/* Hook the function by creating a function with the same name. With
* LD_PRELOAD our function will be preferred. The original function is stored
- * in a static variable (real_*). */
+ * in a static variable (real_*). Any function called in these macros must
+ * make sure to restore the errno if it changes it.
+ *
+ * "Pseudo code" for the following macros. <name> is the name of the hooked
+ * function, <fd> is either a file descriptor or a FILE pointer.
+ *
+ * if (!real_<name>) {
+ * real_<name> = dlsym_function(<name>);
+ * if (!initialized) {
+ * init_from_environment();
+ * }
+ * }
+ * if (tracked_fds_find(<fd>)) {
+ * if (force_write_to_non_tty) {
+ * handle = 1;
+ * } else {
+ * handle = isatty_noinline(<fd>);
+ * }
+ * } else {
+ * handle = 0;
+ * }
+ *
+ * if (handle) {
+ * handle_<fd>_pre(<fd>);
+ * }
+ * <type> result = real_<name>(<args>);
+ * if (handle) {
+ * handle_<fd>_post(<fd>);
+ * }
+ * return result;
+ */
-#define _HOOK_PRE(type, name) \
+#define _HOOK_PRE(type, name, fd) \
int handle; \
- type result; \
- DLSYM_FUNCTION(real_ ## name, #name);
+ if (unlikely(!(real_ ## name ))) { \
+ *(void **) (&(real_ ## name)) = dlsym_function(#name); \
+ /* Initialize our data while we're at it. */ \
+ if (unlikely(!initialized)) { \
+ init_from_environment(); \
+ } \
+ } \
+ /* Check if this fd should be handled. */ \
+ if (unlikely(tracked_fds_find(fd))) { \
+ if (unlikely(force_write_to_non_tty)) { \
+ handle = 1; \
+ } else { \
+ handle = isatty_noinline(fd); \
+ } \
+ } else { \
+ handle = 0; \
+ }
#define _HOOK_PRE_FD(type, name, fd) \
- _HOOK_PRE(type, name) \
- handle = check_handle_fd(fd); \
- if (handle) { \
- handle_fd_pre(fd, handle); \
+ type result; \
+ _HOOK_PRE_FD_(type, name, fd)
+#define _HOOK_PRE_FD_(type, name, fd) \
+ _HOOK_PRE(type, name, fd) \
+ if (unlikely(handle)) { \
+ handle_fd_pre(fd); \
}
#define _HOOK_PRE_FILE(type, name, file) \
- _HOOK_PRE(type, name) \
- handle = check_handle_fd(fileno(file)); \
- if (handle) { \
- handle_file_pre(file, handle); \
+ type result; \
+ _HOOK_PRE(type, name, fileno(file)) \
+ if (unlikely(handle)) { \
+ handle_file_pre(file); \
+ }
+#define _HOOK_POST_FD_(fd) \
+ if (unlikely(handle)) { \
+ handle_fd_post(fd); \
}
-/* Save and restore the errno to make sure we return the errno of the original
- * function call. */
#define _HOOK_POST_FD(fd) \
- if (handle) { \
- int saved_errno = errno; \
- handle_fd_post(fd, handle); \
- errno = saved_errno; \
- } \
+ _HOOK_POST_FD_(fd) \
return result;
#define _HOOK_POST_FILE(file) \
- if (handle) { \
- int saved_errno = errno; \
- handle_file_post(file, handle); \
- errno = saved_errno; \
+ if (unlikely(handle)) { \
+ handle_file_post(file); \
} \
return result;
+#define HOOK_FUNC_DEF1(type, name, type1, arg1) \
+ static type (*real_ ## name)(type1); \
+ type name(type1 arg1)
+#define HOOK_FUNC_DEF2(type, name, type1, arg1, type2, arg2) \
+ static type (*real_ ## name)(type1, type2); \
+ type name(type1 arg1, type2 arg2)
+#define HOOK_FUNC_DEF3(type, name, type1, arg1, type2, arg2, type3, arg3) \
+ static type (*real_ ## name)(type1, type2, type3); \
+ type name(type1 arg1, type2 arg2, type3 arg3)
+
+#define HOOK_FUNC_VAR_DEF2(type, name, type1, arg1, type2, arg2) \
+ static type (*real_ ## name)(type1, type2, ...); \
+ type name(type1 arg1, type2 arg2, ...)
+
+#define HOOK_VOID1(type, name, fd, type1, arg1) \
+ static type (*real_ ## name)(type1); \
+ type name(type1 arg1) { \
+ _HOOK_PRE_FD_(type, name, fd) \
+ real_ ## name(arg1); \
+ _HOOK_POST_FD_(fd) \
+ }
+
+#define HOOK_FD2(type, name, fd, type1, arg1, type2, arg2) \
+ static type (*real_ ## name)(type1, type2); \
+ type name(type1 arg1, type2 arg2) { \
+ _HOOK_PRE_FD(type, name, fd) \
+ result = real_ ## name(arg1, arg2); \
+ _HOOK_POST_FD(fd) \
+ }
#define HOOK_FD3(type, name, fd, type1, arg1, type2, arg2, type3, arg3) \
static type (*real_ ## name)(type1, type2, type3); \
type name(type1 arg1, type2 arg2, type3 arg3) { \
}
#define HOOK_VAR_FILE1(type, name, file, func, type1, arg1) \
- static type (*real_ ## func)(type1, va_list); \
type name(type1 arg1, ...) { \
va_list ap; \
- _HOOK_PRE_FILE(type, func, file) \
va_start(ap, arg1); \
- result = real_ ## func(arg1, ap); \
+ type result = func(arg1, ap); \
va_end(ap); \
- _HOOK_POST_FILE(file) \
+ return result; \
}
#define HOOK_VAR_FILE2(type, name, file, func, type1, arg1, type2, arg2) \
- static type (*real_ ## func)(type1, type2, va_list); \
type name(type1 arg1, type2 arg2, ...) { \
va_list ap; \
- _HOOK_PRE_FILE(type, func, file) \
va_start(ap, arg2); \
- result = real_ ## func(arg1, arg2, ap); \
+ type result = func(arg1, arg2, ap); \
va_end(ap); \
- _HOOK_POST_FILE(file) \
+ return result; \
}
#define HOOK_VAR_FILE3(type, name, file, func, type1, arg1, type2, arg2, type3, arg3) \
- static type (*real_ ## func)(type1, type2, type3, va_list); \
- type name(type1 arg1, type2 arg2, type3 arg3, ...) \
- { \
+ type name(type1 arg1, type2 arg2, type3 arg3, ...) { \
va_list ap; \
- _HOOK_PRE_FILE(type, func, file) \
va_start(ap, arg3); \
- result = real_ ## func(arg1, arg2, arg3, ap); \
+ type result = func(arg1, arg2, arg3, ap); \
va_end(ap); \
- _HOOK_POST_FILE(file) \
+ return result; \
}
#endif