gracefully handle errors on socket-write

[hmcfgusb] / hmland.c

diff --git a/hmland.c b/hmland.c
index 87b79d00f31916df1153be0f778398e2bedcfbd1..04ee740c2855104e4b42eeb4f2c7cad221be2c72 100644 (file)
--- a/hmland.c
+++ b/hmland.c
@@ -1,4 +1,4 @@
-/* HM-CFG-LAN emuldation for HM-CFG-USB
+/* HM-CFG-LAN emulation for HM-CFG-USB
  *
  * Copyright (c) 2013 Michael Gernoth <michael@gernoth.net>
  *
@@ -28,6 +28,7 @@
 #include <string.h>
 #include <strings.h>
 #include <poll.h>
+#include <signal.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -56,6 +57,8 @@ static int verbose = 0;
 
 static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int outlen, int len, int flags)
 {
+       const uint8_t nibble[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+               'A', 'B', 'C', 'D', 'E', 'F'};
        uint8_t *buf_out = *outpos;
        uint8_t *outend = *outpos + outlen;
        uint8_t *inend = *inpos + inlen;
@@ -74,20 +77,13 @@ static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int out
        }
 
        if (flags & FLAG_FORMAT_HEX) {
-               char hex[3];
-
-               memset(hex, 0, sizeof(hex));
-
                CHECK_AVAIL(len);
                CHECK_SPACE(len*2);
                for (i = 0; i < len; i++) {
-                       if (snprintf(hex, sizeof(hex), "%02X", **inpos) != 2) {
-                               fprintf(stderr, "Can't format hex-string!\n");
-                               return 0;
-                       }
-                       *inpos += 1;
-                       memcpy(*outpos, hex, 2);
-                       *outpos += 2;
+                       **outpos = nibble[((**inpos) & 0xf0) >> 4];
+                       *outpos += 1;
+                       **outpos = nibble[((**inpos) & 0xf)];
+                       *inpos += 1; *outpos += 1;
                }
        } else {
                CHECK_AVAIL(len);
@@ -114,14 +110,26 @@ static int format_part_out(uint8_t **inpos, int inlen, uint8_t **outpos, int out
        return *outpos - buf_out;
 }
 
+static uint8_t ascii_to_nibble(uint8_t a)
+{
+       uint8_t c = 0x00;
+
+       if ((a >= '0') && (a <= '9')) {
+               c = a - '0';
+       } else if ((a >= 'A') && (a <= 'F')) {
+               c = (a - 'A') + 10;
+       } else if ((a >= 'a') && (a <= 'f')) {
+               c = (a - 'a') + 10;
+       }
+
+       return c;
+}
+
 static int parse_part_in(uint8_t **inpos, int inlen, uint8_t **outpos, int outlen, int flags)
 {
        uint8_t *buf_out = *outpos;
        uint8_t *outend = *outpos + outlen;
        uint8_t *inend = *inpos + inlen;
-       char hex[3];
-
-       memset(hex, 0, sizeof(hex));
 
        if (flags & FLAG_LENGTH_BYTE) {
                int len = 0;
@@ -155,25 +163,26 @@ static int parse_part_in(uint8_t **inpos, int inlen, uint8_t **outpos, int outle
 
                CHECK_SPACE(1);
                CHECK_AVAIL(2);
-               memcpy(hex, *inpos, 2);
-               *inpos += 2;
 
-               **outpos = strtoul(hex, NULL, 16);
-               *outpos += 1;
+               **outpos = ascii_to_nibble(**inpos) << 4;
+               *inpos += 1;
+               **outpos |= ascii_to_nibble(**inpos);
+               *inpos += 1; *outpos += 1;
        }
 
        return *outpos - buf_out;
 }
 
-static void hmlan_format_out(uint8_t *buf, int buf_len, void *data)
+static int hmlan_format_out(uint8_t *buf, int buf_len, void *data)
 {
        uint8_t out[1024];
        uint8_t *outpos;
        uint8_t *inpos;
        int fd = *((int*)data);
+       int w;
 
        if (buf_len < 1)
-               return;
+               return 1;
 
        memset(out, 0, sizeof(out));
        outpos = out;
@@ -226,9 +235,16 @@ static void hmlan_format_out(uint8_t *buf, int buf_len, void *data)
                        hexdump(buf, buf_len, "Unknown> ");
                        break;
        }
-       write(fd, out, outpos-out);
        if (debug)
                fprintf(stderr, "LAN < %s\n", out);
+
+       w = write(fd, out, outpos-out);
+       if (w <= 0) {
+               perror("write");
+               return 0;
+       }
+
+       return 1;
 }
 
 static int hmlan_parse_in(int fd, void *data)
@@ -251,7 +267,7 @@ static int hmlan_parse_in(int fd, void *data)
                inpos = buf;
 
                if (debug)
-                       fprintf(stderr, "LAN > %s\n", buf);
+                       fprintf(stderr, "\nLAN > %s", buf);
 
                while (inpos < inend) {
                        uint8_t *instart = inpos;
@@ -292,7 +308,7 @@ static int hmlan_parse_in(int fd, void *data)
                                        break;
                        }
 
-                       hmcfgusb_send(dev, out, outpos-out, 1);
+                       hmcfgusb_send(dev, out, sizeof(out), 1);
                }
        } else if (r < 0) {
                perror("read");
@@ -365,6 +381,7 @@ static int comm(int fd_in, int fd_out, int master_socket)
 
 static int socket_server(int port, int daemon)
 {
+       struct sigaction sact;
        struct sockaddr_in sin;
        int sock;
        int n;
@@ -381,6 +398,13 @@ static int socket_server(int port, int daemon)
                }
        }
 
+       memset(&sact, 0, sizeof(sact));
+       sact.sa_handler = SIG_IGN;
+
+       if (sigaction(SIGPIPE, &sact, NULL) == -1) {
+               perror("sigaction");
+       }
+
        impersonate_hmlanif = 1;
 
        sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);