Debian release

[sojka/sterm.git] / sterm.c

diff --git a/sterm.c b/sterm.c
index a3e9786ab82fd0e3e273b0e79f81f31e7183e7f7..2402c95dbd3e1c5ae19b0d7d184cb9d9fe62a075 100644 (file)
--- a/sterm.c
+++ b/sterm.c
@@ -31,6 +31,7 @@
 
 #define _BSD_SOURCE
 #include <sys/ioctl.h>
+#include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <termios.h>
@@ -41,19 +42,20 @@
 #include <stdbool.h>
 #include <string.h>
 #include <signal.h>
+#include <lockdev.h>
 
 #define STRINGIFY(val) #val
 #define TOSTRING(val) STRINGIFY(val)
 #define CHECK(cmd) ({ int ret = (cmd); if (ret == -1) { perror(#cmd " line " TOSTRING(__LINE__)); exit(1); }; ret; })
 #define CHECKPTR(cmd) ({ void *ptr = (cmd); if (ptr == (void*)-1) { perror(#cmd " line " TOSTRING(__LINE__)); exit(1); }; ptr; })
 
-#define VERBOSE(format, ...) do { if (verbose) fprintf(stderr, format, ##__VA_ARGS__); } while (0)
+#define VERBOSE(format, ...) do { if (verbose) fprintf(stderr, "sterm: " format, ##__VA_ARGS__); } while (0)
 
 bool verbose = false;
+bool exit_on_escape = true;
 
-char template[] = "/var/lock/TMPXXXXXX";
-char lockfile[100];
 struct termios stdin_tio_backup;
+char *dev = NULL;
 
 void rm_file(int status, void *arg)
 {
@@ -68,6 +70,11 @@ void restore_stdin_term()
        tcsetattr(0, TCSANOW, &stdin_tio_backup);
 }
 
+void unlock()
+{
+       dev_unlock(dev, getpid());
+}
+
 void sighandler(int arg)
 {
        exit(0); /* Invoke exit handlers */
@@ -89,11 +96,37 @@ int dtr_rts_arg(const char option)
        return val;
 }
 
+void exit_on_escapeseq(const char *buf, int len)
+{
+       static const char escseq[] = "\r~.";
+       static const char *state = escseq+1;
+       int i;
+
+       for (i = 0; i < len; i++) {
+               if (buf[i] == *state) {
+                       state++;
+                       if (*state == 0)
+                               exit(0);
+               } else
+                       state = escseq;
+       }
+}
+
+void usage(const char* argv0)
+{
+       fprintf(stderr, "Usage: %s [options] <device>\n", argv0);
+       fprintf(stderr, "Options:\n");
+       fprintf(stderr, "  -d [+|-] create short positive/negative pulse on DTR\n");
+       fprintf(stderr, "  -e       ignore '~.' escape sequence\n");
+       fprintf(stderr, "  -n       do not switch the device to raw mode\n");
+       fprintf(stderr, "  -r [+|-] create short positive/negative pulse on RTS\n");
+       fprintf(stderr, "  -s <baudrate>\n");
+       fprintf(stderr, "  -v       verbose\n");
+}
 
 int main(int argc, char *argv[])
 {
        int fd;
-       char *dev = NULL;
        int opt;
        speed_t speed = 0;
        int dtr = 0, rts = 0;
@@ -106,9 +139,10 @@ int main(int argc, char *argv[])
                atexit(restore_stdin_term);
        }
 
-       while ((opt = getopt(argc, argv, "nd::r::s:v")) != -1) {
+       while ((opt = getopt(argc, argv, "nd::er::s:v")) != -1) {
                switch (opt) {
                case 'd': dtr = dtr_rts_arg(opt); break;
+               case 'e': exit_on_escape = false; break;
                case 'n': raw = false; break;
                case 'r': rts = dtr_rts_arg(opt); break;
                case 's': {
@@ -145,7 +179,7 @@ int main(int argc, char *argv[])
                        verbose = true;
                        break;
                default: /* '?' */
-                       fprintf(stderr, "Usage: %s [-s baudrate] [-v] <device>\n", argv[0]);
+                       usage(argv[0]);
                        exit(1);
                }
        }
@@ -155,6 +189,7 @@ int main(int argc, char *argv[])
 
        if (!dev) {
                fprintf(stderr, "No device specified\n");
+               usage(argv[0]);
                exit(1);
        }
 
@@ -162,25 +197,15 @@ int main(int argc, char *argv[])
        signal(SIGTERM, sighandler);
        signal(SIGHUP, sighandler);
 
-       if (strncmp(dev, "/dev/", 5) == 0 &&
-           strrchr(dev, '/') == dev + 4 &&
-           dev[5] != 0)
-       { /* Create lock file (to be inter-operable with other programs) */
-               /* This is racy, but what we can do - see also comments in uucp / cu */
-               int tmp = CHECK(mkstemp(template));
-               on_exit(rm_file, template);
-               char pid[20];
-               snprintf(pid, sizeof(pid), "%u", getpid());
-               CHECK(write(tmp, pid, strlen(pid)));
-               close(tmp);
-               snprintf(lockfile, sizeof(lockfile), "/var/lock/LCK..%s", dev + 5);
-               if (link(template, lockfile) == -1) {
-                       perror(lockfile);
-                       exit(1);
-               }
-               rm_file(0, template);
-               on_exit(rm_file, lockfile);
+       pid_t pid = dev_lock(dev);
+       if (pid > 0) {
+               fprintf(stderr, "%s is used by PID %d\n", dev, pid);
+               exit(1);
+       } else if (pid < 0) {
+               perror("dev_lock()");
+               exit(1);
        }
+       atexit(unlock);
 
        if ((fd = open(dev, O_RDWR)) < 0) {
                perror(dev);
@@ -230,16 +255,21 @@ int main(int argc, char *argv[])
                CHECK(tcsetattr(0, TCSANOW, &tio));
        }
 
-       VERBOSE("Connected.\n");
+       VERBOSE("Connected.\r\n");
+       if (exit_on_escape)
+               VERBOSE("Use '<Enter>~.' sequence to exit.\r\n");
+
        while (1) {
                int r1, r2;
                CHECK(poll(fds, 2, -1));
                if (fds[0].revents & POLLIN) {
                        r1 = CHECK(read(0, buf, sizeof(buf)));
                        if (r1 == 0) {
-                               VERBOSE("EOF on stdin\n");
+                               VERBOSE("EOF on stdin\r\n");
                                break;
                        }
+                       if (exit_on_escape)
+                               exit_on_escapeseq(buf, r1);
                        r2 = CHECK(write(fd, buf, r1));
                        if (r1 != r2) {
                                fprintf(stderr, "Not all data written to %s (%d/%d)\n", dev, r1, r2);
@@ -249,7 +279,7 @@ int main(int argc, char *argv[])
                if (fds[1].revents & POLLIN) {
                        r1 = CHECK(read(fd, buf, sizeof(buf)));
                        if (r1 == 0) {
-                               VERBOSE("EOF on %s\n", dev);
+                               VERBOSE("EOF on %s\r\n", dev);
                                break;
                        }
                        r2 = CHECK(write(1, buf, r1));