X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=dd07466cef2623e5aaa053178d7eda9e992e3dcd;hp=b5310f8128c85563bf2f99f30e833eb59455f6e1;hb=b564291f5f15b5bd4a319ea59875023551a705cc;hpb=d7cda933daa35663b2b9b61d62cb514afa37fd18

diff --git a/fd.c b/fd.c
index b5310f81..dd07466c 100644
--- a/fd.c
+++ b/fd.c
@@ -1,4 +1,29 @@
+/*
+ * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ *
+ *     This program is free software; you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation; either version 2 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program; if not, write to the Free Software
+ *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
+ */
+
+/** \file fd.c helper functions for file descriptor handling */
+
 #include "para.h"
+
+#include <fcntl.h>
+#include <sys/select.h>
+
+#include "error.h"
 /**
  * check whether a file exists
  *
@@ -13,15 +38,105 @@ int file_exists(const char *fn)
 	return !stat(fn, &statbuf);
 }
 
+/**
+ * paraslash's wrapper for select(2)
+ *
+ * It calls select(2) (with no exceptfds) and starts over if select() was
+ * interrupted by a signal.
+ *
+ * \param n the highest-numbered descriptor in any of the two sets, plus 1
+ * \param readfds fds that should be checked for readability
+ * \param writefds fds that should be checked for writablility
+ * \param timeout_tv upper bound on the amount of time elapsed before select()
+ * returns
+ *
+ * \return The return value of the underlying select() call.
+ *
+ * All arguments are passed verbatim to select(2).
+ * \sa select(2) select_tut(2)
+ */
 int para_select(int n, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout)
+		struct timeval *timeout_tv)
 {
 	int ret, err;
 	do {
-		ret = select(n, readfds, writefds, NULL, timeout);
+		ret = select(n, readfds, writefds, NULL, timeout_tv);
 		err = errno;
-	} while (ret < 0 && errno == EINTR);
+	} while (ret < 0 && err == EINTR);
 	if (ret < 0)
-		PARA_CRIT_LOG("select error (%s)\n", strerror(err));
+		PARA_CRIT_LOG("select error: %s, max_fileno: %d\n",
+			strerror(err), n);
 	return ret;
 }
+
+/**
+ * set a file descriptor to non-blocking mode
+ *
+ * \param fd The file descriptor
+ *
+ * \returns 1 on success, -E_F_GETFL, -E_F_SETFL, on errors.
+ */
+int mark_fd_nonblock(int fd)
+{
+	int flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -E_F_GETFL;
+	if (fcntl(fd, F_SETFL, ((long)flags) | O_NONBLOCK) < 0)
+		return -E_F_SETFL;
+	return 1;
+}
+
+/**
+ * set a file descriptor in a fd_set
+ *
+ * \param fd the file descriptor to be set
+ * \param fds the file descriptor set
+ * \param max_fileno highest-numbered file descriptor
+ *
+ * This wrapper for FD_SET() passes its first two arguments to \p FD_SET. Upon
+ * return, \a max_fileno contains the maximum of the old_value and \a fd.
+ *
+ * \sa para_select
+*/
+void para_fd_set(int fd, fd_set *fds, int *max_fileno)
+{
+
+	if (fd < 0 || fd >= FD_SETSIZE) {
+		PARA_EMERG_LOG("fatal: tried to add invalid fd %d\n", fd);
+		exit(EXIT_FAILURE);
+	}
+#if 0
+	{
+		int flags = fcntl(fd, F_GETFL);
+		if (!(flags & O_NONBLOCK)) {
+			PARA_EMERG_LOG("fd %d is a blocking file descriptor\n", fd);
+			exit(EXIT_FAILURE);
+		}
+	}
+#endif
+	FD_SET(fd, fds);
+	*max_fileno = PARA_MAX(*max_fileno, fd);
+}
+
+/**
+ * paraslash's wrapper for fread(3)
+ *
+ * \param dest destination pointer
+ * \param nbytes size of one element
+ * \param nmemb number of elements to write
+ * \param stream the input stream
+ *
+ * \return negative on errors, zero on end of file, and the number of bytes
+ * (not elements) read on success.
+ *
+ * \sa fread(3)
+ */
+__must_check int para_fread(void *dest, size_t nbytes, size_t nmemb, FILE *stream)
+{
+	size_t res = fread(dest, nbytes, nmemb, stream);
+	if (res == nmemb)
+		return nbytes * nmemb;
+	if (feof(stream))
+		return 0;
+	return -E_FREAD;
+}