X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=6a26ce5e3d4d5f2993affc76a544e96db1a5738c;hp=a0969e3e651a92983682f29f1ca375b214a6447a;hb=a13a1e0d202a8969374b9a70562556e689597f2d;hpb=7584638594109184f329bead008f1dcdd9030767 diff --git a/fd.c b/fd.c index a0969e3e..6a26ce5e 100644 --- a/fd.c +++ b/fd.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2006-2011 Andre Noll + * Copyright (C) 2006 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -10,8 +10,6 @@ #include #include #include -#include -#include #include "para.h" #include "error.h" @@ -19,62 +17,163 @@ #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. * - * \return Standard. In any case, the number of bytes that have been written is - * stored in \a len. + * 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. + * + * \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. * - * 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. + * \return Negative on fatal errors, number of bytes written else. * - * \return Negative on 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. + * + * 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. + * + * \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. * @@ -86,13 +185,13 @@ int write_nonblock(int fd, const char *buf, size_t len) * * 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. + * Otherwise The function tries to read up to \a sz bytes from \a fd, where \a + * sz is the sum of the lengths of all vectors in \a iov. As for xwrite(), + * \p EAGAIN is not considered an error condition. However, \p 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 \p EAGAIN, 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 @@ -100,7 +199,7 @@ int write_nonblock(int fd, const char *buf, size_t len) * 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) @@ -446,10 +545,11 @@ int para_chdir(const char *path) * \sa getcwd(3). * */ -int para_opendir(const char *dirname, DIR **dir, int *cwd) +static int para_opendir(const char *dirname, DIR **dir, int *cwd) { int ret; + *dir = NULL; if (cwd) { ret = para_open(".", O_RDONLY, 0); if (ret < 0) @@ -480,7 +580,7 @@ close_cwd: * * \return Standard. */ -int para_fchdir(int fd) +static int para_fchdir(int fd) { if (fchdir(fd) < 0) return -ERRNO_TO_PARA_ERROR(errno); @@ -541,6 +641,22 @@ int mmap_full_file(const char *path, int open_mode, void **map, goto out; } *size = file_status.st_size; + /* + * 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, 0, map); out: if (ret < 0 || !fd_ptr) @@ -563,6 +679,9 @@ out: int para_munmap(void *start, size_t length) { int err; + + if (!start) + return 0; if (munmap(start, length) >= 0) return 1; err = errno;