Fixed mixer chunk load and line ending detection for good.

src/modules/systemlib/mixer/mixer.cpp

@@ -116,6 +116,33 @@ Mixer::scale_check(struct mixer_scaler_s &scaler)
 	return 0;
 }
 
+const char *
+Mixer::findtag(const char *buf, unsigned &buflen, char tag)
+{
+	while (buflen >= 2) {
+		if ((buf[0] == tag) && (buf[1] == ':'))
+			return buf;
+		buf++;
+		buflen--;
+	}
+	return nullptr;
+}
+
+const char *
+Mixer::skipline(const char *buf, unsigned &buflen)
+{
+	const char *p;
+
+	/* if we can find a CR or NL in the buffer, skip up to it */
+	if ((p = (const char *)memchr(buf, '\r', buflen)) || (p = (const char *)memchr(buf, '\n', buflen))) {
+		/* skip up to it AND one beyond - could be on the NUL symbol now */
+		buflen -= (p - buf) + 1;
+		return p + 1;
+	}
+
+	return nullptr;
+}
+
 /****************************************************************************/
 
 NullMixer::NullMixer() :

src/modules/systemlib/mixer/mixer.h

@@ -212,6 +212,24 @@ protected:
 	 */
 	static int			scale_check(struct mixer_scaler_s &scaler);
 
+	/**
+	 * Find a tag
+	 *
+	 * @param buf			The buffer to operate on.
+	 * @param buflen		length of the buffer.
+	 * @param tag			character to search for.
+	 */
+	static const char *		findtag(const char *buf, unsigned &buflen, char tag);
+
+	/**
+	 * Skip a line
+	 *
+	 * @param buf			The buffer to operate on.
+	 * @param buflen		length of the buffer.
+	 * @return			0 / OK if a line could be skipped, 1 else
+	 */
+	static const char *		skipline(const char *buf, unsigned &buflen);
+
 private:
 };
 
@@ -240,6 +258,11 @@ public:
 	 */
 	void				reset();
 
+	/**
+	 * Count the mixers in the group.
+	 */
+	unsigned			count();
+
 	/**
 	 * Adds mixers to the group based on a text description in a buffer.
 	 *

src/modules/systemlib/mixer/mixer_group.cpp

@@ -111,6 +111,20 @@ MixerGroup::mix(float *outputs, unsigned space)
 	return index;
 }
 
+unsigned
+MixerGroup::count()
+{
+	Mixer	*mixer = _first;
+	unsigned index = 0;
+
+	while ((mixer != nullptr)) {
+		mixer = mixer->_next;
+		index++;
+	}
+
+	return index;
+}
+
 void
 MixerGroup::groups_required(uint32_t &groups)
 {
@@ -170,6 +184,7 @@ MixerGroup::load_from_buf(const char *buf, unsigned &buflen)
 
 			/* only adjust buflen if parsing was successful */
 			buflen = resid;
+			debug("SUCCESS - buflen: %d", buflen);
 		} else {
 
 			/*

src/modules/systemlib/mixer/mixer_load.c

@@ -38,22 +38,22 @@
  */
 
 #include <nuttx/config.h>
-#include <systemlib/err.h>
 #include <string.h>
 #include <stdio.h>
 #include <ctype.h>
 
 #include "mixer_load.h"
 
-int load_mixer_file(const char *fname, char *buf)
+int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
 {
 	FILE		*fp;
 	char		line[120];
 
 	/* open the mixer definition file */
 	fp = fopen(fname, "r");
-	if (fp == NULL)
-		err(1, "can't open %s", fname);
+	if (fp == NULL) {
+		return 1;
+	}
 
 	/* read valid lines from the file into a buffer */
 	buf[0] = '\0';
@@ -70,7 +70,7 @@ int load_mixer_file(const char *fname, char *buf)
 
 		/* compact whitespace in the buffer */
 		char *t, *f;
-		for (f = buf; *f != '\0'; f++) {
+		for (f = line; *f != '\0'; f++) {
 			/* scan for space characters */
 			if (*f == ' ') {
 				/* look for additional spaces */
@@ -87,8 +87,9 @@ int load_mixer_file(const char *fname, char *buf)
 		}
 
 		/* if the line is too long to fit in the buffer, bail */
-		if ((strlen(line) + strlen(buf) + 1) >= sizeof(buf))
-			break;
+		if ((strlen(line) + strlen(buf) + 1) >= maxlen) {
+			return 1;
+		}
 
 		/* add the line to the buffer */
 		strcat(buf, line);

src/modules/systemlib/mixer/mixer_load.h

@@ -44,7 +44,7 @@
 
 __BEGIN_DECLS
 
-__EXPORT int load_mixer_file(const char *fname, char *buf);
+__EXPORT int load_mixer_file(const char *fname, char *buf, unsigned maxlen);
 
 __END_DECLS
 

src/modules/systemlib/mixer/mixer_multirotor.cpp

@@ -205,11 +205,17 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 	}
 
 	if (used > (int)buflen) {
-		debug("multirotor spec used %d of %u", used, buflen);
+		debug("OVERFLOW: multirotor spec used %d of %u", used, buflen);
 		return nullptr;
 	}
 
-	buflen -= used;
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		return nullptr;
+	}
+
+	debug("remaining in buf: %d, first char: %c", buflen, buf[0]);
 
 	if (!strcmp(geomname, "4+")) {
 		geometry = MultirotorMixer::QUAD_PLUS;

src/modules/systemlib/mixer/mixer_simple.cpp

@@ -55,7 +55,7 @@
 #include "mixer.h"
 
 #define debug(fmt, args...)	do { } while(0)
-// #define debug(fmt, args...)	do { printf("[mixer] " fmt "\n", ##args); } while(0)
+//#define debug(fmt, args...)	do { printf("[mixer] " fmt "\n", ##args); } while(0)
 
 SimpleMixer::SimpleMixer(ControlCallback control_cb,
 			 uintptr_t cb_handle,
@@ -71,28 +71,6 @@ SimpleMixer::~SimpleMixer()
 		free(_info);
 }
 
-static const char *
-findtag(const char *buf, unsigned &buflen, char tag)
-{
-	while (buflen >= 2) {
-		if ((buf[0] == tag) && (buf[1] == ':'))
-			return buf;
-		buf++;
-		buflen--;
-	}
-	return nullptr;
-}
-
-static void
-skipline(const char *buf, unsigned &buflen)
-{
-	const char *p;
-
-	/* if we can find a CR or NL in the buffer, skip up to it */
-	if ((p = (const char *)memchr(buf, '\r', buflen)) || (p = (const char *)memchr(buf, '\n', buflen)))
-		buflen -= (p - buf);
-}
-
 int
 SimpleMixer::parse_output_scaler(const char *buf, unsigned &buflen, mixer_scaler_s &scaler)
 {
@@ -111,7 +89,12 @@ SimpleMixer::parse_output_scaler(const char *buf, unsigned &buflen, mixer_scaler
 		debug("out scaler parse failed on '%s' (got %d, consumed %d)", buf, ret, n);
 		return -1;
 	}
-	skipline(buf, buflen);
+
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		return -1;
+	}
 
 	scaler.negative_scale	= s[0] / 10000.0f;
 	scaler.positive_scale	= s[1] / 10000.0f;
@@ -130,7 +113,7 @@ SimpleMixer::parse_control_scaler(const char *buf, unsigned &buflen, mixer_scale
 
 	buf = findtag(buf, buflen, 'S');
 	if ((buf == nullptr) || (buflen < 16)) {
-		debug("contorl parser failed finding tag, ret: '%s'", buf);
+		debug("control parser failed finding tag, ret: '%s'", buf);
 		return -1;
 	}
 
@@ -139,7 +122,12 @@ SimpleMixer::parse_control_scaler(const char *buf, unsigned &buflen, mixer_scale
 		debug("control parse failed on '%s'", buf);
 		return -1;
 	}
-	skipline(buf, buflen);
+
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		return -1;
+	}
 
 	control_group		= u[0];
 	control_index		= u[1];
@@ -161,29 +149,17 @@ SimpleMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, c
 	int used;
 	const char *end = buf + buflen;
 
-	/* enforce that the mixer ends with space or a new line */
-	for (int i = buflen - 1; i >= 0; i--) {
-		if (buf[i] == '\0')
-			continue;
-
-		/* require a space or newline at the end of the buffer, fail on printable chars */
-		if (buf[i] == ' ' || buf[i] == '\n' || buf[i] == '\r') {
-			/* found a line ending or space, so no split symbols / numbers. good. */
-			break;
-		} else {
-			debug("simple parser rejected: No newline / space at end of buf. (#%d/%d: 0x%02x)", i, buflen-1, buf[i]);
-			goto out;
-		}
-
-	}
-
 	/* get the base info for the mixer */
 	if (sscanf(buf, "M: %u%n", &inputs, &used) != 1) {
 		debug("simple parse failed on '%s'", buf);
 		goto out;
 	}
 
-	buflen -= used;
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		goto out;
+	}
 
 	mixinfo = (mixer_simple_s *)malloc(MIXER_SIMPLE_SIZE(inputs));