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-rw-r--r--bin/1sh/input.c518
1 files changed, 518 insertions, 0 deletions
diff --git a/bin/1sh/input.c b/bin/1sh/input.c
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+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.1/bin/sh/input.c 314436 2017-02-28 23:42:47Z imp $");
+
+#include <stdio.h>	/* defines BUFSIZ */
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * This file implements the input routines used by the parser.
+ */
+
+#include "shell.h"
+#include "redir.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "options.h"
+#include "memalloc.h"
+#include "error.h"
+#include "alias.h"
+#include "parser.h"
+#include "myhistedit.h"
+#include "trap.h"
+
+#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
+
+struct strpush {
+	struct strpush *prev;	/* preceding string on stack */
+	const char *prevstring;
+	int prevnleft;
+	int prevlleft;
+	struct alias *ap;	/* if push was associated with an alias */
+};
+
+/*
+ * The parsefile structure pointed to by the global variable parsefile
+ * contains information about the current file being read.
+ */
+
+struct parsefile {
+	struct parsefile *prev;	/* preceding file on stack */
+	int linno;		/* current line */
+	int fd;			/* file descriptor (or -1 if string) */
+	int nleft;		/* number of chars left in this line */
+	int lleft;		/* number of lines left in this buffer */
+	const char *nextc;	/* next char in buffer */
+	char *buf;		/* input buffer */
+	struct strpush *strpush; /* for pushing strings at this level */
+	struct strpush basestrpush; /* so pushing one is fast */
+};
+
+
+int plinno = 1;			/* input line number */
+int parsenleft;			/* copy of parsefile->nleft */
+static int parselleft;		/* copy of parsefile->lleft */
+const char *parsenextc;		/* copy of parsefile->nextc */
+static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
+static struct parsefile basepf = {	/* top level input file */
+	.nextc = basebuf,
+	.buf = basebuf
+};
+static struct parsefile *parsefile = &basepf;	/* current input file */
+int whichprompt;		/* 1 == PS1, 2 == PS2 */
+
+EditLine *el;			/* cookie for editline package */
+
+static void pushfile(void);
+static int preadfd(void);
+static void popstring(void);
+
+void
+resetinput(void)
+{
+	popallfiles();
+	parselleft = parsenleft = 0;	/* clear input buffer */
+}
+
+
+
+/*
+ * Read a character from the script, returning PEOF on end of file.
+ * Nul characters in the input are silently discarded.
+ */
+
+int
+pgetc(void)
+{
+	return pgetc_macro();
+}
+
+
+static int
+preadfd(void)
+{
+	int nr;
+	parsenextc = parsefile->buf;
+
+retry:
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && el) {
+		static const char *rl_cp;
+		static int el_len;
+
+		if (rl_cp == NULL) {
+			el_resize(el);
+			rl_cp = el_gets(el, &el_len);
+		}
+		if (rl_cp == NULL)
+			nr = el_len == 0 ? 0 : -1;
+		else {
+			nr = el_len;
+			if (nr > BUFSIZ)
+				nr = BUFSIZ;
+			memcpy(parsefile->buf, rl_cp, nr);
+			if (nr != el_len) {
+				el_len -= nr;
+				rl_cp += nr;
+			} else
+				rl_cp = NULL;
+		}
+	} else
+#endif
+		nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
+
+	if (nr <= 0) {
+                if (nr < 0) {
+                        if (errno == EINTR)
+                                goto retry;
+                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
+                                int flags = fcntl(0, F_GETFL, 0);
+                                if (flags >= 0 && flags & O_NONBLOCK) {
+                                        flags &=~ O_NONBLOCK;
+                                        if (fcntl(0, F_SETFL, flags) >= 0) {
+						out2fmt_flush("sh: turning off NDELAY mode\n");
+                                                goto retry;
+                                        }
+                                }
+                        }
+                }
+                nr = -1;
+	}
+	return nr;
+}
+
+/*
+ * Refill the input buffer and return the next input character:
+ *
+ * 1) If a string was pushed back on the input, pop it;
+ * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
+ *    from a string so we can't refill the buffer, return EOF.
+ * 3) If there is more in this buffer, use it else call read to fill it.
+ * 4) Process input up to the next newline, deleting nul characters.
+ */
+
+int
+preadbuffer(void)
+{
+	char *p, *q, *r, *end;
+	char savec;
+
+	while (parsefile->strpush) {
+		/*
+		 * Add a space to the end of an alias to ensure that the
+		 * alias remains in use while parsing its last word.
+		 * This avoids alias recursions.
+		 */
+		if (parsenleft == -1 && parsefile->strpush->ap != NULL)
+			return ' ';
+		popstring();
+		if (--parsenleft >= 0)
+			return (*parsenextc++);
+	}
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return PEOF;
+
+again:
+	if (parselleft <= 0) {
+		if ((parselleft = preadfd()) == -1) {
+			parselleft = parsenleft = EOF_NLEFT;
+			return PEOF;
+		}
+	}
+
+	p = parsefile->buf + (parsenextc - parsefile->buf);
+	end = p + parselleft;
+	*end = '\0';
+	q = strchrnul(p, '\n');
+	if (q != end && *q == '\0') {
+		/* delete nul characters */
+		for (r = q; q != end; q++) {
+			if (*q != '\0')
+				*r++ = *q;
+		}
+		parselleft -= end - r;
+		if (parselleft == 0)
+			goto again;
+		end = p + parselleft;
+		*end = '\0';
+		q = strchrnul(p, '\n');
+	}
+	if (q == end) {
+		parsenleft = parselleft;
+		parselleft = 0;
+	} else /* *q == '\n' */ {
+		q++;
+		parsenleft = q - parsenextc;
+		parselleft -= parsenleft;
+	}
+	parsenleft--;
+
+	savec = *q;
+	*q = '\0';
+
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && hist &&
+	    parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
+		HistEvent he;
+		INTOFF;
+		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
+		    parsenextc);
+		INTON;
+	}
+#endif
+
+	if (vflag) {
+		out2str(parsenextc);
+		flushout(out2);
+	}
+
+	*q = savec;
+
+	return *parsenextc++;
+}
+
+/*
+ * Returns if we are certain we are at EOF. Does not cause any more input
+ * to be read from the outside world.
+ */
+
+int
+preadateof(void)
+{
+	if (parsenleft > 0)
+		return 0;
+	if (parsefile->strpush)
+		return 0;
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return 1;
+	return 0;
+}
+
+/*
+ * Undo the last call to pgetc.  Only one character may be pushed back.
+ * PEOF may be pushed back.
+ */
+
+void
+pungetc(void)
+{
+	parsenleft++;
+	parsenextc--;
+}
+
+/*
+ * Push a string back onto the input at this current parsefile level.
+ * We handle aliases this way.
+ */
+void
+pushstring(const char *s, int len, struct alias *ap)
+{
+	struct strpush *sp;
+
+	INTOFF;
+/*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
+	if (parsefile->strpush) {
+		sp = ckmalloc(sizeof (struct strpush));
+		sp->prev = parsefile->strpush;
+		parsefile->strpush = sp;
+	} else
+		sp = parsefile->strpush = &(parsefile->basestrpush);
+	sp->prevstring = parsenextc;
+	sp->prevnleft = parsenleft;
+	sp->prevlleft = parselleft;
+	sp->ap = ap;
+	if (ap)
+		ap->flag |= ALIASINUSE;
+	parsenextc = s;
+	parsenleft = len;
+	INTON;
+}
+
+static void
+popstring(void)
+{
+	struct strpush *sp = parsefile->strpush;
+
+	INTOFF;
+	if (sp->ap) {
+		if (parsenextc != sp->ap->val &&
+		    (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
+			forcealias();
+		sp->ap->flag &= ~ALIASINUSE;
+	}
+	parsenextc = sp->prevstring;
+	parsenleft = sp->prevnleft;
+	parselleft = sp->prevlleft;
+/*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
+	parsefile->strpush = sp->prev;
+	if (sp != &(parsefile->basestrpush))
+		ckfree(sp);
+	INTON;
+}
+
+/*
+ * Set the input to take input from a file.  If push is set, push the
+ * old input onto the stack first.
+ */
+
+void
+setinputfile(const char *fname, int push)
+{
+	int fd;
+	int fd2;
+
+	INTOFF;
+	if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0)
+		error("cannot open %s: %s", fname, strerror(errno));
+	if (fd < 10) {
+		fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10);
+		close(fd);
+		if (fd2 < 0)
+			error("Out of file descriptors");
+		fd = fd2;
+	}
+	setinputfd(fd, push);
+	INTON;
+}
+
+
+/*
+ * Like setinputfile, but takes an open file descriptor (which should have
+ * its FD_CLOEXEC flag already set).  Call this with interrupts off.
+ */
+
+void
+setinputfd(int fd, int push)
+{
+	if (push) {
+		pushfile();
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	}
+	if (parsefile->fd > 0)
+		close(parsefile->fd);
+	parsefile->fd = fd;
+	if (parsefile->buf == NULL)
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	parselleft = parsenleft = 0;
+	plinno = 1;
+}
+
+
+/*
+ * Like setinputfile, but takes input from a string.
+ */
+
+void
+setinputstring(const char *string, int push)
+{
+	INTOFF;
+	if (push)
+		pushfile();
+	parsenextc = string;
+	parselleft = parsenleft = strlen(string);
+	parsefile->buf = NULL;
+	plinno = 1;
+	INTON;
+}
+
+
+
+/*
+ * To handle the "." command, a stack of input files is used.  Pushfile
+ * adds a new entry to the stack and popfile restores the previous level.
+ */
+
+static void
+pushfile(void)
+{
+	struct parsefile *pf;
+
+	parsefile->nleft = parsenleft;
+	parsefile->lleft = parselleft;
+	parsefile->nextc = parsenextc;
+	parsefile->linno = plinno;
+	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
+	pf->prev = parsefile;
+	pf->fd = -1;
+	pf->strpush = NULL;
+	pf->basestrpush.prev = NULL;
+	parsefile = pf;
+}
+
+
+void
+popfile(void)
+{
+	struct parsefile *pf = parsefile;
+
+	INTOFF;
+	if (pf->fd >= 0)
+		close(pf->fd);
+	if (pf->buf)
+		ckfree(pf->buf);
+	while (pf->strpush)
+		popstring();
+	parsefile = pf->prev;
+	ckfree(pf);
+	parsenleft = parsefile->nleft;
+	parselleft = parsefile->lleft;
+	parsenextc = parsefile->nextc;
+	plinno = parsefile->linno;
+	INTON;
+}
+
+
+/*
+ * Return current file (to go back to it later using popfilesupto()).
+ */
+
+struct parsefile *
+getcurrentfile(void)
+{
+	return parsefile;
+}
+
+
+/*
+ * Pop files until the given file is on top again. Useful for regular
+ * builtins that read shell commands from files or strings.
+ * If the given file is not an active file, an error is raised.
+ */
+
+void
+popfilesupto(struct parsefile *file)
+{
+	while (parsefile != file && parsefile != &basepf)
+		popfile();
+	if (parsefile != file)
+		error("popfilesupto() misused");
+}
+
+/*
+ * Return to top level.
+ */
+
+void
+popallfiles(void)
+{
+	while (parsefile != &basepf)
+		popfile();
+}
+
+
+
+/*
+ * Close the file(s) that the shell is reading commands from.  Called
+ * after a fork is done.
+ */
+
+void
+closescript(void)
+{
+	popallfiles();
+	if (parsefile->fd > 0) {
+		close(parsefile->fd);
+		parsefile->fd = 0;
+	}
+}