X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=d53a3b4521fdbec1e16aa3263ba07f699feac40c;hp=5db30b63fd9ed62148b8d04390ec8456826337a3;hb=262739658bab36f6dc057dfe68a2f7e43a71e41e;hpb=f2a7b00cf72104a38733b7bf3add9fb19dd71c93

diff --git a/fd.c b/fd.c
index 5db30b63..d53a3b45 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
  *
@@ -12,3 +37,132 @@ 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_tv)
+{
+	int ret, err;
+	do {
+		ret = select(n, readfds, writefds, NULL, timeout_tv);
+		err = errno;
+	} while (ret < 0 && err == EINTR);
+	if (ret < 0)
+		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;
+}
+/**
+* paraslash's wrapper for fgets(3)  
+* \param line pointer to the buffer to store the line
+* \param size the size of the buffer given by \a line
+* \param f the stream to read from
+*
+* \return Unlike the standard fgets() function, an integer value
+* is returned. On success, this function returns 1. On errors, -E_FGETS
+* is returned. A zero return value indicates an end of file condition.
+*/
+__must_check int para_fgets(char *line, int size, FILE *f)
+{
+again:
+	if (fgets(line, size, f))
+		return 1;
+	if (feof(f))
+		return 0;
+	if (!ferror(f))
+		return -E_FGETS;
+	if (errno != EINTR) {
+		PARA_ERROR_LOG("%s\n", strerror(errno));
+		return -E_FGETS;
+	}
+	clearerr(f);
+	goto again;
+}