staging: ktap: add to the kernel tree

[karo-tx-linux.git] / drivers / staging / ktap / userspace / ktapio.c

diff --git a/drivers/staging/ktap/userspace/ktapio.c b/drivers/staging/ktap/userspace/ktapio.c
new file mode 100644 (file)
index 0000000..f9bcab4
--- /dev/null
+++ b/drivers/staging/ktap/userspace/ktapio.c
@@ -0,0 +1,108 @@
+/*
+ * ktapio.c - ring buffer transport in userspace
+ *
+ * This file is part of ktap by Jovi Zhangwei.
+ *
+ * Copyright (C) 2012-2013 Jovi Zhangwei <jovi.zhangwei@gmail.com>.
+ *
+ * ktap is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * ktap is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/poll.h>
+#include <sys/signal.h>
+#include <fcntl.h>
+#include <pthread.h>
+
+#define MAX_BUFLEN  131072
+#define PATH_MAX 128
+
+#define handle_error(str) do { perror(str); exit(-1); } while(0)
+
+extern pid_t ktap_pid;
+
+void sigfunc(int signo)
+{
+       /* should not not reach here */
+}
+
+static void block_sigint()
+{
+       sigset_t mask;
+
+       sigemptyset(&mask);
+       sigaddset(&mask, SIGINT);
+
+       pthread_sigmask(SIG_BLOCK, &mask, NULL);
+}
+
+static void *reader_thread(void *data)
+{
+       char buf[MAX_BUFLEN];
+       char filename[PATH_MAX];
+       const char *output = data; 
+       int failed = 0, fd, out_fd, len;
+
+       block_sigint();
+
+       if (output) {
+               out_fd = open(output, O_CREAT | O_WRONLY | O_TRUNC,
+                                       S_IRUSR|S_IWUSR);
+               if (out_fd < 0) {
+                       fprintf(stderr, "Cannot open output file %s\n", output);
+                       return NULL;
+               }
+       } else
+               out_fd = 2;
+
+       sprintf(filename, "/sys/kernel/debug/ktap/trace_pipe_%d", ktap_pid);
+
+ open_again:
+       fd = open(filename, O_RDONLY);
+       if (fd < 0) {
+               usleep(10000);
+
+               if (failed++ == 10) {
+                       fprintf(stderr, "Cannot open file %s\n", filename);
+                       return NULL;
+               }
+               goto open_again;
+       }
+
+       while ((len = read(fd, buf, sizeof(buf))) > 0)
+               write(out_fd, buf, len);
+
+       close(fd);
+       close(out_fd);
+
+       return NULL;
+}
+
+int ktapio_create(const char *output)
+{
+       pthread_t reader;
+
+       signal(SIGINT, sigfunc);
+
+       if (pthread_create(&reader, NULL, reader_thread, (void *)output) < 0)
+               handle_error("pthread_create reader_thread failed\n");
+
+       return 0;
+}
+