1 // Copyright 2024 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_MEMORY_SHARED_MEMORY_SWITCH_H_ 6 #define BASE_MEMORY_SHARED_MEMORY_SWITCH_H_ 7 8 #include <string_view> 9 10 #include "base/base_export.h" 11 #include "base/memory/read_only_shared_memory_region.h" 12 #include "base/memory/unsafe_shared_memory_region.h" 13 #include "base/types/expected.h" 14 #include "build/blink_buildflags.h" 15 #include "build/build_config.h" 16 17 #if !BUILDFLAG(USE_BLINK) 18 #error "This is only intended for platforms that use blink." 19 #endif 20 21 #if BUILDFLAG(IS_APPLE) 22 #include "base/mac/mach_port_rendezvous.h" 23 #endif 24 25 #if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE) 26 #include "base/files/platform_file.h" 27 #include "base/posix/global_descriptors.h" 28 #endif 29 30 namespace base { 31 32 class CommandLine; 33 struct LaunchOptions; 34 35 namespace shared_memory { 36 37 // Indicates failure modes of deserializing a shared memory switch value. 38 enum class SharedMemoryError { 39 kNoError, 40 kUnexpectedTokensCount, 41 kParseInt0Failed, 42 kParseInt4Failed, 43 kUnexpectedHandleType, 44 kInvalidHandle, 45 kGetFDFailed, 46 kDeserializeGUIDFailed, 47 kDeserializeFailed, 48 kCreateTrialsFailed, 49 kUnexpectedSize, 50 }; 51 52 // Updates `command_line` and `launch_options` to use `switch_name` to pass 53 // `read_only_memory_region` to child process that is about to be launched. 54 // This should be called in the parent process as a part of setting up the 55 // launch conditions of the child. This call will update the `command_line` 56 // and `launch_options`. On posix, where we prefer to use a zygote instead of 57 // using the launch_options to launch a new process, the platform 58 // `descriptor_to_share` is returned. The caller is expected to transmit the 59 // descriptor to the launch flow for the zygote. 60 BASE_EXPORT void AddToLaunchParameters( 61 std::string_view switch_name, 62 ReadOnlySharedMemoryRegion read_only_memory_region, 63 #if BUILDFLAG(IS_APPLE) 64 MachPortsForRendezvous::key_type rendezvous_key, 65 #elif BUILDFLAG(IS_POSIX) 66 GlobalDescriptors::Key descriptor_key, 67 ScopedFD& out_descriptor_to_share, 68 #endif 69 CommandLine* command_line, 70 LaunchOptions* launch_options); 71 72 // Updates `command_line` and `launch_options` to use `switch_name` to pass 73 // `unsafe_memory_region` to a child process that is about to be launched. 74 // This should be called in the parent process as a part of setting up the 75 // launch conditions of the child. This call will update the `command_line` 76 // and `launch_options`. On posix, where we prefer to use a zygote instead of 77 // using the launch_options to launch a new process, the platform 78 // `descriptor_to_share` is returned. The caller is expected to transmit the 79 // descriptor to the launch flow for the zygote. 80 BASE_EXPORT void AddToLaunchParameters( 81 std::string_view switch_name, 82 UnsafeSharedMemoryRegion unsafe_memory_region, 83 #if BUILDFLAG(IS_APPLE) 84 MachPortsForRendezvous::key_type rendezvous_key, 85 #elif BUILDFLAG(IS_POSIX) 86 GlobalDescriptors::Key descriptor_key, 87 ScopedFD& out_descriptor_to_share, 88 #endif 89 CommandLine* command_line, 90 LaunchOptions* launch_options); 91 92 // Returns an UnsafeSharedMemoryRegion deserialized from `switch_value`. 93 BASE_EXPORT expected<UnsafeSharedMemoryRegion, SharedMemoryError> 94 UnsafeSharedMemoryRegionFrom(std::string_view switch_value); 95 96 // Returns an ReadOnlySharedMemoryRegion deserialized from `switch_value`. 97 BASE_EXPORT expected<ReadOnlySharedMemoryRegion, SharedMemoryError> 98 ReadOnlySharedMemoryRegionFrom(std::string_view switch_value); 99 100 } // namespace shared_memory 101 } // namespace base 102 103 #endif // BASE_MEMORY_SHARED_MEMORY_SWITCH_H_ 104