parser.c

Vovida 社区开源的 SIP 协议源码

/*
 * parser.c : an XML 1.0 non-verifying parser
 *
 * See Copyright for the status of this software.
 *
 * [e-mail]
 */

#ifdef WIN32
#include "win32config.h"
#else
#include "config.h"
#endif

#include <stdio.h>
#include <string.h> /* for memset() only */
#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ZLIB_H
#include <zlib.h>
#endif

#include <libxml/xmlmemory.h>
#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/entities.h>
#include <libxml/encoding.h>
#include <libxml/valid.h>
#include <libxml/parserInternals.h>
#include <libxml/xmlIO.h>
#include "xml-error.h"

#define XML_PARSER_BIG_BUFFER_SIZE 1000
#define XML_PARSER_BUFFER_SIZE 100

const char *xmlParserVersion = LIBXML_VERSION_STRING;
int xmlGetWarningsDefaultValue = 1;

/*
 * List of XML prefixed PI allowed by W3C specs
 */

const char *xmlW3CPIs[] = {
    "xml-stylesheet",
    NULL
};

void xmlParserHandleReference(xmlParserCtxtPtr ctxt);
void xmlParserHandlePEReference(xmlParserCtxtPtr ctxt);
xmlEntityPtr xmlParseStringPEReference(xmlParserCtxtPtr ctxt,
                                       const xmlChar **str);
/************************************************************************
 *									*
 * 		Input handling functions for progressive parsing	*
 *									*
 ************************************************************************/

/* #define DEBUG_INPUT */
/* #define DEBUG_STACK */
/* #define DEBUG_PUSH */


#define INPUT_CHUNK	250
/* we need to keep enough input to show errors in context */
#define LINE_LEN        80

#ifdef DEBUG_INPUT
#define CHECK_BUFFER(in) check_buffer(in)

void check_buffer(xmlParserInputPtr in) {
    if (in->base != in->buf->buffer->content) {
        fprintf(stderr, "xmlParserInput: base mismatch problem\n");
    }
    if (in->cur < in->base) {
        fprintf(stderr, "xmlParserInput: cur < base problem\n");
    }
    if (in->cur > in->base + in->buf->buffer->use) {
        fprintf(stderr, "xmlParserInput: cur > base + use problem\n");
    }
    fprintf(stderr,"buffer %x : content %x, cur %d, use %d, size %d\n",
            (int) in, (int) in->buf->buffer->content, in->cur - in->base,
	    in->buf->buffer->use, in->buf->buffer->size);
}

#else
#define CHECK_BUFFER(in) 
#endif


/**
 * xmlParserInputRead:
 * @in:  an XML parser input
 * @len:  an indicative size for the lookahead
 *
 * This function refresh the input for the parser. It doesn't try to
 * preserve pointers to the input buffer, and discard already read data
 *
 * Returns the number of xmlChars read, or -1 in case of error, 0 indicate the
 * end of this entity
 */
int
xmlParserInputRead(xmlParserInputPtr in, int len) {
    int ret;
    int used;
    int index;

#ifdef DEBUG_INPUT
    fprintf(stderr, "Read\n");
#endif
    if (in->buf == NULL) return(-1);
    if (in->base == NULL) return(-1);
    if (in->cur == NULL) return(-1);
    if (in->buf->buffer == NULL) return(-1);

    CHECK_BUFFER(in);

    used = in->cur - in->buf->buffer->content;
    ret = xmlBufferShrink(in->buf->buffer, used);
    if (ret > 0) {
	in->cur -= ret;
	in->consumed += ret;
    }
    ret = xmlParserInputBufferRead(in->buf, len);
    if (in->base != in->buf->buffer->content) {
        /*
	 * the buffer has been realloced
	 */
	index = in->cur - in->base;
	in->base = in->buf->buffer->content;
	in->cur = &in->buf->buffer->content[index];
    }

    CHECK_BUFFER(in);

    return(ret);
}

/**
 * xmlParserInputGrow:
 * @in:  an XML parser input
 * @len:  an indicative size for the lookahead
 *
 * This function increase the input for the parser. It tries to
 * preserve pointers to the input buffer, and keep already read data
 *
 * Returns the number of xmlChars read, or -1 in case of error, 0 indicate the
 * end of this entity
 */
int
xmlParserInputGrow(xmlParserInputPtr in, int len) {
    int ret;
    int index;

#ifdef DEBUG_INPUT
    fprintf(stderr, "Grow\n");
#endif
    if (in->buf == NULL) return(-1);
    if (in->base == NULL) return(-1);
    if (in->cur == NULL) return(-1);
    if (in->buf->buffer == NULL) return(-1);

    CHECK_BUFFER(in);

    index = in->cur - in->base;
    if (in->buf->buffer->use > index + INPUT_CHUNK) {

	CHECK_BUFFER(in);

        return(0);
    }
    if (in->buf->readcallback != NULL)
	ret = xmlParserInputBufferGrow(in->buf, len);
    else	
        return(0);

    /*
     * NOTE : in->base may be a "dandling" i.e. freed pointer in this
     *        block, but we use it really as an integer to do some
     *        pointer arithmetic. Insure will raise it as a bug but in
     *        that specific case, that's not !
     */
    if (in->base != in->buf->buffer->content) {
        /*
	 * the buffer has been realloced
	 */
	index = in->cur - in->base;
	in->base = in->buf->buffer->content;
	in->cur = &in->buf->buffer->content[index];
    }

    CHECK_BUFFER(in);

    return(ret);
}

/**
 * xmlParserInputShrink:
 * @in:  an XML parser input
 *
 * This function removes used input for the parser.
 */
void
xmlParserInputShrink(xmlParserInputPtr in) {
    int used;
    int ret;
    int index;

#ifdef DEBUG_INPUT
    fprintf(stderr, "Shrink\n");
#endif
    if (in->buf == NULL) return;
    if (in->base == NULL) return;
    if (in->cur == NULL) return;
    if (in->buf->buffer == NULL) return;

    CHECK_BUFFER(in);

    used = in->cur - in->buf->buffer->content;
    if (used > INPUT_CHUNK) {
	ret = xmlBufferShrink(in->buf->buffer, used - LINE_LEN);
	if (ret > 0) {
	    in->cur -= ret;
	    in->consumed += ret;
	}
    }

    CHECK_BUFFER(in);

    if (in->buf->buffer->use > INPUT_CHUNK) {
        return;
    }
    xmlParserInputBufferRead(in->buf, 2 * INPUT_CHUNK);
    if (in->base != in->buf->buffer->content) {
        /*
	 * the buffer has been realloced
	 */
	index = in->cur - in->base;
	in->base = in->buf->buffer->content;
	in->cur = &in->buf->buffer->content[index];
    }

    CHECK_BUFFER(in);
}

/************************************************************************
 *									*
 * 		Parser stacks related functions and macros		*
 *									*
 ************************************************************************/

int xmlSubstituteEntitiesDefaultValue = 0;
int xmlDoValidityCheckingDefaultValue = 0;
int xmlKeepBlanksDefaultValue = 1;
xmlEntityPtr xmlParseStringEntityRef(xmlParserCtxtPtr ctxt,
                                     const xmlChar ** str);

/*
 * Generic function for accessing stacks in the Parser Context
 */

#define PUSH_AND_POP(scope, type, name)					\
scope int name##Push(xmlParserCtxtPtr ctxt, type value) {		\
    if (ctxt->name##Nr >= ctxt->name##Max) {				\
	ctxt->name##Max *= 2;						\
        ctxt->name##Tab = (void *) xmlRealloc(ctxt->name##Tab,		\
	             ctxt->name##Max * sizeof(ctxt->name##Tab[0]));	\
        if (ctxt->name##Tab == NULL) {					\
	    fprintf(stderr, "realloc failed !\n");			\
	    return(0);							\
	}								\
    }									\
    ctxt->name##Tab[ctxt->name##Nr] = value;				\
    ctxt->name = value;							\
    return(ctxt->name##Nr++);						\
}									\
scope type name##Pop(xmlParserCtxtPtr ctxt) {				\
    type ret;								\
    if (ctxt->name##Nr <= 0) return(0);					\
    ctxt->name##Nr--;							\
    if (ctxt->name##Nr > 0)						\
	ctxt->name = ctxt->name##Tab[ctxt->name##Nr - 1];		\
    else								\
        ctxt->name = NULL;						\
    ret = ctxt->name##Tab[ctxt->name##Nr];				\
    ctxt->name##Tab[ctxt->name##Nr] = 0;				\
    return(ret);							\
}									\

PUSH_AND_POP(extern, xmlParserInputPtr, input)
PUSH_AND_POP(extern, xmlNodePtr, node)
PUSH_AND_POP(extern, xmlChar*, name)

int spacePush(xmlParserCtxtPtr ctxt, int val) {
    if (ctxt->spaceNr >= ctxt->spaceMax) {
	ctxt->spaceMax *= 2;
        ctxt->spaceTab = (void *) xmlRealloc(ctxt->spaceTab,
	             ctxt->spaceMax * sizeof(ctxt->spaceTab[0]));
        if (ctxt->spaceTab == NULL) {
	    fprintf(stderr, "realloc failed !\n");
	    return(0);
	}
    }
    ctxt->spaceTab[ctxt->spaceNr] = val;
    ctxt->space = &ctxt->spaceTab[ctxt->spaceNr];
    return(ctxt->spaceNr++);
}

int spacePop(xmlParserCtxtPtr ctxt) {
    int ret;
    if (ctxt->spaceNr <= 0) return(0);
    ctxt->spaceNr--;
    if (ctxt->spaceNr > 0)
	ctxt->space = &ctxt->spaceTab[ctxt->spaceNr - 1];
    else
        ctxt->space = NULL;
    ret = ctxt->spaceTab[ctxt->spaceNr];
    ctxt->spaceTab[ctxt->spaceNr] = -1;
    return(ret);
}

/*
 * Macros for accessing the content. Those should be used only by the parser,
 * and not exported.
 *
 * Dirty macros, i.e. one need to make assumption on the context to use them
 *
 *   CUR_PTR return the current pointer to the xmlChar to be parsed.
 *           To be used with extreme caution since operations consuming
 *           characters may move the input buffer to a different location !
 *   CUR     returns the current xmlChar value, i.e. a 8 bit value if compiled
 *           in ISO-Latin or UTF-8. 
 *           This should be used internally by the parser
 *           only to compare to ASCII values otherwise it would break when
 *           running with UTF-8 encoding.
 *   NXT(n)  returns the n'th next xmlChar. Same as CUR is should be used only
 *           to compare on ASCII based substring.
 *   SKIP(n) Skip n xmlChar, and must also be used only to skip ASCII defined
 *           strings within the parser.
 *
 * Clean macros, not dependent of an ASCII context, expect UTF-8 encoding
 *
 *   NEXT    Skip to the next character, this does the proper decoding
 *           in UTF-8 mode. It also pop-up unfinished entities on the fly.
 *   COPY(to) copy one char to *to, increment CUR_PTR and to accordingly
 *   CUR_CHAR Return the current char as an int as well as its lenght.
 */

#define RAW (ctxt->token ? -1 : (*ctxt->input->cur))
#define CUR (ctxt->token ? ctxt->token : (*ctxt->input->cur))
#define NXT(val) ctxt->input->cur[(val)]
#define CUR_PTR ctxt->input->cur

#define SKIP(val) ctxt->nbChars += (val),ctxt->input->cur += (val);	\
    if (*ctxt->input->cur == '%') xmlParserHandlePEReference(ctxt);	\
    if (*ctxt->input->cur == '&') xmlParserHandleReference(ctxt);	\
    if ((*ctxt->input->cur == 0) &&					\
        (xmlParserInputGrow(ctxt->input, INPUT_CHUNK) <= 0))		\
	    xmlPopInput(ctxt)

#define SHRINK  xmlParserInputShrink(ctxt->input);			\
    if ((*ctxt->input->cur == 0) &&					\
        (xmlParserInputGrow(ctxt->input, INPUT_CHUNK) <= 0))		\
	    xmlPopInput(ctxt)

#define GROW  xmlParserInputGrow(ctxt->input, INPUT_CHUNK);		\
    if ((*ctxt->input->cur == 0) &&					\
        (xmlParserInputGrow(ctxt->input, INPUT_CHUNK) <= 0))		\
	    xmlPopInput(ctxt)

#define SKIP_BLANKS xmlSkipBlankChars(ctxt);

#define NEXT xmlNextChar(ctxt);

#define NEXTL(l)							\
    if (*(ctxt->input->cur) == '\n') {					\
	ctxt->input->line++; ctxt->input->col = 1;			\
    } else ctxt->input->col++;						\
    ctxt->token = 0; ctxt->input->cur += l;				\
    if (*ctxt->input->cur == '%') xmlParserHandlePEReference(ctxt);	\
    if (*ctxt->input->cur == '&') xmlParserHandleReference(ctxt);

#define CUR_CHAR(l) xmlCurrentChar(ctxt, &l);
#define CUR_SCHAR(s, l) xmlStringCurrentChar(ctxt, s, &l);

#define COPY_BUF(l,b,i,v)						\
    if (l == 1) b[i++] = (xmlChar) v;					\
    else i += xmlCopyChar(l,&b[i],v);

/**
 * xmlNextChar:
 * @ctxt:  the XML parser context
 *
 * Skip to the next char input char.
 */

void
xmlNextChar(xmlParserCtxtPtr ctxt) {
    /*
     * TODO: 2.11 End-of-Line Handling
     *   the literal two-character sequence "#xD#xA" or a standalone
     *   literal #xD, an XML processor must pass to the application
     *   the single character #xA. 
     */
    if (ctxt->token != 0) ctxt->token = 0;
    else {
	if ((*ctxt->input->cur == 0) &&
	    (xmlParserInputGrow(ctxt->input, INPUT_CHUNK) <= 0) &&
	    (ctxt->instate != XML_PARSER_COMMENT)) {
	        /*
		 * If we are at the end of the current entity and
		 * the context allows it, we pop consumed entities
		 * automatically.
		 * TODO: the auto closing should be blocked in other cases
		 */
		xmlPopInput(ctxt);
	} else {
	    if (*(ctxt->input->cur) == '\n') {
		ctxt->input->line++; ctxt->input->col = 1;
	    } else ctxt->input->col++;
	    if (ctxt->encoding == NULL) {
		/*
		 * We are supposed to handle UTF8, check it's valid
		 * From rfc2044: encoding of the Unicode values on UTF-8:
		 *
		 * UCS-4 range (hex.)           UTF-8 octet sequence (binary)
		 * 0000 0000-0000 007F   0xxxxxxx
		 * 0000 0080-0000 07FF   110xxxxx 10xxxxxx
		 * 0000 0800-0000 FFFF   1110xxxx 10xxxxxx 10xxxxxx 
		 *
		 * Check for the 0x110000 limit too
		 */
		const unsigned char *cur = ctxt->input->cur;
		unsigned char c;

		c = *cur;
		if (c & 0x80) {
		    if (cur[1] == 0)
			xmlParserInputGrow(ctxt->input, INPUT_CHUNK);
		    if ((cur[1] & 0xc0) != 0x80)
			goto encoding_error;
		    if ((c & 0xe0) == 0xe0) {
			unsigned int val;

			if (cur[2] == 0)
			    xmlParserInputGrow(ctxt->input, INPUT_CHUNK);