Added scatter-gather variants of [x,xp][read,write]() and [p]read_in_full().
Signed-off-by: Sasha Levin <[email protected]> --- tools/kvm/include/kvm/read-write.h | 13 +++ tools/kvm/read-write.c | 172 ++++++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+), 0 deletions(-) diff --git a/tools/kvm/include/kvm/read-write.h b/tools/kvm/include/kvm/read-write.h index 069326b..3351103 100644 --- a/tools/kvm/include/kvm/read-write.h +++ b/tools/kvm/include/kvm/read-write.h @@ -2,6 +2,7 @@ #define KVM_READ_WRITE_H #include <sys/types.h> +#include <sys/uio.h> #include <unistd.h> ssize_t xread(int fd, void *buf, size_t count); @@ -16,4 +17,16 @@ ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset); ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset); ssize_t pwrite_in_full(int fd, const void *buf, size_t count, off_t offset); +ssize_t xreadv(int fd, const struct iovec *iov, int iovcnt); +ssize_t xwritev(int fd, const struct iovec *iov, int iovcnt); + +ssize_t readv_in_full(int fd, const struct iovec *iov, int iovcnt); +ssize_t writev_in_full(int fd, const struct iovec *iov, int iovcnt); + +ssize_t xpreadv(int fd, const struct iovec *iov, int iovcnt, off_t offset); +ssize_t xpwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset); + +ssize_t preadv_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset); +ssize_t pwritev_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset); + #endif /* KVM_READ_WRITE_H */ diff --git a/tools/kvm/read-write.c b/tools/kvm/read-write.c index 398918b..449e8a2 100644 --- a/tools/kvm/read-write.c +++ b/tools/kvm/read-write.c @@ -152,3 +152,175 @@ ssize_t pwrite_in_full(int fd, const void *buf, size_t count, off_t offset) return total; } + +/* Same as readv(2) except that this function never returns EAGAIN or EINTR. */ +ssize_t xreadv(int fd, const struct iovec *iov, int iovcnt) +{ + ssize_t nr; + +restart: + nr = readv(fd, iov, iovcnt); + if ((nr < 0) && ((errno == EAGAIN) || (errno == EINTR))) + goto restart; + + return nr; +} + +/* Same as writev(2) except that this function never returns EAGAIN or EINTR. */ +ssize_t xwritev(int fd, const struct iovec *iov, int iovcnt) +{ + ssize_t nr; + +restart: + nr = write(fd, iov, iovcnt); + if ((nr < 0) && ((errno == EAGAIN) || (errno == EINTR))) + goto restart; + + return nr; +} + +static inline ssize_t get_iov_size(const struct iovec *iov, int iovcnt) +{ + size_t size = 0; + while (iovcnt--) + size += (iov++)->iov_len; + + return size; +} + +ssize_t readv_in_full(int fd, const struct iovec *iov, int iovcnt) +{ + ssize_t total = 0; + ssize_t count = get_iov_size(iov, iovcnt); + + while (count > 0) { + ssize_t nr; + + nr = xreadv(fd, iov, iovcnt); + if (nr <= 0) { + if (total > 0) + return total; + + return -1; + } + + while ((size_t)nr >= iov->iov_len) { + nr -= iov->iov_len; + total += iov->iov_len; + count -= iov->iov_len; + iovcnt--; + iov++; + } + } + + return total; +} + +ssize_t writev_in_full(int fd, const struct iovec *iov, int iovcnt) +{ + ssize_t total = 0; + size_t count = get_iov_size(iov, iovcnt); + + while (count > 0) { + ssize_t nr; + + nr = xwritev(fd, iov, iovcnt); + if (nr < 0) + return -1; + if (nr == 0) { + errno = ENOSPC; + return -1; + } + + while ((size_t)nr >= iov->iov_len) { + nr -= iov->iov_len; + total += iov->iov_len; + count -= iov->iov_len; + iovcnt--; + iov++; + } + } + + return total; +} + +/* Same as preadv(2) except that this function never returns EAGAIN or EINTR. */ +ssize_t xpreadv(int fd, const struct iovec *iov, int iovcnt, off_t offset) +{ + ssize_t nr; + +restart: + nr = preadv(fd, iov, iovcnt, offset); + if ((nr < 0) && ((errno == EAGAIN) || (errno == EINTR))) + goto restart; + + return nr; +} + +/* Same as pwritev(2) except that this function never returns EAGAIN or EINTR. */ +ssize_t xpwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset) +{ + ssize_t nr; + +restart: + nr = pwritev(fd, iov, iovcnt, offset); + if ((nr < 0) && ((errno == EAGAIN) || (errno == EINTR))) + goto restart; + + return nr; +} + +ssize_t preadv_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset) +{ + ssize_t total = 0; + size_t count = get_iov_size(iov, iovcnt); + + while (count > 0) { + ssize_t nr; + + nr = xpreadv(fd, iov, iovcnt, offset); + if (nr <= 0) { + if (total > 0) + return total; + + return -1; + } + + while ((size_t)nr >= iov->iov_len) { + nr -= iov->iov_len; + total += iov->iov_len; + count -= iov->iov_len; + iovcnt--; + iov++; + } + } + + return total; +} + +ssize_t pwritev_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset) +{ + ssize_t total = 0; + size_t count = get_iov_size(iov, iovcnt); + + while (count > 0) { + ssize_t nr; + + nr = xpwritev(fd, iov, iovcnt, offset); + if (nr < 0) + return -1; + if (nr == 0) { + errno = ENOSPC; + return -1; + } + while ((size_t)nr >= iov->iov_len) { + nr -= iov->iov_len; + total += iov->iov_len; + count -= iov->iov_len; + iovcnt--; + iov++; + } + } + + return total; +} -- 1.7.5.rc1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
