/*
- * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2007 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.
+ * Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file fd.c helper functions for file descriptor handling */
-
-#include "para.h"
+/** \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.
*/
}
/**
- * paraslash's wrapper for select(2)
+ * 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 upper bound on the amount of time elapsed before select()
- * returns
+ * \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.
+ * \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)
+ * \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 && err == EINTR);
if (ret < 0)
- PARA_CRIT_LOG("select error: %s, max_fileno: %d\n",
- strerror(err), n);
+ return -ERRNO_TO_PARA_ERROR(errno);
return ret;
}
/**
- * set a file descriptor to non-blocking mode
+ * Set a file descriptor to non-blocking mode.
*
- * \param fd The file descriptor
+ * \param fd The file descriptor.
*
- * \returns 1 on success, -E_F_GETFL, -E_F_SETFL, on errors.
+ * \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
+ * 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
+ * \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
+ * \sa para_select.
*/
void para_fd_set(int fd, fd_set *fds, int *max_fileno)
{
}
/**
- * paraslash's wrapper for fread(3)
+* 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.
*
- * \param dest destination pointer
- * \param nbytes size of one element
- * \param nmemb number of elements to write
- * \param stream the input stream
+ * The mode parameter must be specified when O_CREAT is in the flags, and is
+ * ignored otherwise.
*
- * \return negative on errors, zero on end of file, and the number of bytes
- * (not elements) read on success.
+ * \return The file descriptor on success, negative on errors.
*
- * \sa fread(3)
+ * \sa open(2).
*/
-__must_check int para_fread(void *dest, size_t nbytes, size_t nmemb, FILE *stream)
+int para_open(const char *path, int flags, mode_t mode)
{
- size_t res = fread(dest, nbytes, nmemb, stream);
- if (res == nmemb)
- return nbytes * nmemb;
- if (feof(stream))
- return 0;
- return -E_FREAD;
+ 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);
+}
+
+/**
+ * Map a file 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.
+ *
+ * \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.
+ *
+ * \sa para_open(), mmap(2).
+ */
+int mmap_full_file(const char *path, int open_mode, void **map,
+ size_t *size, int *fd_ptr)
+{
+ int fd, ret, mmap_prot, mmap_flags;
+ struct stat file_status;
+
+ if (open_mode == O_RDONLY) {
+ mmap_prot = PROT_READ;
+ mmap_flags = MAP_PRIVATE;
+ } else {
+ mmap_prot = PROT_READ | PROT_WRITE;
+ mmap_flags = MAP_SHARED;
+ }
+ ret = para_open(path, open_mode, 0);
+ if (ret < 0)
+ return ret;
+ fd = ret;
+ if (fstat(fd, &file_status) < 0) {
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+ goto out;
+ }
+ *size = file_status.st_size;
+ ret = -E_EMPTY;
+ PARA_DEBUG_LOG("%s: size %zu\n", path, *size);
+ if (!*size)
+ goto out;
+ *map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
+ if (*map == MAP_FAILED) {
+ *map = NULL;
+ ret = -E_MMAP;
+ goto out;
+ }
+ ret = 1;
+out:
+ if (ret < 0 || !fd_ptr)
+ close(fd);
+ else
+ *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;
}
projects / paraslash.git / blobdiff