X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=01c7ed8e83552734b1077d444fc055f89f7695c9;hp=7336bd51de6182c8b6899bbca82420db2fd32d08;hb=864024c003d678dbb436cdfc1148b201e4e47018;hpb=840725e10602abd8187428924040f4bf3e04594c diff --git a/fd.c b/fd.c index 7336bd51..01c7ed8e 100644 --- a/fd.c +++ b/fd.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2006-2010 Andre Noll + * Copyright (C) 2006-2012 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -19,67 +19,93 @@ #include "fd.h" /** - * Write a buffer to a file descriptor, re-write on short writes. + * Write a buffer to a file descriptor, re-writing on short writes. * * \param fd The file descriptor. - * \param buf The buffer to be sent. - * \param len The length of \a buf. - * - * \return Standard. In any case, the number of bytes that have been written is - * stored in \a len. + * \param buf The buffer to write. + * \param len The number of bytes to write. + * + * 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. */ -int write_all(int fd, const char *buf, size_t *len) +int write_nonblock(int fd, const char *buf, size_t len) { - size_t total = *len; + size_t written = 0; - 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; + while (written < len) { + ssize_t ret = write(fd, buf + written, len - written); + if (ret >= 0) { + written += ret; + 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; + /* fatal error */ + return -ERRNO_TO_PARA_ERROR(errno); } - return 1; + return written; } /** - * Write a buffer to a non-blocking file descriptor. + * Write all data 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 max_bytes_per_write Do not write more than that many bytes at once. - * - * If \a max_bytes_per_write is non-zero, do not send more than that many bytes - * per write(). + * \param buf The buffer to be sent. + * \param len The length of \a buf. * - * 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. + * This is like \ref write_nonblock() but returns \p -E_SHORT_WRITE if not + * all data could be written. * - * \return Negative on errors, number of bytes written else. + * \return Number of bytes written on success, negative error code else. */ -int write_nonblock(int fd, const char *buf, size_t len, - size_t max_bytes_per_write) +int write_all(int fd, const char *buf, size_t len) { - size_t written = 0; - int ret = 0; + int ret = write_nonblock(fd, buf, len); - while (written < len) { - size_t num = len - written; + if (ret < 0) + return ret; + if (ret != len) + return -E_SHORT_WRITE; + return ret; +} - if (max_bytes_per_write && max_bytes_per_write < num) - num = max_bytes_per_write; - ret = write(fd, buf + written, num); - if (ret < 0 && errno == EAGAIN) - return written; - if (ret < 0) - return -ERRNO_TO_PARA_ERROR(errno); - written += ret; - } - return written; +/** + * 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; + + PARA_VSPRINTF(fmt, msg); + ret = write_buffer(fd, msg); + free(msg); + return ret; } /** @@ -104,7 +130,7 @@ int write_nonblock(int fd, const char *buf, size_t len, * 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 * EAGAIN). Note that even if the function returns negative, some data might - * have been read before the error occured. In this case \a num_bytes is + * have been read before the error occurred. In this case \a num_bytes is * positive. * * \sa \ref write_nonblock(), read(2), readv(2). @@ -453,7 +479,7 @@ 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; @@ -487,7 +513,7 @@ 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); @@ -570,6 +596,9 @@ out: int para_munmap(void *start, size_t length) { int err; + + if (!start) + return 0; if (munmap(start, length) >= 0) return 1; err = errno;