shell: split read builtin from ash

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 205 insertions, 0 deletions

diff --git a/shell/builtin_read.c b/shell/builtin_read.c
new file mode 100644
index 0000000..7f667e9
--- /dev/null
+++ b/shell/builtin_read.c
@@ -0,0 +1,205 @@
+/* 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"
+
+const char* FAST_FUNC
+builtin_read(void (*setvar)(const char *name, const char *val, int flags),
+	char       **argv,
+	const char *ifs,
+	int        read_flags,
+	const char *opt_n,
+	const char *opt_p,
+	const char *opt_t,
+	const char *opt_u
+)
+{
+	static const char *const arg_REPLY[] = { "REPLY", NULL };
+
+	unsigned end_ms; /* -t TIMEOUT */
+	int fd; /* -u FD */
+	int nchars; /* -n NUM */
+	char *buffer;
+	struct termios tty, old_tty;
+	const char *retval;
+	int bufpos; /* need to be able to hold -1 */
+	int startword;
+	smallint backslash;
+
+	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 (argv[0] == NULL)
+		argv = (char**)arg_REPLY;
+	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;
+		const char *is_ifs;
+
+		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 */
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
+		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, 0);
+			argv++;
+			/* can we skip one non-space ifs char? (2: yes) */
+			startword = isspace(c) ? 2 : 1;
+			continue;
+		}
+ put:
+		bufpos++;
+	} while (--nchars);
+
+	/* Remove trailing space ifs chars */
+	while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
+		continue;
+	buffer[bufpos + 1] = '\0';
+
+	setvar(*argv, buffer, 0);
+
+	while (*++argv != NULL)
+		setvar(*argv, "", 0);
+ ret:
+	free(buffer);
+	if (read_flags & BUILTIN_READ_SILENT)
+		tcsetattr(fd, TCSANOW, &old_tty);
+	return retval;
+}