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capn-malloc.c
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capn-malloc.c
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/* vim: set sw=8 ts=8 sts=8 noet: */
/* capn-malloc.c
*
* Copyright (C) 2013 James McKaskill
* Copyright (C) 2014 Steve Dee
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
#ifdef __GNUC__
#pragma GCC diagnostic ignored "-Wunused-parameter"
#endif
#include "capnp_c.h"
#include "capnp_priv.h"
#ifndef __KERNEL__
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>
#else /* ! __KERNEL__ */
#include <linux/slab.h>
#endif /* ! __KERNEL__ */
/*
* 8 byte alignment is required for struct capn_segment.
* This struct check_segment_alignment verifies this at compile time.
*
* Unless capn_segment is defined with 8 byte alignment, check_segment_alignment
* fails to compile in x86 mode (or on another CPU with 32-bit pointers),
* as (sizeof(struct capn_segment)&7) -> (44 & 7) evaluates to 4.
* It compiles in x64 mode (or on another CPU with 64-bit pointers),
* as (sizeof(struct capn_segment)&7) -> (80 & 7) evaluates to 0.
*/
struct check_segment_alignment {
unsigned int foo : (sizeof(struct capn_segment)&7) ? -1 : 1;
};
static struct capn_segment *create(void *u, uint32_t id, int sz) {
struct capn_segment *s;
sz += sizeof(*s);
if (sz < 4096) {
sz = 4096;
} else {
sz = (sz + 4095) & ~4095;
}
s = (struct capn_segment*) calloc(1, sz);
s->data = (char*) (s+1);
s->cap = sz - sizeof(*s);
s->user = s;
return s;
}
static struct capn_segment *create_local(void *u, int sz) {
return create(u, 0, sz);
}
void capn_init_malloc(struct capn *c) {
memset(c, 0, sizeof(*c));
c->create = &create;
c->create_local = &create_local;
}
void capn_free(struct capn *c) {
struct capn_segment *s = c->seglist;
while (s != NULL) {
struct capn_segment *n = s->next;
free(s->user);
s = n;
}
capn_reset_copy(c);
}
void capn_reset_copy(struct capn *c) {
struct capn_segment *s = c->copylist;
while (s != NULL) {
struct capn_segment *n = s->next;
free(s->user);
s = n;
}
c->copy = NULL;
c->copylist = NULL;
}
#define ZBUF_SZ 4096
static int read_fp(void *p, size_t sz, FILE *f, struct capn_stream *z, uint8_t* zbuf, int packed) {
#ifndef __KERNEL__
if (f && packed) {
z->next_out = (uint8_t*) p;
z->avail_out = sz;
while (z->avail_out && capn_inflate(z) == CAPN_NEED_MORE) {
int r;
memmove(zbuf, z->next_in, z->avail_in);
r = fread(zbuf+z->avail_in, 1, ZBUF_SZ - z->avail_in, f);
if (r <= 0)
return -1;
z->avail_in += r;
}
return 0;
} else if (f && !packed) {
return fread(p, sz, 1, f) != 1;
} else
#endif /* ! __KERNEL__ */
if (packed) {
z->next_out = (uint8_t*) p;
z->avail_out = sz;
return capn_inflate(z) != 0;
} else {
if (z->avail_in < sz)
return -1;
memcpy(p, z->next_in, sz);
z->next_in += sz;
z->avail_in -= sz;
return 0;
}
}
static int init_fp(struct capn *c, FILE *f, struct capn_stream *z, int packed) {
/*
* Initialize 'c' from the contents of 'f', assuming the message has been
* serialized with the standard framing format. From https://capnproto.org/encoding.html:
*
* When transmitting over a stream, the following should be sent. All integers are unsigned and little-endian.
* (4 bytes) The number of segments, minus one (since there is always at least one segment).
* (N * 4 bytes) The size of each segment, in words.
* (0 or 4 bytes) Padding up to the next word boundary.
* The content of each segment, in order.
*/
struct capn_segment *s = NULL;
uint32_t i, segnum, total = 0;
uint32_t hdr[1024];
uint8_t zbuf[ZBUF_SZ];
char *data = NULL;
capn_init_malloc(c);
/* Read the first four bytes to know how many headers we have */
if (read_fp(&segnum, 4, f, z, zbuf, packed))
goto err;
segnum = capn_flip32(segnum);
if (segnum > 1023)
goto err;
segnum++; /* The wire encoding was zero-based */
/* Read the header list */
if (read_fp(hdr, 8 * (segnum/2) + 4, f, z, zbuf, packed))
goto err;
for (i = 0; i < segnum; i++) {
uint32_t n = capn_flip32(hdr[i]);
if (n > INT_MAX/8 || n > UINT32_MAX/8 || UINT32_MAX - total < n*8)
goto err;
hdr[i] = n*8;
total += hdr[i];
}
/* Allocate space for the data and the capn_segment structs */
s = (struct capn_segment*) calloc(1, total + (sizeof(*s) * segnum));
if (!s)
goto err;
/* Now read the data and setup the capn_segment structs */
data = (char*) (s+segnum);
if (read_fp(data, total, f, z, zbuf, packed))
goto err;
for (i = 0; i < segnum; i++) {
s[i].len = s[i].cap = hdr[i];
s[i].data = data;
data += s[i].len;
capn_append_segment(c, &s[i]);
}
/* Set the entire region to be freed on the last segment */
s[segnum-1].user = s;
return 0;
err:
memset(c, 0, sizeof(*c));
free(s);
return -1;
}
int capn_init_fp(struct capn *c, FILE *f, int packed) {
struct capn_stream z;
memset(&z, 0, sizeof(z));
return init_fp(c, f, &z, packed);
}
int capn_init_mem(struct capn *c, const uint8_t *p, size_t sz, int packed) {
struct capn_stream z;
memset(&z, 0, sizeof(z));
z.next_in = p;
z.avail_in = sz;
return init_fp(c, NULL, &z, packed);
}
static void header_calc(struct capn *c, uint32_t *headerlen, size_t *headersz)
{
/* segnum == 1:
* [segnum][segsiz]
* segnum == 2:
* [segnum][segsiz][segsiz][zeroes]
* segnum == 3:
* [segnum][segsiz][segsiz][segsiz]
* segnum == 4:
* [segnum][segsiz][segsiz][segsiz][segsiz][zeroes]
*/
*headerlen = ((2 + c->segnum) / 2) * 2;
*headersz = 4 * *headerlen;
}
static int header_render(struct capn *c, struct capn_segment *seg, uint32_t *header, uint32_t headerlen, size_t *datasz)
{
size_t i;
header[0] = capn_flip32(c->segnum - 1);
header[headerlen-1] = 0; /* Zero out the spare position in the header sizes */
for (i = 0; i < c->segnum; i++, seg = seg->next) {
if (0 == seg)
return -1;
*datasz += seg->len;
header[1 + i] = capn_flip32(seg->len / 8);
}
if (0 != seg)
return -1;
return 0;
}
static int capn_write_mem_packed(struct capn *c, uint8_t *p, size_t sz)
{
struct capn_segment *seg;
struct capn_ptr root;
uint32_t headerlen;
size_t headersz, datasz = 0;
uint32_t *header;
struct capn_stream z;
int ret;
root = capn_root(c);
header_calc(c, &headerlen, &headersz);
header = (uint32_t*) (p + headersz + 2); /* must reserve two bytes for worst case expansion */
if (sz < headersz*2 + 2) /* We must have space for temporary writing of header to deflate */
return -1;
ret = header_render(c, root.seg, header, headerlen, &datasz);
if (ret != 0)
return -1;
memset(&z, 0, sizeof(z));
z.next_in = (uint8_t *)header;
z.avail_in = headersz;
z.next_out = p;
z.avail_out = sz;
// pack the headers
ret = capn_deflate(&z);
if (ret != 0 || z.avail_in != 0)
return -1;
for (seg = root.seg; seg; seg = seg->next) {
z.next_in = (uint8_t *)seg->data;
z.avail_in = seg->len;
ret = capn_deflate(&z);
if (ret != 0 || z.avail_in != 0)
return -1;
}
return sz - z.avail_out;
}
int
capn_write_mem(struct capn *c, uint8_t *p, size_t sz, int packed)
{
struct capn_segment *seg;
struct capn_ptr root;
uint32_t headerlen;
size_t headersz, datasz = 0;
uint32_t *header;
int ret;
if (c->segnum == 0)
return -1;
if (packed)
return capn_write_mem_packed(c, p, sz);
root = capn_root(c);
header_calc(c, &headerlen, &headersz);
header = (uint32_t*) p;
if (sz < headersz)
return -1;
ret = header_render(c, root.seg, header, headerlen, &datasz);
if (ret != 0)
return -1;
if (sz < headersz + datasz)
return -1;
p += headersz;
for (seg = root.seg; seg; seg = seg->next) {
memcpy(p, seg->data, seg->len);
p += seg->len;
}
return headersz+datasz;
}
static int _write_fd(ssize_t (*write_fd)(int fd, const void *p, size_t count), int fd, void *p, size_t count)
{
ssize_t ret;
size_t sent = 0;
while (sent < count) {
ret = write_fd(fd, ((uint8_t*)p)+sent, count-sent);
if (ret < 0) {
#ifndef __KERNEL__
// Still not sure about this interface
if (errno == EAGAIN || errno == EINTR)
continue;
else
#endif /* ! __KERNEL__ */
return -1;
}
sent += ret;
}
return 0;
}
int capn_write_fd(struct capn *c, ssize_t (*write_fd)(int fd, const void *p, size_t count), int fd, int packed)
{
unsigned char buf[4096];
struct capn_segment *seg;
struct capn_ptr root;
uint32_t headerlen;
size_t headersz, datasz = 0;
int ret;
struct capn_stream z;
unsigned char *p;
if (c->segnum == 0)
return -1;
root = capn_root(c);
header_calc(c, &headerlen, &headersz);
if (sizeof(buf) < headersz)
return -1;
ret = header_render(c, root.seg, (uint32_t*)buf, headerlen, &datasz);
if (ret != 0)
return -1;
if (packed) {
const int headerrem = sizeof(buf) - headersz;
const int maxpack = headersz + 2;
if (headerrem < maxpack)
return -1;
memset(&z, 0, sizeof(z));
z.next_in = buf;
z.avail_in = headersz;
z.next_out = buf + headersz;
z.avail_out = headerrem;
ret = capn_deflate(&z);
if (ret != 0)
return -1;
p = buf + headersz;
headersz = headerrem - z.avail_out;
} else {
p = buf;
}
ret = _write_fd(write_fd, fd, p, headersz);
if (ret < 0)
return -1;
datasz = headersz;
for (seg = root.seg; seg; seg = seg->next) {
size_t bufsz;
if (packed) {
memset(&z, 0, sizeof(z));
z.next_in = (uint8_t*)seg->data;
z.avail_in = seg->len;
z.next_out = buf;
z.avail_out = sizeof(buf);
ret = capn_deflate(&z);
if (ret != 0)
return -1;
p = buf;
bufsz = sizeof(buf) - z.avail_out;
} else {
p = (uint8_t*)seg->data;
bufsz = seg->len;
}
ret = _write_fd(write_fd, fd, p, bufsz);
if (ret < 0)
return -1;
datasz += bufsz;
}
return datasz;
}