bin/sh: Fix history long line truncation/corruption

When reading from standard input with editline history enabled, increase buffer size to accomodate long lines so that history is recorded correctly. Cleanup el_gets() handling avoiding potentially dangerous retention of pointers to editline buffers across calls. Ensure struct parsefile objects are properly zero initialised when created. Remove push argument from setinputstring() and simplify logic as it was always called with a value of one and as was written was potentially dangerous if ever called with a value of zero. This commit does not fix long lines when history is enabled but editing is not (e.g. if there is no terminal). MFC after: 3 weeks Pull Request: https://github.com/freebsd/freebsd-src/pull/2028 Signed-off-by: Kristofer Peterson <[email protected]>
2026-11-07 04:36:52 -10:00 · 2026-05-24 19:06:07 +02:00
1 parent db513f3a55
commit 95e4fce8f0
@@ -154,7 +154,7 @@ evalstring(const char *s, int flags)
 	flags &= ~EV_EXIT;
 	any = 0;
 	setstackmark(&smark);
-	setinputstring(s, 1);
+	setinputstring(s);
 	while ((n = parsecmd(0)) != NEOF) {
 		if (n != NULL && !nflag) {
 			if (flags_exit && preadateof())
@@ -81,6 +81,7 @@ struct parsefile {
 	int lleft;		/* number of lines left in this buffer */
 	const char *nextc;	/* next char in buffer */
 	char *buf;		/* input buffer */
+	size_t bufsize;		/* input buffer size */
 	struct strpush *strpush; /* for pushing strings at this level */
 	struct strpush basestrpush; /* so pushing one is fast */
 };
@@ -93,7 +94,8 @@ 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
+	.buf = basebuf,
+	.bufsize = sizeof(basebuf),
 };
 static struct parsefile *parsefile = &basepf;	/* current input file */
 int whichprompt;		/* 1 == PS1, 2 == PS2 */
@@ -127,52 +129,61 @@ 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;
+		const char *line;

-		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;
+		el_resize(el);
+		line = el_gets(el, &nr);
+		if (nr > 0 && parsefile->bufsize < (size_t)nr + 1) {
+			size_t bufsize;
+
+			INTOFF;
+			if (parsefile->buf != basebuf) {
+				ckfree(parsefile->buf);
+				parsefile->buf = NULL;
+				parsefile->bufsize = 0;
+			}
+			bufsize = (size_t)nr + BUFSIZ + 1;
+			bufsize -= bufsize % BUFSIZ;
+			parsefile->buf = ckmalloc(bufsize);
+			parsefile->bufsize = bufsize;
+			INTON;
 		}
+		if (nr > 0 && line != NULL)
+			memcpy(parsefile->buf, line, nr);
+		else
+			nr = nr ? -1 : 0;
 	} else
 #endif
-		nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
+	nr = read(parsefile->fd, parsefile->buf, parsefile->bufsize - 1);

-	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;
-                                        }
-                                }
-                        }
+	if (nr < 0)
+		switch (errno) {
+			int flags;
+
+		case EINTR:
+			goto retry;
+		case EWOULDBLOCK:
+			if (parsefile->fd != 0)
+				break;
+			if ((flags = fcntl(0, F_GETFL, 0)) < 0)
+				break;
+			if (!(flags & O_NONBLOCK))
+				break;
+			if (fcntl(0, F_SETFL, flags & ~O_NONBLOCK) < 0)
+				break;
+			out2fmt_flush("sh: turning off NDELAY mode\n");
+			goto retry;
                }
-                nr = -1;
-	}
+	else if (nr > 0)
+		parsefile->buf[nr] = '\0';
+	else
+		nr = -1;
+
+	parsenextc = parsefile->buf;
 	return nr;
 }

@@ -189,7 +200,8 @@ retry:
 int
 preadbuffer(void)
 {
-	char *p, *q, *r, *end;
+	const char *end;
+	char *q, *r;
 	char savec;

 	while (parsefile->strpush) {
@@ -208,31 +220,22 @@ preadbuffer(void)
 		return PEOF;

 again:
-	if (parselleft <= 0) {
-		if ((parselleft = preadfd()) == -1) {
-			parselleft = parsenleft = EOF_NLEFT;
-			return PEOF;
-		}
+	if (parselleft <= 0 && (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') {
+	end = parsenextc + parselleft;
+	q = strchrnul(parsenextc, '\n');
+	if (*q == '\0' && q != end) {
 		/* delete nul characters */
-		for (r = q; q != end; q++) {
+		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');
+		*r = '\0';
+		parselleft = r - parsenextc;
+		goto again;
 	}
-	if (q == end) {
+	if (*q == '\0') {
 		parsenleft = parselleft;
 		parselleft = 0;
 	} else /* *q == '\n' */ {
@@ -307,7 +310,7 @@ pushstring(const char *s, int len, struct alias *ap)
 	INTOFF;
 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
 	if (parsefile->strpush) {
-		sp = ckmalloc(sizeof (struct strpush));
+		sp = ckmalloc(sizeof(struct strpush));
 		sp->prev = parsefile->strpush;
 		parsefile->strpush = sp;
 	} else
@@ -391,15 +394,15 @@ setinputfile(const char *fname, int push, int verify)
 void
 setinputfd(int fd, int push)
 {
-	if (push) {
+	if (push)
 		pushfile();
-		parsefile->buf = ckmalloc(BUFSIZ + 1);
-	}
 	if (parsefile->fd > 0)
 		close(parsefile->fd);
 	parsefile->fd = fd;
-	if (parsefile->buf == NULL)
+	if (parsefile->buf == NULL) {
 		parsefile->buf = ckmalloc(BUFSIZ + 1);
+		parsefile->bufsize = BUFSIZ + 1;
+	}
 	parselleft = parsenleft = 0;
 	plinno = 1;
 }
@@ -410,14 +413,12 @@ setinputfd(int fd, int push)
 */

 void
-setinputstring(const char *string, int push)
+setinputstring(const char *string)
 {
 	INTOFF;
-	if (push)
-		pushfile();
+	pushfile();
 	parsenextc = string;
 	parselleft = parsenleft = strlen(string);
-	parsefile->buf = NULL;
 	plinno = 1;
 	INTON;
 }
@@ -434,15 +435,12 @@ pushfile(void)
 {
 	struct parsefile *pf;

+	pf = (struct parsefile *)ckmalloc(sizeof(struct parsefile));
+	*pf = (struct parsefile){ .prev = parsefile, .fd = -1 };
 	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;
 }

@@ -54,7 +54,7 @@ void pungetc(void);
 void pushstring(const char *, int, struct alias *);
 void setinputfile(const char *, int, int);
 void setinputfd(int, int);
-void setinputstring(const char *, int);
+void setinputstring(const char *);
 void popfile(void);
 struct parsefile *getcurrentfile(void);
 void popfilesupto(struct parsefile *);
@@ -1167,7 +1167,7 @@ parsebackq(char *out, struct nodelist **pbqlist,
 		INTOFF;
 		ostr = ckmalloc(olen);
 		memcpy(ostr, stackblock(), olen);
-		setinputstring(ostr, 1);
+		setinputstring(ostr);
 		INTON;
        }
 	nlpp = pbqlist;
@@ -2368,7 +2368,7 @@ expandstr(const char *ps)
 	if (!setjmp(jmploc.loc)) {
 		handler = &jmploc;
 		parser_temp = NULL;
-		setinputstring(ps, 1);
+		setinputstring(ps);
 		doprompt = 0;
 		readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
 		if (backquotelist != NULL)