[PATCH v4 3/5] drm: Add dispatcher and driver identification for DRM

[Patrik Jakobsson]

* Makefile.am: Add compilation of drm.c.
* defs.h: Add extern declaration of drm_ioctl when drm headers are found.
* drm.c: New file.
* ioctl.c (ioctl_decode): Dispatch drm ioctls when drm headers are found.

Signed-off-by: Patrik Jakobsson <patrik.jakobsson at linux.intel.com>
---
 Makefile.am |   1 +
 defs.h      |   3 ++
 drm.c       | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ioctl.c     |   4 +++
 4 files changed, 115 insertions(+)
 create mode 100644 drm.c

diff --git a/Makefile.am b/Makefile.am
index f70f6d2..c7c6080 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -42,6 +42,7 @@ strace_SOURCES =	\
 	count.c		\
 	desc.c		\
 	dirent.c	\
+	drm.c		\
 	epoll.c		\
 	evdev.c		\
 	eventfd.c	\
diff --git a/defs.h b/defs.h
index bc3bd83..dd3c720 100644
--- a/defs.h
+++ b/defs.h
@@ -612,6 +612,9 @@ extern const char *sprint_open_modes(int);
 extern void print_seccomp_filter(struct tcb *tcp, unsigned long);
 
 extern int block_ioctl(struct tcb *, const unsigned int, long);
+#if defined(HAVE_DRM_H) || defined(HAVE_DRM_DRM_H)
+extern int drm_ioctl(struct tcb *, const unsigned int, long);
+#endif
 extern int evdev_ioctl(struct tcb *, const unsigned int, long);
 extern int loop_ioctl(struct tcb *, const unsigned int, long);
 extern int mtd_ioctl(struct tcb *, const unsigned int, long);
diff --git a/drm.c b/drm.c
new file mode 100644
index 0000000..0829803
--- /dev/null
+++ b/drm.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2015 Intel Corporation
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors:
+ *    Patrik Jakobsson <patrik.jakobsson at linux.intel.com>
+ */
+
+#include "defs.h"
+
+#if defined(HAVE_DRM_H) || defined(HAVE_DRM_DRM_H)
+
+#ifdef HAVE_DRM_H
+#include <drm.h>
+#else
+#include <drm/drm.h>
+#endif
+
+#include <sys/param.h>
+
+#define DRM_MAX_NAME_LEN 128
+
+inline int drm_is_priv(const unsigned int num)
+{
+	return (_IOC_NR(num) >= DRM_COMMAND_BASE &&
+		_IOC_NR(num) < DRM_COMMAND_END);
+}
+
+static char *drm_get_driver_name(struct tcb *tcp)
+{
+	char path[PATH_MAX];
+	char link[PATH_MAX];
+	int ret;
+
+	if (getfdpath(tcp, tcp->u_arg[0], path, PATH_MAX - 1) < 0)
+		return NULL;
+
+	snprintf(link, PATH_MAX, "/sys/class/drm/%s/device/driver",
+		 basename(path));
+
+	ret = readlink(link, path, PATH_MAX - 1);
+	if (ret < 0)
+		return NULL;
+
+	path[ret] = '\0';
+	return strdup(basename(path));
+}
+
+static void drm_free_priv(void *data)
+{
+	free(data);
+}
+
+int drm_is_driver(struct tcb *tcp, const char *name)
+{
+	char *priv;
+
+	/*
+	 * If no private data is allocated we are detecting the driver name for
+	 * the first time and must resolve it.
+	 */
+	if (tcp->priv_data == NULL) {
+		tcp->priv_data = drm_get_driver_name(tcp);
+		if (tcp->priv_data == NULL)
+			return 0;
+
+		tcp->free_priv_data = drm_free_priv;
+	}
+
+	priv = tcp->priv_data;
+
+	return strncmp(name, priv, DRM_MAX_NAME_LEN) == 0;
+}
+
+int drm_decode_number(struct tcb *tcp, unsigned int code)
+{
+	return 0;
+}
+
+int drm_ioctl(struct tcb *tcp, const unsigned int code, long arg)
+{
+	return 0;
+}
+
+#endif /* HAVE_DRM_H || HAVE_DRM_DRM_H */
diff --git a/ioctl.c b/ioctl.c
index 284828a..dfd35d8 100644
--- a/ioctl.c
+++ b/ioctl.c
@@ -248,6 +248,10 @@ ioctl_decode(struct tcb *tcp)
 	case 0x22:
 		return scsi_ioctl(tcp, code, arg);
 #endif
+#if defined(HAVE_DRM_H) || defined(HAVE_DRM_DRM_H)
+	case 'd':
+		return drm_ioctl(tcp, code, arg);
+#endif
 	case 'L':
 		return loop_ioctl(tcp, code, arg);
 	case 'M':
-- 
2.1.4