[sysprof/ftrace: 10/16] More cleanup

[Søren Sandmann Pedersen <ssp src gnome org>]

commit 580cef3e87ff87cd28ec862889166d987d22557e
Author: Søren Sandmann Pedersen <sandmann daimi au dk>
Date:   Fri Aug 14 02:02:35 2009 -0400

    More cleanup

 TODO        |    2 +
 collector.c |  120 +++++++++++++++++++++++-----------------------------------
 collector.h |    3 +-
 3 files changed, 52 insertions(+), 73 deletions(-)
---
diff --git a/TODO b/TODO
index 4e51bdd..f39f7bd 100644
--- a/TODO
+++ b/TODO
@@ -23,6 +23,8 @@ Before 1.0.4:
 
 Before 1.2:
 
+* Give an informative error message if run as root
+
 * Find out why gtk_tree_view_columns_autosize() apparently doesn't
   work on empty tree views.
 
diff --git a/collector.c b/collector.c
index 79d470d..de7d728 100644
--- a/collector.c
+++ b/collector.c
@@ -37,7 +37,9 @@ typedef struct CPUInfo CPUInfo;
 
 #define N_CPU 8		/* FIXME: Arbitrary number of CPU's */
 
-#define SYSPROF_FILE "/sys/kernel/debug/tracing/trace_pipe"
+#define SYSPROF_DIR  "/sys/kernel/debug/tracing/"
+#define SYSPROF_FILE (SYSPROF_DIR "trace_pipe")
+
 
 enum
 {
@@ -212,28 +214,24 @@ in_dead_period (Collector *collector)
     return FALSE;
 }
 
-static void
-warn (const char *text)
-{
-    g_warning ("%s: (%s)\n", text, strerror (errno));
-}
-
 static gboolean
-write_text (const char *file, const char *text)
+write_text (const char *file, const char *text, GError **err)
 {
     int fd = open (file, O_RDWR);
 
     if (fd < 0)
     {
-	g_print ("open %s fail\n",file);
-	warn ("Failed to open");
+	g_set_error (err, COLLECTOR_ERROR, COLLECTOR_ERROR_IO_ERROR,
+		     "Could not open %s", file);
+	
 	return FALSE;
     }
     
     if (write (fd, text, strlen (text)) < 0)
     {
-	g_print ("write to %s failed\n", file);
-	warn ("asdf");
+	g_set_error (err, COLLECTOR_ERROR, COLLECTOR_ERROR_IO_ERROR,
+		     "Could not write %s to %s", text, file);
+	
 	return FALSE;
     }
 
@@ -243,22 +241,22 @@ write_text (const char *file, const char *text)
 
 void
 collector_set_tracing (Collector *collector,
-		       gboolean trace)
+		       gboolean	  trace)
 {
     if (trace)
-	write_text ("/sys/kernel/debug/tracing/tracing_enabled", "1\n");
+	write_text ("/sys/kernel/debug/tracing/tracing_enabled", "1\n", NULL);
     else
-	write_text ("/sys/kernel/debug/tracing/tracing_enabled", "0\n");
+	write_text ("/sys/kernel/debug/tracing/tracing_enabled", "0\n", NULL);
 }
 
 typedef struct Entry
 {
-    guint32 pid;
-    guint32 cpu;
-    guint64 timestamp;
-    glong type;
-    gulong address;
-    gulong location;
+    guint32	pid;
+    guint32	cpu;
+    guint64	timestamp;
+    glong	type;
+    gulong	address;
+    gulong	location;
 } Entry;
 
 static void
@@ -422,72 +420,56 @@ static gboolean
 start_tracing (Collector  *collector,
 	       GError    **err)
 {
+    typedef struct
+    {
+	const char file[56];
+	const char text[8];
+    } Setting;
+
+    static const Setting settings[] =
+    {
+	{ SYSPROF_DIR "trace_options",         "noblock" },
+	{ SYSPROF_DIR "current_tracer",        "sysprof" },
+	{ SYSPROF_DIR "trace_options",         "raw" },
+	{ SYSPROF_DIR "trace_options",         "bin" },
+	{ SYSPROF_DIR "sysprof_sample_period", "10000" },
+    };
+    
     int fd;
     int i;
     
-    if (access ("/sys/kernel/debug/tracing", X_OK) < 0)
+    if (access (SYSPROF_DIR, X_OK) < 0)
     {
 	mount ("nodev", "/sys/kernel/debug", "debugfs", 0, NULL);
 
-	if (access ("/sys/kernel/debug/tracing", X_OK) < 0)
+	if (access (SYSPROF_DIR, X_OK) < 0)
 	{
-	    g_print ("couldn't mount directory FIXME error\n");
+	    g_set_error (err, COLLECTOR_ERROR, COLLECTOR_ERROR_IO_ERROR,
+			 "Could not mount tracer directory");
+	    
 	    return FALSE;
 	}
     }
 
-    if (!write_text ("/sys/kernel/debug/tracing/trace_options", "noblock"))
-    {
-	return FALSE;
-    }
-    
-    if (!write_text ("/sys/kernel/debug/tracing/current_tracer", "sysprof\n"))
-    {
-	warn ("Failed to append sysprof\n");
-	return FALSE;
-    }
-
-    if (!write_text ("/sys/kernel/debug/tracing/tracing_enabled", "0\n"))
+    for (i = 0; i < G_N_ELEMENTS (settings); ++i)
     {
+	const Setting *setting = &settings[i];
 	
+	if (!write_text (setting->file, setting->text, err))
+	    return FALSE;
     }
     
-    if (!write_text ("/sys/kernel/debug/tracing/trace_options", "raw\n"))
-    {
-	g_print ("Failed to make raw\n");
-	return FALSE;
-    }
-
-    if (!write_text ("/sys/kernel/debug/tracing/trace_options", "bin\n"))
-    {
-	g_print ("Failed to make binary\n");
-	return FALSE;
-    }
-
-    if (!write_text ("/sys/kernel/debug/tracing/sysprof_sample_period", "10000\n"))
-    {
-	g_print ("Failed to set sample period\n");
-	return FALSE;
-    }
-
     fd = open (SYSPROF_FILE, O_RDONLY | O_NONBLOCK);
     if (fd < 0)
     {
-	g_print ("Failed to open trace pipe\n");
+	g_set_error (err, COLLECTOR_ERROR, COLLECTOR_ERROR_IO_ERROR,
+		     "Could not open %s", SYSPROF_FILE);
+	
 	return FALSE;
     }
 
-    g_print ("fd: %d\n", fd);
-    
-    if (!write_text ("/sys/kernel/debug/tracing/tracing_enabled", "1\n"))
-    {
-	g_print ("Failed to enable\n");
+    if (!write_text (SYSPROF_DIR "tracing_enabled", "1\n", err))
 	return FALSE;
-    }
-    else
-    {
-	g_print ("enabled\n");
-    }
 
     fd_add_watch (fd, collector);
     
@@ -503,8 +485,6 @@ gboolean
 collector_start (Collector  *collector,
 		 GError    **err)
 {
-    g_print ("start\n");
-    
     if (collector->fd < 0 && !start_tracing (collector, err))
 	return FALSE;
     
@@ -527,8 +507,7 @@ collector_stop (Collector *collector)
 	
 	close (collector->fd);
     
-	if (!write_text ("/sys/kernel/debug/tracing/tracing_enabled", "0\n"))
-	    g_print ("Failed to disable\n");
+	write_text ("/sys/kernel/debug/tracing/tracing_enabled", "0\n", NULL);
 	
 	collector->fd = -1;
     }
@@ -551,9 +530,6 @@ collector_reset (Collector *collector)
 int
 collector_get_n_samples (Collector *collector)
 {
-#if 0
-    g_print ("returning %d samples\n", collector->n_samples);
-#endif
     return collector->n_samples;
 }
 
diff --git a/collector.h b/collector.h
index 11131db..aa83dc6 100644
--- a/collector.h
+++ b/collector.h
@@ -30,7 +30,8 @@ GQuark collector_error_quark (void);
 
 typedef enum
 {
-    COLLECTOR_ERROR_CANT_OPEN_FILE
+    COLLECTOR_ERROR_CANT_OPEN_FILE,
+    COLLECTOR_ERROR_IO_ERROR,
 } CollectorError;
 
 /* callback is called whenever a new sample arrives */