VUNSETATTR (var, att_invisible);
787 xfree (input_string);
791 /* This code implements the Posix.2 spec for splitting the words
792 read and assigning them to variables. */
793 orig_input_string = input_string;
795 /* Remove IFS white space at the beginning of the input string. If
796 $IFS is null, no field splitting is performed. */
797 for (t = input_string; ifs_chars && *ifs_chars && spctabnl(*t) && isifs(*t); t++)
800 for (; list->next; list = list->next)
802 varname = list->word->word;
803 #if defined (ARRAY_VARS)
804 if (legal_identifier (varname) == 0 && valid_array_reference (varname) == 0)
806 if (legal_identifier (varname) == 0)
809 sh_invalidid (varname);
810 xfree (orig_input_string);
811 return (EXECUTION_FAILURE);
814 /* If there are more variables than words read from the input,
815 the remaining variables are set to the empty string. */
818 /* This call updates INPUT_STRING. */
819 t = get_word_from_string (&input_string, ifs_chars, &e);
822 /* Don't bother to remove the CTLESC unless we added one
823 somewhere while reading the string. */
826 t1 = dequote_string (t);
827 var = bind_read_variable (varname, t1);
831 var = bind_read_variable (varname, t ? t : "");
836 var = bind_read_variable (varname, "");
842 xfree (orig_input_string);
843 return (EXECUTION_FAILURE);
846 stupidly_hack_special_variables (varname);
847 VUNSETATTR (var, att_invisible);
850 /* Now assign the rest of the line to the last variable argument. */
851 #if defined (ARRAY_VARS)
852 if (legal_identifier (list->word->word) == 0 && valid_array_reference (list->word->word) == 0)
854 if (legal_identifier (list->word->word) == 0)
857 sh_invalidid (list->word->word);
858 xfree (orig_input_string);
859 return (EXECUTION_FAILURE);
863 /* This has to be done this way rather than using string_list
864 and list_string because Posix.2 says that the last variable gets the
865 remaining words and their intervening separators. */
866 input_string = strip_trailing_ifs_whitespace (input_string, ifs_chars, saw_escape);
868 /* Check whether or not the number of fields is exactly the same as the
869 number of variables. */
874 t = get_word_from_string (&input_string, ifs_chars, &e);
875 if (*input_string == 0)
876 tofree = input_string = t;
879 input_string = strip_trailing_ifs_whitespace (t1, ifs_chars, saw_escape);
885 if (saw_escape && input_string && *input_string)
887 t = dequote_string (input_string);
888 var = bind_read_variable (list->word->word, t);
892 var = bind_read_variable (list->word->word, input_string ? input_string : "");
896 stupidly_hack_special_variables (list->word->word);
897 VUNSETATTR (var, att_invisible);
900 retval = EXECUTION_FAILURE;
903 xfree (orig_input_string);
909 bind_read_variable (name, value)
914 #if defined (ARRAY_VARS)
915 if (valid_array_reference (name) == 0)
916 v = bind_variable (name, value, 0);
918 v = assign_array_element (name, value, 0);
919 #else /* !ARRAY_VARS */
920 v = bind_variable (name, value, 0);
921 #endif /* !ARRAY_VARS */
923 : ((readonly_p (v) || noassign_p (v)) ? (SHELL_VAR *)NULL : v));
926 #if defined (HANDLE_MULTIBYTE)
928 read_mbchar (fd, string, ind, ch, unbuffered)
931 int ind, ch, unbuffered;
933 char mbchar[MB_LEN_MAX + 1];
937 mbstate_t ps, ps_back;
940 memset (&ps, '\0', sizeof (mbstate_t));
941 memset (&ps_back, '\0', sizeof (mbstate_t));
945 for (n = 0; n <= MB_LEN_MAX; n++)
948 ret = mbrtowc (&wc, mbchar, i, &ps);
949 if (ret == (size_t)-2)
952 /* We don't want to be interrupted during a multibyte char read */
954 r = zread (fd, &c, 1);
962 else if (ret == (size_t)-1 || ret == (size_t)0 || ret > (size_t)0)
967 if (i > 1) /* read a multibyte char */
968 /* mbchar[0] is already string[ind-1] */
969 for (r = 1; r < i; r++)
970 string[ind+r-1] = mbchar[r];
980 ttsetattr (ttp->fd, ttp->attrs);
983 #if defined (READLINE)
984 static rl_completion_func_t *old_attempted_completion_function = 0;
985 static rl_hook_func_t *old_startup_hook;
986 static char *deftext;
989 reset_attempted_completion_function (cp)
992 if (rl_attempted_completion_function == 0 && old_attempted_completion_function)
993 rl_attempted_completion_function = old_attempted_completion_function;
1002 if (old_startup_hook)
1003 r1 = (*old_startup_hook) ();
1006 r2 = rl_insert_text (deftext);
1007 deftext = (char *)NULL;
1008 rl_startup_hook = old_startup_hook;
1009 old_startup_hook = (rl_hook_func_t *)NULL;
1015 edit_line (p, itext)
1022 if (bash_readline_initialized == 0)
1023 initialize_readline ();
1025 old_attempted_completion_function = rl_attempted_completion_function;
1026 rl_attempted_completion_function = (rl_completion_func_t *)NULL;
1027 bashline_set_event_hook ();
1030 old_startup_hook = rl_startup_hook;
1031 rl_startup_hook = set_itext;
1037 rl_attempted_completion_function = old_attempted_completion_function;
1038 old_attempted_completion_function = (rl_completion_func_t *)NULL;
1039 bashline_reset_event_hook ();
1044 ret = (char *)xrealloc (ret, len + 2);
1050 static int old_delim_ctype;
1051 static rl_command_func_t *old_delim_func;
1052 static int old_newline_ctype;
1053 static rl_command_func_t *old_newline_func;
1055 static unsigned char delim_char;
1063 if (bash_readline_initialized == 0)
1064 initialize_readline ();
1065 cmap = rl_get_keymap ();
1067 /* Change newline to self-insert */
1068 old_newline_ctype = cmap[RETURN].type;
1069 old_newline_func = cmap[RETURN].function;
1070 cmap[RETURN].type = ISFUNC;
1071 cmap[RETURN].function = rl_insert;
1073 /* Bind the delimiter character to accept-line. */
1074 old_delim_ctype = cmap[c].type;
1075 old_delim_func = cmap[c].function;
1076 cmap[c].type = ISFUNC;
1077 cmap[c].function = rl_newline;
1083 reset_eol_delim (cp)
1088 cmap = rl_get_keymap ();
1090 cmap[RETURN].type = old_newline_ctype;
1091 cmap[RETURN].function = old_newline_func;
1093 cmap[delim_char].type = old_delim_ctype;
1094 cmap[delim_char].function = old_delim_func;