libc: implement read and write by async_read and async_write

Issue genodelabs#5302
chelmuth · Sep 6, 2024 · 39838ce · 39838ce
1 parent 6ff558d
commit 39838ce
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Showing 4 changed files with 220 additions and 123 deletions.
diff --git a/repos/libports/src/lib/libc/internal/plugin.h b/repos/libports/src/lib/libc/internal/plugin.h
@@ -30,7 +30,7 @@ namespace Genode { class Env; }
 namespace Libc {
 
 	using namespace Genode;
-	
+
 	class File_descriptor;
 
 	using Absolute_path = Genode::Path<PATH_MAX>;
@@ -78,6 +78,19 @@ namespace Libc {
 			virtual bool supports_unlink(const char *path);
 			virtual bool supports_mmap();
 
+			/*
+			 * Asynchronous helper methods
+			 */
+			struct Async_read_state {
+				bool complete_read { false };
+			};
+			virtual bool async_read(File_descriptor *, void *, ::size_t, ::off_t, ssize_t &, int &, Async_read_state &);
+
+			struct Async_write_state {
+				size_t bytes_written { 0 };
+			};
+			virtual bool async_write(File_descriptor *, const void *, ::size_t, ::off_t, ssize_t &, int &, Async_write_state &);
+
 			/*
 			 * Should be overwritten for plugins that require the Genode environment
 			 */

diff --git a/repos/libports/src/lib/libc/internal/vfs_plugin.h b/repos/libports/src/lib/libc/internal/vfs_plugin.h
@@ -223,6 +223,12 @@ class Libc::Vfs_plugin final : public Plugin
 		bool supports_unlink(const char *)                     override { return true; }
 		bool supports_mmap()                                   override { return true; }
 
+		/*
+		 * Helper functions to use in the context of a monitor job
+		 */
+		bool async_read(File_descriptor *, void *, ::size_t, ::off_t, ssize_t &, int &, Async_read_state &) override;
+		bool async_write(File_descriptor *, const void *, ::size_t, ::off_t, ssize_t &, int &, Async_write_state &) override;
+
 		/* kernel-specific API without monitor */
 		File_descriptor *open_from_kernel(const char *, int, int libc_fd);
 		int close_from_kernel(File_descriptor *);

diff --git a/repos/libports/src/lib/libc/plugin.cc b/repos/libports/src/lib/libc/plugin.cc
@@ -21,6 +21,8 @@
 #include <internal/init.h>
 #include <internal/resume.h>
 
+#include <errno.h>
+
 using namespace Libc;
 
 
@@ -140,6 +142,27 @@ bool Plugin::supports_mmap()
 }
 
 
+/*
+ * Asynchronous helper functions
+ */
+bool Plugin::async_read(File_descriptor *, void *, ::size_t, ::off_t, ssize_t &retval, int &error, Async_read_state &)
+{
+	error = EBADF;
+	retval = -1;
+
+	return true;
+}
+
+
+bool Plugin::async_write(File_descriptor *, const void *, ::size_t, ::off_t, ssize_t &retval, int &error, Async_write_state &)
+{
+	error = EBADF;
+	retval = -1;
+
+	return true;
+}
+
+
 /**
  * Generate dummy member function of Plugin class
  */