+
+/**
+ * A wrapper for munmap(2).
+ *
+ * \param start The start address of the memory mapping.
+ * \param length The size of the mapping.
+ *
+ * \return Standard.
+ *
+ * \sa munmap(2), mmap_full_file().
+ */
+int para_munmap(void *start, size_t length)
+{
+ int err;
+ if (munmap(start, length) >= 0)
+ return 1;
+ err = errno;
+ PARA_ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
+ strerror(err));
+ return -ERRNO_TO_PARA_ERROR(err);
+}
+
+/**
+ * Check a file descriptor for writability.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return positive if fd is ready for writing, zero if it isn't, negative if
+ * an error occurred.
+ */
+
+int write_ok(int fd)
+{
+ struct timeval tv;
+ fd_set wfds;
+
+ FD_ZERO(&wfds);
+ FD_SET(fd, &wfds);
+ tv.tv_sec = 0;
+ tv.tv_usec = 0;
+ return para_select(fd + 1, NULL, &wfds, &tv);
+}
+
+/**
+ * Ensure that file descriptors 0, 1, and 2 are valid.
+ *
+ * Common approach that opens /dev/null until it gets a file descriptor greater
+ * than two.
+ *
+ * \sa okir's Black Hats Manual.
+ */
+void valid_fd_012(void)
+{
+ while (1) {
+ int fd = open("/dev/null", O_RDWR);
+ if (fd < 0)
+ exit(EXIT_FAILURE);
+ if (fd > 2) {
+ close(fd);
+ break;
+ }
+ }
+}
+
+/**
+ * Traverse the given directory recursively.
+ *
+ * \param dirname The directory to traverse.
+ * \param func The function to call for each entry.
+ * \param private_data Pointer to an arbitrary data structure.
+ *
+ * For each regular file under \a dirname, the supplied function \a func is
+ * called. The full path of the regular file and the \a private_data pointer
+ * are passed to \a func. Directories for which the calling process has no
+ * permissions to change to are silently ignored.
+ *
+ * \return Standard.
+ */
+int for_each_file_in_dir(const char *dirname,
+ int (*func)(const char *, void *), void *private_data)
+{
+ DIR *dir;
+ struct dirent *entry;
+ int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
+
+ if (ret < 0)
+ return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;
+ /* scan cwd recursively */
+ while ((entry = readdir(dir))) {
+ mode_t m;
+ char *tmp;
+ struct stat s;
+
+ if (!strcmp(entry->d_name, "."))
+ continue;
+ if (!strcmp(entry->d_name, ".."))
+ continue;
+ if (lstat(entry->d_name, &s) == -1)
+ continue;
+ m = s.st_mode;
+ if (!S_ISREG(m) && !S_ISDIR(m))
+ continue;
+ tmp = make_message("%s/%s", dirname, entry->d_name);
+ if (!S_ISDIR(m)) {
+ ret = func(tmp, private_data);
+ free(tmp);
+ if (ret < 0)
+ goto out;
+ continue;
+ }
+ /* directory */
+ ret = for_each_file_in_dir(tmp, func, private_data);
+ free(tmp);
+ if (ret < 0)
+ goto out;
+ }
+ ret = 1;
+out:
+ closedir(dir);
+ ret2 = para_fchdir(cwd_fd);
+ if (ret2 < 0 && ret >= 0)
+ ret = ret2;
+ close(cwd_fd);
+ return ret;
+}