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+/*
+ * amidicat
+ *
+ * Copyright © 2010-2014 Joshua Lehan <alsa@krellan.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/*
+ * After searching for a while, it seems there is no program
+ * to simply send MIDI data into the ALSA MIDI system,
+ * with a minimum of fuss.
+ *
+ * The program aplaymidi(1) will play .MID files,
+ * but not "live" MIDI data from standard input.
+ *
+ * The program amidi(1) can send live data, but only works for
+ * devices in the ALSA "RawMIDI" namespace, not the overall
+ * MIDI system, so it can't be used to drive software
+ * MIDI synthesizers such as TiMidity.
+ *
+ * Creating stub .MID files on-the-fly and rapidly playing them
+ * is a common workaround, but this is undesirable for
+ * all but the most trivial of uses.
+ *
+ * This program attempts to rectify these limitations,
+ * similarly to the purpose of netcat(1).
+ *
+ * What's more, this program also works in both directions
+ * simultaneously: MIDI data can also be read out from
+ * the ALSA MIDI system, and made available as standard
+ * output.
+ *
+ * This program is an ALSA sequencer client.
+ *
+ * Much code was borrowed from vkeybd(1).
+ */
+
+
+#include <pthread.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <alsa/asoundlib.h>
+#include <errno.h>
+#include <time.h>
+
+#include "version.h"
+
+
+/* Constants */
+#define DEFAULT_SEQ_NAME ("default")
+#define DEFAULT_CLI_NAME ("amidicat")
+#define ERR_OPEN (10)
+#define ERR_FINDPORT (11)
+#define ERR_CONNPORT (12)
+#define ERR_PARAM (13)
+#define ERR_THREAD (14)
+#define DEFAULT_BUFSIZE (65536)
+#define MAX_WAIT (1000)
+#define MAX_DELAY (1000)
+#define FILE_STDIN ("-")
+#define MAX_HEX_DIGITS (2)
+
+
+/* Globals */
+pthread_mutex_t g_mutex;
+pthread_cond_t g_cond;
+int g_is_endinput;
+
+
+/* Structures */
+struct in_args_t {
+ char **args_ptr;
+ snd_seq_t *handle;
+ int is_hex;
+ int cli_id;
+ int port_id;
+ int target_cli;
+ int target_port;
+ int spacing_us;
+ int wait_sec;
+ int is_read;
+};
+
+struct out_args_t {
+ snd_seq_t *handle;
+ int is_hex;
+};
+
+
+/*
+ * Better atoi() that returns -1, not 0, if error
+ * and checks entire string, not just first part, for validity
+ */
+int
+better_atoi(const char *nptr)
+{
+ char *endptr;
+ long num;
+ int ret;
+
+ num = strtol(nptr, &endptr, 0);
+ if (NULL != nptr && '\0' == *endptr) {
+ /* String is valid */
+ ret = num;
+
+ /* Guard against size mismatch by comparing int and long */
+ if (ret == num)
+ return ret;
+ }
+
+ return -1;
+}
+
+
+/*
+ * Better usleep() that does not use signals,
+ * so is safe to use along with threads
+ */
+void
+microsleep(long usec)
+{
+ struct timespec tv;
+
+ /* No need to sleep if time is not positive */
+ if (usec > 0) {
+ tv.tv_sec = usec / 1000000;
+ tv.tv_nsec = (usec % 1000000) * 1000;
+
+ /* Ignore return value, waking up early is not a problem */
+ nanosleep(&tv, NULL);
+ }
+}
+
+
+/* Prettyprints capabilities mask */
+void
+prettyprint_capmask(unsigned int capmask)
+{
+ /* The r/w letters indicate read/write capability */
+ /* Capital R/W letters indicate subscription */
+ printf("%s%s%s%s"
+ , ((capmask & SND_SEQ_PORT_CAP_READ) ? "r" : "-")
+ , ((capmask & SND_SEQ_PORT_CAP_WRITE) ? "w" : "-")
+ , ((capmask & SND_SEQ_PORT_CAP_SUBS_READ) ? "R" : "-")
+ , ((capmask & SND_SEQ_PORT_CAP_SUBS_WRITE) ? "W" : "-")
+ );
+}
+
+
+/*
+ * Iterates through list of all active ALSA sequencer ports
+ * handle = ALSA sequencer handle
+ * str = String to search for a match for, or NULL to ignore
+ * is_print = Set to 1 if you want to see output
+ * outcli = Receives found client ID, if searching
+ * outport = Receives found port ID, if searching
+ * Returns 0 if a match was found, -1 if no matches were found
+ * The search is by exact string match (no wildcards or
+ * substrings yet). The column of port names will be
+ * searched first, in top-down order, then the column of
+ * client names will be similarly searched. First match wins.
+ */
+int
+discover_ports(snd_seq_t *handle, char *str, int is_print,
+int *outcli, int *outport)
+{
+ snd_seq_client_info_t *cli_info;
+ snd_seq_port_info_t *port_info;
+ char *cli_name;
+ char *port_name;
+ unsigned int port_capmask;
+ unsigned int port_typemask;
+ int r;
+ int cli_id;
+ int cli_num_ports;
+ int port_id;
+ int lowest_port;
+ int match_bycli_cli_id = -1;
+ int match_bycli_port_id = -1;
+ int match_byport_cli_id = -1;
+ int match_byport_port_id = -1;
+ int is_first = 1;
+
+ snd_seq_client_info_malloc(&cli_info);
+ snd_seq_port_info_malloc(&port_info);
+
+ /* Iterate through all clients */
+ snd_seq_client_info_set_client(cli_info, -1);
+ for (;;) {
+ r = snd_seq_query_next_client(handle, cli_info);
+ if (r < 0)
+ break;
+
+ /* Got a client */
+ cli_id = snd_seq_client_info_get_client(cli_info);
+ cli_name = strdup(snd_seq_client_info_get_name(cli_info));
+ cli_num_ports = snd_seq_client_info_get_num_ports(cli_info);
+
+ /* Iterate through all ports on this client */
+ snd_seq_port_info_set_client(port_info, cli_id);
+ lowest_port = -1;
+ snd_seq_port_info_set_port(port_info, lowest_port);
+ for (;;) {
+ r = snd_seq_query_next_port(handle, port_info);
+ if (r < 0)
+ break;
+
+ /* Got a port */
+ port_id =
+ snd_seq_port_info_get_port(port_info);
+ port_name = strdup(
+ snd_seq_port_info_get_name(port_info));
+ port_typemask =
+ snd_seq_port_info_get_type(port_info);
+ port_capmask =
+ snd_seq_port_info_get_capability(port_info);
+
+ /* Arbitrarily use lowest port number on this client
+ * when matching by name */
+ if (-1 == lowest_port)
+ lowest_port = port_id;
+
+ /* Print header */
+ if (is_first) {
+ /* The field lengths of strings
+ * are taken from "aplaymidi -l" */
+ if (is_print)
+ printf(" Port %-32s %-32s rwRW\n"
+ , "Client name"
+ , "Port name"
+ );
+
+ is_first = 0;
+ }
+
+ /* Print line */
+ /* FUTURE: Perhaps also print type bits if relevant */
+ if (is_print) {
+ printf("%3d:%-3d %-32s %-32s "
+ , cli_id
+ , port_id
+ , cli_name
+ , port_name
+ );
+ prettyprint_capmask(port_capmask);
+ printf("\n");
+ }
+
+ /* FUTURE: Perhaps also make use of this information */
+ /* Suppress warning message */
+ (void)cli_num_ports;
+ (void)port_typemask;
+
+ /* Test for match, if not already matched by port */
+ if (NULL != str && -1 == match_byport_cli_id) {
+ if (0 == strcasecmp(str, port_name)) {
+ match_byport_cli_id = cli_id;
+ match_byport_port_id = port_id;
+ }
+ }
+
+ free(port_name);
+ }
+
+ /* Test for match, if not already matched by client */
+ if (NULL != str && -1 == match_bycli_cli_id) {
+ if (0 == strcasecmp(str, cli_name)) {
+ if (-1 != lowest_port) {
+ match_bycli_cli_id = cli_id;
+ match_bycli_port_id = lowest_port;
+ }
+ }
+ }
+
+ free(cli_name);
+ }
+
+ snd_seq_port_info_free(port_info);
+ snd_seq_client_info_free(cli_info);
+
+ /* If both matched, prefer port match (most specific)
+ * over client match */
+ if (-1 != match_byport_cli_id) {
+ *outcli = match_byport_cli_id;
+ *outport = match_byport_port_id;
+ return 0;
+ }
+ if (-1 != match_bycli_cli_id) {
+ *outcli = match_bycli_cli_id;
+ *outport = match_bycli_port_id;
+ return 0;
+ }
+
+ /* No match found, or no string given to match by */
+ return 1;
+}
+
+
+/*
+ * Parses string into ALSA client:port numbers
+ * String can be 2 numbers separated by ":" or "." or "-" delimiters,
+ * or the name of a client or port can be given
+ * and a lookup will be done in order to learn the numbers.
+ * Results stored in "outcli" and "outport".
+ * Returns 0 if successful, or -1 if unparseable or not found.
+ */
+int
+str_to_cli_port(snd_seq_t *handle, char *str, int *outcli, int *outport)
+{
+ char *delim;
+ char *nextstr;
+ int cli_id = -1;
+ int port_id = -1;
+ int r;
+ char savedch;
+
+ /* Fairly generous in choice of delimiters */
+ delim = strpbrk(str, ":.-");
+ if (delim) {
+ /* Look at string immediately following the delimiter */
+ nextstr = delim + 1;
+
+ /* Perform string fission */
+ savedch = *delim;
+ *delim = '\0';
+
+ cli_id = better_atoi(str);
+ port_id = better_atoi(nextstr);
+
+ *delim = savedch;
+ }
+
+ /* If not parseable as numbers, try string match */
+ if (cli_id < 0 || port_id < 0) {
+ r = discover_ports(handle, str, 0, &cli_id, &port_id);
+
+ /* Return error, regardless of ID, if discovery failed */
+ if (r < 0)
+ return -1;
+ }
+
+ /* Not found or not parseable */
+ if (cli_id < 0 || port_id < 0)
+ return -1;
+
+ /* Both are good results */
+ *outcli = cli_id;
+ *outport = port_id;
+ return 0;
+}
+
+
+/*
+ * Opens a new connection to the ALSA sequencer
+ * Can be opened for input (read), output (write), or both
+ * Returns handle or NULL if error, prints message if error
+ */
+snd_seq_t *
+seq_open(int is_read, int is_write)
+{
+ snd_seq_t *handle;
+ int err;
+ int mode;
+
+ /* Default to duplex unless told otherwise */
+ mode = SND_SEQ_OPEN_DUPLEX;
+
+ /* Read only */
+ if (is_read && !is_write)
+ mode = SND_SEQ_OPEN_INPUT;
+
+ /* Write only */
+ if (is_write && !is_read)
+ mode = SND_SEQ_OPEN_OUTPUT;
+
+ /* Always use the default "sequencer name" here,
+ * this is not the client name */
+ err = snd_seq_open(&handle, DEFAULT_SEQ_NAME, mode, 0);
+ if (err < 0) {
+ fprintf(stderr, "Unable to open ALSA sequencer: %s\n",
+ strerror(errno));
+ return NULL;
+ }
+ return handle;
+}
+
+
+/*
+ * Closes the connection to the ALSA sequencer
+ */
+void
+seq_close(snd_seq_t *handle)
+{
+ snd_seq_close(handle);
+}
+
+
+/*
+ * Sets up the ALSA sequencer for use
+ * Sets our client name
+ * Allocates our port
+ * Connects to remote client and port,
+ * unless they are -1 then use ALSA subscription mechanism instead
+ * Learns our own ID's and saves them in "outcli" and "outport"
+ * Returns 0 if all went well, or -1 if error, prints message if error
+ */
+int
+seq_setup(snd_seq_t *handle, char *cli_name, int target_cli, int target_port,
+int is_read, int is_write, int *outcli, int *outport)
+{
+ int cli_id;
+ int port_id;
+ int r;
+ int caps = 0;
+ int is_subs = 0;
+
+ /* Get our client ID */
+ cli_id = snd_seq_client_id(handle);
+ *outcli = cli_id;
+
+ /* Set our name */
+ r = snd_seq_set_client_name(handle, cli_name);
+ if (r < 0) {
+ /* This early in the program, it's not threaded,
+ * errno is OK to use */
+ fprintf(stderr, "Unable to set ALSA client name: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ /* Enable reading and/or writing */
+ if (is_read)
+ caps |= SND_SEQ_PORT_CAP_READ;
+ if (is_write)
+ caps |= SND_SEQ_PORT_CAP_WRITE;
+ if (is_read && is_write)
+ caps |= SND_SEQ_PORT_CAP_DUPLEX;
+
+ if (target_cli < 0 || target_port < 0) {
+ /* Use ALSA subscription mechanism if target not given */
+ /* FUTURE: Might want both subscription and target at once */
+ if (is_read)
+ caps |= SND_SEQ_PORT_CAP_SUBS_READ;
+ if (is_write)
+ caps |= SND_SEQ_PORT_CAP_SUBS_WRITE;
+
+ /* There is no corresponding SUBS_DUPLEX flag */
+ is_subs = 1;
+ }
+
+ /* Open origin port */
+ /* FUTURE: Do we need any more type bits here? */
+ port_id = snd_seq_create_simple_port(handle, cli_name, caps,
+ SND_SEQ_PORT_TYPE_MIDI_GENERIC);
+ if (port_id < 0) {
+ fprintf(stderr, "Unable to open ALSA sequencer port: %s\n",
+ strerror(errno));
+ return -1;
+ }
+
+ /* Connect both to and from target port, if not using subscription */
+ if (!is_subs) {
+ if (is_write) {
+ r = snd_seq_connect_to(handle, port_id,
+ target_cli, target_port);
+ if (r < 0) {
+ fprintf(stderr,
+ "Unable to connect to ALSA port %d:%d: %s\n"
+ , target_cli
+ , target_port
+ , strerror(errno)
+ );
+ return -1;
+ }
+ }
+ if (is_read) {
+ r = snd_seq_connect_from(handle, port_id,
+ target_cli, target_port);
+ if (r < 0) {
+ fprintf(stderr,
+ "Unable to connect from ALSA port %d:%d: %s\n"
+ , target_cli
+ , target_port
+ , strerror(errno)
+ );
+ return -1;
+ }
+ }
+ }
+
+ /* Should be all good to go now */
+ *outcli = cli_id;
+ *outport = port_id;
+ return 0;
+}
+
+
+/*
+ * Writes an event into ALSA
+ * Blocks/retries until ALSA has received and delivered
+ * the event (as best as we can verify)
+ * Tries its best to avoid flooding the ALSA input queue
+ * ev = The event to be sent into ALSA
+ * port_id = Our port ID
+ * target_cli, target_port = The target's client and port ID,
+ * or -1 to just send to "subscribers"
+ * spacing_us = Spacing time, in microseconds,
+ * to be used when busywaiting some loops
+ * Returns negative error code if error,
+ * or the number of retries required if successful
+ */
+int
+write_event(snd_seq_t *handle, snd_seq_event_t *ev, int port_id,
+ int target_cli, int target_port, int spacing_us)
+{
+ int r;
+ int ct_output = 0;
+ int ct_drain = 0;
+ int ct_sync = 0;
+ int is_draingood;
+ int is_syncgood;
+ int total;
+
+ /* Fill in event data structure, these are macros and never fail */
+ snd_seq_ev_set_source(ev, port_id);
+
+ if (target_cli < 0 || target_port < 0)
+ /* Send to all subscribers,
+ * possibly playing to an empty house */
+ snd_seq_ev_set_subs(ev);
+ else
+ snd_seq_ev_set_dest(ev, target_cli, target_port);
+
+ snd_seq_ev_set_direct(ev);
+
+ /* Fire event */
+ for (;;) {
+ /* FUTURE: Maybe have option to let user choose
+ * between output and output_direct? */
+ r = snd_seq_event_output_direct(handle, ev);
+ if (r < 0) {
+ /* Return if a real error happened */
+ if (-EAGAIN != r)
+ return r;
+
+ /* Error was "Try again", wait and do just that */
+ microsleep(spacing_us);
+ ct_output++;
+ continue;
+ }
+
+ /* Event sent into ALSA, do NOT try again */
+ break;
+ }
+
+ /* Loop until output is fully pushed into ALSA */
+ /* FUTURE: Even though this loop works,
+ * it's still too easy to flood the other end and overrun,
+ * perhaps a queuing bug internally within ALSA? */
+ for (;;) {
+ is_draingood = 0;
+ is_syncgood = 0;
+
+ r = snd_seq_drain_output(handle);
+ if (r < 0) {
+ /* Return if a real error happened */
+ if (-EAGAIN != r)
+ return r;
+ }
+
+ /* Stop retrying only when there are no more
+ * events left to be drained */
+ if (0 == r)
+ is_draingood = 1;
+ else
+ ct_drain++;
+
+ r = snd_seq_sync_output_queue(handle);
+ if (r < 0) {
+ /* Return if a real error happened */
+ if (-EAGAIN != r)
+ return r;
+ }
+
+ /* FUTURE: Why does snd_seq_sync_output_queue()
+ * always return 1, not 0 as it should? */
+ if (0 == r || 1 == r)
+ is_syncgood = 1;
+ else
+ ct_sync++;
+
+ /* Only return if both drain and sync are clear */
+ if (is_draingood && is_syncgood)
+ break;
+
+ /* Throttle CPU when busywaiting */
+ microsleep(spacing_us);
+ }
+
+ total = ct_output + ct_drain + ct_sync;
+ /* FUTURE: Suppress this text if verbose flag
+ * was given (it becomes redundant) */
+ if (total > 0) {
+ fprintf(stderr, "Incoming congestion");
+ if (ct_output > 0)
+ fprintf(stderr, ", %d output retries", ct_output);
+ if (ct_drain > 0)
+ fprintf(stderr, ", %d drain retries", ct_drain);
+ if (ct_sync > 0)
+ fprintf(stderr, ", %d sync retries", ct_sync);
+ fprintf(stderr, "\n");
+ }
+
+ return total;
+}
+
+
+/*
+ * Writes a buffer to stdout
+ * Returns 0 if successful or nonzero if error
+ * Writes either as binary bytes or hex digits
+ */
+int
+write_stdout(unsigned char *buf, long bufsize, int is_hex)
+{
+ unsigned char *bufptr;
+ long size_left;
+ long size_written;
+ unsigned int ui;
+ int r;
+ unsigned char uc;
+
+ bufptr = buf;
+ size_left = bufsize;
+ if (is_hex) {
+ /* Print hex bytes, e.g. 90 3C 7F */
+ while (size_left > 0) {
+ uc = *bufptr;
+ ui = uc;
+
+ /* Separate by spaces,
+ * unless it's the last one which gets newline */
+ r = printf("%02X%s", ui,
+ ((size_left > 1) ? " " : "\n"));
+ if (r < 0)
+ return -1;
+
+ bufptr++;
+ size_left--;
+ }
+ } else {
+ /* Full write to stdout */
+ while (size_left > 0) {
+ size_written = write(STDOUT_FILENO,
+ bufptr,
+ size_left);
+ if (size_written < 0)
+ return -1;
+
+ bufptr += size_written;
+ size_left -= size_written;
+ }
+ }
+
+ return 0;
+}
+
+
+/*
+ * Parses an incoming unsigned byte of ASCII text, representing a
+ * hex digit, eventually building up and returning complete hex numbers
+ * Uses static variables to keep state across calls
+ * Hex digits are separated by whitespace, or if enough hex digits
+ * have been read and maximum size has been reached, no separator
+ * is necessary (so digits can all be ran together)
+ * If not whitespace, each byte of text must be in range [0-9A-Fa-f]
+ * Returns unsigned hex number if successful
+ * Returns -1 if error (unrecognized byte of ASCII text)
+ * Returns -2 if the complete hex number is not available yet (still good)
+ * As a special case, pass in a value of -2 when at an input boundary,
+ * this will reset the state and return the hex number that was in
+ * progress (if any)
+ */
+int
+parse_hex_byte(int ch)
+{
+ static int hex_value;
+ static int read_nybbles;
+
+ int ret;
+ int nybble;
+
+ /* Parse human-readable digit into nybble value */
+ nybble = -1;
+ if (ch >= '0' && ch <= '9')
+ nybble = ch - '0';
+ if (ch >= 'A' && ch <= 'F')
+ nybble = 10 + (ch - 'A');
+ if (ch >= 'a' && ch <= 'f')
+ nybble = 10 + (ch - 'a');
+
+ if (-1 == nybble) {
+ switch (ch) {
+ /* Special case accept -2 as a zero-length reset request */
+ case -2:
+ /* Fall through */
+
+ /* Standard C whitespace */
+ /* Avoid usage of isspace()
+ * because that would introduce locale variations */
+ case ' ':
+ case '\f':
+ case '\n':
+ case '\r':
+ case '\t':
+ case '\v':
+ /* Clear state, and return -2
+ * if there was nothing to begin with */
+ ret = -2;
+ if (read_nybbles > 0)
+ ret = hex_value;
+
+ hex_value = 0;
+ read_nybbles = 0;
+ return ret;
+
+ /* No default */
+ }
+
+ /* Unrecognized character */
+ return -1;
+ }
+
+ /* Digit is valid, build up a number with it */
+ hex_value <<= 4;
+ hex_value += nybble;
+ read_nybbles++;
+
+ /* Force number to be finished, if maximum digit count reached */
+ if (read_nybbles >= MAX_HEX_DIGITS) {
+ ret = hex_value;
+ hex_value = 0;
+ read_nybbles = 0;
+ return ret;
+ }
+
+ /* Successfully stored digit, but nothing to return yet */
+ return -2;
+}
+
+
+/*
+ * Reads a byte of input from various sources
+ * Fills in byte_ptr with the byte that was read
+ * Uses static variables to keep state across calls
+ * Pass in the argc array from the command line,
+ * after all options have been removed.
+ * Each string in the array should be a filename, and will
+ * be opened and read from.
+ * The filename "-" is special, and means standard input.
+ * Passing in a pointer that is valid but points to NULL,
+ * indicating an empty command line,
+ * is also special, and means standard input.
+ * If is_hex is true, will read human-readable hex digits,
+ * assemble them into bytes, and return the bytes.
+ * Returns 1 if successful, -1 if error,
+ * or 0 if clean EOF after finishing all files.
+ */
+int
+input_byte(char **args_ptr, int is_hex, char *byte_ptr)
+{
+ /* Static variables for holding state */
+ static char **args_iter;
+ static char *file_name;
+ static int file_fd = -1;
+ static int need_open;
+ static int is_inited;
+ static int is_delayed_eof;
+
+ unsigned char byte_buf;
+ int ret;
+ int val;
+ int r;
+
+ /* Only do initialization once */
+ if (!is_inited) {
+ args_iter = args_ptr;
+ need_open = 1;
+
+ is_inited = 1;
+ }
+
+ /* Keep looping around, opening next files as necessary,
+ * until we have something to return */
+ for (;;) {
+ /* This gets set if previous file reached EOF,
+ * or during init */
+ if (need_open) {
+ /* Open next file pointed to */
+ file_name = *args_iter;
+ if (NULL != file_name) {
+ /* Filename given */
+ if (0 == strcmp(FILE_STDIN, file_name)) {
+ /* Special case
+ * filename "-" is stdin */
+ file_fd = STDIN_FILENO;
+ } else {
+ /* Open the given filename */
+ if (-1 != file_fd) {
+ fprintf(stderr,
+ "Internal error, failed to close previous file\n"
+ );
+ return -1;
+ }
+ file_fd = open(file_name, O_RDONLY);
+ if (-1 == file_fd) {
+ /* FUTURE: Should it
+ * auto-advance to next file,
+ * instead of erroring out? */
+ fprintf(stderr,
+ "Unable to open file %s: %s\n"
+ , file_name
+ , strerror(errno)
+ );
+ return file_fd;
+ }
+ }
+ } else {
+ /* No files at all on command line,
+ * special case read from stdin */
+ file_name = "standard input";
+ file_fd = STDIN_FILENO;
+ }
+
+ /* Successfully at beginning of next file */
+ if (is_hex) {
+ /* Init hex state, better already be empty
+ * from previous file */
+ val = parse_hex_byte(-2);
+ if (-2 != val) {
+ fprintf(stderr,
+ "Internal error, failed to clear hex state across files\n"
+ );
+ return -1;
+ }
+ }
+ need_open = 0;
+ }
+
+ /* Should have a valid file_fd at this point */
+ if (is_delayed_eof) {
+ /* No new reading of data during this pass,
+ * just held over EOF from last time */
+ ret = 0;
+ is_delayed_eof = 0;
+ } else {
+ /* Read a byte of raw input (might be a hex digit) */
+ ret = read(file_fd, &byte_buf, 1);
+ }
+
+ if (-1 == ret) {
+ /* Ignore harmless errors and retry */
+ if (EINTR == errno || EAGAIN == errno)
+ continue;
+
+ fprintf(stderr,
+ "Problem reading from file %s: %s\n",
+ file_name, strerror(errno));
+ return ret;
+ }
+
+ /* Advance to next file, if EOF detected in this file */
+ if (0 == ret) {
+ /* The file might have ended
+ * in the middle of a hex digit */
+ if (is_hex) {
+ val = parse_hex_byte(-2);
+ if (-2 != val) {
+ /* Poor man's coroutine: delay EOF by
+ * one pass, insert this final byte */
+ is_delayed_eof = 1;
+
+ /* Return final byte */
+ *byte_ptr = (char)val;
+ return 1;
+ }
+ }
+
+ if (-1 != file_fd) {
+ /* Don't close stdin, we may need it again if
+ * user gives "-" more than once
+ * on command line */
+ if (file_fd != STDIN_FILENO) {
+ r = close(file_fd);
+ if (0 != r) {
+ /* This error is nonfatal,
+ * don't return here */
+ fprintf(stderr,
+ "Problem closing file %s: %s\n"
+ , file_name
+ , strerror(errno)
+ );
+ }
+ }
+ file_fd = -1;
+ }
+
+ /* Take another look at command line */
+ file_name = *args_iter;
+ if (NULL != file_name) {
+ /* Advance to next file in sequence */
+ args_iter++;
+
+ file_name = *args_iter;
+ if (NULL != file_name) {
+ /* Next file will be opened
+ * after we loop around */
+ need_open = 1;
+ continue;
+ } else {
+ /* Finished with all files
+ * on command line */
+ return 0;
+ }
+ } else {
+ /* No files at all on command line,
+ * EOF means end of stdin */
+ return 0;
+ }
+ }
+
+ /* Successfully read a byte of data */
+ if (1 == ret) {
+ /* Piece hex number together */
+ if (is_hex) {
+ val = parse_hex_byte(byte_buf);
+
+ /* Successfully read a byte,
+ * but hex number not complete yet */
+ if (-2 == val)
+ continue;
+
+ if (-1 == val) {
+ fprintf(stderr,
+ "Unrecognizable hex digit text in file %s: %c (%d)\n"
+ , file_name
+ , (int)byte_buf
+ , (int)byte_buf
+ );
+ return -1;
+ }
+
+ /* Successfully assembled hex number */
+ *byte_ptr = (char)val;
+ return ret;
+ }
+
+ /* Hex not used, return byte exactly as it was read */
+ *byte_ptr = (char)byte_buf;
+ return ret;
+ }
+
+ /* Should never get here */
+ break;
+ }
+
+ /* Should never get here */
+ fprintf(stderr, "Internal error in file reading: %d\n", ret);
+ return -1;
+}
+
+
+void *
+stdin_loop(void *args)
+{
+ struct in_args_t *in_args;
+ char **args_ptr;
+ snd_midi_event_t *parser;
+ snd_seq_t *handle;
+ snd_seq_event_t ev;
+ long ct_bytes = 0;
+ int cli_id;
+ int port_id;
+ int target_cli;
+ int target_port;
+ int spacing_us;
+ int wait_sec;
+ int is_read;
+ int is_hex;
+ int r;
+ int i;
+ int is_active = 1;
+ int ct_events = 0;
+ int ct_congested = 0;
+ char bytein;
+
+ /* Recover arguments */
+ in_args = (struct in_args_t *)args;
+ args_ptr = in_args->args_ptr;
+ is_hex = in_args->is_hex;
+ handle = in_args->handle;
+ cli_id = in_args->cli_id;
+ port_id = in_args->port_id;
+ target_cli = in_args->target_cli;
+ target_port = in_args->target_port;
+ spacing_us = in_args->spacing_us;
+ wait_sec = in_args->wait_sec;
+ is_read = in_args->is_read;
+
+ snd_midi_event_new(DEFAULT_BUFSIZE, &parser);
+ snd_midi_event_init(parser);
+ snd_midi_event_reset_decode(parser);
+
+ snd_midi_event_no_status(parser, 1);
+
+ /* Reset event */
+ snd_seq_ev_clear(&ev);
+
+ /* FUTURE: Might need to maintain our own buffer,
+ * to overcome ALSA SysEx size limitation */
+ while (is_active) {
+ /* Read from input, either stdin or files */
+ r = input_byte(args_ptr, is_hex, &bytein);
+ switch (r) {
+ case 0: /* Clean EOF */
+ is_active = 0;
+ break;
+
+ case 1: /* Byte received */
+ /* No action necessary */
+ ct_bytes++;
+ break;
+
+ default:
+ /* Error messages already printed by input_byte() */
+ is_active = 0;
+ break;
+ }
+
+ /* Feed byte into parser, as int */
+ i = bytein;
+ r = snd_midi_event_encode_byte(parser, i, &ev);
+ switch (r) {
+ case 0: /* More bytes needed for event */
+ /* No action necessary */
+ break;
+
+ case 1: /* Message complete */
+ /* Send completed event into ALSA */
+ r = write_event(handle, &ev, port_id,
+ target_cli, target_port, spacing_us);
+ if (r < 0) {
+ fprintf(stderr,
+ "Event write error: %s\n",
+ strerror(-r));
+ is_active = 0;
+ break;
+ }
+
+ /* The return value was the number of retries */
+ if (r > 0)
+ ct_congested++;
+
+ /* Reset event after write */
+ snd_seq_ev_clear(&ev);
+ ct_events++;
+
+ /* Wait for spacing between events, if desired */
+ microsleep(spacing_us);
+ break;
+
+ default: /* Error */
+ fprintf(stderr,
+ "Internal error, from ALSA event encode byte: %s\n"
+ , strerror(-r)
+ );
+ is_active = 0;
+ break;
+ }
+ }
+
+ /* Input finished */
+ /* FUTURE: Perhaps an option to suppress this */
+ fprintf(stderr,
+ "Input total: %d MIDI messages, %ld bytes",
+ ct_events, ct_bytes);
+ if (ct_congested > 0) {
+ fprintf(stderr,
+ ", %d events congested", ct_congested);
+ }
+ fprintf(stderr, "\n");
+
+ /* Give some time for output-only if the user desires */
+ microsleep(1000000 * wait_sec);
+
+ /* Set global variable, under mutex, so other thread sees it */
+ pthread_mutex_lock(&g_mutex);
+ g_is_endinput = 1;
+ pthread_mutex_unlock(&g_mutex);
+
+ /* Tell the reader thread that we are done */
+ if (is_read) {
+ /* Send a dummy message to ourself,
+ * so ALSA gets unblocked in other thread */
+ snd_seq_ev_clear(&ev);
+ r = write_event(handle, &ev, port_id, cli_id,
+ port_id, spacing_us);
+
+ /* FUTURE: Indicate error result to reader thread */
+ if (r < 0) {
+ fprintf(stderr,
+ "Final event write error: %s\n"
+ , strerror(-r)
+ );
+ }
+ }
+
+ snd_midi_event_free(parser);
+
+ /* FUTURE: Perhaps bubble up an error result */
+ return NULL;
+}
+
+
+void *
+stdout_loop(void *args)
+{
+ struct out_args_t *out_args;
+ unsigned char *buffer;
+ snd_seq_t *handle;
+ snd_midi_event_t *parser;
+ snd_seq_event_t *evptr;
+ long size_ev;
+ long ct_bytes = 0;
+ int is_hex;
+ int r;
+ int is_active = 1;
+ int ct_overruns = 0;
+ int ct_events = 0;
+ int ct_nonevents = 0;
+ int is_endinput;
+
+ /* Recover arguments */
+ out_args = (struct out_args_t *)args;
+ handle = out_args->handle;
+ is_hex = out_args->is_hex;
+
+ snd_midi_event_new(DEFAULT_BUFSIZE, &parser);
+ snd_midi_event_init(parser);
+ snd_midi_event_reset_decode(parser);
+
+ snd_midi_event_no_status(parser, 1);
+
+ /* Allocate buffer */
+ buffer = malloc(DEFAULT_BUFSIZE);
+
+ while (is_active) {
+ /* ALSA will set this pointer to somewhere within itself,
+ * if successful */
+ /* FUTURE: This is not threadsafe, but since this is
+ * the only thread that does ALSA event input,
+ * hopefully it's OK for now */
+ evptr = NULL;
+
+ /* BLOCK until event comes in from ALSA */
+ r = snd_seq_event_input(handle, &evptr);
+ if (r < 0) {
+ /* ENOSPC indicates that ALSA's internal buffer
+ * overran and we lost some events */
+ if (-ENOSPC == r) {
+ /* FUTURE: Only show this
+ * if verbose is turned on */
+ fprintf(stderr,
+ "Reported overrun while reading from ALSA to output\n"
+ );
+ ct_overruns++;
+ continue;
+ } else {
+ fprintf(stderr,
+ "Error reading event from ALSA to output: %s\n"
+ , strerror(-r)
+ );
+ is_active = 0;
+ break;
+ }
+ }
+ if (NULL == evptr) {
+ /* FUTURE: Shouldn't happen, perhaps remove this */
+ fprintf(stderr,
+ "Internal error reading event from ALSA\n");
+ is_active = 0;
+ break;
+ }
+
+ /* Check global flag, under lock,
+ * see if other thread is telling us to exit */
+ pthread_mutex_lock(&g_mutex);
+ is_endinput = g_is_endinput;
+ pthread_mutex_unlock(&g_mutex);
+ if (is_endinput) {
+ /* Clean exit */
+ is_active = 0;
+ break;
+ }
+
+ /* Unpack event into bytes */
+ size_ev = snd_midi_event_decode(parser, buffer,
+ DEFAULT_BUFSIZE, evptr);
+ if (size_ev < 0) {
+ /* ENOENT indicates an event that is
+ * not a MIDI message, silently skip it */
+ if (-ENOENT == size_ev) {
+ ct_nonevents++;
+ /* FUTURE: Suppress this with quiet option */
+ fprintf(stderr,
+ "Received non-MIDI message\n");
+ continue;
+ } else {
+ fprintf(stderr,
+ "Error decoding event from ALSA to output: %s\n"
+ , strerror(-size_ev)
+ );
+ is_active = 0;
+ break;
+ }
+ }
+
+ /* FUTURE: Might need some code here to cat multiple
+ * SysEx events together (0xF0 ... 0xF7), to overcome ALSA
+ * internal size limit splitting them */
+
+ /* Output to stdout */
+ if (size_ev > 0) {
+ r = write_stdout(buffer, size_ev, is_hex);
+ if (r < 0) {
+ fprintf(stderr,
+ "Error writing output: %s\n",
+ strerror(errno));
+ is_active = 0;
+ break;
+ }
+
+ ct_bytes += size_ev;
+ }
+
+ ct_events++;
+ }
+
+ /* This block will only be reached
+ * once other thread tells us to exit */
+ /* If blocked in ALSA above,
+ * a dummy event will need to be faked up,
+ * to get ALSA to return */
+ /* FUTURE: Perhaps suppress this text with quiet option */
+ fprintf(stderr,
+ "Output total: %d MIDI messages, %ld bytes",
+ ct_events, ct_bytes);
+ if (ct_nonevents > 0)
+ fprintf(stderr, ", %d non-MIDI events", ct_nonevents);
+ if (ct_overruns > 0)
+ fprintf(stderr, ", %d ALSA read overruns", ct_overruns);
+ fprintf(stderr, "\n");
+
+ free(buffer);
+ snd_midi_event_free(parser);
+
+ /* FUTURE: Perhaps bubble up an error result */
+ return NULL;
+}
+
+
+/* Trivial function */
+void
+show_version(void)
+{
+ printf("amidicat version %s by Joshua Lehan <alsa@krellan.com>\n",
+ SND_UTIL_VERSION_STR);
+}
+
+
+void
+help_screen(char *exename)
+{
+ /* Put help screen on stdout, not stderr,
+ * because help screen replaces normal output */
+ /* Apologies for the awkward line breaks,
+ * the mandate of the checkpatch script left no alternative */
+ printf("Usage: %s\n", exename);
+ printf(" [--help] [--version] [--list]\n");
+ printf(" [--name STRING]\n");
+ printf(" [--port CLIENT:PORT] [--addr CLIENT:PORT]\n");
+ printf(" [--hex] [--verbose] [--nowrite] [--noread]\n");
+ printf(" [--delay MILLISECONDS] [--wait SECONDS]\n");
+ printf(" input files....\n");
+ printf(
+ "amidicat(1) hooks up standard input and standard output to the ALSA sequencer.\n"
+ );
+ printf(
+ "Like cat(1), this program will concatenate multiple input files together.\n"
+ );
+ printf("--help = Show this help screen and exit.\n");
+ printf("--version = Show version line and exit. This version: %s\n",
+ SND_UTIL_VERSION_STR);
+ printf(
+ "--list = Show list of all ALSA sequencer devices and exit:\n"
+ );
+ printf(
+ " For each usable ALSA client and port, number and name are shown,\n"
+ );
+ printf(
+ " and flags: r,w = port can be read from or written to directly,\n"
+ );
+ printf(
+ " R,W = also can use ALSA \"subscription\" to read or write.\n"
+ );
+ printf(
+ "--name = Sets name of this program's ALSA connection, as shown\n"
+ );
+ printf(" in --list, default is \"%s\".\n",
+ DEFAULT_CLI_NAME);
+ printf(
+ "--port = Makes direct connection to ALSA port, for reading and\n"
+ );
+ printf(
+ " writing, instead of the default which is just to set up\n"
+ );
+ printf(
+ " a passive connection for use with ALSA \"subscription\".\n"
+ );
+ printf(
+ " Syntax is either numeric CLIENT:PORT (example: 128:0), or name of\n"
+ );
+ printf(
+ " another program's ALSA connection (use --list to see available).\n"
+ );
+ printf(
+ "--addr = For compatibility, an exact synonym of the --port option.\n"
+ );
+ printf(
+ "--hex = Change input and output to be human-readable hex\n"
+ );
+ printf(
+ " digits (example: 90 3C 7F) instead of binary MIDI bytes.\n"
+ );
+ printf(
+ "--verbose = Provide additional, useful, output to standard error.\n"
+ );
+ printf(
+ "--nowrite = Disable writing data to ALSA from standard input.\n"
+ );
+ printf(
+ " Intended for allowing connection to read-only devices.\n"
+ );
+ printf(
+ " Input files may not be given when this option is used.\n"
+ );
+ printf(
+ "--noread = Disable reading data from ALSA for standard output.\n"
+ );
+ printf(
+ " Intended for allowing connection to write-only devices.\n"
+ );
+ printf(
+ "--delay = Inserts a delay, in milliseconds, between each MIDI\n"
+ );
+ printf(" event submitted to ALSA from standard input.\n");
+ printf(
+ " Intended for avoiding event loss due to queue congestion.\n"
+ );
+ printf(
+ "--wait = After all input is finished, continue running program for\n"
+ );
+ printf(" this amount of time, in seconds.\n");
+ printf(
+ " Intended for allowing output to continue after input.\n"
+ );
+}
+
+
+int
+main(int argc, char **argv)
+{
+ /* For getopt */
+ struct option long_options[] = {
+ { "help", 0, NULL, 'h' },
+ { "list", 0, NULL, 'l' },
+ { "name", 1, NULL, 'n' },
+ { "port", 1, NULL, 'p' },
+ { "addr", 1, NULL, 'a' },
+ { "hex", 0, NULL, 'x' },
+ { "delay", 1, NULL, 'd' },
+ { "wait", 1, NULL, 'w' },
+ { "verbose", 0, NULL, 'v' },
+ { "version", 0, NULL, 'V' },
+ { "nowrite", 0, NULL, 'W' },
+ { "noread", 0, NULL, 'R' },
+ { NULL, 0, NULL, 0 }
+ };
+
+ /* For threading */
+ struct in_args_t in_args;
+ struct out_args_t out_args;
+ pthread_t in_thread;
+ pthread_t out_thread;
+ int is_in_started = 0;
+ int is_out_started = 0;
+
+ snd_seq_t *handle = NULL;
+ char *cli_name;
+ int cli_id;
+ int port_id;
+ int target_cli = -1;
+ int target_port = -1;
+ int ret;
+ int c;
+ int r;
+ int is_write = 1;
+ int is_read = 1;
+ int is_done = 0;
+ int is_list = 0;
+ int is_hex = 0;
+ int is_verbose = 0;
+ int is_help = 0;
+ int is_version = 0;
+ int spacing_us = 0;
+ int wait_sec = 0;
+
+ /* Initialize defaults */
+ cli_name = strdup(DEFAULT_CLI_NAME);
+
+ /* Parse options */
+ while (!is_done) {
+ c = getopt_long(argc, argv, "hln:p:a:xd:w:vVWR",
+ long_options, NULL);
+ switch (c) {
+ case 'h': /* --help */
+ is_help = 1;
+ break;
+
+ case 'l': /* --list */
+ is_list = 1;
+ break;
+
+ case 'n': /* --name */
+ free(cli_name);
+ cli_name = strdup(optarg);
+ break;
+
+ case 'p': /* --port */
+ case 'a': /* --addr, exactly the same */
+ /* Open ALSA sequencer early,
+ * we need it for port lookup */
+ if (NULL == handle)
+ handle = seq_open(is_read, is_write);
+ if (NULL == handle) {
+ /* Abort program if unable to open */
+ ret = ERR_OPEN;
+ goto cleanup;
+ }
+ r = str_to_cli_port(handle, optarg,
+ &target_cli, &target_port);
+ if (r < 0) {
+ /* Abort program if unable
+ * to locate target port */
+ fprintf(stderr,
+ "Unable to find ALSA sequencer port: %s\n"
+ , optarg
+ );
+ ret = ERR_FINDPORT;
+ goto cleanup;
+ }
+ break;
+
+ case 'x': /* --hex */
+ is_hex = 1;
+ break;
+
+ case 'd': /* --delay */
+ spacing_us = better_atoi(optarg);
+ if (spacing_us < 0) {
+ fprintf(stderr,
+ "Parameter for --delay must be a positive integer: %s\n"
+ , optarg
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ if (spacing_us > MAX_DELAY) {
+ fprintf(stderr,
+ "Parameter for --delay must be %d or less: %s\n"
+ , MAX_DELAY
+ , optarg
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ /* Argument is in milliseconds,
+ * but stored value is in microseconds */
+ spacing_us *= 1000;
+ break;
+
+ case 'w': /* --wait */
+ wait_sec = better_atoi(optarg);
+ if (wait_sec < 0) {
+ fprintf(stderr,
+ "Parameter for --wait must be a positive integer: %s\n"
+ , optarg
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ if (wait_sec > MAX_WAIT) {
+ fprintf(stderr,
+ "Parameter for --wait must be %d or less: %s\n"
+ , MAX_WAIT
+ , optarg
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ break;
+
+ case 'v': /* --verbose */
+ /* FUTURE: Perhaps multiple verbosity levels */
+ is_verbose = 1;
+ break;
+
+ case 'V': /* --version */
+ is_version = 1;
+ break;
+
+ case 'W': /* --nowrite */
+ is_write = 0;
+ break;
+
+ case 'R': /* --noread */
+ is_read = 0;
+ break;
+
+ case -1: /* Clean end of getopt processing */
+ is_done = 1;
+ break;
+
+ default: /* Error */
+ /* Error message already has been printed by getopt */
+ ret = ERR_PARAM;
+ goto cleanup;
+ break;
+ }
+ }
+
+ /* If both read and write are disabled, there's no point in running */
+ if (!is_read && !is_write) {
+ fprintf(stderr,
+ "Parameters --noread and --nowrite cannot coexist\n");
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+
+ /* If write to ALSA is disabled, nothing to do with input files */
+ if (!is_write) {
+ /* Command line must be empty after the options */
+ if (NULL != argv[optind]) {
+ fprintf(stderr,
+ "Parameter --nowrite must not be used with any input files\n"
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ }
+
+ /* If write to ALSA is disabled, no input,
+ * so no waiting after input */
+ if (!is_write) {
+ if (wait_sec > 0) {
+ fprintf(stderr,
+ "Parameters --nowrite and --wait cannot coexist\n"
+ );
+ ret = ERR_PARAM;
+ goto cleanup;
+ }
+ }
+
+ /* For --help, show help screen and exit successfully */
+ if (is_help) {
+ help_screen(argv[0]);
+ ret = 0;
+ goto cleanup;
+ }
+
+ /* For --version, show version line and exit successfully */
+ if (is_version) {
+ show_version();
+ ret = 0;
+ goto cleanup;
+ }
+
+ /* Open ALSA sequencer, if it is not already open */
+ if (NULL == handle)
+ handle = seq_open(is_read, is_write);
+ if (NULL == handle) {
+ /* Abort program if unable to open */
+ ret = ERR_OPEN;
+ goto cleanup;
+ }
+
+ /* Set up connection */
+ r = seq_setup(handle, cli_name, target_cli, target_port,
+ is_read, is_write, &cli_id, &port_id);
+ if (r < 0) {
+ ret = ERR_CONNPORT;
+ goto cleanup;
+ }
+
+ /* For --list, show list of ports and exit successfully */
+ if (is_list) {
+ discover_ports(handle, NULL, 1, NULL, NULL);
+ ret = 0;
+ goto cleanup;
+ }
+
+ if (is_verbose) {
+ fprintf(stderr,
+ "Connected to ALSA sequencer on port %d:%d\n",
+ cli_id, port_id);
+ }
+
+ /* Initialize globals used for thread synchronization */
+ pthread_mutex_init(&g_mutex, NULL);
+ pthread_cond_init(&g_cond, NULL);
+ g_is_endinput = 0;
+
+ /* The output thread reads from ALSA and provides output */
+ if (is_read) {
+ /* Start output thread first, to avoid input backlog */
+ out_args.handle = handle;
+ out_args.is_hex = is_hex;
+
+ r = pthread_create(&out_thread, NULL, stdout_loop, &out_args);
+ if (r != 0) {
+ fprintf(stderr,
+ "Unable to start output thread: %s\n",
+ strerror(errno));
+ ret = ERR_THREAD;
+ goto threadwait;
+ }
+
+ is_out_started = 1;
+ }
+
+ /* The input thread takes input and writes to ALSA */
+ if (is_write) {
+ /* Start input thread */
+ /* Save pointer to rest of command line, after options */
+ in_args.args_ptr = &(argv[optind]);
+ in_args.handle = handle;
+ in_args.is_hex = is_hex;
+ in_args.cli_id = cli_id;
+ in_args.port_id = port_id;
+ in_args.target_cli = target_cli;
+ in_args.target_port = target_port;
+ in_args.spacing_us = spacing_us;
+ in_args.wait_sec = wait_sec;
+ in_args.is_read = is_read;
+
+ r = pthread_create(&in_thread, NULL, stdin_loop, &in_args);
+ if (r != 0) {
+ fprintf(stderr,
+ "Unable to start input thread: %s\n",
+ strerror(errno));
+ ret = ERR_THREAD;
+ goto threadwait;
+ }
+
+ is_in_started = 1;
+ }
+
+ /* Initialization successful, now just wait for threads to exit */
+ ret = 0;
+
+threadwait:
+ /* Reap threads */
+ if (is_in_started)
+ pthread_join(in_thread, NULL);
+ if (is_out_started)
+ pthread_join(out_thread, NULL);
+
+cleanup:
+ /* Cleanup */
+ if (handle != NULL)
+ seq_close(handle);
+ free(cli_name);
+
+ return ret;
+}
Signed-off-by: Josh Lehan <alsa@krellan.com>