std.os.getrandom does a libc version check

closes #397
ziglang · Jul 8, 2019 · fc9e28e · fc9e28e
1 parent 4953e84
commit fc9e28e
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Showing 3 changed files with 35 additions and 4 deletions.
diff --git a/src/ir.cpp b/src/ir.cpp
@@ -11191,7 +11191,7 @@ static IrBasicBlock *ir_get_new_bb_runtime(IrAnalyze *ira, IrBasicBlock *old_bb,
 }
 
 static void ir_start_bb(IrAnalyze *ira, IrBasicBlock *old_bb, IrBasicBlock *const_predecessor_bb) {
- assert(!old_bb->suspended);
+ ir_assert(!old_bb->suspended, old_bb->instruction_list.at(0));
  ira->instruction_index = 0;
  ira->old_irb.current_basic_block = old_bb;
  ira->const_predecessor_bb = const_predecessor_bb;

diff --git a/std/c.zig b/std/c.zig
@@ -21,6 +21,33 @@ pub fn getErrno(rc: var) u16 {
  }
 }
 
+/// The return type is `type` to force comptime function call execution.
+/// TODO: https:/ziglang/zig/issues/425
+/// If not linking libc, returns struct{pub const ok = false;}
+/// If linking musl libc, returns struct{pub const ok = true;}
+/// If linking gnu libc (glibc), the `ok` value will be true if the target
+/// version is greater than or equal to `glibc_version`.
+/// If linking a libc other than these, returns `false`.
+pub fn versionCheck(glibc_version: builtin.Version) type {
+ return struct {
+ pub const ok = blk: {
+ if (!builtin.link_libc) break :blk false;
+ switch (builtin.abi) {
+ .musl, .musleabi, .musleabihf => break :blk true,
+ .gnu, .gnuabin32, .gnuabi64, .gnueabi, .gnueabihf, .gnux32 => {
+ const ver = builtin.glibc_version orelse break :blk false;
+ if (ver.major < glibc_version.major) break :blk false;
+ if (ver.major > glibc_version.major) break :blk true;
+ if (ver.minor < glibc_version.minor) break :blk false;
+ if (ver.minor > glibc_version.minor) break :blk true;
+ break :blk ver.patch >= glibc_version.patch;
+ },
+ else => break :blk false,
+ }
+ };
+ };
+}
+
 // TODO https:/ziglang/zig/issues/265 on this whole file
 
 pub extern "c" fn fopen(filename: [*]const u8, modes: [*]const u8) ?*FILE;

diff --git a/std/os.zig b/std/os.zig
@@ -105,14 +105,18 @@ pub fn getrandom(buf: []u8) GetRandomError!void {
  }
  if (linux.is_the_target) {
  while (true) {
- // Bypass libc because it's missing on even relatively new versions.
- switch (linux.getErrno(linux.getrandom(buf.ptr, buf.len, 0))) {
+ const err = if (std.c.versionCheck(builtin.Version{ .major = 2, .minor = 25, .patch = 0 }).ok) blk: {
+ break :blk errno(std.c.getrandom(buf.ptr, buf.len, 0));
+ } else blk: {
+ break :blk linux.getErrno(linux.getrandom(buf.ptr, buf.len, 0));
+ };
+ switch (err) {
  0 => return,
  EINVAL => unreachable,
  EFAULT => unreachable,
  EINTR => continue,
  ENOSYS => return getRandomBytesDevURandom(buf),
- else => |err| return unexpectedErrno(err),
+ else => return unexpectedErrno(err),
  }
  }
  }