trace-cmd: Rename tracecmd_open to tracecmd_alloc

The tracecmd_open() currently returns a tracecmd_input descriptor
that is not finished. The headers still need to be read and data
needs to be initialized.

Rename tracecmd_open and tracecmd_open_fd to tracecmd_alloc and
tracecmd_alloc_fd respectively, and create a new tracecmd_open()
and tracecmd_open_fd() that returns a usable descriptor.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

3 files changed, 65 insertions, 3 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index d0b5c92..18d615c 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -41,6 +41,8 @@ char *tracecmd_find_tracing_dir(void);
 
 /* --- Opening and Reading the trace.dat file --- */
 
+struct tracecmd_input *tracecmd_alloc(const char *file);
+struct tracecmd_input *tracecmd_alloc_fd(int fd);
 struct tracecmd_input *tracecmd_open(const char *file);
 struct tracecmd_input *tracecmd_open_fd(int fd);
 void tracecmd_close(struct tracecmd_input *handle);
diff --git a/trace-input.c b/trace-input.c
index 1462b4b..13896eb 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -1470,10 +1470,20 @@ void tracecmd_print_events(struct tracecmd_input *handle)
 }
 
 /**
- * tracecmd_open_fd - create a tracecmd_handle from the trace.dat file descriptor
+ * tracecmd_alloc_fd - create a tracecmd_input handle from a file descriptor
  * @fd: the file descriptor for the trace.dat file
+ *
+ * Allocate a tracecmd_input handle from a file descriptor and open the
+ * file. This tests if the file is of trace-cmd format and allocates
+ * a parse event descriptor.
+ *
+ * The returned pointer is not ready to be read yet. A tracecmd_read_headers()
+ * and tracecmd_init_data() still need to be called on the descriptor.
+ *
+ * Unless you know what you are doing with this, you want to use
+ * tracecmd_open_fd() instead.
  */
-struct tracecmd_input *tracecmd_open_fd(int fd)
+struct tracecmd_input *tracecmd_alloc_fd(int fd)
 {
         struct tracecmd_input *handle;
         char test[] = { 23, 8, 68 };
@@ -1531,6 +1541,56 @@ struct tracecmd_input *tracecmd_open_fd(int fd)
 }
 
 /**
+ * tracecmd_alloc_fd - create a tracecmd_input handle from a file name
+ * @file: the file name of the file that is of tracecmd data type.
+ *
+ * Allocate a tracecmd_input handle from a given file name and open the
+ * file. This tests if the file is of trace-cmd format and allocates
+ * a parse event descriptor.
+ *
+ * The returned pointer is not ready to be read yet. A tracecmd_read_headers()
+ * and tracecmd_init_data() still need to be called on the descriptor.
+ *
+ * Unless you know what you are doing with this, you want to use
+ * tracecmd_open() instead.
+ */
+struct tracecmd_input *tracecmd_alloc(const char *file)
+{
+        int fd;
+
+        fd = open(file, O_RDONLY);
+        if (fd < 0)
+                return NULL;
+
+        return tracecmd_open_fd(fd);
+}
+
+/**
+ * tracecmd_open_fd - create a tracecmd_handle from the trace.dat file descriptor
+ * @fd: the file descriptor for the trace.dat file
+ */
+struct tracecmd_input *tracecmd_open_fd(int fd)
+{
+        struct tracecmd_input *handle;
+
+        handle = tracecmd_alloc_fd(fd);
+        if (!handle)
+                return NULL;
+
+        if (tracecmd_read_headers(handle) < 0)
+                goto fail;
+
+        if (tracecmd_init_data(handle) < 0)
+                goto fail;
+
+        return handle;
+
+fail:
+        tracecmd_close(handle);
+        return NULL;
+}
+
+/**
  * tracecmd_open - create a tracecmd_handle from a given file
  * @file: the file name of the file that is of tracecmd data type.
  */
diff --git a/trace-read.c b/trace-read.c
index f2c7de2..306fa3a 100644
--- a/trace-read.c
+++ b/trace-read.c
@@ -276,7 +276,7 @@ struct tracecmd_input *read_trace_header(void)
         if (input_fd < 0)
                 die("opening '%s'\n", input_file);
 
-        return tracecmd_open_fd(input_fd);
+        return tracecmd_alloc_fd(input_fd);
 }
 
 void trace_report (int argc, char **argv)