busybox/shell/builtin_read.c

/* 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 <herbert@gondor.apana.org.au>
 * was re-ported from NetBSD and debianized.
 *
 * Copyright (c) 2010 Denys Vlasenko
 * Split from ash.c
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */
#include "libbb.h"
#include "shell_common.h"
#include "builtin_read.h"

//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(void FAST_FUNC (*setvar)(const char *name, const char *val),
	char       **argv,
	const char *ifs,
	int        read_flags,
	const char *opt_n,
	const char *opt_p,
	const char *opt_t,
	const char *opt_u
)
{
	unsigned end_ms; /* -t TIMEOUT */
	int fd; /* -u FD */
	int nchars; /* -n NUM */
	char **pp;
	char *buffer;
	struct termios tty, old_tty;
	const char *retval;
	int bufpos; /* need to be able to hold -1 */
	int startword;
	smallint backslash;

	pp = argv;
	while (*pp) {
		if (!is_well_formed_var_name(*pp, '\0')) {
			/* Mimic bash message */
			bb_error_msg("read: '%s': not a valid identifier", *pp);
			return (const char *)(uintptr_t)1;
		}
		pp++;
	}

	nchars = 0; /* if != 0, -n is in effect */
	if (opt_n) {
		nchars = bb_strtou(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 (opt_t) {
		end_ms = bb_strtou(opt_t, NULL, 10);
		if (errno || end_ms > UINT_MAX / 2048)
			return "invalid timeout";
		end_ms *= 1000;
#if 0 /* even bash has no -t N.NNN support */
		ts.tv_sec = bb_strtou(opt_t, &p, 10);
		ts.tv_usec = 0;
		/* EINVAL means number is ok, but not terminated by NUL */
		if (*p == '.' && errno == EINVAL) {
			char *p2;
			if (*++p) {
				int scale;
				ts.tv_usec = bb_strtou(p, &p2, 10);
				if (errno)
					return "invalid timeout";
				scale = p2 - p;
				/* normalize to usec */
				if (scale > 6)
					return "invalid timeout";
				while (scale++ < 6)
					ts.tv_usec *= 10;
			}
		} else if (ts.tv_sec < 0 || errno) {
			return "invalid timeout";
		}
		if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
			return "invalid timeout";
		}
#endif /* if 0 */
	}
	fd = STDIN_FILENO;
	if (opt_u) {
		fd = bb_strtou(opt_u, NULL, 10);
		if (fd < 0 || errno)
			return "invalid file descriptor";
	}

	if (opt_p && isatty(fd)) {
		fputs(opt_p, stderr);
		fflush_all();
	}

	if (ifs == NULL)
		ifs = defifs;

	if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
		tcgetattr(fd, &tty);
		old_tty = tty;
		if (nchars) {
			tty.c_lflag &= ~ICANON;
			tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
		}
		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 (end_ms) /* NB: end_ms stays nonzero: */
		end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
	buffer = NULL;
	bufpos = 0;
	do {
		char c;

		if (end_ms) {
			int timeout;
			struct pollfd pfd[1];

			pfd[0].fd = fd;
			pfd[0].events = POLLIN;
			timeout = end_ms - (unsigned)monotonic_ms();
			if (timeout <= 0 /* already late? */
			 || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
			) { /* timed out! */
				retval = (const char *)(uintptr_t)1;
				goto ret;
			}
		}

		if ((bufpos & 0xff) == 0)
			buffer = xrealloc(buffer, bufpos + 0x100);
		if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
			retval = (const char *)(uintptr_t)1;
			break;
		}
		c = buffer[bufpos];
		if (c == '\0')
			continue;
		if (backslash) {
			backslash = 0;
			if (c != '\n')
				goto put;
			continue;
		}
		if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
			backslash = 1;
			continue;
		}
		if (c == '\n')
			break;

		/* $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;
				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';
		/* Use the remainder as a value for the next variable */
		setvar(*argv, buffer);
		/* Set the rest to "" */
		while (*++argv)
			setvar(*argv, "");
	} else {
		/* Note: no $IFS removal */
		buffer[bufpos] = '\0';
		setvar("REPLY", buffer);
	}

 ret:
	free(buffer);
	if (read_flags & BUILTIN_READ_SILENT)
		tcsetattr(fd, TCSANOW, &old_tty);
	return retval;
}
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 the GPL v2 or later, see the file LICENSE in this tarball.
18	*/
19	#include "libbb.h"
20	#include "shell_common.h"
21	#include "builtin_read.h"
22
23	//TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
24	//string. hush naturally has it, and ash has setvareq().
25	//Here we can simply store "VAR=" at buffer start and store read data directly
26	//after "=", then pass buffer to setvar() to consume.
27
28	const char* FAST_FUNC
29	shell_builtin_read(void FAST_FUNC (setvar)(const char name, const char *val),
30	char **argv,
31	const char *ifs,
32	int read_flags,
33	const char *opt_n,
34	const char *opt_p,
35	const char *opt_t,
36	const char *opt_u
37	)
38	{
39	unsigned end_ms; /* -t TIMEOUT */
40	int fd; /* -u FD */
41	int nchars; /* -n NUM */
42	char **pp;
43	char *buffer;
44	struct termios tty, old_tty;
45	const char *retval;
46	int bufpos; /* need to be able to hold -1 */
47	int startword;
48	smallint backslash;
49
50	pp = argv;
51	while (*pp) {
52	if (!is_well_formed_var_name(*pp, '\0')) {
53	/* Mimic bash message */
54	bb_error_msg("read: '%s': not a valid identifier", *pp);
55	return (const char *)(uintptr_t)1;
56	}
57	pp++;
58	}
59
60	nchars = 0; /* if != 0, -n is in effect */
61	if (opt_n) {
62	nchars = bb_strtou(opt_n, NULL, 10);
63	if (nchars < 0 \|\| errno)
64	return "invalid count";
65	/* note: "-n 0": off (bash 3.2 does this too) */
66	}
67	end_ms = 0;
68	if (opt_t) {
69	end_ms = bb_strtou(opt_t, NULL, 10);
70	if (errno \|\| end_ms > UINT_MAX / 2048)
71	return "invalid timeout";
72	end_ms *= 1000;
73	#if 0 /* even bash has no -t N.NNN support */
74	ts.tv_sec = bb_strtou(opt_t, &p, 10);
75	ts.tv_usec = 0;
76	/* EINVAL means number is ok, but not terminated by NUL */
77	if (*p == '.' && errno == EINVAL) {
78	char *p2;
79	if (*++p) {
80	int scale;
81	ts.tv_usec = bb_strtou(p, &p2, 10);
82	if (errno)
83	return "invalid timeout";
84	scale = p2 - p;
85	/* normalize to usec */
86	if (scale > 6)
87	return "invalid timeout";
88	while (scale++ < 6)
89	ts.tv_usec *= 10;
90	}
91	} else if (ts.tv_sec < 0 \|\| errno) {
92	return "invalid timeout";
93	}
94	if (!(ts.tv_sec \| ts.tv_usec)) { /* both are 0? */
95	return "invalid timeout";
96	}
97	#endif /* if 0 */
98	}
99	fd = STDIN_FILENO;
100	if (opt_u) {
101	fd = bb_strtou(opt_u, NULL, 10);
102	if (fd < 0 \|\| errno)
103	return "invalid file descriptor";
104	}
105
106	if (opt_p && isatty(fd)) {
107	fputs(opt_p, stderr);
108	fflush_all();
109	}
110
111	if (ifs == NULL)
112	ifs = defifs;
113
114	if (nchars \|\| (read_flags & BUILTIN_READ_SILENT)) {
115	tcgetattr(fd, &tty);
116	old_tty = tty;
117	if (nchars) {
118	tty.c_lflag &= ~ICANON;
119	tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
120	}
121	if (read_flags & BUILTIN_READ_SILENT) {
122	tty.c_lflag &= ~(ECHO \| ECHOK \| ECHONL);
123	}
124	/* This forces execution of "restoring" tcgetattr later */
125	read_flags \|= BUILTIN_READ_SILENT;
126	/* if tcgetattr failed, tcsetattr will fail too.
127	* Ignoring, it's harmless. */
128	tcsetattr(fd, TCSANOW, &tty);
129	}
130
131	retval = (const char *)(uintptr_t)0;
132	startword = 1;
133	backslash = 0;
134	if (end_ms) /* NB: end_ms stays nonzero: */
135	end_ms = ((unsigned)monotonic_ms() + end_ms) \| 1;
136	buffer = NULL;
137	bufpos = 0;
138	do {
139	char c;
140
141	if (end_ms) {
142	int timeout;
143	struct pollfd pfd[1];
144
145	pfd[0].fd = fd;
146	pfd[0].events = POLLIN;
147	timeout = end_ms - (unsigned)monotonic_ms();
148	if (timeout <= 0 /* already late? */
149	\|\| safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
150	) { /* timed out! */
151	retval = (const char *)(uintptr_t)1;
152	goto ret;
153	}
154	}
155
156	if ((bufpos & 0xff) == 0)
157	buffer = xrealloc(buffer, bufpos + 0x100);
158	if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
159	retval = (const char *)(uintptr_t)1;
160	break;
161	}
162	c = buffer[bufpos];
163	if (c == '\0')
164	continue;
165	if (backslash) {
166	backslash = 0;
167	if (c != '\n')
168	goto put;
169	continue;
170	}
171	if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
172	backslash = 1;
173	continue;
174	}
175	if (c == '\n')
176	break;
177
178	/* $IFS splitting. NOT done if we run "read"
179	* without variable names (bash compat).
180	* Thus, "read" and "read REPLY" are not the same.
181	*/
182	if (argv[0]) {
183	/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
184	const char *is_ifs = strchr(ifs, c);
185	if (startword && is_ifs) {
186	if (isspace(c))
187	continue;
188	/* it is a non-space ifs char */
189	startword--;
190	if (startword == 1) /* first one? */
191	continue; /* yes, it is not next word yet */
192	}
193	startword = 0;
194	if (argv[1] != NULL && is_ifs) {
195	buffer[bufpos] = '\0';
196	bufpos = 0;
197	setvar(*argv, buffer);
198	argv++;
199	/* can we skip one non-space ifs char? (2: yes) */
200	startword = isspace(c) ? 2 : 1;
201	continue;
202	}
203	}
204	put:
205	bufpos++;
206	} while (--nchars);
207
208	if (argv[0]) {
209	/* Remove trailing space $IFS chars */
210	while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
211	continue;
212	buffer[bufpos + 1] = '\0';
213	/* Use the remainder as a value for the next variable */
214	setvar(*argv, buffer);
215	/* Set the rest to "" */
216	while (*++argv)
217	setvar(*argv, "");
218	} else {
219	/* Note: no $IFS removal */
220	buffer[bufpos] = '\0';
221	setvar("REPLY", buffer);
222	}
223
224	ret:
225	free(buffer);
226	if (read_flags & BUILTIN_READ_SILENT)
227	tcsetattr(fd, TCSANOW, &old_tty);
228	return retval;
229	}