lib: If log writing to log process is blocking, show it in process title

This change also makes the log pipe non-blocking.

diff --git a/src/lib/failures.c b/src/lib/failures.c
index 3cdb94bc4e4412a86d3c9876b1b76c048a1ecdeb..738828bef7daad0f3c817ae6e1e767292f4b28a2 100644 (file)
--- a/src/lib/failures.c
+++ b/src/lib/failures.c
@@ -5,6 +5,8 @@
 #include "str.h"
 #include "hostpid.h"
 #include "net.h"
+#include "fd-set-nonblock.h"
+#include "process-title.h"
 #include "lib-signals.h"
 #include "backtrace-string.h"
 #include "printf-format-fix.h"
@@ -123,16 +125,31 @@ static int log_fd_write(int fd, const unsigned char *data, size_t len)
                        return -1;
                }
                switch (errno) {
-               case EAGAIN:
+               case EAGAIN: {
                        /* wait until we can write more. this can happen at
                           least when writing to terminal, even if fd is
-                          blocking. */
+                          blocking. Internal logging fd is also now
+                          non-blocking, so we can show warnings about blocking
+                          on a log write. */
+                       const char *title, *old_title =
+                               t_strdup(process_title_get());
+
+                       if (old_title == NULL)
+                               title = "[blocking on log write]";
+                       else
+                               title = t_strdup_printf("%s - [blocking on log write]",
+                                                       old_title);
+                       process_title_set(title);
+
                        ioloop = io_loop_create();
                        io = io_add(fd, IO_WRITE, log_fd_flush_stop, ioloop);
                        io_loop_run(ioloop);
                        io_remove(&io);
                        io_loop_destroy(&ioloop);
+
+                       process_title_set(old_title);
                        break;
+               }
                case EINTR:
                        if (prev_signal_term_counter == signal_term_counter) {
                                /* non-terminal signal. ignore. */
@@ -680,6 +697,7 @@ i_internal_error_handler(const struct failure_context *ctx,
 
 void i_set_failure_internal(void)
 {
+       fd_set_nonblock(STDERR_FILENO, TRUE);
        i_set_fatal_handler(i_internal_fatal_handler);
        i_set_error_handler(i_internal_error_handler);
        i_set_info_handler(i_internal_error_handler);