X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=7079b51cc95c683af1187f0b4af1412b07e40950;hp=01c7ed8e83552734b1077d444fc055f89f7695c9;hb=3256f3c144a66a50423d025c13564035c22230f7;hpb=864024c003d678dbb436cdfc1148b201e4e47018 diff --git a/fd.c b/fd.c index 01c7ed8e..7079b51c 100644 --- a/fd.c +++ b/fd.c @@ -1,8 +1,4 @@ -/* - * Copyright (C) 2006-2012 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" @@ -19,32 +13,80 @@ #include "fd.h" /** - * Write a buffer to a file descriptor, re-writing on short writes. + * Change the name or location of a file. + * + * \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. + * + * \sa rename(2). + */ +int xrename(const char *oldpath, const char *newpath) +{ + int ret = rename(oldpath, newpath); + + 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 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 to write. + * \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 \a len 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: A positive return value < \a - * len indicates that some bytes have been written but the next write would - * block. + * \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. + * + * 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; - - while (written < len) { - ssize_t ret = write(fd, buf + written, len - written); + 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) @@ -66,6 +108,23 @@ int write_nonblock(int fd, const char *buf, size_t len) 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. * @@ -73,14 +132,14 @@ int write_nonblock(int fd, const char *buf, size_t len) * \param buf The buffer to be sent. * \param len The length of \a buf. * - * This is like \ref write_nonblock() but returns \p -E_SHORT_WRITE if not + * 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 = write_nonblock(fd, buf, len); + int ret = xwrite(fd, buf, len); if (ret < 0) return ret; @@ -101,9 +160,12 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) { char *msg; int ret; + va_list ap; - PARA_VSPRINTF(fmt, msg); - ret = write_buffer(fd, msg); + va_start(ap, fmt); + ret = xvasprintf(&msg, fmt, ap); + va_end(ap); + ret = write_all(fd, msg, ret); free(msg); return ret; } @@ -119,13 +181,13 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) * * 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 @@ -133,7 +195,7 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) * 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) @@ -254,9 +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; @@ -339,7 +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) { @@ -483,6 +545,7 @@ 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) @@ -506,20 +569,6 @@ 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). * @@ -574,6 +623,22 @@ 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) @@ -591,7 +656,7 @@ out: * * \return Standard. * - * \sa munmap(2), mmap_full_file(). + * \sa munmap(2), \ref mmap_full_file(). */ int para_munmap(void *start, size_t length) { @@ -633,8 +698,6 @@ 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) { @@ -668,7 +731,7 @@ 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; @@ -704,9 +767,8 @@ 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; }