1 files changed, 122 insertions, 0 deletions
diff --git a/rts/eventlog/EventLogWriter.c b/rts/eventlog/EventLogWriter.c
new file mode 100644
index 0000000000..d6db743119
--- /dev/null
+++ b/rts/eventlog/EventLogWriter.c
@@ -0,0 +1,122 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 2008-2009
+ *
+ * Support for fast binary event logging.
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "PosixSource.h"
+#include "Rts.h"
+
+#include "RtsUtils.h"
+#include "rts/EventLogWriter.h"
+
+#include <string.h>
+#include <stdio.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+// PID of the process that writes to event_log_filename (#4512)
+static pid_t event_log_pid = -1;
+
+// File for logging events
+static FILE *event_log_file = NULL;
+
+static void initEventLogFileWriter(void);
+static bool writeEventLogFile(void *eventlog, size_t eventlog_size);
+static void flushEventLogFile(void);
+static void stopEventLogFileWriter(void);
+
+static void
+initEventLogFileWriter(void)
+{
+    char *prog, *event_log_filename;
+
+    prog = stgMallocBytes(strlen(prog_name) + 1, "initEventLogFileWriter");
+    strcpy(prog, prog_name);
+#ifdef mingw32_HOST_OS
+    // on Windows, drop the .exe suffix if there is one
+    {
+        char *suff;
+        suff = strrchr(prog,'.');
+        if (suff != NULL && !strcmp(suff,".exe")) {
+            *suff = '\0';
+        }
+    }
+#endif
+    event_log_filename = stgMallocBytes(strlen(prog)
+                                        + 10 /* .%d */
+                                        + 10 /* .eventlog */,
+                                        "initEventLogFileWriter");
+
+    if (event_log_pid == -1) { // #4512
+        // Single process
+        sprintf(event_log_filename, "%s.eventlog", prog);
+        event_log_pid = getpid();
+    } else {
+        // Forked process, eventlog already started by the parent
+        // before fork
+        event_log_pid = getpid();
+        // We don't have a FMT* symbol for pid_t, so we go via Word64
+        // to be sure of not losing range. It would be nicer to have a
+        // FMT* symbol or similar, though.
+        sprintf(event_log_filename, "%s.%" FMT_Word64 ".eventlog",
+                prog, (StgWord64)event_log_pid);
+    }
+    stgFree(prog);
+
+    /* Open event log file for writing. */
+    if ((event_log_file = fopen(event_log_filename, "wb")) == NULL) {
+        sysErrorBelch(
+            "initEventLogFileWriter: can't open %s", event_log_filename);
+        stg_exit(EXIT_FAILURE);
+    }
+
+    stgFree(event_log_filename);
+}
+
+static bool
+writeEventLogFile(void *eventlog, size_t eventlog_size)
+{
+    unsigned char *begin = eventlog;
+    size_t remain = eventlog_size;
+
+    while (remain > 0) {
+        size_t written = fwrite(begin, 1, remain, event_log_file);
+        if (written == 0) {
+            return false;
+        }
+        remain -= written;
+        begin += written;
+    }
+
+    return true;
+}
+
+static void
+flushEventLogFile(void)
+{
+    if (event_log_file != NULL) {
+        fflush(event_log_file);
+    }
+}
+
+static void
+stopEventLogFileWriter(void)
+{
+    if (event_log_file != NULL) {
+        fclose(event_log_file);
+    }
+}
+
+const EventLogWriter FileEventLogWriter = {
+    .initEventLogWriter = initEventLogFileWriter,
+    .writeEventLog = writeEventLogFile,
+    .flushEventLog = flushEventLogFile,
+    .stopEventLogWriter = stopEventLogFileWriter
+};