hush: fix read builtin to not read ahead past eol and to not use

insane amounts of stack. Testsuite updated.

include/libbb.h

@@ -400,7 +400,11 @@ extern ssize_t safe_read(int fd, void *buf, size_t count);
 extern ssize_t full_read(int fd, void *buf, size_t count);
 extern void xread(int fd, void *buf, size_t count);
 extern unsigned char xread_char(int fd);
+// Read one line a-la fgets. Uses one read(), works only on seekable streams
 extern char *reads(int fd, char *buf, size_t count);
+// Read one line a-la fgets. Reads byte-by-byte.
+// Useful when it is important to not read ahead.
+extern char *xmalloc_reads(int fd, char *pfx);
 extern ssize_t read_close(int fd, void *buf, size_t count);
 extern ssize_t open_read_close(const char *filename, void *buf, size_t count);
 extern void *xmalloc_open_read_close(const char *filename, size_t *sizep);

libbb/read.c

@@ -38,10 +38,8 @@ ssize_t full_read(int fd, void *buf, size_t len)
 
 		if (cc < 0)
 			return cc;	/* read() returns -1 on failure. */
-
 		if (cc == 0)
 			break;
-
 		buf = ((char *)buf) + cc;
 		total += cc;
 		len -= cc;
@@ -64,9 +62,7 @@ void xread(int fd, void *buf, size_t count)
 unsigned char xread_char(int fd)
 {
 	char tmp;
-
 	xread(fd, &tmp, 1);
-
 	return tmp;
 }
 
@@ -95,6 +91,37 @@ char *reads(int fd, char *buffer, size_t size)
 	return buffer;
 }
 
+// Read one line a-la fgets. Reads byte-by-byte.
+// Useful when it is important to not read ahead.
+char *xmalloc_reads(int fd, char *buf)
+{
+	char *p;
+	int sz = buf ? strlen(buf) : 0;
+
+	goto jump_in;
+	while (1) {
+		if (p - buf == sz) {
+ jump_in:
+			buf = xrealloc(buf, sz + 128);
+			p = buf + sz;
+			sz += 128;
+		}
+		if (safe_read(fd, p, 1) != 1) { /* EOF/error */
+			if (p == buf) {
+				/* we read nothing [and buf was NULL initially] */
+				free(buf);
+				return NULL;
+			}
+			break;
+		}
+		if (*p == '\n')
+			break;
+		p++;
+	}
+	*p++ = '\0';
+	return xrealloc(buf, p - buf);
+}
+
 ssize_t read_close(int fd, void *buf, size_t size)
 {
 	int e;
@@ -113,18 +140,21 @@ ssize_t open_read_close(const char *filename, void *buf, size_t size)
 	return read_close(fd, buf, size);
 }
 
+// Read (potentially big) files in one go. File size is estimated by
+// lseek to end.
 void *xmalloc_open_read_close(const char *filename, size_t *sizep)
 {
 	char *buf;
 	size_t size = sizep ? *sizep : INT_MAX;
-	int fd = xopen(filename, O_RDONLY);
+	int fd;
+	off_t len;
+
+	fd = xopen(filename, O_RDONLY);
 	/* /proc/N/stat files report len 0 here */
 	/* In order to make such files readable, we add small const */
-	off_t len = xlseek(fd, 0, SEEK_END) + 256;
+	len = xlseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
 	xlseek(fd, 0, SEEK_SET);
-
-	if (len > size)
-		bb_error_msg_and_die("file '%s' is too big", filename);
+	if (len < size)
 		size = len;
 	buf = xmalloc(size + 1);
 	size = read_close(fd, buf, size);
@@ -132,6 +162,7 @@ void *xmalloc_open_read_close(const char *filename, size_t *sizep)
 		bb_perror_msg_and_die("'%s'", filename);
 	xrealloc(buf, size + 1);
 	buf[size] = '\0';
-	if (sizep) *sizep = size;
+	if (sizep)
+		*sizep = size;
 	return buf;
 }

modutils/insmod.c

@@ -4262,6 +4262,7 @@ int insmod_ng_main(int argc, char **argv)
 {
 	long ret;
 	size_t len;
+	int optlen;
 	void *map;
 	char *filename, *options;
 
@@ -4270,12 +4271,12 @@ int insmod_ng_main(int argc, char **argv)
 		bb_show_usage();
 
 	/* Rest is options */
-	options = xstrdup("");
+	options = xzalloc(1);
+	optlen = 0;
 	while (*++argv) {
-		int optlen = strlen(options);
 		options = xrealloc(options, optlen + 2 + strlen(*argv) + 2);
 		/* Spaces handled by "" pairs, but no way of escaping quotes */
-		sprintf(options + optlen, (strchr(*argv,' ') ? "\"%s\" " : "%s "), *argv);
+		optlen += sprintf(options + optlen, (strchr(*argv,' ') ? "\"%s\" " : "%s "), *argv);
 	}
 
 #if 0

modutils/modprobe.c

@@ -234,7 +234,7 @@ static void include_conf(struct dep_t **first, struct dep_t **current, char *buf
 {
 	int continuation_line = 0;
 
-	// alias parsing is not 100% correct (no correct handling of continuation lines within an alias) !
+	// alias parsing is not 100% correct (no correct handling of continuation lines within an alias)!
 
 	while (reads(fd, buffer, buflen)) {
 		int l;

shell/README

@@ -1,5 +1,8 @@
 Various bits of what is known about busybox shells, in no particular order.
 
+2007-06-13
+hush: exec <"$1" doesn't do parameter subst
+
 2007-05-24
 hush: environment-related memory leak plugged, with net code size
 decrease.

shell/ash.c

@@ -11567,8 +11567,8 @@ readcmd(int argc, char **argv)
 #endif
 #if ENABLE_ASH_READ_TIMEOUT
 	if (ts.tv_sec || ts.tv_usec) {
-		FD_ZERO (&set);
-		FD_SET (0, &set);
+		FD_ZERO(&set);
+		FD_SET(0, &set);
 
 		i = select(FD_SETSIZE, &set, NULL, NULL, &ts);
 		if (!i) {

shell/hush.c

@@ -942,21 +942,11 @@ static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
 /* built-in 'read VAR' handler */
 static int builtin_read(char **argv)
 {
-	char string[BUFSIZ];
-	char *p;
+	char *string;
 	const char *name = argv[1] ? argv[1] : "REPLY";
-	int name_len = strlen(name);
 
-	if (name_len >= sizeof(string) - 2)
-		return EXIT_FAILURE;
-	strcpy(string, name);
-	p = string + name_len;
-	*p++ = '=';
-	*p = '\0'; /* In case stdin has only EOF */
-	/* read string. name_len+1 chars are already used by 'name=' */
-	fgets(p, sizeof(string) - 1 - name_len, stdin);
-	chomp(p);
-	return set_local_var(xstrdup(string), 0);
+	string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name));
+	return set_local_var(string, 0);
 }
 
 /* built-in 'set [VAR=value]' handler */

shell/hush_test/hush-misc/read.right

@@ -0,0 +1,4 @@
+read
+cat
+echo "REPLY=$REPLY"
+REPLY=exec <read.tests

shell/hush_test/hush-misc/read.tests

@@ -0,0 +1,4 @@
+exec <read.tests
+read
+cat
+echo "REPLY=$REPLY"

util-linux/readprofile.c

@@ -99,7 +99,7 @@ int readprofile_main(int argc, char **argv)
 	/*
 	 * Use an fd for the profiling buffer, to skip stdio overhead
 	 */
-	len = INT_MAX;
+	len = MAXINT(ssize_t);
 	buf = xmalloc_open_read_close(proFile, &len);
 	if (!optNative) {
 		int entries = len/sizeof(*buf);