+/*
+ * 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
+ * Check whether a file exists.
*
- * \param fn the file name
+ * \param fn The file name.
*
* \return Non-zero iff file exists.
*/
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 on success, the
+ * negative system error code on errors.
+ *
+ * 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));
+ return -ERRNO_TO_PARA_ERROR(errno);
return ret;
}
+/**
+ * Set a file descriptor to non-blocking mode.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return Standard.
+ */
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 -ERRNO_TO_PARA_ERROR(errno);
+ flags = fcntl(fd, F_SETFL, ((long)flags) | O_NONBLOCK);
+ if (flags < 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ 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 The file descriptor 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;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Wrapper for chdir(2).
+ *
+ * \param path The specified directory.
+ *
+ * \return Standard.
+ */
+int para_chdir(const char *path)
+{
+ int ret = chdir(path);
+
+ if (ret >= 0)
+ return 1;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * 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 Standard.
+ *
+ * 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 = para_chdir(dirname);
+ if (ret < 0)
+ goto close_cwd;
+ *dir = opendir(".");
+ if (*dir)
+ return 1;
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+/* Ignore return value of fchdir() and close(). We're busted anyway. */
+ if (cwd)
+ fchdir(*cwd);
+close_cwd:
+ if (cwd)
+ close(*cwd);
+ return ret;
+}
+
+/**
+ * A wrapper for fchdir().
+ *
+ * \param fd An open file descriptor.
+ *
+ * \return Standard.
+ */
+int para_fchdir(int fd)
+{
+ if (fchdir(fd) < 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
return 1;
}
+/**
+ * A wrapper for mkdir(2).
+ *
+ * \param path Name of the directory to create.
+ * \param mode The permissions to use.
+ *
+ * \return Standard.
+ */
+int para_mkdir(const char *path, mode_t mode)
+{
+ if (!mkdir(path, mode))
+ return 1;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}