/* 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) \
int handle; \
- 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(); \
+ } \
+ }
#define _HOOK_PRE_FD(type, name, fd) \
type result; \
_HOOK_PRE_FD_(type, name, fd)
#define _HOOK_PRE_FD_(type, name, fd) \
_HOOK_PRE(type, name) \
- handle = check_handle_fd(fd); \
- if (handle) { \
- handle_fd_pre(fd, handle); \
+ if (unlikely(tracked_fds_find(fd))) { \
+ if (unlikely(force_write_to_non_tty)) { \
+ handle = 1; \
+ } else { \
+ handle = isatty_noinline(fd); \
+ } \
+ } else { \
+ handle = 0; \
+ } \
+ if (unlikely(handle)) { \
+ handle_fd_pre(fd); \
}
#define _HOOK_PRE_FILE(type, name, file) \
type result; \
_HOOK_PRE(type, name) \
- handle = check_handle_fd(fileno(file)); \
- if (handle) { \
- handle_file_pre(file, handle); \
+ if (unlikely(tracked_fds_find(fileno(file)))) { \
+ if (unlikely(force_write_to_non_tty)) { \
+ handle = 1; \
+ } else { \
+ handle = isatty_noinline(fileno(file)); \
+ } \
+ } else { \
+ handle = 0; \
+ } \
+ if (unlikely(handle)) { \
+ handle_file_pre(file); \
}
-/* 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; \
+ if (unlikely(handle)) { \
+ handle_fd_post(fd); \
}
#define _HOOK_POST_FD(fd) \
_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;