diff options
Diffstat (limited to 'lib/std')
| -rw-r--r-- | lib/std/fs.zig | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/lib/std/fs.zig b/lib/std/fs.zig index 052343599e..f7a9249f1c 100644 --- a/lib/std/fs.zig +++ b/lib/std/fs.zig @@ -2547,6 +2547,15 @@ pub const SelfExePathError = os.ReadLinkError || os.SysCtlError || os.RealPathEr /// `selfExePath` except allocates the result on the heap. /// Caller owns returned memory. pub fn selfExePathAlloc(allocator: Allocator) ![]u8 { + if (builtin.os.tag == .wasi) { + var args = try std.process.argsWithAllocator(allocator); + defer args.deinit(); + // On WASI, argv[0] is always just the basename of the current executable + const exe_name = args.next() orelse return error.FileNotFound; + + var buf: [MAX_PATH_BYTES]u8 = undefined; + return allocator.dupe(u8, try selfExePathWasi(&buf, exe_name)); + } // Use of MAX_PATH_BYTES here is justified as, at least on one tested Linux // system, readlink will completely fail to return a result larger than // PATH_MAX even if given a sufficiently large buffer. This makes it @@ -2643,10 +2652,48 @@ pub fn selfExePath(out_buffer: []u8) SelfExePathError![]u8 { const end_index = std.unicode.utf16leToUtf8(out_buffer, utf16le_slice) catch unreachable; return out_buffer[0..end_index]; }, + .wasi => @compileError("std.fs.selfExePath not supported for WASI. Use std.fs.selfExePathAlloc instead."), else => @compileError("std.fs.selfExePath not supported for this target"), } } +/// WASI-specific implementation of selfExePath +/// +/// On WASI argv0 is always just the executable basename, so this function relies +/// using a fixed executable directory path: "/zig" +/// +/// This path can be configured in wasmtime using `--mapdir=/zig::/path/to/zig/dir/` +fn selfExePathWasi(out_buffer: []u8, argv0: []const u8) SelfExePathError![]const u8 { + var allocator = std.heap.FixedBufferAllocator.init(out_buffer); + var alloc = allocator.allocator(); + + // Check these paths: + // 1. "/zig/{exe_name}" + // 2. "/zig/bin/{exe_name}" + const base_paths_to_check = &[_][]const u8{ "/zig", "/zig/bin" }; + const exe_names_to_check = &[_][]const u8{ path.basename(argv0), "zig.wasm" }; + + for (base_paths_to_check) |base_path| { + for (exe_names_to_check) |exe_name| { + const test_path = path.join(alloc, &.{ base_path, exe_name }) catch continue; + + // Make sure it's a file we're pointing to + const file = os.fstatat(os.wasi.AT.FDCWD, test_path, 0) catch continue; + if (file.filetype != .REGULAR_FILE) continue; + + // Path seems to be valid, let's try to turn it into an absolute path + var real_path_buf: [MAX_PATH_BYTES]u8 = undefined; + if (os.realpath(test_path, &real_path_buf)) |real_path| { + if (real_path.len > out_buffer.len) + return error.NameTooLong; + mem.copy(u8, out_buffer, real_path); + return out_buffer[0..real_path.len]; + } else |_| continue; + } + } + return error.FileNotFound; +} + /// The result is UTF16LE-encoded. pub fn selfExePathW() [:0]const u16 { const image_path_name = &os.windows.peb().ProcessParameters.ImagePathName; |