}
/**
- * Map a file into memory.
+ * Open a file and map it into memory.
*
* \param path Name of the regular file to map.
* \param open_mode Either \p O_RDONLY or \p O_RDWR.
- * \param obj On success, the mapping is returned here.
+ * \param map On success, the mapping is returned here.
+ * \param size size of the mapping.
+ * \param fd_ptr The file descriptor of the mapping.
+ *
+ * If \a fd_ptr is \p NULL, the file descriptor resulting from the underlying
+ * open call is closed after mmap(). Otherwise the file is kept open and the
+ * file descriptor is returned in \a fd_ptr.
*
* \return Positive on success, negative on errors. Possible errors include: \p
* E_FSTAT, any errors returned by para_open(), \p E_EMPTY, \p E_MMAP.
*fd_ptr = fd;
return ret;
}
+
+/**
+ * A wrapper for munmap(2).
+ *
+ * \param start The start address of the memory mapping.
+ * \param length The size of the mapping.
+ *
+ * \return Positive on success, \p -E_MUNMAP on errors.
+ *
+ * \sa munmap(2), mmap_full_file().
+ */
+int para_munmap(void *start, size_t length)
+{
+ if (munmap(start, length) >= 0)
+ return 1;
+ PARA_ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
+ strerror(errno));
+ return -E_MUNMAP;
+}
+
+/**
+ * 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 = {0, 0};
+ fd_set wfds;
+ int ret;
+again:
+ FD_ZERO(&wfds);
+ FD_SET(fd, &wfds);
+ tv.tv_sec = 0;
+ tv.tv_usec = 0;
+ ret = select(fd + 1, NULL, &wfds, NULL, &tv);
+ if (ret < 0 && errno == EINTR)
+ goto again;
+ return ret;
+}