X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=fd.c;h=763f756cdc3b5086ee9d26f432dbbfb760e02e4a;hb=539d39f36549c10656d8b31f3dea32702e9649df;hp=4d4a859b08cf0e13dddea8aa724f94099a0518b1;hpb=fb9209248297242c899ac270afa5ad45b2d084f7;p=paraslash.git diff --git a/fd.c b/fd.c index 4d4a859b..763f756c 100644 --- a/fd.c +++ b/fd.c @@ -1,8 +1,4 @@ -/* - * Copyright (C) 2006-2013 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. */ @@ -10,14 +6,36 @@ #include #include #include -#include -#include #include "para.h" #include "error.h" #include "string.h" #include "fd.h" +/** + * 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. * @@ -146,6 +164,7 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) va_start(ap, fmt); ret = xvasprintf(&msg, fmt, ap); + va_end(ap); ret = write_all(fd, msg, ret); free(msg); return ret; @@ -157,18 +176,15 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) * \param fd The file descriptor to read from. * \param iov Scatter/gather array used in readv(). * \param iovcnt Number of elements in \a iov. - * \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, 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. + * This function 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 @@ -178,24 +194,12 @@ __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...) * * \sa \ref xwrite(), read(2), readv(2). */ -int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds, - size_t *num_bytes) +int readv_nonblock(int fd, struct iovec *iov, int iovcnt, size_t *num_bytes) { int ret, i, j; *num_bytes = 0; - /* - * Avoid a shortcoming of select(): Reads from a non-blocking fd might - * return EAGAIN even if FD_ISSET() returns true. However, FD_ISSET() - * returning false definitely means that no data can currently be read. - * This is the common case, so it is worth to avoid the overhead of the - * read() system call in this case. - */ - if (rfds && !FD_ISSET(fd, rfds)) - return 0; - for (i = 0, j = 0; i < iovcnt;) { - /* fix up the first iov */ assert(j < iov[i].iov_len); iov[i].iov_base += j; @@ -207,7 +211,7 @@ 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); } @@ -232,7 +236,6 @@ int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds, * \param fd The file descriptor to read from. * \param buf The buffer to read data to. * \param sz The size of \a buf. - * \param rfds \see \ref readv_nonblock(). * \param num_bytes \see \ref readv_nonblock(). * * This is a simple wrapper for readv_nonblock() which uses an iovec with a single @@ -240,10 +243,10 @@ int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds, * * \return The return value of the underlying call to readv_nonblock(). */ -int read_nonblock(int fd, void *buf, size_t sz, fd_set *rfds, size_t *num_bytes) +int read_nonblock(int fd, void *buf, size_t sz, size_t *num_bytes) { struct iovec iov = {.iov_base = buf, .iov_len = sz}; - return readv_nonblock(fd, &iov, 1, rfds, num_bytes); + return readv_nonblock(fd, &iov, 1, num_bytes); } /** @@ -252,7 +255,6 @@ int read_nonblock(int fd, void *buf, size_t sz, fd_set *rfds, size_t *num_bytes) * \param fd The file descriptor to receive from. * \param pattern The expected pattern. * \param bufsize The size of the internal buffer. - * \param rfds Passed to read_nonblock(). * * This function tries to read at most \a bufsize bytes from the non-blocking * file descriptor \a fd. If at least \p strlen(\a pattern) bytes have been @@ -264,11 +266,11 @@ int read_nonblock(int fd, void *buf, size_t sz, fd_set *rfds, size_t *num_bytes) * * \sa \ref read_nonblock(), \sa strncasecmp(3). */ -int read_pattern(int fd, const char *pattern, size_t bufsize, fd_set *rfds) +int read_pattern(int fd, const char *pattern, size_t bufsize) { size_t n, len; - char *buf = para_malloc(bufsize + 1); - int ret = read_nonblock(fd, buf, bufsize, rfds, &n); + char *buf = alloc(bufsize + 1); + int ret = read_nonblock(fd, buf, bufsize, &n); buf[n] = '\0'; if (ret < 0) @@ -297,45 +299,15 @@ 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; return !stat(fn, &statbuf); } -/** - * 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_tv upper bound on the amount of time elapsed before select() - * returns. - * - * \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). - */ -int para_select(int n, fd_set *readfds, fd_set *writefds, - struct timeval *timeout_tv) -{ - int ret; - do - ret = select(n, readfds, writefds, NULL, timeout_tv); - while (ret < 0 && errno == EINTR); - if (ret < 0) - return -ERRNO_TO_PARA_ERROR(errno); - return ret; -} - /** * Set a file descriptor to blocking mode. * @@ -372,62 +344,6 @@ __must_check int mark_fd_nonblocking(int fd) return 1; } -/** - * 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. - * - * 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. -*/ -void para_fd_set(int fd, fd_set *fds, int *max_fileno) -{ - assert(fd >= 0 && fd < FD_SETSIZE); -#if 0 - { - int flags = fcntl(fd, F_GETFL); - if (!(flags & O_NONBLOCK)) { - PARA_EMERG_LOG("fd %d is a blocking file descriptor\n", fd); - exit(EXIT_FAILURE); - } - } -#endif - FD_SET(fd, fds); - *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. * @@ -436,22 +352,20 @@ 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: @@ -550,20 +464,6 @@ 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). * @@ -634,7 +534,7 @@ int mmap_full_file(const char *path, int open_mode, void **map, if (S_ISDIR(file_status.st_mode)) goto out; - ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map); + ret = para_mmap(*size, mmap_prot, mmap_flags, fd, map); out: if (ret < 0 || !fd_ptr) close(fd); @@ -651,7 +551,7 @@ out: * * \return Standard. * - * \sa munmap(2), mmap_full_file(). + * \sa munmap(2), \ref mmap_full_file(). */ int para_munmap(void *start, size_t length) { @@ -667,6 +567,47 @@ int para_munmap(void *start, size_t length) return -ERRNO_TO_PARA_ERROR(err); } +/** + * Simple wrapper for poll(2). + * + * It calls poll(2) and starts over if the call was interrupted by a signal. + * + * \param fds See poll(2). + * \param nfds See poll(2). + * \param timeout See poll(2). + * + * \return The return value of the underlying poll() call on success, the + * negative paraslash error code on errors. + * + * All arguments are passed verbatim to poll(2). + */ +int xpoll(struct pollfd *fds, nfds_t nfds, int timeout) +{ + int ret; + + do + ret = poll(fds, nfds, timeout); + while (ret < 0 && errno == EINTR); + return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : ret; +} + +/** + * Check a file descriptor for readability. + * + * \param fd The file descriptor. + * + * \return positive if fd is ready for reading, zero if it isn't, negative if + * an error occurred. + * + * \sa \ref write_ok(). + */ +int read_ok(int fd) +{ + struct pollfd pfd = {.fd = fd, .events = POLLIN}; + int ret = xpoll(&pfd, 1, 0); + return ret < 0? ret : pfd.revents & POLLIN; +} + /** * Check a file descriptor for writability. * @@ -674,18 +615,14 @@ int para_munmap(void *start, size_t length) * * \return positive if fd is ready for writing, zero if it isn't, negative if * an error occurred. + * + * \sa \ref read_ok(). */ - int write_ok(int fd) { - struct timeval tv; - fd_set wfds; - - FD_ZERO(&wfds); - FD_SET(fd, &wfds); - tv.tv_sec = 0; - tv.tv_usec = 0; - return para_select(fd + 1, NULL, &wfds, &tv); + struct pollfd pfd = {.fd = fd, .events = POLLOUT}; + int ret = xpoll(&pfd, 1, 0); + return ret < 0? ret : pfd.revents & POLLOUT; } /** @@ -693,8 +630,6 @@ 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) { @@ -728,7 +663,7 @@ 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; @@ -764,9 +699,8 @@ 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; }