Cleanup when mem mapping failed

Author: wysaid

src/ccap_imp_linux.cpp

@@ -407,6 +407,7 @@ bool ProviderV4L2::allocateBuffers() {
 
         if (ioctl(m_fd, VIDIOC_QUERYBUF, &buf) < 0) {
             reportError(ErrorCode::MemoryAllocationFailed, "Query device buffer failed: " + std::string(strerror(errno)));
+            releaseAndFreeDriverBuffers();
             return false;
         }
 
@@ -416,6 +417,7 @@ bool ProviderV4L2::allocateBuffers() {
 
         if (m_buffers[i].start == MAP_FAILED) {
             reportError(ErrorCode::MemoryAllocationFailed, "Memory mapping failed: " + std::string(strerror(errno)));
+            releaseAndFreeDriverBuffers();
             return false;
         }
     }
@@ -433,6 +435,19 @@ void ProviderV4L2::releaseBuffers() {
     m_buffers.clear();
 }
 
+void ProviderV4L2::releaseAndFreeDriverBuffers() {
+    // Unmap any mapped buffers we have and clear the vector
+    releaseBuffers();
+
+    // Hint the driver to free any requested buffers
+    struct v4l2_requestbuffers zero = {};
+    zero.count = 0;
+    zero.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    zero.memory = V4L2_MEMORY_MMAP;
+    // Ignoring return value: this is a best-effort hint during cleanup
+    ioctl(m_fd, VIDIOC_REQBUFS, &zero);
+}
+
 bool ProviderV4L2::startStreaming() {
     // Queue all buffers
     for (size_t i = 0; i < m_buffers.size(); i++) {

src/ccap_imp_linux.h

@@ -90,6 +90,8 @@ class ProviderV4L2 : public ProviderImp {
     bool isVideoDevice(const std::string& devicePath);
     std::string getDeviceDescription(const std::string& devicePath);
 
+    void releaseAndFreeDriverBuffers();
+
 private:
     // Device state
     int m_fd = -1;
@@ -99,12 +101,12 @@ class ProviderV4L2 : public ProviderImp {
     bool m_isStreaming = false;
 
     // V4L2 device capabilities
-    struct v4l2_capability m_caps {};
+    struct v4l2_capability m_caps{};
     std::vector<V4L2Format> m_supportedFormats;
     std::vector<DeviceInfo::Resolution> m_supportedResolutions;
 
     // Current format
-    struct v4l2_format m_currentFormat {};
+    struct v4l2_format m_currentFormat{};
 
     // Buffer management
     std::vector<V4L2Buffer> m_buffers;