4 files changed, 74 insertions, 14 deletions

diff --git a/include/drm++/drm.hpp b/include/drm++/drm.hpp
index 2833adf..4e94010 100644
--- a/include/drm++/drm.hpp
+++ b/include/drm++/drm.hpp
@@ -133,6 +133,8 @@
 #include "helper/macros.hpp"
 #include "helper/types.hpp"
 
+#include <string>
+
 namespace drm {
 
 ///
@@ -146,6 +148,11 @@ public:
     /// @throws std::invalid_argument if fd is invalid
     Device(int fd);
 
+    /// Set the client name for this file descriptor, useful for debugging and tracking.
+    void setClientName(const std::string& name) const;
+
+    /* Authentication */
+
     /// Attempt to acquire DRM master on the device. This will fail if another process is
     /// already DRM master.
     void acquireMaster() const;
@@ -153,16 +160,23 @@ public:
     /// Release DRM master on the device.
     void releaseMaster() const;
 
+    /// Fetch the magic token.
+    [[nodiscard]] u32 magic() const;
+
     /// Authenticate a file descriptor via magic token, allowing for access to
     /// restricted ioctls (such as mode setting).
     void authenticate(u32 magic) const;
 
+    /* Device information */
+
+    /// Get the unique string for this device. This operation is restricted to the DRM master.
+    [[nodiscard]] std::string unique() const;
+
     // Private access
     GETTER(fd)
-    GETTER(magic)
 
     // Move constructor/operator
-    Device(Device&& other) noexcept : m_fd(other.m_fd), m_magic(other.m_magic) {
+    Device(Device&& other) noexcept : m_fd(other.m_fd) {
         other.m_fd = -1; // invalidate other
     }
 
@@ -170,7 +184,6 @@ public:
         if (this != &other) {
             this->destruct();
             this->m_fd = other.m_fd;
-            this->m_magic = other.m_magic;
             other.m_fd = -1; // invalidate other
         }
 
@@ -187,7 +200,6 @@ public:
 
 private:
     int m_fd; // indicates device validity (>= 0)
-    u32 m_magic;
 
     void destruct() noexcept;
 };
diff --git a/include/drm++/helper/ioctl.hpp b/include/drm++/helper/ioctl.hpp
index fe87f3c..bd6c44a 100644
--- a/include/drm++/helper/ioctl.hpp
+++ b/include/drm++/helper/ioctl.hpp
@@ -15,6 +15,7 @@ namespace drm::ioctl {
 /// Type of ioctl() error.
 enum class Error : u8 {
     BadFileDescriptor,
+    NoAccess,
     InvalidArgument,
     NotSupported,
     Other //!< Check errno field
diff --git a/src/drm.cpp b/src/drm.cpp
index 3046412..66fe147 100644
--- a/src/drm.cpp
+++ b/src/drm.cpp
@@ -7,6 +7,7 @@
 #include <stdexcept>
 
 #include <drm.h>
+#include <string>
 #include <unistd.h>
 
 using namespace drm;
@@ -15,14 +16,27 @@ Device::Device(int fd) : m_fd(fd) {
     if (this->m_fd < 0) {
         throw std::invalid_argument("invalid file descriptor");
     }
+}
 
-    drm_auth args{
-
+void Device::setClientName(const std::string& name) const {
+    drm_set_client_name name_args{
+        .name_len = name.size(),
+        .name = reinterpret_cast<u64>(name.data())
     };
-    ioctl::perform(this->m_fd, DRM_IOCTL_GET_MAGIC, args);
-    this->m_magic = args.magic;
+    ioctl::perform(this->m_fd, DRM_IOCTL_SET_CLIENT_NAME, name_args);
 }
 
+void Device::destruct() noexcept {
+    if (this->m_fd < 0) {
+        return;
+    }
+
+    ::close(this->m_fd);
+    this->m_fd = -1;
+}
+
+/* Authentication */
+
 void Device::acquireMaster() const {
     ioctl::perform(this->m_fd, DRM_IOCTL_SET_MASTER);
 }
@@ -31,6 +45,14 @@ void Device::releaseMaster() const {
     ioctl::perform(this->m_fd, DRM_IOCTL_DROP_MASTER);
 }
 
+u32 Device::magic() const {
+    drm_auth auth_args{
+        .magic = 0
+    };
+    ioctl::perform(this->m_fd, DRM_IOCTL_GET_MAGIC, auth_args);
+    return auth_args.magic;
+}
+
 void Device::authenticate(u32 magic) const {
     drm_auth args{
         .magic = magic
@@ -38,11 +60,29 @@ void Device::authenticate(u32 magic) const {
     ioctl::perform(this->m_fd, DRM_IOCTL_AUTH_MAGIC, args);
 }
 
-void Device::destruct() noexcept {
-    if (this->m_fd < 0) {
-        return;
-    }
+/* Device information */
 
-    ::close(this->m_fd);
-    this->m_fd = -1;
+std::string Device::unique() const {
+    drm_set_version version_args{
+        .drm_di_major = 1,
+        .drm_di_minor = 4, // See kernel drm_ioctl.c for why this is here
+        .drm_dd_major = -1,
+        .drm_dd_minor = -1
+    };
+    ioctl::perform(this->m_fd, DRM_IOCTL_SET_VERSION, version_args);
+
+    drm_unique unique_args{
+        .unique_len = 0,
+    };
+    ioctl::perform(this->m_fd, DRM_IOCTL_GET_UNIQUE, unique_args);
+
+    std::string unique(unique_args.unique_len, '\0');
+
+    unique_args = {
+        .unique_len = unique.size(),
+        .unique = unique.data()
+    };
+    ioctl::perform(this->m_fd, DRM_IOCTL_GET_UNIQUE, unique_args);
+
+    return unique;
 }
diff --git a/src/helper/ioctl.cpp b/src/helper/ioctl.cpp
index 21a1ccb..8889efc 100644
--- a/src/helper/ioctl.cpp
+++ b/src/helper/ioctl.cpp
@@ -19,6 +19,13 @@ Exception::Exception(int fd, unsigned long op)
                 this->m_fd, this->m_op
             );
             break;
+        case EACCES:
+            this->m_code = Error::NoAccess;
+            this->m_what = std::format(
+                "ioctl({}, 0x{:x}) failed: Permission denied",
+                this->m_fd, this->m_op
+            );
+            break;
         case EINVAL:
         case ENOTTY:
             this->m_code = Error::InvalidArgument;