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fix footguns in File readAll functions

master
Andrew Kelley 2020-03-11 13:06:30 -04:00
parent ed13cffca4
commit d96b6c0d9f
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GPG Key ID: 7C5F548F728501A9
4 changed files with 75 additions and 37 deletions
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33
lib/std/fs.zig
View File

@ -96,6 +96,7 @@ pub fn updateFile(source_path: []const u8, dest_path: []const u8) !PrevStatus {
/// atime, and mode of the source file so that the next call to `updateFile` will not need a copy.
/// Returns the previous status of the file before updating.
/// If any of the directories do not exist for dest_path, they are created.
/// TODO rework this to integrate with Dir
pub fn updateFileMode(source_path: []const u8, dest_path: []const u8, mode: ?File.Mode) !PrevStatus {
const my_cwd = cwd();
@ -141,29 +142,25 @@ pub fn updateFileMode(source_path: []const u8, dest_path: []const u8, mode: ?Fil
/// there is a possibility of power loss or application termination leaving temporary files present
/// in the same directory as dest_path.
/// Destination file will have the same mode as the source file.
/// TODO rework this to integrate with Dir
pub fn copyFile(source_path: []const u8, dest_path: []const u8) !void {
var in_file = try cwd().openFile(source_path, .{});
defer in_file.close();
const mode = try in_file.mode();
const in_stream = &in_file.inStream().stream;
const stat = try in_file.stat();
var atomic_file = try AtomicFile.init(dest_path, mode);
var atomic_file = try AtomicFile.init(dest_path, stat.mode);
defer atomic_file.deinit();
var buf: [mem.page_size]u8 = undefined;
while (true) {
const amt = try in_stream.readFull(buf[0..]);
try atomic_file.file.write(buf[0..amt]);
if (amt != buf.len) {
return atomic_file.finish();
}
}
try atomic_file.file.writeFileAll(in_file, .{ .in_len = stat.size });
return atomic_file.finish();
}
/// Guaranteed to be atomic. However until https://patchwork.kernel.org/patch/9636735/ is
/// merged and readily available,
/// Guaranteed to be atomic.
/// On Linux, until https://patchwork.kernel.org/patch/9636735/ is merged and readily available,
/// there is a possibility of power loss or application termination leaving temporary files present
/// in the same directory as dest_path.
/// TODO rework this to integrate with Dir
pub fn copyFileMode(source_path: []const u8, dest_path: []const u8, mode: File.Mode) !void {
var in_file = try cwd().openFile(source_path, .{});
defer in_file.close();
@ -171,14 +168,8 @@ pub fn copyFileMode(source_path: []const u8, dest_path: []const u8, mode: File.M
var atomic_file = try AtomicFile.init(dest_path, mode);
defer atomic_file.deinit();
var buf: [mem.page_size * 6]u8 = undefined;
while (true) {
const amt = try in_file.read(buf[0..]);
try atomic_file.file.write(buf[0..amt]);
if (amt != buf.len) {
return atomic_file.finish();
}
}
try atomic_file.file.writeFileAll(in_file, .{});
return atomic_file.finish();
}
/// TODO update this API to avoid a getrandom syscall for every operation. It

42
lib/std/fs/file.zig
View File

@ -250,11 +250,16 @@ pub const File = struct {
}
}
pub fn readAll(self: File, buffer: []u8) ReadError!void {
/// Returns the number of bytes read. If the number read is smaller than `buffer.len`, it
/// means the file reached the end. Reaching the end of a file is not an error condition.
pub fn readAll(self: File, buffer: []u8) ReadError!usize {
var index: usize = 0;
while (index < buffer.len) {
index += try self.read(buffer[index..]);
while (index != buffer.len) {
const amt = try self.read(buffer[index..]);
if (amt == 0) break;
index += amt;
}
return index;
}
pub fn pread(self: File, buffer: []u8, offset: u64) PReadError!usize {
@ -265,11 +270,16 @@ pub const File = struct {
}
}
pub fn preadAll(self: File, buffer: []u8, offset: u64) PReadError!void {
/// Returns the number of bytes read. If the number read is smaller than `buffer.len`, it
/// means the file reached the end. Reaching the end of a file is not an error condition.
pub fn preadAll(self: File, buffer: []u8, offset: u64) PReadError!usize {
var index: usize = 0;
while (index < buffer.len) {
index += try self.pread(buffer[index..], offset + index);
while (index != buffer.len) {
const amt = try self.pread(buffer[index..], offset + index);
if (amt == 0) break;
index += amt;
}
return index;
}
pub fn readv(self: File, iovecs: []const os.iovec) ReadError!usize {
@ -280,19 +290,27 @@ pub const File = struct {
}
}
/// Returns the number of bytes read. If the number read is smaller than the total bytes
/// from all the buffers, it means the file reached the end. Reaching the end of a file
/// is not an error condition.
/// The `iovecs` parameter is mutable because this function needs to mutate the fields in
/// order to handle partial reads from the underlying OS layer.
pub fn readvAll(self: File, iovecs: []os.iovec) ReadError!void {
pub fn readvAll(self: File, iovecs: []os.iovec) ReadError!usize {
if (iovecs.len == 0) return;
var i: usize = 0;
var off: usize = 0;
while (true) {
var amt = try self.readv(iovecs[i..]);
var eof = amt == 0;
off += amt;
while (amt >= iovecs[i].iov_len) {
amt -= iovecs[i].iov_len;
i += 1;
if (i >= iovecs.len) return;
if (i >= iovecs.len) return off;
eof = false;
}
if (eof) return off;
iovecs[i].iov_base += amt;
iovecs[i].iov_len -= amt;
}
@ -306,6 +324,9 @@ pub const File = struct {
}
}
/// Returns the number of bytes read. If the number read is smaller than the total bytes
/// from all the buffers, it means the file reached the end. Reaching the end of a file
/// is not an error condition.
/// The `iovecs` parameter is mutable because this function needs to mutate the fields in
/// order to handle partial reads from the underlying OS layer.
pub fn preadvAll(self: File, iovecs: []const os.iovec, offset: u64) PReadError!void {
@ -315,12 +336,15 @@ pub const File = struct {
var off: usize = 0;
while (true) {
var amt = try self.preadv(iovecs[i..], offset + off);
var eof = amt == 0;
off += amt;
while (amt >= iovecs[i].iov_len) {
amt -= iovecs[i].iov_len;
i += 1;
if (i >= iovecs.len) return;
if (i >= iovecs.len) return off;
eof = false;
}
if (eof) return off;
iovecs[i].iov_base += amt;
iovecs[i].iov_len -= amt;
}

5
lib/std/io/in_stream.zig
View File

@ -28,10 +28,7 @@ pub fn InStream(
return readFn(self.context, buffer);
}
/// Deprecated: use `readAll`.
pub const readFull = readAll;
/// Returns the number of bytes read. If the number read is smaller than buf.len, it
/// Returns the number of bytes read. If the number read is smaller than `buffer.len`, it
/// means the stream reached the end. Reaching the end of a stream is not an error
/// condition.
pub fn readAll(self: Self, buffer: []u8) Error!usize {

32
lib/std/os/test.zig
View File

@ -95,15 +95,41 @@ test "sendfile" {
},
};
var written_buf: [header1.len + header2.len + 10 + trailer1.len + trailer2.len]u8 = undefined;
var written_buf: [100]u8 = undefined;
try dest_file.writeFileAll(src_file, .{
.in_offset = 1,
.in_len = 10,
.headers_and_trailers = &hdtr,
.header_count = 2,
});
try dest_file.preadAll(&written_buf, 0);
expect(mem.eql(u8, &written_buf, "header1\nsecond header\nine1\nsecontrailer1\nsecond trailer\n"));
const amt = try dest_file.preadAll(&written_buf, 0);
expect(mem.eql(u8, written_buf[0..amt], "header1\nsecond header\nine1\nsecontrailer1\nsecond trailer\n"));
}
test "fs.copyFile" {
const data = "u6wj+JmdF3qHsFPE BUlH2g4gJCmEz0PP";
const src_file = "tmp_test_copy_file.txt";
const dest_file = "tmp_test_copy_file2.txt";
const dest_file2 = "tmp_test_copy_file3.txt";
try fs.cwd().writeFile(src_file, data);
defer fs.cwd().deleteFile(src_file) catch {};
try fs.copyFile(src_file, dest_file);
defer fs.cwd().deleteFile(dest_file) catch {};
try fs.copyFileMode(src_file, dest_file2, File.default_mode);
defer fs.cwd().deleteFile(dest_file2) catch {};
try expectFileContents(dest_file, data);
try expectFileContents(dest_file2, data);
}
fn expectFileContents(file_path: []const u8, data: []const u8) !void {
const contents = try fs.cwd().readFileAlloc(testing.allocator, file_path, 1000);
defer testing.allocator.free(contents);
testing.expectEqualSlices(u8, data, contents);
}
test "std.Thread.getCurrentId" {