X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=398bf2ce818345a6cc3d98648953fa05096a8b48;hp=b5310f8128c85563bf2f99f30e833eb59455f6e1;hb=a8509af9116e9a045ace70ff312e40569c5ace16;hpb=d7cda933daa35663b2b9b61d62cb514afa37fd18;ds=sidebyside

diff --git a/fd.c b/fd.c
index b5310f81..398bf2ce 100644
--- a/fd.c
+++ b/fd.c
@@ -1,4 +1,19 @@
+/*
+ * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file fd.c helper functions for file descriptor handling */
+
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/select.h>
+
 #include "para.h"
+#include "error.h"
 /**
  * check whether a file exists
  *
@@ -13,15 +28,260 @@ 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 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;
+}
+
+/**
+ * Paraslash's wrapper for mmap.
+ *
+ * \param length number of bytes to mmap
+ * \param prot either PROT_NONE or the bitwise OR of one or more of
+ * PROT_EXEC PROT_READ PROT_WRITE
+ * \param flags exactly one of MAP_SHARED and MAP_PRIVATE
+ * \param fd the file to mmap from
+ * \param offset mmap start
+ *
+ * \return This function either returns a valid pointer to the mapped area
+ * or calls exit() on errors.
+ */
+void *para_mmap(size_t length, int prot, int flags, int fd, off_t offset)
+{
+	void *ret = mmap(NULL, length, prot, flags, fd, offset);
+	if (ret != MAP_FAILED)
+		return ret;
+	PARA_EMERG_LOG("mmap failed: %s\n", strerror(errno));
+	PARA_EMERG_LOG("length: %zu, flags: %d, fd: %d, offset: %zu\n",
+		length, flags, fd, (size_t)offset);
+	exit(EXIT_FAILURE);
+}
+
+/**
+ * Wrapper for the open(2) system call.
+ *
+ * \param path The filename.
+ * \param flags The usual open(2) flags.
+ * \param mode Specifies the permissions to use.
+ *
+ * The mode parameter must be specified when O_CREAT is in the flags, and is ignored
+ * otherwise.
+ *
+ * \return Positive on success, negative on errors.
+ *
+ * \sa open(2).
+ */
+int para_open(const char *path, int flags, mode_t mode)
+{
+	int ret = open(path, flags, mode);
+
+	if (ret >= 0)
+		return ret;
+	switch (errno) {
+	case EEXIST:
+		ret = -E_EXIST;
+		break;
+	case EISDIR:
+		ret = -E_ISDIR;
+		break;
+	case ENOENT:
+		ret = -E_NOENT;
+		break;
+	case EPERM:
+		ret = -E_OPEN_PERM;
+		break;
+	};
+	PARA_ERROR_LOG("failed to open %s: %s\n", path, strerror(errno));
+	return ret;
+}
+
+/**
+ * Save the cwd and open a given directory.
+ *
+ * \param dirname Path to the directory to open.
+ * \param dir Result pointer.
+ * \param cwd File descriptor of the current working directory.
+ *
+ * \return Positive on success, negative on errors.
+ *
+ * Opening the current directory (".") and calling fchdir() to return is
+ * usually faster and more reliable than saving cwd in some buffer and calling
+ * chdir() afterwards.
+ *
+ * If \a cwd is not \p NULL "." is opened and the resulting file descriptor is
+ * stored in \a cwd. If the function returns success, and \a cwd is not \p
+ * NULL, the caller must close this file descriptor (probably after calling
+ * fchdir(*cwd)).
+ *
+ * On errors, the function undos everything, so the caller needs neither close
+ * any files, nor change back to the original working directory.
+ *
+ * \sa getcwd(3).
+ *
+ */
+int para_opendir(const char *dirname, DIR **dir, int *cwd)
+{
+	int ret;
+
+	if (cwd) {
+		ret = para_open(".", O_RDONLY, 0);
+		if (ret < 0)
+			return ret;
+		*cwd = ret;
+	}
+	ret = -E_CHDIR;
+	if (chdir(dirname) < 0)
+		goto close_cwd;
+	ret = -E_OPENDIR;
+	*dir = opendir(".");
+	if (!*dir)
+		goto change_to_orig_dir;
+	return 1;
+/* Ignore return value of fchdir() and close(). We're busted anyway. */
+change_to_orig_dir:
+	if (cwd)
+		fchdir(*cwd);
+close_cwd:
+	if (cwd)
+		close(*cwd);
 	return ret;
 }
+
+/**
+ * A wrapper for fchdir().
+ *
+ * \param fd An open file descriptor
+ *
+ * \return Positive on success, negative on errors.
+ */
+int para_fchdir(int fd)
+{
+	if (fchdir(fd) < 0)
+		return -E_FCHDIR;
+	return 1;
+}
+
+/**
+ * A wrapper for mkdir(2).
+ *
+ * \param path Name of the directory to create.
+ * \param mode The permissions to use.
+ *
+ * \return positive on success, negative on errors.
+ */
+int para_mkdir(const char *path, mode_t mode)
+{
+	if (!mkdir(path, mode))
+		return 1;
+	if (errno == EEXIST)
+		return -E_EXIST;
+	if (errno == ENOSPC)
+		return -E_NOSPC;
+	if (errno == ENOTDIR)
+		return -E_NOTDIR;
+	if (errno == EPERM)
+		return -E_MKDIR_PERM;
+	return -E_MKDIR;
+}