XV6 信号与 macOS 信号冲突

Question

我正在尝试在 XV6-riscv 版本上实现信号支持为了做到这一点，我定义了一个 sigaction struct 和一些信号宏，比如 SIG_IGN。问题是当我使用 make clean qemu 编译它时出现以下错误：

In file included from mkfs/mkfs.c:9:
./kernel/types.h:12:8: error: redefinition of 'sigaction'
struct sigaction {
       ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/signal.h:286:9: note: previous definition is here
struct  sigaction {
        ^
In file included from mkfs/mkfs.c:9:
./kernel/types.h:13:12: error: expected ')'
    void (*sa_handler) (int);
           ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/signal.h:295:38: note: expanded from macro 'sa_handler'
#define sa_handler      __sigaction_u.__sa_handler
                                     ^
./kernel/types.h:13:10: note: to match this '('
    void (*sa_handler) (int);
         ^
In file included from mkfs/mkfs.c:12:
./kernel/param.h:14:9: error: 'SIG_DFL' macro redefined [-Werror,-Wmacro-redefined]
#define SIG_DFL      0       // default signal handling
        ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/signal.h:131:9: note: previous definition is here
#define SIG_DFL         (void (*)(int))0
        ^
In file included from mkfs/mkfs.c:12:
./kernel/param.h:15:9: error: 'SIG_IGN' macro redefined [-Werror,-Wmacro-redefined]
#define SIG_IGN      1       // ignore signal
        ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/signal.h:132:9: note: previous definition is here
#define SIG_IGN         (void (*)(int))1
        ^
4 errors generated.
make: *** [mkfs/mkfs] Error 1

据我了解 sys，我所做的新定义已经存在于 macOS signal.h 文件中，我不明白为什么编译器还要检查这个文件？因为它与 XV6 毫无关系，我该如何解决这个问题？任何帮助将不胜感激！

Answer 1

如果以后有人遇到同样的问题，解决办法：

mkfs/mkfs.c 不是 xv6 的一部分。它只是一个构建 xv6 的实用程序。但 kernel/types.h 包含在 mkfs/mkfs.c 中。这个 mkfs/mkfs.c 像普通程序一样编译 (see here)。所以它重新定义了之前在 macOS signal.h

中定义的 struct sigaction

解决方法就是不使用kernel/types.h来实现.

只需创建一些新的头文件，并保持 kernel/types.h 的原始状态不变。

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