liblinux++

commit 0dda04fa914c3932d10a52f3517ed51650aa8f64
parent 0a27f7f2616afb73e29ca56a05004d715dc17a1c
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Tue,  6 Jan 2026 01:00:07 +0000

Add errno.hpp generation and exec

Diffstat:
M
Tupfile
 | 
6
++++--
A
errno.sh
 | 
6
++++++
A
exec.cpp
 | 
17
+++++++++++++++++
M
linux.hpp
 | 
12
+++---------
M
syscalls.h
 | 
4
++++

5 files changed, 34 insertions(+), 11 deletions(-)
diff --git a/Tupfile b/Tupfile
@@ -1,8 +1,10 @@
 CXXFLAGS = -std=c++23 -Werror -g -fno-exceptions -fno-rtti -fno-asynchronous-unwind-tables -fno-builtin -fno-pic -fno-pie -fno-stack-protector -fdiagnostics-color=always
 LDFLAGS = --gc-sections
 
-: foreach *.cpp |> ^j^ clang++ --target=aarch64 $(CXXFLAGS) -c -o %o %f |> obj/%B.aarch64.o {objs-aarch64}
-: foreach *.cpp |> ^j^ clang++ --target=x86_64 $(CXXFLAGS) -c -o %o %f |> obj/%B.x86_64.o {objs-x86_64}
+: |> ./errno.sh > %o |> errno.hpp {pre-compile}
+
+: foreach *.cpp | {pre-compile} |> ^j^ clang++ --target=aarch64 $(CXXFLAGS) -c -o %o %f |> obj/%B.aarch64.o {objs-aarch64}
+: foreach *.cpp | {pre-compile} |> ^j^ clang++ --target=x86_64 $(CXXFLAGS) -c -o %o %f |> obj/%B.x86_64.o {objs-x86_64}
 
 : foreach *.S |> clang --target=%B -c -o %o %f |> obj/%B.o
 
diff --git a/errno.sh b/errno.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+set -eu
+
+echo -e '#pragma once\n\nenum class errno_t : int16_t {'
+sed -En 's/#[[:space:]]*define[[:space:]]+E([[:alnum:]]+)[[:space:]]+([[:digit:]]+)/E\1 = -\2,/p' /usr/include/asm-generic/errno{,-base}.h
+echo '};'
diff --git a/exec.cpp b/exec.cpp
@@ -0,0 +1,17 @@
+#include "linux.hpp"
+#include "errno.hpp"
+
+int main(int argc, char* argv[], char* envp[])
+{
+	if (argc < 2)
+		return 1;
+	switch (execve(argv[1], argv + 1, envp).err())
+	{
+	case errno_t::ENOENT:
+		*write(stderr, "ENOENT: No such file or directory\n");
+		break;
+	default:
+		__builtin_trap();
+	}
+	return 1;
+}
diff --git a/linux.hpp b/linux.hpp
@@ -92,15 +92,7 @@ constexpr file const stdin{0};
 constexpr file const stdout{1};
 constexpr file const stderr{2};
 
-enum class errno_t : int16_t
-{
-	EPERM = -1,	/* Operation not permitted */
-	ENOENT = -2,	/* No such file or directory */
-	ESRCH = -3,	/* No such process */
-	EINTR = -4,	/* Interrupted system call */
-
-	EINVAL = -22,	/* Invalid argument */
-};
+enum class errno_t : int16_t;
 
 template <typename T>
 struct [[nodiscard]] syscall_result
@@ -197,6 +189,8 @@ enum class unlink_flags : int
 
 extern syscall_result<void> unlinkat(file dir, c_str path, unlink_flags flags);
 
+extern syscall_result<void> execve(c_str path, char *const /*_Nullable*/ argv[], char *const /*_Nullable*/ envp[]);
+
 extern "C"
 {
 
diff --git a/syscalls.h b/syscalls.h
@@ -28,6 +28,10 @@ extern close
 extern_alias _Z5close4file
 SYS(close)
 
+extern execve
+extern_alias _Z6execve5c_strPKPcS2_
+SYS(execve)
+
 extern exit
 extern_alias _Z4exiti
 SYS(exit)