Add serial I/O helpers

git-svn-id: https://bucket.mit.edu/svn/nilm/zoom@7604 ddd99763-3ecb-0310-9145-efcb8ce7c51f

pc/Makefile

@@ -1 +1,13 @@
+CFLAGS=-Wall -Werror
+
 all: read calibrate
+
+serial-util.o: serial-util.h
+
+read.o: serial-util.h
+
+calibrate.o: serial-util.h
+
+read: read.o serial-util.o
+
+calibrate: calibrate.o serial-util.o

pc/calibrate.c

@@ -1,18 +1,16 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <termio.h>
 #include <sys/types.h>
-#include <sys/ioctl.h>
 #include <errno.h>
 #include <unistd.h>
 #include <getopt.h>
 #include <stdint.h>
 #include <string.h>
 #include <syslog.h>
-#include <fcntl.h>
 #include <err.h>
 #include <linux/serial.h>
 #include <sys/signal.h>
+#include "serial-util.h"
 
 int zoom, gpib;
 
@@ -26,62 +24,11 @@ void handle_sig(int sig)
 	quit = 1;
 }
 
-int serial_open(const char *device, int rate)
-{
-	struct termios options;
-	struct serial_struct serinfo;
-	int fd;
-	int speed = 0;
-
-	/* Open and configure serial port */
-	if ((fd = open(device,O_RDWR|O_NOCTTY)) == -1)
-		err(1, "%s", device);
-
-	switch (rate) {
-	case 9600: speed = B9600; break;
-	case 115200: speed = B115200; break;
-	}
-
-	if (speed == 0) {
-		serinfo.reserved_char[0] = 0;
-		if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
-			err(1, "%s: TIOCGSERIAL", device);
-		serinfo.flags &= ~ASYNC_SPD_MASK;
-		serinfo.flags |= ASYNC_SPD_CUST;
-		serinfo.custom_divisor = (serinfo.baud_base + (rate / 2)) / rate;
-		if (serinfo.custom_divisor < 1) 
-			serinfo.custom_divisor = 1;
-		if (ioctl(fd, TIOCSSERIAL, &serinfo) < 0)
-			err(1, "%s: TIOCSSERIAL", device);
-		if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
-			err(1, "%s: TIOCGSERIAL 2", device);
-		if (serinfo.custom_divisor * rate != serinfo.baud_base) {
-			warnx("actual baudrate is %d / %d = %f",
-			      serinfo.baud_base, serinfo.custom_divisor,
-			      (float)serinfo.baud_base / serinfo.custom_divisor);
-		}
-	}
-
-	fcntl(fd, F_SETFL, 0);
-	tcgetattr(fd, &options);
-	cfsetispeed(&options, speed ?: B38400);
-	cfsetospeed(&options, speed ?: B38400);
-	cfmakeraw(&options);
-	options.c_cflag |= (CLOCAL | CREAD);
-	options.c_cflag &= ~CRTSCTS;
-	if (tcsetattr(fd, TCSANOW, &options) != 0)
-		err(1, "TCSANOW");
-
-	return fd;
-}
-
 int main(int argc, char *argv[])
 {
 	char *zoomdev=strdup("/dev/ttyUSB1");
 	char *gpibdev=strdup("/dev/ttyUSB0");
 	int getopt_index;
-	int i;
-	char buf[1024];
 
 	static struct option long_opts[] = {
 		{ "zoom-device", required_argument, NULL, 'z' },
@@ -92,6 +39,16 @@ int main(int argc, char *argv[])
 	int help=0;
 	char c;
 
+	{
+		char buf[1024];
+		drain(0);
+		fdprintf(1,"type a string in 5 sec: ");
+		fdgets(buf, 1024, 0, 5000);		
+		chomp(buf);
+		fdprintf(1,"you typed: '%s' len %d\n", buf, strlen(buf));
+		abort();
+	}
+
 	while ((c = getopt_long(argc, argv, "z:g:h?",
 				long_opts, &getopt_index)) != -1) {
 		switch(c) 

pc/read.c

@@ -1,17 +1,15 @@
 #include <stdio.h>
 #include <stdlib.h>
-#include <termio.h>
 #include <sys/types.h>
-#include <sys/ioctl.h>
 #include <errno.h>
 #include <unistd.h>
 #include <getopt.h>
 #include <stdint.h>
 #include <string.h>
 #include <syslog.h>
-#include <fcntl.h>
 #include <err.h>
 #include <linux/serial.h>
+#include "serial-util.h"
 
 int hex = 0;
 int dec = 0;
@@ -21,54 +19,12 @@ int total = 0;
 
 int process(const uint8_t *buf, int len);
 
-int serial_open(const char *device, int rate)
-{
-	struct termios options;
-	struct serial_struct serinfo;
-	int fd;
-
-	/* Open and configure serial port */
-	if ((fd = open(device,O_RDWR|O_NOCTTY)) == -1)
-		err(1, "%s", device);
-
-        serinfo.reserved_char[0] = 0;
-        if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
-		err(1, "%s: TIOCGSERIAL", device);
-	serinfo.flags &= ~ASYNC_SPD_MASK;
-	serinfo.flags |= ASYNC_SPD_CUST;
-	serinfo.custom_divisor = (serinfo.baud_base + (rate / 2)) / rate;
-	if (serinfo.custom_divisor < 1) 
-		serinfo.custom_divisor = 1;
-        if (ioctl(fd, TIOCSSERIAL, &serinfo) < 0)
-		err(1, "%s: TIOCSSERIAL", device);
-        if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
-		err(1, "%s: TIOCGSERIAL 2", device);
-	if (serinfo.custom_divisor * rate != serinfo.baud_base) {
-		warnx("actual baudrate is %d / %d = %f",
-		      serinfo.baud_base, serinfo.custom_divisor,
-		      (float)serinfo.baud_base / serinfo.custom_divisor);
-	}
-
-	fcntl(fd, F_SETFL, 0);
-	tcgetattr(fd, &options);
-	cfsetispeed(&options, B38400);
-	cfsetospeed(&options, B38400);
-	cfmakeraw(&options);
-	options.c_cflag |= (CLOCAL | CREAD);
-	options.c_cflag &= ~CRTSCTS;
-	if (tcsetattr(fd, TCSANOW, &options) != 0)
-		err(1, "TCSANOW");
-
-	return fd;
-}
-
 int main(int argc, char *argv[])
 {
 	char *device=strdup("/dev/ttyUSB0");
 	int rate=500000;
 	int fd;
 	int getopt_index;
-	int i;
 	char buf[1024];
 	int len;
 
@@ -146,7 +102,7 @@ int main(int argc, char *argv[])
 		if (n <= 0) 
 			err(1, "read");
 		len += n;
-		processed = process(buf, len);
+		processed = process((uint8_t *) buf, len);
 		memmove(buf, buf + processed, len - processed);
 		len -= processed;
 	}

pc/serial-util.c

@@ -0,0 +1,199 @@
+/*
+ * Serial I/O helper routines
+ *
+ * Jim Paris <jim@jtan.com>
+ * $Id$
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <termio.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <err.h>
+#include <linux/serial.h>
+#include <poll.h>
+#include <stdarg.h>
+#include "serial-util.h"
+
+static int rate_to_constant(int baudrate) {
+#define B(x) case x: return B##x
+	switch(baudrate) {
+		B(50);     B(75);     B(110);    B(134);    B(150);
+		B(200);    B(300);    B(600);    B(1200);   B(1800);
+		B(2400);   B(4800);   B(9600);   B(19200);  B(38400);
+		B(57600);  B(115200); B(230400); B(460800); B(500000); 
+		B(576000); B(921600); B(1000000);B(1152000);B(1500000); 
+	default: return 0;
+	}
+#undef B
+}    
+
+/* Open serial port in raw mode, with custom baudrate if necessary */
+int serial_open(const char *device, int rate)
+{
+	struct termios options;
+	struct serial_struct serinfo;
+	int fd;
+	int speed = 0;
+
+	/* Open and configure serial port */
+	if ((fd = open(device,O_RDWR|O_NOCTTY)) == -1)
+		return -1;
+
+	speed = rate_to_constant(rate);
+
+	if (speed == 0) {
+		serinfo.reserved_char[0] = 0;
+		if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
+			return -1;
+		serinfo.flags &= ~ASYNC_SPD_MASK;
+		serinfo.flags |= ASYNC_SPD_CUST;
+		serinfo.custom_divisor = (serinfo.baud_base + (rate / 2)) / rate;
+		if (serinfo.custom_divisor < 1) 
+			serinfo.custom_divisor = 1;
+		if (ioctl(fd, TIOCSSERIAL, &serinfo) < 0)
+			return -1;
+		if (ioctl(fd, TIOCGSERIAL, &serinfo) < 0)
+			return -1;
+		if (serinfo.custom_divisor * rate != serinfo.baud_base) {
+			warnx("actual baudrate is %d / %d = %f",
+			      serinfo.baud_base, serinfo.custom_divisor,
+			      (float)serinfo.baud_base / serinfo.custom_divisor);
+		}
+	}
+
+	fcntl(fd, F_SETFL, 0);
+	tcgetattr(fd, &options);
+	cfsetispeed(&options, speed ?: B38400);
+	cfsetospeed(&options, speed ?: B38400);
+	cfmakeraw(&options);
+	options.c_cflag |= (CLOCAL | CREAD);
+	options.c_cflag &= ~CRTSCTS;
+	if (tcsetattr(fd, TCSANOW, &options) != 0)
+		return -1;
+
+	return fd;
+}
+
+/* Like read(), but restarts after EINTR, and reads until count bytes
+   are received or a timeout occurs. */
+int saferead_timeout(int fd, void *buf, size_t count, int timeout_ms)
+{
+	struct pollfd pfd;
+	int r;
+	size_t nread = 0;
+
+	while (count > 0) {
+		pfd.fd = fd;
+		pfd.events = POLLIN;
+		r = poll(&pfd, 1, timeout_ms);
+		if (r < 0 && errno == EINTR) /* retry */
+			continue;
+		else if (r == 0) /* timeout */
+			return nread;
+		else if (r == 1 && (pfd.revents & POLLIN)) { /* readable */
+			r = read(fd, buf, count);
+			if (r < 0 && errno == EINTR) /* retry */
+				continue;
+			if (r < 0) /* error */
+				return r;
+			if (r == 0) /* EOF */
+				return nread;
+			buf = (char *) buf + r;
+			count -= r;
+			nread += r;
+		} else {
+			/* error */
+			return -1;
+		}
+	}
+	return nread;
+}
+
+/* Like write(), but restarts after EINTR */
+ssize_t safewrite(int fd, const void *buf, size_t count)
+{
+	size_t nwritten = 0;
+	while (count > 0) {
+		ssize_t r = write(fd, buf, count);
+ 
+		if (r < 0 && errno == EINTR)
+			continue;
+		if (r < 0)
+			return r;
+		if (r == 0)
+			return nwritten;
+		buf = (const char *)buf + r;
+		count -= r;
+		nwritten += r;
+	}
+	return nwritten;
+}
+
+/* Read bytes until no more are available for 0.1 sec */
+int drain(int fd)
+{
+	char buf[1024];
+	int ret;
+	while (1) {
+		ret = saferead_timeout(fd, buf, sizeof(buf), 100);
+		if (ret <= 0) 
+			return ret;
+	}	
+}
+
+/* Like fprintf, but to a fd, using safewrite. */
+static int vfdprintf(int fd, const char *fmt, va_list args)
+{
+	static char buf[1024];
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	return safewrite(fd, buf, strlen(buf));
+}
+int fdprintf(int fd, const char *fmt, ...)
+{
+	int ret;
+	va_list args;
+	va_start(args, fmt);
+	ret = vfdprintf(fd, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+/* Like fgets, but from a fd, using saferead_timeout. */
+char *fdgets(char *s, int size, int fd, int timeout_ms)
+{
+	int ret;
+	int nread = 0;
+
+	/* Not very efficient, needs to read one char at a time to avoid buffering */
+	while (nread < (size - 1)) {
+		ret = saferead_timeout(fd, &s[nread], 1, timeout_ms);
+		if (ret <= 0) {
+			s[nread] = '\0';
+			return NULL;
+		}
+		if (ret == 1) {
+			nread++;
+
+			/* found terminator? */
+			if (s[nread-1] == '\n')
+				break;
+		}
+	}
+	s[nread] = '\0';
+	return s;
+}
+
+/* Like perl chomp. */
+void chomp(char *s)
+{
+	int len = strlen(s);
+	/* do it twice to remove \r\n as well */
+	if (len > 1 && (s[len - 1] == '\r' || s[len - 1] == '\n')) s[--len] = '\0';
+	if (len > 1 && (s[len - 1] == '\r' || s[len - 1] == '\n')) s[--len] = '\0';
+}

pc/serial-util.h

@@ -0,0 +1,34 @@
+/*
+ * Serial I/O helper routines
+ *
+ * Jim Paris <jim@jtan.com>
+ * $Id$
+ */
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <unistd.h>
+
+/* Open serial port in raw mode, with custom baudrate if necessary */
+int serial_open(const char *device, int rate);
+
+/* Like read(), but restarts after EINTR, and reads until count bytes
+   are received or a timeout occurs. */
+int saferead_timeout(int fd, void *buf, size_t count, int timeout_ms);
+
+/* Like write(), but restarts after EINTR */
+ssize_t safewrite(int fd, const void *buf, size_t count);
+
+/* Read bytes until no more are available for 0.1 sec */
+int drain(int fd);
+
+/* Like fprintf, but to a fd, using safewrite */
+int fdprintf(int fd, const char *fmt, ...);
+
+/* Like fgets, but from a fd, using saferead_timeout. */
+char *fdgets(char *s, int size, int fd, int timeout_ms);
+
+/* Like perl chomp. */
+void chomp(char *s);
+
+#endif