-/*
- * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file 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/uio.h>
#include "para.h"
#include "error.h"
#include "fd.h"
/**
- * Write a buffer to a file descriptor, re-write on short writes.
+ * Change the name or location of a file.
*
- * \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
+ * \param oldpath File to be moved.
+ * \param newpath Destination.
+ *
+ * This is just a simple wrapper for the rename(2) system call which returns a
+ * paraslash error code and prints an error message on failure.
*
- * \return Standard. In any case, the number of bytes that have been written is
- * stored in \a len.
+ * \return Standard.
+ *
+ * \sa rename(2).
*/
-int write_all(int fd, const char *buf, size_t *len)
+int xrename(const char *oldpath, const char *newpath)
{
- size_t total = *len;
+ int ret = rename(oldpath, newpath);
- assert(total);
- *len = 0;
- while (*len < total) {
- int ret = write(fd, buf + *len, total - *len);
- if (ret == -1)
- return -ERRNO_TO_PARA_ERROR(errno);
- *len += ret;
- }
- return 1;
+ if (ret >= 0)
+ return 1;
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+ PARA_ERROR_LOG("failed to rename %s -> %s\n", oldpath, newpath);
+ return ret;
}
/**
- * Write a buffer to a non-blocking file descriptor.
+ * Write an array of buffers to a file descriptor.
*
* \param fd The file descriptor.
- * \param buf the buffer to write.
- * \param len the number of bytes of \a buf.
+ * \param iov Pointer to one or more buffers.
+ * \param iovcnt The number of buffers.
+ *
+ * EAGAIN/EWOULDBLOCK is not considered a fatal error condition. For example
+ * DCCP CCID3 has a sending wait queue which fills up and is emptied
+ * asynchronously. The EAGAIN case means that there is currently no space in
+ * the wait queue, but this can change at any moment.
+ *
+ * \return Negative on fatal errors, number of bytes written else.
+ *
+ * For blocking file descriptors, this function returns either the sum of all
+ * buffer sizes, or the error code of the fatal error that caused the last
+ * write call to fail.
*
- * EAGAIN is not considered an error condition. For example CCID3 has a
- * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
- * case means that there is currently no space in the wait queue, but this can
- * change at any moment.
+ * For nonblocking file descriptors there is a third possibility: Any positive
+ * return value less than the sum of the buffer sizes indicates that some bytes
+ * have been written but the next write would block.
*
- * \return Negative on errors, number of bytes written else.
+ * \sa writev(2), \ref xwrite().
*/
-int write_nonblock(int fd, const char *buf, size_t len)
+int xwritev(int fd, struct iovec *iov, int iovcnt)
{
size_t written = 0;
- int ret = 0;
-
- while (written < len) {
- size_t num = len - written;
-
- ret = write(fd, buf + written, num);
- if (ret < 0 && errno == EAGAIN)
+ int i;
+ struct iovec saved_iov, *curiov;
+
+ i = 0;
+ curiov = iov;
+ saved_iov = *curiov;
+ while (i < iovcnt && curiov->iov_len > 0) {
+ ssize_t ret = writev(fd, curiov, iovcnt - i);
+ if (ret >= 0) {
+ written += ret;
+ while (ret > 0) {
+ if (ret < curiov->iov_len) {
+ curiov->iov_base += ret;
+ curiov->iov_len -= ret;
+ break;
+ }
+ ret -= curiov->iov_len;
+ *curiov = saved_iov;
+ i++;
+ if (i >= iovcnt)
+ return written;
+ curiov++;
+ saved_iov = *curiov;
+ }
+ continue;
+ }
+ if (errno == EINTR)
+ /*
+ * The write() call was interrupted by a signal before
+ * any data was written. Try again.
+ */
+ continue;
+ if (errno == EAGAIN || errno == EWOULDBLOCK)
+ /*
+ * We don't consider this an error. Note that POSIX
+ * allows either error to be returned, and does not
+ * require these constants to have the same value.
+ */
return written;
- if (ret < 0)
- return -ERRNO_TO_PARA_ERROR(errno);
- written += ret;
+ /* fatal error */
+ return -ERRNO_TO_PARA_ERROR(errno);
}
return written;
}
+/**
+ * Write a buffer to a file descriptor, re-writing on short writes.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to write.
+ * \param len The number of bytes to write.
+ *
+ * This is a simple wrapper for \ref xwritev().
+ *
+ * \return The return value of the underlying call to \ref xwritev().
+ */
+int xwrite(int fd, const char *buf, size_t len)
+{
+ struct iovec iov = {.iov_base = (void *)buf, .iov_len = len};
+ return xwritev(fd, &iov, 1);
+}
+
+/**
+ * Write all data to a file descriptor.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * This is like \ref xwrite() but returns \p -E_SHORT_WRITE if not
+ * all data could be written.
+ *
+ * \return Number of bytes written on success, negative error code else.
+ */
+int write_all(int fd, const char *buf, size_t len)
+{
+ int ret = xwrite(fd, buf, len);
+
+ if (ret < 0)
+ return ret;
+ if (ret != len)
+ return -E_SHORT_WRITE;
+ return ret;
+}
+
+/**
+ * Write a buffer given by a format string.
+ *
+ * \param fd The file descriptor.
+ * \param fmt A format string.
+ *
+ * \return The return value of the underlying call to \ref write_all().
+ */
+__printf_2_3 int write_va_buffer(int fd, const char *fmt, ...)
+{
+ char *msg;
+ int ret;
+ va_list ap;
+
+ va_start(ap, fmt);
+ ret = xvasprintf(&msg, fmt, ap);
+ va_end(ap);
+ ret = write_all(fd, msg, ret);
+ free(msg);
+ return ret;
+}
+
/**
* Read from a non-blocking file descriptor into multiple buffers.
*
* \param rfds An optional fd set pointer.
* \param num_bytes Result pointer. Contains the number of bytes read from \a fd.
*
- * If \a rfds is not \p NULL and the (non-blocking) file descriptor \a fd is
- * not set in \a rfds, this function returns early without doing anything.
- * Otherwise The function tries to read up to \a sz bytes from \a fd. As for
- * write_nonblock(), EAGAIN is not considered an error condition. However, EOF
- * is.
+ * If rfds is not NULL and the (non-blocking) file descriptor fd is not set in
+ * rfds, this function returns early without doing anything. Otherwise it tries
+ * to read up to sz bytes from fd, where sz is the sum of the lengths of all
+ * vectors in iov. Like \ref xwrite(), EAGAIN and EINTR are not considered
+ * error conditions. However, EOF is.
*
* \return Zero or a negative error code. If the underlying call to readv(2)
* returned zero (indicating an end of file condition) or failed for some
- * reason other than \p EAGAIN, a negative return value is returned.
+ * reason other than EAGAIN or EINTR, a negative error code is returned.
*
* In any case, \a num_bytes contains the number of bytes that have been
* successfully read from \a fd (zero if the first readv() call failed with
* have been read before the error occurred. In this case \a num_bytes is
* positive.
*
- * \sa \ref write_nonblock(), read(2), readv(2).
+ * \sa \ref xwrite(), read(2), readv(2).
*/
int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds,
size_t *num_bytes)
if (ret == 0)
return -E_EOF;
if (ret < 0) {
- if (errno == EAGAIN)
+ if (errno == EAGAIN || errno == EINTR)
return 0;
return -ERRNO_TO_PARA_ERROR(errno);
}
*
* \param fn The file name.
*
- * \return Non-zero iff file exists.
+ * \return True iff file exists.
*/
-int file_exists(const char *fn)
+bool file_exists(const char *fn)
{
struct stat statbuf;
* 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 \ref para_select.
*/
void para_fd_set(int fd, fd_set *fds, int *max_fileno)
{
*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.
*
* 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.
* \param map Result pointer.
*
* \return Standard.
*
* \sa mmap(2).
*/
-int para_mmap(size_t length, int prot, int flags, int fd, off_t offset,
- void *map)
+int para_mmap(size_t length, int prot, int flags, int fd, void *map)
{
void **m = map;
errno = EINVAL;
if (!length)
goto err;
- *m = mmap(NULL, length, prot, flags, fd, offset);
+ *m = mmap(NULL, length, prot, flags, fd, (off_t)0);
if (*m != MAP_FAILED)
return 1;
err:
{
int ret;
+ *dir = NULL;
if (cwd) {
ret = para_open(".", O_RDONLY, 0);
if (ret < 0)
return ret;
}
-/**
- * A wrapper for fchdir().
- *
- * \param fd An open file descriptor.
- *
- * \return Standard.
- */
-static int para_fchdir(int fd)
-{
- if (fchdir(fd) < 0)
- return -ERRNO_TO_PARA_ERROR(errno);
- return 1;
-}
-
/**
* A wrapper for mkdir(2).
*
goto out;
}
*size = file_status.st_size;
- ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
+ /*
+ * If the file is empty, *size is zero and mmap() would return EINVAL
+ * (Invalid argument). This error is common enough to spend an extra
+ * error code which explicitly states the problem.
+ */
+ ret = -E_EMPTY;
+ if (*size == 0)
+ goto out;
+ /*
+ * If fd refers to a directory, mmap() returns ENODEV (No such device),
+ * at least on Linux. "Is a directory" seems to be more to the point.
+ */
+ ret = -ERRNO_TO_PARA_ERROR(EISDIR);
+ if (S_ISDIR(file_status.st_mode))
+ goto out;
+
+ ret = para_mmap(*size, mmap_prot, mmap_flags, fd, map);
out:
if (ret < 0 || !fd_ptr)
close(fd);
*
* \return Standard.
*
- * \sa munmap(2), mmap_full_file().
+ * \sa munmap(2), \ref mmap_full_file().
*/
int para_munmap(void *start, size_t length)
{
*
* Common approach that opens /dev/null until it gets a file descriptor greater
* than two.
- *
- * \sa okir's Black Hats Manual.
*/
void valid_fd_012(void)
{
{
DIR *dir;
struct dirent *entry;
- int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
+ int cwd_fd, ret = para_opendir(dirname, &dir, &cwd_fd);
if (ret < 0)
return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;
ret = 1;
out:
closedir(dir);
- ret2 = para_fchdir(cwd_fd);
- if (ret2 < 0 && ret >= 0)
- ret = ret2;
+ if (fchdir(cwd_fd) < 0 && ret >= 0)
+ ret = -ERRNO_TO_PARA_ERROR(errno);
close(cwd_fd);
return ret;
}
projects / paraslash.git / blobdiff