--- /dev/null
+/*
+ * Minimalistic implementation of the xmodem-1k and ymodem sender protocol.
+ * https://en.wikipedia.org/wiki/XMODEM
+ * https://en.wikipedia.org/wiki/YMODEM
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later OR MIT-0
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <termios.h>
+#include "misc.h"
+
+#define STX 0x02
+#define ACK 0x06
+#define NAK 0x15
+#define CAN 0x18
+#define EOT "\004"
+
+#define OK 0
+#define ERR (-1)
+
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
+struct xpacket {
+ uint8_t type;
+ uint8_t seq;
+ uint8_t nseq;
+ uint8_t data[1024];
+ uint8_t crc_hi;
+ uint8_t crc_lo;
+} __attribute__((packed));
+
+/* See https://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks */
+static uint16_t crc16(const uint8_t *data, uint16_t size)
+{
+ uint16_t crc, s;
+
+ for (crc = 0; size > 0; size--) {
+ s = *data++ ^ (crc >> 8);
+ s ^= (s >> 4);
+ crc = (crc << 8) ^ s ^ (s << 5) ^ (s << 12);
+ }
+ return crc;
+}
+
+static int xmodem(int sio, const void *data, size_t len, int seq)
+{
+ struct xpacket packet;
+ const uint8_t *buf = data;
+ char resp = 0;
+ int rc, crc;
+
+ /* Drain pending characters from serial line. Insist on the
+ * last drained character being 'C'.
+ */
+ while(1) {
+ if (key_hit)
+ return -1;
+ if (read(sio, &resp, 1) < 0) {
+ if (errno == EWOULDBLOCK) {
+ if (resp == 'C') break;
+ if (resp == CAN) return ERR;
+ usleep(50000);
+ continue;
+ }
+ perror("Read sync from serial failed");
+ return ERR;
+ }
+ }
+
+ /* Always work with 1K packets */
+ packet.seq = seq;
+ packet.type = STX;
+
+ while (len) {
+ size_t sz, z = 0;
+ char *from, status;
+
+ /* Build next packet, pad with 0 to full seq */
+ z = min(len, sizeof(packet.data));
+ memcpy(packet.data, buf, z);
+ memset(packet.data + z, 0, sizeof(packet.data) - z);
+ crc = crc16(packet.data, sizeof(packet.data));
+ packet.crc_hi = crc >> 8;
+ packet.crc_lo = crc;
+ packet.nseq = 0xff - packet.seq;
+
+ /* Send packet */
+ from = (char *) &packet;
+ sz = sizeof(packet);
+ while (sz) {
+ if (key_hit)
+ return ERR;
+ if ((rc = write(sio, from, sz)) < 0 ) {
+ if (errno == EWOULDBLOCK) {
+ usleep(1000);
+ continue;
+ }
+ perror("Write packet to serial failed");
+ return ERR;
+ }
+ from += rc;
+ sz -= rc;
+ }
+
+ /* 'lrzsz' does not ACK ymodem's fin packet */
+ if (seq == 0 && packet.data[0] == 0) resp = ACK;
+
+ /* Read receiver response, timeout 1 s */
+ for(int n=0; n < 20; n++) {
+ if (key_hit)
+ return ERR;
+ if (read(sio, &resp, 1) < 0) {
+ if (errno == EWOULDBLOCK) {
+ usleep(50000);
+ continue;
+ }
+ perror("Read ack/nak from serial failed");
+ return ERR;
+ }
+ break;
+ }
+
+ /* Update "progress bar" */
+ switch (resp) {
+ case NAK: status = 'N'; break;
+ case ACK: status = '.'; break;
+ case 'C': status = 'C'; break;
+ case CAN: status = '!'; return ERR;
+ default: status = '?';
+ }
+ write(STDOUT_FILENO, &status, 1);
+
+ /* Move to next block after ACK */
+ if (resp == ACK) {
+ packet.seq++;
+ len -= z;
+ buf += z;
+ }
+ }
+
+ /* Send EOT at 1 Hz until ACK or CAN received */
+ while (seq) {
+ if (key_hit)
+ return ERR;
+ if (write(sio, EOT, 1) < 0) {
+ perror("Write EOT to serial failed");
+ return ERR;
+ }
+ write(STDOUT_FILENO, "|", 1);
+ usleep(1000000); /* 1 s timeout*/
+ if (read(sio, &resp, 1) < 0) {
+ if (errno == EWOULDBLOCK) continue;
+ perror("Read from serial failed");
+ return ERR;
+ }
+ if (resp == ACK || resp == CAN) {
+ write(STDOUT_FILENO, "\r\n", 2);
+ return (resp == ACK) ? OK : ERR;
+ }
+ }
+ return 0; /* not reached */
+}
+
+int xymodem_send(int sio, const char *filename, char mode)
+{
+ size_t len;
+ int rc, fd;
+ struct stat stat;
+ const uint8_t *buf;
+
+ /* Open file, map into memory */
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ perror("Could not open file");
+ return ERR;
+ }
+ fstat(fd, &stat);
+ len = stat.st_size;
+ buf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (!buf) {
+ close(fd);
+ perror("Could not mmap file");
+ return ERR;
+ }
+
+ /* Do transfer */
+ key_hit = 0;
+ if (mode == 'x') {
+ rc = xmodem(sio, buf, len, 1);
+ }
+ else {
+ /* Ymodem: hdr + file + fin */
+ while(1) {
+ char hdr[1024], *p;
+
+ rc = -1;
+ if (strlen(filename) > 977) break; /* hdr block overrun */
+ p = stpcpy(hdr, filename) + 1;
+ p += sprintf(p, "%ld %lo %o", len, stat.st_mtime, stat.st_mode);
+
+ if (xmodem(sio, hdr, p - hdr, 0) < 0) break; /* hdr with metadata */
+ if (xmodem(sio, buf, len, 1) < 0) break; /* xmodem file */
+ if (xmodem(sio, "", 1, 0) < 0) break; /* empty hdr = fin */
+ rc = 0; break;
+ }
+ }
+ key_hit = 0xff;
+
+ /* Flush serial and release resources */
+ tcflush(sio, TCIOFLUSH);
+ munmap((void *)buf, len);
+ close(fd);
+ return rc;
+}
projects / tio / blobdiff