/* $OpenBSD: buffer.c,v 1.4 2009/07/23 18:58:42 eric Exp $ */ /* * Copyright (c) 2003, 2004 Henning Brauer * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include "imsg.h" int buf_realloc(struct buf *, size_t); void buf_enqueue(struct msgbuf *, struct buf *); void buf_dequeue(struct msgbuf *, struct buf *); struct buf * buf_open(size_t len) { struct buf *buf; if ((buf = calloc(1, sizeof(struct buf))) == NULL) return (NULL); if ((buf->buf = malloc(len)) == NULL) { free(buf); return (NULL); } buf->size = buf->max = len; buf->fd = -1; return (buf); } struct buf * buf_dynamic(size_t len, size_t max) { struct buf *buf; if (max < len) return (NULL); if ((buf = buf_open(len)) == NULL) return (NULL); if (max > 0) buf->max = max; return (buf); } int buf_realloc(struct buf *buf, size_t len) { u_char *b; /* on static buffers max is eq size and so the following fails */ if (buf->wpos + len > buf->max) { errno = ENOMEM; return (-1); } b = realloc(buf->buf, buf->wpos + len); if (b == NULL) return (-1); buf->buf = b; buf->size = buf->wpos + len; return (0); } int buf_add(struct buf *buf, const void *data, size_t len) { if (buf->wpos + len > buf->size) if (buf_realloc(buf, len) == -1) return (-1); memcpy(buf->buf + buf->wpos, data, len); buf->wpos += len; return (0); } void * buf_reserve(struct buf *buf, size_t len) { void *b; if (buf->wpos + len > buf->size) if (buf_realloc(buf, len) == -1) return (NULL); b = buf->buf + buf->wpos; buf->wpos += len; return (b); } void * buf_seek(struct buf *buf, size_t pos, size_t len) { /* only allowed to seek in already written parts */ if (pos + len > buf->wpos) return (NULL); return (buf->buf + pos); } size_t buf_size(struct buf *buf) { return (buf->wpos); } size_t buf_left(struct buf *buf) { return (buf->max - buf->wpos); } void buf_close(struct msgbuf *msgbuf, struct buf *buf) { buf_enqueue(msgbuf, buf); } int buf_write(struct msgbuf *msgbuf) { struct iovec iov[IOV_MAX]; struct buf *buf, *next; unsigned int i = 0; ssize_t n; bzero(&iov, sizeof(iov)); TAILQ_FOREACH(buf, &msgbuf->bufs, entry) { if (i >= IOV_MAX) break; iov[i].iov_base = buf->buf + buf->rpos; iov[i].iov_len = buf->wpos - buf->rpos; i++; } if ((n = writev(msgbuf->fd, iov, i)) == -1) { if (errno == EAGAIN || errno == ENOBUFS || errno == EINTR) /* try later */ return (0); else return (-1); } if (n == 0) { /* connection closed */ errno = 0; return (-2); } for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0; buf = next) { next = TAILQ_NEXT(buf, entry); if (buf->rpos + n >= buf->wpos) { n -= buf->wpos - buf->rpos; buf_dequeue(msgbuf, buf); } else { buf->rpos += n; n = 0; } } return (0); } void buf_free(struct buf *buf) { free(buf->buf); free(buf); } void msgbuf_init(struct msgbuf *msgbuf) { msgbuf->queued = 0; msgbuf->fd = -1; TAILQ_INIT(&msgbuf->bufs); } void msgbuf_clear(struct msgbuf *msgbuf) { struct buf *buf; while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL) buf_dequeue(msgbuf, buf); } int msgbuf_write(struct msgbuf *msgbuf) { struct iovec iov[IOV_MAX]; struct buf *buf, *next; unsigned int i = 0; ssize_t n; struct msghdr msg; struct cmsghdr *cmsg; union { struct cmsghdr hdr; char buf[CMSG_SPACE(sizeof(int))]; } cmsgbuf; bzero(&iov, sizeof(iov)); bzero(&msg, sizeof(msg)); TAILQ_FOREACH(buf, &msgbuf->bufs, entry) { if (i >= IOV_MAX) break; iov[i].iov_base = buf->buf + buf->rpos; iov[i].iov_len = buf->wpos - buf->rpos; i++; if (buf->fd != -1) break; } msg.msg_iov = iov; msg.msg_iovlen = i; if (buf != NULL && buf->fd != -1) { msg.msg_control = (caddr_t)&cmsgbuf.buf; msg.msg_controllen = sizeof(cmsgbuf.buf); cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_len = CMSG_LEN(sizeof(int)); cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = SCM_RIGHTS; *(int *)CMSG_DATA(cmsg) = buf->fd; } if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) { if (errno == EAGAIN || errno == ENOBUFS || errno == EINTR) /* try later */ return (0); else return (-1); } if (n == 0) { /* connection closed */ errno = 0; return (-2); } /* * assumption: fd got sent if sendmsg sent anything * this works because fds are passed one at a time */ if (buf != NULL && buf->fd != -1) { close(buf->fd); buf->fd = -1; } for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0; buf = next) { next = TAILQ_NEXT(buf, entry); if (buf->rpos + n >= buf->wpos) { n -= buf->wpos - buf->rpos; buf_dequeue(msgbuf, buf); } else { buf->rpos += n; n = 0; } } return (0); } void buf_enqueue(struct msgbuf *msgbuf, struct buf *buf) { TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry); msgbuf->queued++; } void buf_dequeue(struct msgbuf *msgbuf, struct buf *buf) { TAILQ_REMOVE(&msgbuf->bufs, buf, entry); if (buf->fd != -1) close(buf->fd); msgbuf->queued--; buf_free(buf); }