use std_options for keep_sigpipe and existence of SIG.PIPE to check for support

This commit is contained in:
Jonathan Marler 2023-02-18 11:46:24 -07:00
parent 0a8fe34b11
commit dafefe9c9d
3 changed files with 19 additions and 33 deletions

View File

@ -7057,42 +7057,12 @@ pub fn timerfd_gettime(fd: i32) TimerFdGetError!linux.itimerspec {
};
}
/// Whether or not the current target support SIGPIPE
pub const have_sigpipe_support = switch (builtin.os.tag) {
.linux,
.macos,
.netbsd,
.solaris,
.freebsd,
.openbsd,
=> true,
else => false,
};
pub const keep_sigpipe: bool = if (@hasDecl(root, "keep_sigpipe"))
root.keep_sigpipe
else
false;
pub const have_sigpipe_support = @hasDecl(@This(), "SIG") and @hasDecl(SIG, "PIPE");
fn noopSigHandler(_: c_int) callconv(.C) void {}
/// This function will tell the kernel to ignore SIGPIPE rather than terminate
/// the process. This function is automatically called in `start.zig` before
/// `main`. This behavior can be disabled by adding this to your root module:
///
/// pub const keep_sigpipe = true;
///
/// SIGPIPE is triggered when a process attempts to write to a broken pipe.
/// By default, SIGPIPE will terminate the process without giving the program
/// an opportunity to handle the situation. Unlike a segfault, it doesn't
/// trigger the panic handler so all the developer sees is that the program
/// terminated with no indication as to why.
///
/// By telling the kernel to instead ignore SIGPIPE, writes to broken pipes
/// will return the EPIPE error (error.BrokenPipe) and the program can handle
/// it like any other error.
pub fn maybeIgnoreSigpipe() void {
if (have_sigpipe_support and !keep_sigpipe) {
if (have_sigpipe_support and !std.options.keep_sigpipe) {
const act = Sigaction{
// We set handler to a noop function instead of SIG.IGN so we don't leak our
// signal disposition to a child process

View File

@ -167,6 +167,22 @@ pub const options = struct {
options_override.crypto_always_getrandom
else
false;
/// By default Zig disables SIGPIPE by setting a "no-op" handler for it. Set this option
/// to `true` to prevent that.
///
/// Note that we use a "no-op" handler instead of SIG_IGN because it will not be inherited by
/// any child process.
///
/// SIGPIPE is triggered when a process attempts to write to a broken pipe. By default, SIGPIPE
/// will terminate the process instead of exiting. It doesn't trigger the panic handler so in many
/// cases it's unclear why the process was terminated. By capturing SIGPIPE instead, functions that
/// write to broken pipes will return the EPIPE error (error.BrokenPipe) and the program can handle
/// it like any other error.
pub const keep_sigpipe: bool = if (@hasDecl(options_override, "keep_sigpipe"))
options_override.keep_sigpipe
else
false;
};
// This forces the start.zig file to be imported, and the comptime logic inside that

View File

@ -1,7 +1,7 @@
const std = @import("std");
const build_options = @import("build_options");
pub usingnamespace if (build_options.keep_sigpipe) struct {
pub const std_options = if (build_options.keep_sigpipe) struct {
pub const keep_sigpipe = true;
} else struct {
// intentionally not setting keep_sigpipe to ensure the default behavior is equivalent to false