/* -*- mode: c; c-file-style: "openbsd" -*- */
/*
* Copyright (c) 2012 Vincent Bernat <bernat@luffy.cx>
*
* Permission to use, copy, modify, and/or 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.
*/
#define MARSHAL_EXPORT
#include "marshal.h"
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <string.h>
#include "compat/compat.h"
#include "log.h"
#include "lldpd-structs.h"
/* Stolen from CCAN */
#if HAVE_ALIGNOF
# define ALIGNOF(t) (__alignof__(t))
#else
# define ALIGNOF(t) ((sizeof(t) > 1)?((char *)(&((struct { char c; t _h; } *)0)->_h) - (char *)0):1)
#endif
/* A serialized object */
struct marshal_serialized {
void *orig; /* Original reference. Also enforce alignment. */
size_t size;
unsigned char object[0];
};
struct marshal_info marshal_info_string = {
.name = "null string",
.size = 0,
.pointers = {MARSHAL_SUBINFO_NULL},
};
struct marshal_info marshal_info_fstring = {
.name = "fixed string",
.size = 0,
.pointers = {MARSHAL_SUBINFO_NULL},
};
struct marshal_info marshal_info_ignore = {
.name = "ignored",
.size = 0,
.pointers = {MARSHAL_SUBINFO_NULL},
};
/* List of already seen pointers */
struct ref {
TAILQ_ENTRY(ref) next;
void *pointer;
int dummy; /* To renumerate pointers */
};
TAILQ_HEAD(ref_l, ref);
/* Serialize the given object. */
ssize_t
marshal_serialize_(struct marshal_info *mi, void *unserialized, void **input,
int skip, void *_refs, int osize)
{
struct ref_l *refs = _refs;
struct ref *cref;
int size;
size_t len;
struct marshal_subinfo *current;
struct marshal_serialized *new = NULL, *serialized = NULL;
int dummy = 1;
log_debug("marshal", "start serialization of %s", mi->name);
/* Check if we have already serialized this one. */
if (!refs) {
refs = calloc(1, sizeof(struct ref_l));
if (!refs) {
log_warnx("marshal", "unable to allocate memory for list of references");
return -1;
}
TAILQ_INIT(refs);
}
TAILQ_FOREACH(cref, refs, next) {
if (unserialized == cref->pointer)
return 0;
/* dummy should be higher than any existing dummy */
if (cref->dummy >= dummy) dummy = cref->dummy + 1;
}
/* Handle special cases. */
size = mi->size;
if (!strcmp(mi->name, "null string"))
/* We know we can't be called with NULL */
size = strlen((char *)unserialized) + 1;
else if (!strcmp(mi->name, "fixed string"))
size = osize;
/* Allocate serialized structure */
len = sizeof(struct marshal_serialized) + (skip?0:size);
serialized = calloc(1, len);
if (!serialized) {
log_warnx("marshal", "unable to allocate memory to serialize structure %s",
mi->name);
len = -1;
goto marshal_error;
}
/* We don't use the original pointer but a dummy one. */
serialized->orig = (unsigned char*)NULL + dummy;
/* Append the new reference */
if (!(cref = calloc(1, sizeof(struct ref)))) {
log_warnx("marshal", "unable to allocate memory for list of references");
free(serialized);
len = -1;
goto marshal_error;
}
cref->pointer = unserialized;
cref->dummy = dummy;
TAILQ_INSERT_TAIL(refs, cref, next);
/* First, serialize the main structure */
if (!skip)
memcpy(serialized->object, unserialized, size);
/* Then, serialize inner structures */
for (current = mi->pointers; current->mi; current++) {
size_t sublen;
size_t padlen;
void *source;
void *target = NULL;
if (current->kind == ignore) continue;
if (current->kind == pointer) {
memcpy(&source,
(unsigned char *)unserialized + current->offset,
sizeof(void *));
if (source == NULL) continue;
} else
source = (void *)((unsigned char *)unserialized + current->offset);
if (current->offset2)
memcpy(&osize, (unsigned char*)unserialized + current->offset2, sizeof(int));
target = NULL;
sublen = marshal_serialize_(current->mi,
source, &target,
current->kind == substruct, refs, osize);
if (sublen == -1) {
log_warnx("marshal", "unable to serialize substructure %s for %s",
current->mi->name, mi->name);
free(serialized);
return -1;
}
/* We want to put the renumerated pointer instead of the real one. */
if (current->kind == pointer && !skip) {
TAILQ_FOREACH(cref, refs, next) {
if (source == cref->pointer) {
void *fakepointer = (unsigned char*)NULL + cref->dummy;
memcpy((unsigned char *)serialized->object + current->offset,
&fakepointer, sizeof(void *));
break;
}
}
}
if (sublen == 0) continue; /* This was already serialized */
/* Append the result, force alignment to be able to unserialize it */
padlen = ALIGNOF(struct marshal_serialized);
padlen = (padlen - (len % padlen)) % padlen;
new = realloc(serialized, len + padlen + sublen);
if (!new) {
log_warnx("marshal", "unable to allocate more memory to serialize structure %s",
mi->name);
free(serialized);
free(target);
len = -1;
goto marshal_error;
}
memset((unsigned char *)new + len, 0, padlen);
memcpy((unsigned char *)new + len + padlen, target, sublen);
free(target);
len += sublen + padlen;
serialized = (struct marshal_serialized *)new;
}
serialized->size = len;
*input = serialized;
marshal_error:
if (refs && !_refs) {
struct ref *cref, *cref_next;
for (cref = TAILQ_FIRST(refs);
cref != NULL;
cref = cref_next) {
cref_next = TAILQ_NEXT(cref, next);
TAILQ_REMOVE(refs, cref, next);
free(cref);
}
free(refs);
}
return len;
}
/* This structure is used to track memory allocation when serializing */
struct gc {
TAILQ_ENTRY(gc) next;
void *pointer;
void *orig; /* Original reference (not valid anymore !) */
};
TAILQ_HEAD(gc_l, gc);
static void*
marshal_alloc(struct gc_l *pointers, size_t len, void *orig)
{
struct gc *gpointer = NULL;
void *result = calloc(1, len);
if (!result) return NULL;
if ((gpointer = (struct gc *)calloc(1,
sizeof(struct gc))) == NULL) {
free(result);
return NULL;
}
gpointer->pointer = result;
gpointer->orig = orig;
TAILQ_INSERT_TAIL(pointers, gpointer, next);
return result;
}
static void
marshal_free(struct gc_l *pointers, int gconly)
{
struct gc *pointer, *pointer_next;
for (pointer = TAILQ_FIRST(pointers);
pointer != NULL;
pointer = pointer_next) {
pointer_next = TAILQ_NEXT(pointer, next);
TAILQ_REMOVE(pointers, pointer, next);
if (!gconly)
free(pointer->pointer);
free(pointer);
}
}
/* Unserialize the given object. */
size_t
marshal_unserialize_(struct marshal_info *mi, void *buffer, size_t len, void **output,
void *_pointers, int skip, int osize)
{
int total_len = sizeof(struct marshal_serialized) + (skip?0:mi->size);
struct marshal_serialized *serialized = buffer;
struct gc_l *pointers = _pointers;
int size, already, extra = 0;
void *new;
struct marshal_subinfo *current;
struct gc *apointer;
log_debug("marshal", "start unserialization of %s", mi->name);
if (len < sizeof(struct marshal_serialized) || len < total_len) {
log_warnx("marshal", "data to deserialize is too small (%zu) for structure %s",
len, mi->name);
return 0;
}
/* Initialize garbage collection */
if (!pointers) {
pointers = calloc(1, sizeof(struct gc_l));
if (!pointers) {
log_warnx("marshal", "unable to allocate memory for garbage collection");
return 0;
}
TAILQ_INIT(pointers);
}
/* Special cases */
size = mi->size;
if (!strcmp(mi->name, "null string") || !strcmp(mi->name, "fixed string")) {
switch (mi->name[0]) {
case 'n': size = strnlen((char *)serialized->object,
len - sizeof(struct marshal_serialized)) + 1; break;
case 'f': size = osize; extra=1; break; /* The extra byte is to ensure that
the string is null terminated. */
}
if (size > len - sizeof(struct marshal_serialized)) {
log_warnx("marshal", "data to deserialize contains a string too long");
total_len = 0;
goto unmarshal_error;
}
total_len += size;
}
/* First, the main structure */
if (!skip) {
if ((*output = marshal_alloc(pointers, size + extra, serialized->orig)) == NULL) {
log_warnx("marshal", "unable to allocate memory to unserialize structure %s",
mi->name);
total_len = 0;
goto unmarshal_error;
}
memcpy(*output, serialized->object, size);
}
/* Then, each substructure */
for (current = mi->pointers; current->mi; current++) {
size_t sublen;
size_t padlen;
new = (unsigned char *)*output + current->offset;
if (current->kind == ignore) {
memset((unsigned char *)*output + current->offset,
0, sizeof(void *));
continue;
}
if (current->kind == pointer) {
if (*(void **)new == NULL) continue;
/* Did we already see this reference? */
already = 0;
TAILQ_FOREACH(apointer, pointers, next)
if (apointer->orig == *(void **)new) {
memcpy((unsigned char *)*output + current->offset,
&apointer->pointer, sizeof(void *));
already = 1;
break;
}
if (already) continue;
}
/* Deserialize */
if (current->offset2)
memcpy(&osize, (unsigned char *)*output + current->offset2, sizeof(int));
padlen = ALIGNOF(struct marshal_serialized);
padlen = (padlen - (total_len % padlen)) % padlen;
if (len < total_len + padlen || ((sublen = marshal_unserialize_(current->mi,
(unsigned char *)buffer + total_len + padlen,
len - total_len - padlen, &new, pointers,
current->kind == substruct, osize)) == 0)) {
log_warnx("marshal", "unable to serialize substructure %s for %s",
current->mi->name, mi->name);
total_len = 0;
goto unmarshal_error;
}
/* Link the result */
if (current->kind == pointer)
memcpy((unsigned char *)*output + current->offset,
&new, sizeof(void *));
total_len += sublen + padlen;
}
unmarshal_error:
if (pointers && !_pointers) {
marshal_free(pointers, (total_len > 0));
free(pointers);
}
return total_len;
}