refactor(utils): enhance prctl/ioctl error diagnostics

src/linyaps_box/container.cpp

@@ -23,12 +23,11 @@
 #include "linyaps_box/utils/signal.h"
 #include "linyaps_box/utils/symlink.h"
 
 #include <linux/magic.h>
 #include <sys/mount.h>
-#include <sys/prctl.h>
 #include <sys/signalfd.h>
 #include <sys/statfs.h>
 #include <sys/sysmacros.h>
 
 #include <algorithm>
 #include <cassert>
@@ -1564,10 +1563,7 @@
     }
 
     // keep current capabilities, we need these caps on later
-    ret = prctl(PR_SET_KEEPCAPS, 1);
-    if (ret < 0) {
-        throw std::system_error(errno, std::system_category(), "keep current capabilities");
-    }
+    std::ignore = linyaps_box::utils::prctl(PR_SET_KEEPCAPS, 1);
 
     const auto &process = config.process;
     ret = setresuid(process.user.uid, process.user.uid, process.user.uid);
@@ -1586,26 +1582,18 @@
     }
 
 #ifdef PR_CAP_AMBIENT
-    ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0L, 0L, 0L);
-    if (ret < 0) {
-        throw std::system_error(errno, std::system_category(), "cap_ambient_clear_all");
-    }
+    std::ignore = linyaps_box::utils::prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0L, 0L, 0L);
 
     std::for_each(capabilities.ambient.cbegin(), capabilities.ambient.cend(), [](cap_value_t cap) {
-        auto ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap, 0L, 0L);
-        if (ret < 0) {
-            throw std::system_error(errno, std::system_category(), "cap_ambient_raise");
-        }
+        std::ignore = linyaps_box::utils::prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap, 0L, 0L);
     });
 #endif
 
 #endif
 
     if (config.process.no_new_privileges) {
         LINYAPS_BOX_DEBUG() << "Set no new privileges";
-        if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
-            throw std::system_error(errno, std::system_category(), "prctl");
-        }
+        std::ignore = linyaps_box::utils::prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
     }
 }
 
@@ -2477,7 +2465,7 @@
 {
     int container_process_exit_code{ -1 };
 
-    utils::prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
+    std::ignore = utils::prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
 
     try {
         // TODO: there are some thing that should be done before starting the container process

src/linyaps_box/container_ref.cpp

@@ -48,7 +48,7 @@ auto linyaps_box::container_ref::exec(exec_container_option option) -> int
     auto target = std::to_string(this->status().PID);
 
     // TODO: support detach later
-    utils::prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
+    std::ignore = utils::prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
 
     std::optional<unix_socket> recv_socketpair;
     if (option.proc.terminal && !option.console_socket) {

src/linyaps_box/terminal.cpp

@@ -29,7 +29,7 @@ auto create_pty_pair() -> std::pair<terminal_master, terminal_slave>
 
 auto terminal_master::resize(struct winsize size) -> void
 {
-    utils::ioctl(master_, TIOCSWINSZ, &size);
+    std::ignore = utils::ioctl(master_, TIOCSWINSZ, &size);
 }
 
 terminal_slave::terminal_slave(terminal_slave &&other) noexcept
@@ -56,17 +56,17 @@ auto terminal_slave::setup_stdio() -> void
     slave_.duplicate_to(STDIN_FILENO, 0);
     slave_.duplicate_to(STDOUT_FILENO, 0);
     slave_.duplicate_to(STDERR_FILENO, 0);
-    utils::ioctl(slave_, TIOCSCTTY, 0);
+    std::ignore = utils::ioctl(slave_, TIOCSCTTY, 0);
 }
 
 auto terminal_slave::set_size(struct winsize size) -> void
 {
     if (size.ws_col == 0 || size.ws_row == 0) {
         auto default_tty = utils::open("/dev/tty", O_RDWR | O_CLOEXEC);
-        utils::ioctl(default_tty, TIOCGWINSZ, &size);
+        std::ignore = utils::ioctl(default_tty, TIOCGWINSZ, &size);
     }
 
-    utils::ioctl(slave_, TIOCSWINSZ, &size);
+    std::ignore = utils::ioctl(slave_, TIOCSWINSZ, &size);
 }
 
 auto terminal_slave::set_raw() -> void
@@ -91,7 +91,7 @@ auto terminal_slave::set_raw() -> void
 auto terminal_slave::get_size() -> struct winsize
 {
     struct winsize size{ };
-    utils::ioctl(slave_, TIOCGWINSZ, &size);
+    std::ignore = utils::ioctl(slave_, TIOCGWINSZ, &size);
     return size;
 }
 

src/linyaps_box/utils/ioctl.h

@@ -11,14 +11,20 @@
 
 namespace linyaps_box::utils {
 
+using request_t = extract_t<decltype(get_n_params_type<1>(::ioctl))>;
+
 template<typename... Args>
-auto ioctl(const file_descriptor &fd,
-           decltype(get_n_params_type<1>(ioctl))::type request,
-           Args... args) -> unsigned int
+[[nodiscard]] auto ioctl(const file_descriptor &fd, request_t request, Args... args) -> int
 {
     auto ret = ::ioctl(fd.get(), request, std::forward<Args>(args)...);
     if (ret != 0) {
-        throw std::system_error(errno, std::system_category(), "ioctl");
+        auto msg =
+                "ioctl fd " + std::to_string(fd.get()) + ", request op " + std::to_string(request);
+        bool first = true;
+        ((msg += (first ? "" : ", ") + stringify_arg(args), first = false), ...);
+        msg.push_back(']');
+
+        throw std::system_error(errno, std::system_category(), msg);
     }
 
     return ret;

src/linyaps_box/utils/process.h

@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include "utils.h"
+
 #include <sys/prctl.h>
 
 #include <cstdint>
@@ -27,11 +29,17 @@ struct WaitResult
 auto waitpid(pid_t pid, int options) -> WaitResult;
 
 template<typename... Args>
-auto prctl(int option, Args... args) -> uint
+[[nodiscard]] auto prctl(int option, Args... args) -> int
 {
     auto ret = ::prctl(option, std::forward<Args>(args)...);
     if (ret < 0) {
-        throw std::system_error(errno, std::system_category(), "prctl");
+        auto msg = "prctl op " + std::to_string(option) + " with args: [";
+
+        bool first = true;
+        ((msg += (first ? "" : ", ") + stringify_arg(args), first = false), ...);
+        msg.push_back(']');
+
+        throw std::system_error(errno, std::system_category(), msg);
     }
 
     return ret;

src/linyaps_box/utils/utils.h

@@ -1,10 +1,14 @@
-// SPDX-FileCopyrightText: 2025 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2025 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: LGPL-3.0-or-later
 
 #pragma once
 
+#include <array>
+#include <charconv>
 #include <cstddef>
+#include <cstdint>
+#include <string>
 #include <tuple>
 
 #if defined(__GNUC__) || defined(__clang__)
@@ -23,18 +27,21 @@ struct type_entity
     using type = T;
 };
 
+template<typename Entity>
+using extract_t = typename Entity::type;
+
 template<std::size_t N, typename R, typename... Args>
 constexpr auto get_n_params_type([[maybe_unused]] R (*ptr)(Args...))
 {
-    static_assert(N >= 1 && N <= sizeof...(Args), "index out of range");
-    return type_entity<std::tuple_element_t<N - 1, std::tuple<Args...>>>{};
+    static_assert(N < sizeof...(Args), "index out of range");
+    return type_entity<std::tuple_element_t<N, std::tuple<Args...>>>{ };
 }
 
 template<std::size_t N, typename R, typename... Args>
 constexpr auto get_n_params_type([[maybe_unused]] R (*ptr)(Args..., ...))
 {
-    static_assert(N >= 1 && N <= sizeof...(Args), "index out of range");
-    return type_entity<std::tuple_element_t<N - 1, std::tuple<Args...>>>{};
+    static_assert(N < sizeof...(Args), "index out of range");
+    return type_entity<std::tuple_element_t<N, std::tuple<Args...>>>{ };
 }
 
 template<typename... T>
@@ -46,4 +53,27 @@ struct Overload : T...
 template<typename... T>
 Overload(T...) -> Overload<T...>;
 
+template<typename T>
+std::string stringify_arg(T arg)
+{
+    if constexpr (std::is_convertible_v<T, std::string_view>) {
+        if (arg == nullptr) {
+            return "nullptr";
+        }
+
+        return std::string(arg);
+    } else if constexpr (std::is_pointer_v<T>) {
+        if (arg == nullptr) {
+            return "nullptr";
+        }
+
+        std::array<char, 20> buf{ };
+        auto [ptr, ec] =
+                std::to_chars(buf.begin(), buf.end(), reinterpret_cast<uintptr_t>(arg), 16);
+        return "0x" + std::string(buf.begin(), ptr);
+    } else {
+        return std::to_string(arg);
+    }
+}
+
 } // namespace linyaps_box::utils