prefix.c

/*

  Copyright (c) 2017 Martin Sustrik

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"),
  to deal in the Software without restriction, including without limitation
  the rights to use, copy, modify, merge, publish, distribute, sublicense,
  and/or sell copies of the Software, and to permit persons to whom
  the Software is furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  IN THE SOFTWARE.

*/

#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#define DILL_DISABLE_RAW_NAMES
#include "libdillimpl.h"
#include "utils.h"

dill_unique_id(dill_prefix_type);

static void *dill_prefix_hquery(struct dill_hvfs *hvfs, const void *type);
static void dill_prefix_hclose(struct dill_hvfs *hvfs);
static int dill_prefix_msendl(struct dill_msock_vfs *mvfs,
    struct dill_iolist *first, struct dill_iolist *last, int64_t deadline);
static ssize_t dill_prefix_mrecvl(struct dill_msock_vfs *mvfs,
    struct dill_iolist *first, struct dill_iolist *last, int64_t deadline);

struct dill_prefix_sock {
    struct dill_hvfs hvfs;
    struct dill_msock_vfs mvfs;
    int u;
    size_t hdrlen;
    unsigned int bigendian : 1;
    unsigned int inerr : 1;
    unsigned int outerr : 1;
    unsigned int mem : 1;
};

DILL_CHECK_STORAGE(dill_prefix_sock, dill_prefix_storage)

static void *dill_prefix_hquery(struct dill_hvfs *hvfs, const void *type) {
    struct dill_prefix_sock *self = (struct dill_prefix_sock*)hvfs;
    if(type == dill_msock_type) return &self->mvfs;
    if(type == dill_prefix_type) return self;
    errno = ENOTSUP;
    return NULL;
}

int dill_prefix_attach_mem(int s, size_t hdrlen, int flags,
      struct dill_prefix_storage *mem) {
    int err;
    if(dill_slow(!mem || hdrlen == 0)) {err = EINVAL; goto error;}
    /* Take ownership of the underlying socket. */
    s = dill_hown(s);
    if(dill_slow(s < 0)) {err = errno; goto error;}
    /* Check whether underlying socket is a bytestream. */
    void *q = dill_hquery(s, dill_bsock_type);
    if(dill_slow(!q && errno == ENOTSUP)) {err = EPROTO; goto error;}
    if(dill_slow(!q)) {err = errno; goto error;}
    /* Create the object. */
    struct dill_prefix_sock *self = (struct dill_prefix_sock*)mem;
    self->hvfs.query = dill_prefix_hquery;
    self->hvfs.close = dill_prefix_hclose;
    self->mvfs.msendl = dill_prefix_msendl;
    self->mvfs.mrecvl = dill_prefix_mrecvl;
    self->u = s;
    self->hdrlen = hdrlen;
    self->bigendian = !(flags & DILL_PREFIX_LITTLE_ENDIAN);
    self->inerr = 0;
    self->outerr = 0;
    self->mem = 1;
    /* Create the handle. */
    int h = dill_hmake(&self->hvfs);
    if(dill_slow(h < 0)) {err = errno; goto error;}
    return h;
error:
    if(s >= 0) dill_hclose(s);
    errno = err;
    return -1;
}

int dill_prefix_attach(int s, size_t hdrlen, int flags) {
    int err;
    struct dill_prefix_sock *obj = malloc(sizeof(struct dill_prefix_sock));
    if(dill_slow(!obj)) {err = ENOMEM; goto error1;}
    s = dill_prefix_attach_mem(s, hdrlen, flags,
        (struct dill_prefix_storage*)obj);
    if(dill_slow(s < 0)) {err = errno; goto error2;}
    obj->mem = 0;
    return s;
error2:
    free(obj);
error1:
    if(s >= 0) dill_hclose(s);
    errno = err;
    return -1;
}

int dill_prefix_detach(int s) {
    int err;
    struct dill_prefix_sock *self = dill_hquery(s, dill_prefix_type);
    if(dill_slow(!self)) {err = errno; goto error;}
    if(dill_slow(self->inerr || self->outerr)) {err = ECONNRESET; goto error;}
    int u = self->u;
    if(!self->mem) free(self);
    return u;
error:
    if(s >= 0) dill_hclose(s);
    errno = err;
    return -1;
}

static int dill_prefix_msendl(struct dill_msock_vfs *mvfs,
      struct dill_iolist *first, struct dill_iolist *last, int64_t deadline) {
    struct dill_prefix_sock *self = dill_cont(mvfs, struct dill_prefix_sock,
        mvfs);
    if(dill_slow(self->outerr)) {errno = ECONNRESET; return -1;}
    uint8_t szbuf[self->hdrlen];
    size_t sz = 0;
    struct dill_iolist *it;
    for(it = first; it; it = it->iol_next)
        sz += it->iol_len;
    int i;
    for(i = 0; i != self->hdrlen; ++i) {
        szbuf[self->bigendian ? (self->hdrlen - i - 1) : i] = sz & 0xff;
        sz >>= 8;
    }
    struct dill_iolist hdr = {szbuf, sizeof(szbuf), first, 0};
    int rc = dill_bsendl(self->u, &hdr, last, deadline);
    if(dill_slow(rc < 0)) {self->outerr = 1; return -1;}
    return 0;
}

static ssize_t dill_prefix_mrecvl(struct dill_msock_vfs *mvfs,
      struct dill_iolist *first, struct dill_iolist *last, int64_t deadline) {
    struct dill_prefix_sock *self = dill_cont(mvfs, struct dill_prefix_sock,
        mvfs);
    if(dill_slow(self->inerr)) {errno = ECONNRESET; return -1;}
    uint8_t szbuf[self->hdrlen];
    int rc = dill_brecv(self->u, szbuf, self->hdrlen, deadline);
    if(dill_slow(rc < 0)) {self->inerr = 1; return -1;}
    uint64_t sz = 0;
    int i;
    for(i = 0; i != self->hdrlen; ++i) {
        uint8_t c = szbuf[self->bigendian ? i : (self->hdrlen - i - 1)];
        sz <<= 8;
        sz |= c;
    }
    /* Skip the message. */
    if(!first) {
        rc = dill_brecv(self->u, NULL, sz, deadline);
        if(dill_slow(rc < 0)) {self->inerr = 1; return -1;}
        return sz;
    }
    /* Trim iolist to reflect the size of the message. */
    size_t rmn = sz;
    struct dill_iolist *it = first;
    while(1) {
        if(it->iol_len >= rmn) break;
        rmn -= it->iol_len;
        it = it->iol_next;
        if(dill_slow(!it)) {self->inerr = 1; errno = EMSGSIZE; return -1;}
    }
    size_t old_len = it->iol_len;
    struct dill_iolist *old_next = it->iol_next;
    it->iol_len = rmn;
    it->iol_next = NULL;
    rc = dill_brecvl(self->u, first, last, deadline);
    /* Get iolist to its original state. */
    it->iol_len = old_len;
    it->iol_next = old_next;
    if(dill_slow(rc < 0)) {self->inerr = 1; return -1;}
    return sz;
}

static void dill_prefix_hclose(struct dill_hvfs *hvfs) {
    struct dill_prefix_sock *self = (struct dill_prefix_sock*)hvfs;
    if(dill_fast(self->u >= 0)) {
        int rc = dill_hclose(self->u);
        dill_assert(rc == 0);
    }
    if(!self->mem) free(self);
}