X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=33891d2e6c9f1c3568428b1df93b4b92e295ef61;hp=6f9266f47a56cd8dee3e99b8651d12a89bb4069b;hb=9d232e636d79a2321e280fe3eee6839c8f45c36f;hpb=1c8226eae0e976d940366cd10bd708d8e4d0bca5 diff --git a/fd.c b/fd.c index 6f9266f4..33891d2e 100644 --- a/fd.c +++ b/fd.c @@ -1,8 +1,4 @@ -/* - * Copyright (C) 2006-2011 Andre Noll - * - * Licensed under the GPL v2. For licencing details see COPYING. - */ +/* Copyright (C) 2006 Andre Noll , see file COPYING. */ /** \file fd.c Helper functions for file descriptor handling. */ @@ -10,8 +6,6 @@ #include #include #include -#include -#include #include "para.h" #include "error.h" @@ -19,62 +13,163 @@ #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. + * + * 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. * @@ -84,15 +179,15 @@ int write_nonblock(int fd, const char *buf, size_t len) * \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 @@ -100,7 +195,7 @@ 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) @@ -131,7 +226,7 @@ int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds, 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); } @@ -221,9 +316,9 @@ out: * * \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; @@ -306,7 +401,7 @@ __must_check int mark_fd_nonblocking(int fd) * 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) { @@ -324,34 +419,6 @@ 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. * @@ -360,22 +427,20 @@ again: * 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: @@ -450,6 +515,7 @@ 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) @@ -473,20 +539,6 @@ close_cwd: 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). * @@ -541,7 +593,23 @@ int mmap_full_file(const char *path, int open_mode, void **map, 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); @@ -558,11 +626,14 @@ out: * * \return Standard. * - * \sa munmap(2), mmap_full_file(). + * \sa munmap(2), \ref mmap_full_file(). */ int para_munmap(void *start, size_t length) { int err; + + if (!start) + return 0; if (munmap(start, length) >= 0) return 1; err = errno; @@ -597,8 +668,6 @@ int write_ok(int fd) * * 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) { @@ -632,7 +701,7 @@ int for_each_file_in_dir(const char *dirname, { 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; @@ -668,9 +737,8 @@ int for_each_file_in_dir(const char *dirname, 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; }