gpioset: new mode of operation

Add a new mode: 'signal', which makes the program set GPIO values and
then wait until it receives SIGTERM or SIGINT.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/src/tools/gpioset.c b/src/tools/gpioset.c
index 13654381b09b0aefec2675fd5659b4dca9284fc2..1fc1f4c7fbcee13699cc58cb722611b5fe2dd2d8 100644 (file)
--- a/src/tools/gpioset.c
+++ b/src/tools/gpioset.c
@@ -15,7 +15,12 @@
 #include <string.h>
 #include <getopt.h>
 #include <sys/select.h>
+#include <signal.h>
+#include <sys/signalfd.h>
+#include <sys/poll.h>
 #include <limits.h>
+#include <errno.h>
+#include <unistd.h>
 
 static const struct option longopts[] = {
        { "help",               no_argument,            NULL,   'h' },
@@ -47,6 +52,7 @@ static void print_help(void)
        printf("  exit:\tset values and exit immediately\n");
        printf("  wait:\tset values and wait for user to press ENTER\n");
        printf("  time:\tset values and sleep for a specified amount of time\n");
+       printf("  signal:\tset values and wait for SIGINT or SIGTERM\n");
 }
 
 struct callback_data {
@@ -66,10 +72,48 @@ static void wait_time(void *data)
        select(0, NULL, NULL, NULL, &cbdata->tv);
 }
 
+static void wait_signal(void *data UNUSED)
+{
+       int sigfd, status;
+       struct pollfd pfd;
+       sigset_t sigmask;
+
+       sigemptyset(&sigmask);
+       sigaddset(&sigmask, SIGTERM);
+       sigaddset(&sigmask, SIGINT);
+
+       status = sigprocmask(SIG_BLOCK, &sigmask, NULL);
+       if (status < 0)
+               die("sigprocmask: %s", strerror(errno));
+
+       sigfd = signalfd(-1, &sigmask, 0);
+       if (sigfd < 0)
+               die("signalfd: %s", strerror(errno));
+
+       memset(&pfd, 0, sizeof(pfd));
+       pfd.fd = sigfd;
+       pfd.events = POLLIN | POLLPRI;
+
+       for (;;) {
+               status = poll(&pfd, 1, 1000 /* one second */);
+               if (status < 0)
+                       die("poll: %s", strerror(errno));
+               else if (status > 0)
+                       break;
+       }
+
+       /*
+        * Don't bother reading siginfo - it's enough to know that we
+        * received any signal.
+        */
+       close(sigfd);
+}
+
 enum {
        MODE_EXIT = 0,
        MODE_WAIT,
        MODE_TIME,
+       MODE_SIGNAL,
 };
 
 struct mode_mapping {
@@ -93,7 +137,12 @@ static const struct mode_mapping modes[] = {
                .id             = MODE_TIME,
                .name           = "time",
                .callback       = wait_time,
-       }
+       },
+       [MODE_SIGNAL] = {
+               .id             = MODE_SIGNAL,
+               .name           = "signal",
+               .callback       = wait_signal,
+       },
 };
 
 static const struct mode_mapping * parse_mode(const char *mode)