From 4ff5e75c986b37c8540f90422d3231d2756a073b Mon Sep 17 00:00:00 2001
From: Rajendraprasad K J <KarammelJayakumar.Rajendraprasad@in.bosch.com>
Date: Tue, 14 Feb 2023 10:04:35 +0530
Subject: simple-weston-client: Improve signal handling

Currently signal handling is not properly done while listening for events on
wayland socket. As a result process waits on poll() for idefinite time even
after receiving signal.

Modify poll() to accept signals while listening to events on wayland socket.

Signed-off-by: Rajendraprasad K J <KarammelJayakumar.Rajendraprasad@in.bosch.com>
---
 .../src/simple-weston-client.c                     | 66 +++++++++++++++++-----
 1 file changed, 51 insertions(+), 15 deletions(-)

diff --git a/ivi-layermanagement-examples/simple-weston-client/src/simple-weston-client.c b/ivi-layermanagement-examples/simple-weston-client/src/simple-weston-client.c
index a0632c7..fe3d1d0 100644
--- a/ivi-layermanagement-examples/simple-weston-client/src/simple-weston-client.c
+++ b/ivi-layermanagement-examples/simple-weston-client/src/simple-weston-client.c
@@ -29,6 +29,7 @@
 #include <sys/mman.h>
 #include <assert.h>
 #include <pthread.h>
+#include <sys/signalfd.h>
 #include <signal.h>
 #include <poll.h>
 
@@ -90,6 +91,7 @@ typedef struct _WaylandContext {
     int                     pipefd[2];
 #endif
     uint8_t                 enable_cursor;
+    int                     signal_fd;
 }WaylandContextStruct;
 
 struct debug_stream {
@@ -751,21 +753,39 @@ weston_dlt_thread_function(void *data)
 #endif
 
 static void
-signal_int(int signum)
+signal_int(int signal_fd)
 {
+    struct signalfd_siginfo fdsi;
+
+    if (read(signal_fd, &fdsi, sizeof(fdsi)) != sizeof(fdsi)) {
+        fprintf(stderr, "reading signalfd failed: %s\n",
+                strerror(errno));
+        return;
+    }
+
+    fprintf(stderr, "simple-weston-client: caught signal %d \n",
+            fdsi.ssi_signo);
+
     running = 0;
 }
 
 static int
-display_poll(struct wl_display *display, short int events)
+display_poll(struct wl_display *display, int signal_fd,
+             short int events)
 {
     int ret;
-    struct pollfd pfd[1];
+    struct pollfd pfd[2];
 
     pfd[0].fd = wl_display_get_fd(display);
     pfd[0].events = events;
+    pfd[1].fd = signal_fd;
+    pfd[1].events = POLLIN;
+
     do {
-        ret = poll(pfd, 1, -1);
+        ret = poll(pfd, 2, -1);
+
+        if (ret > 0 && pfd[1].revents)
+            signal_int(signal_fd);
     } while (ret == -1 && errno == EINTR && running);
 
     if(0 == running)
@@ -779,9 +799,11 @@ display_poll(struct wl_display *display, short int events)
  * the poll is continuing because the generated errno is EINTR,
  * so added running flag also to decide whether to continue polling or not */
 static int
-display_dispatch(struct wl_display *display)
+display_dispatch(WaylandContextStruct *wlcontext)
 {
     int ret;
+    int signal_fd = wlcontext->signal_fd;
+    struct wl_display *display = wlcontext->wl_display;
 
     if (wl_display_prepare_read(display) == -1)
         return wl_display_dispatch_pending(display);
@@ -792,7 +814,7 @@ display_dispatch(struct wl_display *display)
         if (ret != -1 || errno != EAGAIN)
             break;
 
-        if (display_poll(display, POLLOUT) == -1) {
+        if (display_poll(display, signal_fd, POLLOUT) == -1) {
             wl_display_cancel_read(display);
             return -1;
         }
@@ -805,7 +827,7 @@ display_dispatch(struct wl_display *display)
         return -1;
     }
 
-    if (display_poll(display, POLLIN) == -1) {
+    if (display_poll(display, signal_fd, POLLIN) == -1) {
         wl_display_cancel_read(display);
         return -1;
     }
@@ -821,16 +843,28 @@ int main (int argc, const char * argv[])
     WaylandContextStruct* wlcontext;
     BkGndSettingsStruct* bkgnd_settings;
 
-    struct sigaction sigint;
     int ret = 0;
-
-    sigint.sa_handler = signal_int;
-    sigemptyset(&sigint.sa_mask);
-    sigaction(SIGINT, &sigint, NULL);
-    sigaction(SIGTERM, &sigint, NULL);
-    sigaction(SIGSEGV, &sigint, NULL);
+    sigset_t mask;
 
     wlcontext = (WaylandContextStruct*)calloc(1, sizeof(WaylandContextStruct));
+    wlcontext->signal_fd = -1;
+
+    ret = sigemptyset(&mask);
+    sigaddset(&mask, SIGINT);
+    sigaddset(&mask, SIGTERM);
+    ret = sigprocmask(SIG_BLOCK, &mask, NULL);
+    if (ret == -1) {
+        fprintf(stderr, "sigprocmask failed with error '%s'\n",
+                strerror(errno));
+        return -1;
+    }
+
+    wlcontext->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
+    if (wlcontext->signal_fd < 0) {
+        fprintf(stderr, "invalid signalfd file descriptor. error '%s'\n",
+                strerror(errno));
+        goto ErrorSignalFd;
+    }
 
     /*get bkgnd settings and create shm-surface*/
     bkgnd_settings = get_bkgnd_settings_cursor_info(wlcontext);
@@ -883,7 +917,7 @@ int main (int argc, const char * argv[])
     draw_bkgnd_surface(wlcontext);
 
     while (running && (ret != -1))
-        ret = display_dispatch(wlcontext->wl_display);
+        ret = display_dispatch(wlcontext);
 
 Error:
 #ifdef LIBWESTON_DEBUG_PROTOCOL
@@ -924,6 +958,8 @@ ErrorContext:
     destroy_wayland_context(wlcontext);
 
     free(bkgnd_settings);
+    close(wlcontext->signal_fd);
+ErrorSignalFd:
     free(wlcontext);
 
     return 0;
-- 
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