libui+wind+libos: Move shared memory handling code to os::SharedMemory

libos/CMakeLists.txt

@@ -17,6 +17,7 @@ set(SOURCES
     src/LocalServer.cpp
     src/LocalClient.cpp
     src/IPC.cpp
+    src/SharedMemory.cpp
 )
 
 add_library(os ${SOURCES})

libos/include/os/SharedMemory.h

@@ -0,0 +1,36 @@
+/**
+ * @file SharedMemory.h
+ * @author apio (cloudapio.eu)
+ * @brief Create and map areas of memory shared between processes.
+ *
+ * @copyright Copyright (c) 2023, the Luna authors.
+ *
+ */
+
+#include <luna/Result.h>
+#include <luna/StringView.h>
+
+namespace os
+{
+    namespace SharedMemory
+    {
+        /**
+         * @brief Create a new shared memory region and map it.
+         *
+         * @param path The shared memory path to use. It must be of the same format as shm_open().
+         * @param size The amount of bytes to use for the shared memory region.
+         * @return Result<u8*> An error, or a pointer to the shared memory region.
+         */
+        Result<u8*> create(StringView path, usize size);
+
+        /**
+         * @brief Map an existing shared memory region, possibly created by another process.
+         *
+         * @param path The shared memory path to use. It must be of the same format as shm_open().
+         * @param size The amount of bytes to map from the shared memory region.
+         * @param delete_fs Whether to delete the region from the file system so no other processes can open it.
+         * @return Result<u8*> An error, or a pointer to the shared memory region.
+         */
+        Result<u8*> adopt(StringView path, usize size, bool delete_fs = true);
+    };
+}

libos/src/SharedMemory.cpp

@@ -0,0 +1,77 @@
+/**
+ * @file SharedMemory.cpp
+ * @author apio (cloudapio.eu)
+ * @brief Create and map areas of memory shared between processes.
+ *
+ * @copyright Copyright (c) 2023, the Luna authors.
+ *
+ */
+
+#include <errno.h>
+#include <luna/Alignment.h>
+#include <os/File.h>
+#include <os/SharedMemory.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+namespace os::SharedMemory
+{
+    Result<u8*> create(StringView path, usize size)
+    {
+        int fd = shm_open(path.chars(), O_RDWR | O_CREAT | O_EXCL, 0600);
+        if (fd < 0)
+        {
+            int olderr = errno;
+            os::eprintln("os: could not create shared memory region: shm_open failed (%s) - %s", path,
+                         strerror(olderr));
+            return err(olderr);
+        }
+
+        size = align_up<PAGE_SIZE>(size);
+
+        if (ftruncate(fd, size) < 0)
+        {
+            int olderr = errno;
+            os::eprintln("os: could not create shared memory region: ftruncate failed (%d, %zu) - %s", fd, size,
+                         strerror(olderr));
+            shm_unlink(path.chars());
+            close(fd);
+            return err(olderr);
+        }
+
+        void* p = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+        if (p == MAP_FAILED)
+        {
+            int olderr = errno;
+            os::eprintln("os: could not create shared memory region: mmap failed (%zu, %d) - %s", size, fd,
+                         strerror(olderr));
+            shm_unlink(path.chars());
+            close(fd);
+            return err(olderr);
+        }
+
+        close(fd);
+        return (u8*)p;
+    }
+
+    Result<u8*> adopt(StringView path, usize size, bool delete_fs)
+    {
+        int fd = shm_open(path.chars(), O_RDWR, 0600);
+        if (delete_fs) shm_unlink(path.chars());
+        if (fd < 0) return err(errno);
+
+        void* p = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+        if (p == MAP_FAILED)
+        {
+            int olderr = errno;
+            os::eprintln("os: could not adopt shared memory region: mmap failed (%zu, %d) - %s", size, fd,
+                         strerror(olderr));
+            close(fd);
+            return 0;
+        }
+
+        close(fd);
+        return (u8*)p;
+    }
+}

libui/src/Window.cpp

@@ -7,35 +7,12 @@
  *
  */
 
-#include <errno.h>
+#include <luna/String.h>
-#include <fcntl.h>
+#include <os/SharedMemory.h>
 #include <sys/mman.h>
 #include <ui/App.h>
 #include <ui/Window.h>
 #include <ui/ipc/Server.h>
-#include <unistd.h>
-
-static Result<u32*> create_shm_region(const char* path, int* outfd, ui::Rect rect)
-{
-    int fd = shm_open(path, O_RDWR, 0600);
-    shm_unlink(path);
-    if (fd < 0) return err(errno);
-
-    usize size = rect.width * rect.height * 4; // 4 bytes per pixel
-
-    void* p = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-    if (p == MAP_FAILED)
-    {
-        shm_unlink(path);
-        close(fd);
-        return 0;
-    }
-
-    if (outfd) *outfd = fd;
-    else
-        close(fd);
-    return (u32*)p;
-}
 
 namespace ui
 {
@@ -48,7 +25,9 @@ namespace ui
         request.decorated = decorated;
         auto response = TRY(os::IPC::send_sync<ui::CreateWindowResponse>(App::the().client(), request));
 
-        u32* pixels = TRY(create_shm_region(response.shm_path, nullptr, rect));
+        auto path = COPY_IPC_STRING(response.shm_path);
+
+        u32* pixels = (u32*)TRY(os::SharedMemory::adopt(path.view(), rect.height * rect.width * 4));
 
         window->m_canvas = ui::Canvas { rect.width, rect.height, rect.width, (u8*)pixels };
         window->m_id = response.window;

wind/IPC.cpp

@@ -1,13 +1,10 @@
 #include "IPC.h"
 #include "Screen.h"
-#include <errno.h>
 #include <luna/Alignment.h>
 #include <luna/String.h>
 #include <os/File.h>
-#include <string.h>
+#include <os/SharedMemory.h>
-#include <sys/mman.h>
 #include <time.h>
-#include <unistd.h>
 
 #define TRY_OR_IPC_ERROR(expr)                                                                                         \
     ({                                                                                                                 \
@@ -21,45 +18,6 @@
         _expr_rc.release_value();                                                                                      \
     })
 
-static Result<u32*> create_shm_region(const char* path, int* outfd, ui::Rect rect)
-{
-    int fd = shm_open(path, O_RDWR | O_CREAT | O_EXCL, 0600);
-    if (fd < 0)
-    {
-        int olderr = errno;
-        os::eprintln("wind: could not create shared memory region: shm_open failed (%s) - %s", path, strerror(olderr));
-        return err(olderr);
-    }
-
-    usize size = align_up<PAGE_SIZE>(rect.width * rect.height * 4); // 4 bytes per pixel
-
-    if (ftruncate(fd, size) < 0)
-    {
-        int olderr = errno;
-        os::eprintln("wind: could not create shared memory region: ftruncate failed (%d, %zu) - %s", fd, size,
-                     strerror(olderr));
-        shm_unlink(path);
-        close(fd);
-        return err(olderr);
-    }
-
-    void* p = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-    if (p == MAP_FAILED)
-    {
-        int olderr = errno;
-        os::eprintln("wind: could not create shared memory region: mmap failed (%zu, %d) - %s", size, fd,
-                     strerror(olderr));
-        shm_unlink(path);
-        close(fd);
-        return err(olderr);
-    }
-
-    if (outfd) *outfd = fd;
-    else
-        close(fd);
-    return (u32*)p;
-}
-
 #define READ_MESSAGE(request)                                                                                          \
     do {                                                                                                               \
         auto rc = client.conn.recv_typed(request);                                                                     \
@@ -96,8 +54,6 @@ static Result<void> handle_create_window_message(Client& client)
     ui::CreateWindowRequest request;
     READ_MESSAGE(request);
 
-    request.rect = request.rect.normalized();
-
     if (request.decorated)
     {
         request.rect.height +=
@@ -105,6 +61,8 @@ static Result<void> handle_create_window_message(Client& client)
         request.rect.pos.y -= Window::titlebar_height(); // Adjust it so the contents begin at the expected coordinates.
     }
 
+    request.rect = request.rect.normalized();
+
     auto name = TRY(String::from_cstring("Window"));
 
     auto* window = new (std::nothrow) Window(request.rect, move(name), request.decorated);
@@ -116,7 +74,8 @@ static Result<void> handle_create_window_message(Client& client)
 
     auto shm_path = TRY_OR_IPC_ERROR(String::format("/wind-shm-%d-%lu"_sv, client.conn.fd(), time(NULL)));
 
-    window->pixels = TRY_OR_IPC_ERROR(create_shm_region(shm_path.chars(), nullptr, window->contents));
+    window->pixels = (u32*)TRY_OR_IPC_ERROR(
+        os::SharedMemory::create(shm_path.view(), window->contents.height * window->contents.width * 4));
 
     TRY_OR_IPC_ERROR(client.windows.try_append(window));
     int id = static_cast<int>(client.windows.size() - 1);