Yet another Dasynq update

[oweals/dinit.git] / src / dinit-log.cc

diff --git a/src/dinit-log.cc b/src/dinit-log.cc
index 431c2a5eed5d71d53adef599efba33667daa4d6c..43062f0f15a400ca938c7d188be6b9f9d5dcc28b 100644 (file)
--- a/src/dinit-log.cc
+++ b/src/dinit-log.cc
@@ -4,8 +4,9 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/syslog.h>
+#include <sys/uio.h>
 
-#include "dasync.h"
+#include "dasynq.h"
 
 #include "service.h"
 #include "dinit-log.h"
@@ -19,7 +20,7 @@ LogLevel log_level[2] = { LogLevel::WARN, LogLevel::WARN };
 static ServiceSet *service_set = nullptr;  // Reference to service set
 
 namespace {
-class BufferedLogStream : public PosixFdWatcher<NullMutex>
+class BufferedLogStream : public EventLoop_t::FdWatcher
 {
     private:
 
@@ -105,7 +106,7 @@ void BufferedLogStream::flushForRelease()
     
     // Try to flush any messages that are currently buffered. (Console is non-blocking
     // so it will fail gracefully).
-    if (gotEvent(&eventLoop, fd, out_events) == Rearm::DISARM) {
+    if (gotEvent(&eventLoop, fd, OUT_EVENTS) == Rearm::DISARM) {
         // Console has already been released at this point.
         setEnabled(&eventLoop, false);
     }
@@ -153,8 +154,14 @@ Rearm BufferedLogStream::gotEvent(EventLoop_t *loop, int fd, int flags) noexcept
             return Rearm::DISARM;
         }
         
-        char *ptr = log_stream.log_buffer.get_ptr(0);
-        int len = log_stream.log_buffer.get_contiguous_length(ptr);
+        // We try to find a complete line (terminated by '\n') in the buffer, and write it
+        // out. Since it may span the circular buffer end, it may consist of two distinct spans,
+        // and so we use writev to write them atomically.
+        
+        struct iovec logiov[2];
+        
+        char *ptr = log_buffer.get_ptr(0);
+        int len = log_buffer.get_contiguous_length(ptr);
         char *creptr = ptr + len;  // contiguous region end
         char *eptr = std::find(ptr, creptr, '\n');
         
@@ -166,7 +173,27 @@ Rearm BufferedLogStream::gotEvent(EventLoop_t *loop, int fd, int flags) noexcept
 
         len = eptr - ptr;
         
-        int r = write(fd, ptr, len);
+        logiov[0].iov_base = ptr;
+        logiov[0].iov_len = len;
+        int iovs_to_write = 1;
+        
+        // Do we need the second span?
+        if (! will_complete && len != log_buffer.get_length()) {
+            ptr = log_buffer.get_buf_base();
+            creptr = static_cast<char *>(logiov[1].iov_base) + log_buffer.get_length() - len;
+            eptr = std::find(ptr, creptr, '\n');
+            if (eptr != creptr) {
+                eptr++; // include '\n'
+                // It should not ever be the case that we do not now have a complete message
+                will_complete = true;
+            }
+            logiov[1].iov_base = ptr;
+            logiov[1].iov_len = eptr - ptr;
+            len += logiov[1].iov_len;
+            iovs_to_write = 2;
+        }
+        
+        ssize_t r = writev(fd, logiov, iovs_to_write);
 
         if (r >= 0) {
             bool complete = (r == len) && will_complete;
@@ -196,7 +223,7 @@ Rearm BufferedLogStream::gotEvent(EventLoop_t *loop, int fd, int flags) noexcept
 void init_log(ServiceSet *sset)
 {
     service_set = sset;
-    log_stream[DLOG_CONS].registerWith(&eventLoop, STDOUT_FILENO, out_events); // TODO register in disabled state
+    log_stream[DLOG_CONS].registerWith(&eventLoop, STDOUT_FILENO, OUT_EVENTS); // TODO register in disabled state
     enable_console_log(true);
 }
 
@@ -205,7 +232,7 @@ void init_log(ServiceSet *sset)
 void setup_main_log(int fd)
 {
     log_stream[DLOG_MAIN].init(fd);
-    log_stream[DLOG_MAIN].registerWith(&eventLoop, fd, out_events);
+    log_stream[DLOG_MAIN].registerWith(&eventLoop, fd, OUT_EVENTS);
 }
 
 bool is_log_flushed() noexcept