breaking: let posixRead() return less than buffer size, introduce pos…

…ixReadFull() posixRead should be as thin an abstraction on top of read() as possible. posixReadFull() really should be in io somewhere.
ziglang · Aug 28, 2018 · 9691422 · 9691422
1 parent 4003cd4
commit 9691422
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 13 deletions.
diff --git a/std/os/child_process.zig b/std/os/child_process.zig
@@ -757,6 +757,6 @@ fn writeIntFd(fd: i32, value: ErrInt) !void {
 
 fn readIntFd(fd: i32) !ErrInt {
     var bytes: [@sizeOf(ErrInt)]u8 = undefined;
-    os.posixRead(fd, bytes[0..]) catch return error.SystemResources;
+    os.posixReadFull(fd, bytes[0..]) catch return error.SystemResources;
     return mem.readInt(bytes[0..], ErrInt, builtin.endian);
 }
diff --git a/std/os/index.zig b/std/os/index.zig
@@ -31,7 +31,7 @@ pub const posix = switch (builtin.os) {
     Os.zen => zen,
     else => @compileError("Unsupported OS"),
 };
-pub const net = @import("net.zig");
+pub const net = std.net;
 
 pub const ChildProcess = @import("child_process.zig").ChildProcess;
 pub const path = @import("path.zig");
@@ -114,7 +114,7 @@ pub fn getRandomBytes(buf: []u8) !void {
                         const fd = try posixOpenC(c"/dev/urandom", posix.O_RDONLY | posix.O_CLOEXEC, 0);
                         defer close(fd);
 
-                        try posixRead(fd, buf);
+                        try posixReadFull(fd, buf);
                         return;
                     },
                     else => return unexpectedErrorPosix(err),
@@ -126,7 +126,7 @@ pub fn getRandomBytes(buf: []u8) !void {
             const fd = try posixOpenC(c"/dev/urandom", posix.O_RDONLY | posix.O_CLOEXEC, 0);
             defer close(fd);
 
-            try posixRead(fd, buf);
+            try posixReadFull(fd, buf);
         },
         Os.windows => {
             // Call RtlGenRandom() instead of CryptGetRandom() on Windows
@@ -229,15 +229,10 @@ pub fn close(handle: FileHandle) void {
 }
 
 /// Calls POSIX read, and keeps trying if it gets interrupted.
-pub fn posixRead(fd: i32, buf: []u8) !void {
-    // Linux can return EINVAL when read amount is > 0x7ffff000
-    // See https://github.com/ziglang/zig/pull/743#issuecomment-363158274
-    const max_buf_len = 0x7ffff000;
-
-    var index: usize = 0;
-    while (index < buf.len) {
-        const want_to_read = math.min(buf.len - index, usize(max_buf_len));
-        const rc = posix.read(fd, buf.ptr + index, want_to_read);
+pub fn posixRead(fd: i32, buf: []u8) !usize {
+    // Just for EINTR
+    while (true) {
+        const rc = posix.read(fd, buf.ptr, buf.len);
         const err = posix.getErrno(rc);
         if (err > 0) {
             return switch (err) {
@@ -251,6 +246,20 @@ pub fn posixRead(fd: i32, buf: []u8) !void {
                 else => unexpectedErrorPosix(err),
             };
         }
+        return rc;
+    }
+}
+
+/// Calls POSIX read, and keeps trying if it gets interrupted.
+pub fn posixReadFull(fd: i32, buf: []u8) !void {
+    // Linux can return EINVAL when read amount is > 0x7ffff000
+    // See https://github.com/ziglang/zig/pull/743#issuecomment-363158274
+    const max_buf_len = 0x7ffff000;
+
+    var index: usize = 0;
+    while (index < buf.len) {
+        const want_to_read = math.min(buf.len - index, usize(max_buf_len));
+        const rc = try posixRead(fd, buf[index..]);
         index += rc;
     }
 }