/* Parse HyperText Document Address HTParse.c
** ================================
*/
#include "HTUtils.h"
#include "tcp.h"
#include "HTParse.h"
#include "LYLeaks.h"
#define FREE(x) if (x) {free(x); x = NULL;}
#define HEX_ESCAPE '%'
struct struct_parts {
char * access;
char * host;
char * absolute;
char * relative;
/* char * search; no - treated as part of path */
char * anchor;
};
/* Strip white space off a string. HTStrip()
** -------------------------------
**
** On exit,
** Return value points to first non-white character, or to 0 if none.
** All trailing white space is OVERWRITTEN with zero.
*/
PUBLIC char * HTStrip ARGS1(
char *, s)
{
#define SPACE(c) ((c == ' ') || (c == '\t') || (c == '\n'))
char * p = s;
for (p = s; *p; p++)
; /* Find end of string */
for (p--; p >= s; p--) {
if (SPACE(*p))
*p = '\0'; /* Zap trailing blanks */
else
break;
}
while (SPACE(*s))
s++; /* Strip leading blanks */
return s;
}
/* Scan a filename for its consituents. scan()
** ------------------------------------
**
** On entry,
** name points to a document name which may be incomplete.
** On exit,
** absolute or relative may be nonzero (but not both).
** host, anchor and access may be nonzero if they were specified.
** Any which are nonzero point to zero terminated strings.
*/
PRIVATE void scan ARGS2(
char *, name,
struct struct_parts *, parts)
{
char * after_access;
char * p;
#ifdef NOTDEFINED
int length = strlen(name);
#endif
parts->access = NULL;
parts->host = NULL;
parts->absolute = NULL;
parts->relative = NULL;
parts->anchor = NULL;
/*
** Scan left-to-right for a scheme (access).
*/
after_access = name;
for (p = name; *p; p++) {
if (*p==':') {
*p = '\0';
parts->access = name; /* Access name has been specified */
after_access = (p + 1);
break;
}
if (*p == '/' || *p == '#' || *p == ';' || *p == '?')
break;
}
#ifdef NOTDEFINED
for (p = (name + length-1); p >= name; p--) {
#endif /* NOTDEFINED */
/*
** Scan left-to-right for a fragment (anchor).
*/
for (p = after_access; *p; p++) {
if (*p =='#') {
parts->anchor = (p + 1);
*p = '\0'; /* terminate the rest */
}
}
/*
** Scan left-to-right for a host or absolute path.
*/
p = after_access;
if (*p == '/') {
if (p[1] == '/') {
parts->host = (p + 2); /* host has been specified */
*p = '\0'; /* Terminate access */
p = strchr(parts->host, '/'); /* look for end of host name if any */
if (p != NULL) {
*p = '\0'; /* Terminate host */
parts->absolute = (p + 1); /* Root has been found */
}
} else {
parts->absolute = (p + 1); /* Root found but no host */
}
} else {
parts->relative = (*after_access) ?
after_access : NULL; /* NULL for "" */
}
/*
** Check schemes that commonly have unescaped hashes.
*/
if (parts->access && parts->anchor) {
if ((!parts->host && strcasecomp(parts->access, "lynxcgi")) ||
!strcasecomp(parts->access, "nntp") ||
!strcasecomp(parts->access, "snews") ||
!strcasecomp(parts->access, "news") ||
!strcasecomp(parts->access, "data")) {
/*
* Access specified but no host and not a lynxcgi URL, so the
* anchor may not really be one, e.g., news:j462#36487@foo.bar,
* or it's an nntp or snews URL, or news URL with a host.
* Restore the '#' in the address.
*/
*(parts->anchor - 1) = '#';
parts->anchor = NULL;
}
}
#ifdef NOT_DEFINED /* search is just treated as part of path */
{
char *p = (relative ? relative : absolute);
if (p != NULL) {
char *q = strchr(p, '?'); /* Any search string? */
if (q != NULL) {
*q = '\0'; /* If so, chop that off. */
parts->search = (q + 1);
}
}
}
#endif /* NOT_DEFINED */
} /*scan */
/* Parse a Name relative to another name. HTParse()
** --------------------------------------
**
** This returns those parts of a name which are given (and requested)
** substituting bits from the related name where necessary.
**
** On entry,
** aName A filename given
** relatedName A name relative to which aName is to be parsed
** wanted A mask for the bits which are wanted.
**
** On exit,
** returns A pointer to a malloc'd string which MUST BE FREED
*/
PUBLIC char * HTParse ARGS3(
CONST char *, aName,
CONST char *, relatedName,
int, wanted)
{
char * result = NULL;
char * return_value = NULL;
int len;
char * name = NULL;
char * rel = NULL;
char * p;
char * access;
struct struct_parts given, related;
if (TRACE)
fprintf(stderr,
"HTParse: aName:%s relatedName:%s\n", aName, relatedName);
/*
** Allocate the output string.
*/
len = strlen(aName) + strlen(relatedName) + 10;
result = (char *)malloc(len); /* Lots of space: more than enough */
if (result == NULL)
outofmem(__FILE__, "HTParse");
result[0] = '\0'; /* Clear string */
/*
** Make working copies of the input strings to cut up.
*/
StrAllocCopy(name, aName);
StrAllocCopy(rel, relatedName);
/*
** Cut up the strings into URL fields.
*/
scan(name, &given);
scan(rel, &related);
/*
** Handle the scheme (access) field.
*/
if (given.access && given.host && !given.relative && !given.absolute) {
if (!strcmp(given.access, "http") ||
!strcmp(given.access, "https") ||
!strcmp(given.access, "ftp"))
/*
** Assume root.
*/
given.absolute = "";
}
access = given.access ? given.access : related.access;
if (wanted & PARSE_ACCESS) {
if (access) {
strcat(result, access);
if (wanted & PARSE_PUNCTUATION)
strcat(result, ":");
}
}
/*
** If different schemes, inherit nothing.
**
** We'll try complying with RFC 1808 and
** the Fielding draft, and inherit nothing
** if both schemes are given, rather than
** only when they differ, except for
** file URLs - FM
**
** After trying it for a while, it's still
** premature, IHMO, to go along with it, so
** this is back to inheriting for identical
** schemes whether or not they are "file".
** If you want to try it again yourself,
** uncomment the strncasecomp() below. - FM
*/
if ((given.access && related.access) &&
(/* strcasecomp(given.access, "file") || */
strcmp(given.access, related.access))) {
related.host = NULL;
related.absolute = NULL;
related.relative = NULL;
related.anchor = NULL;
}
/*
** Handle the host field.
*/
if (wanted & PARSE_HOST)
if (given.host || related.host) {
char *tail = result + strlen(result);
if (wanted & PARSE_PUNCTUATION)
strcat(result, "//");
strcat(result, given.host ? given.host : related.host);
#define CLEAN_URLS
#ifdef CLEAN_URLS
/*
** Ignore default port numbers, and trailing dots on FQDNs,
** which will only cause identical addresses to look different.
*/
{
char *p, *h;
if ((p = strchr(result, '@')) != NULL)
tail = (p + 1);
p = strchr(tail, ':');
if (p != NULL && !isdigit((unsigned char)p[1]))
/*
** Colon not followed by a port number.
*/
*p = '\0';
if (p != NULL && p != '\0' && access != NULL) {
/*
** Port specified.
*/
if ((!strcmp(access, "http" ) && !strcmp(p, ":80" )) ||
(!strcmp(access, "https" ) && !strcmp(p, ":443")) ||
(!strcmp(access, "gopher" ) && !strcmp(p, ":70" )) ||
(!strcmp(access, "ftp" ) && !strcmp(p, ":21" )) ||
(!strcmp(access, "wais" ) && !strcmp(p, ":210")) ||
(!strcmp(access, "nntp" ) && !strcmp(p, ":119")) ||
(!strcmp(access, "news" ) && !strcmp(p, ":119")) ||
(!strcmp(access, "newspost" ) && !strcmp(p, ":119")) ||
(!strcmp(access, "newsreply" ) && !strcmp(p, ":119")) ||
(!strcmp(access, "snews" ) && !strcmp(p, ":563")) ||
(!strcmp(access, "snewspost" ) && !strcmp(p, ":563")) ||
(!strcmp(access, "snewsreply") && !strcmp(p, ":563")) ||
(!strcmp(access, "finger" ) && !strcmp(p, ":79" )) ||
(!strcmp(access, "telnet" ) && !strcmp(p, ":23" )) ||
(!strcmp(access, "tn3270" ) && !strcmp(p, ":23" )) ||
(!strcmp(access, "rlogin" ) && !strcmp(p, ":513")) ||
(!strcmp(access, "cso" ) && !strcmp(p, ":105")))
*p = '\0'; /* It is the default: ignore it */
}
if (p == NULL) {
int len = strlen(tail);
if (len > 0) {
h = tail + len - 1; /* last char of hostname */
if (*h == '.')
*h = '\0'; /* chop final . */
}
} else {
h = p;
h--; /* End of hostname */
if (*h == '.') {
/*
** Slide p over h.
*/
while (*p != '\0')
*h++ = *p++;
*h = '\0'; /* terminate */
}
}
}
#endif /* CLEAN_URLS */
}
/*
** If different hosts, inherit no path.
*/
if (given.host && related.host)
if (strcmp(given.host, related.host) != 0) {
related.absolute = NULL;
related.relative = NULL;
related.anchor = NULL;
}
/*
** Handle the path.
*/
if (wanted & PARSE_PATH) {
if (access && !given.absolute && given.relative) {
if (!strcasecomp(access, "nntp") ||
!strcasecomp(access, "snews") ||
(!strcasecomp(access, "news") &&
!strncasecomp(result, "news://", 7))) {
/*
* Treat all given nntp or snews paths,
* or given paths for news URLs with a host,
* as absolute.
*/
given.absolute = given.relative;
given.relative = NULL;
}
}
if (given.absolute) { /* All is given */
if (wanted & PARSE_PUNCTUATION)
strcat(result, "/");
strcat(result, given.absolute);
if (TRACE)
fprintf(stderr, "1\n");
} else if (related.absolute) { /* Adopt path not name */
strcat(result, "/");
strcat(result, related.absolute);
if (given.relative) {
p = strchr(result, '?'); /* Search part? */
if (p == NULL)
p = (result + strlen(result) - 1);
for (; *p != '/'; p--)
; /* last / */
p[1] = '\0'; /* Remove filename */
strcat(result, given.relative); /* Add given one */
HTSimplify (result);
}
if (TRACE)
fprintf(stderr, "2\n");
} else if (given.relative) {
strcat(result, given.relative); /* what we've got */
if (TRACE)
fprintf(stderr, "3\n");
} else if (related.relative) {
strcat(result, related.relative);
if (TRACE)
fprintf(stderr, "4\n");
} else { /* No inheritance */
if (strncasecomp(aName, "lynxcgi:", 8) &&
strncasecomp(aName, "lynxexec:", 9) &&
strncasecomp(aName, "lynxprog:", 9)) {
strcat(result, "/");
}
if (!strcmp(result, "news:/"))
result[5] = '*';
if (TRACE)
fprintf(stderr, "5\n");
}
}
/*
** Handle the fragment (anchor).
*/
if (wanted & PARSE_ANCHOR)
if ((given.anchor && *given.anchor) ||
(!given.anchor && related.anchor)) {
if (wanted & PARSE_PUNCTUATION)
strcat(result, "#");
strcat(result, (given.anchor) ?
given.anchor : related.anchor);
}
if (TRACE)
fprintf(stderr, "HTParse: result:%s\n", result);
FREE(rel);
FREE(name);
StrAllocCopy(return_value, result);
FREE(result);
return return_value; /* exactly the right length */
}
/* Simplify a filename. HTSimplify()
** --------------------
**
** A unix-style file is allowed to contain the seqeunce xxx/../ which may
** be replaced by "" , and the seqeunce "/./" which may be replaced by "/".
** Simplification helps us recognize duplicate filenames.
**
** Thus, /etc/junk/../fred becomes /etc/fred
** /etc/junk/./fred becomes /etc/junk/fred
**
** but we should NOT change
** http://fred.xxx.edu/../..
**
** or ../../albert.html
*/
PUBLIC void HTSimplify ARGS1(
char *, filename)
{
char *p;
char *q, *q1;
if (filename == NULL)
return;
if ((filename[0] && filename[1]) && strchr(filename, '/') != NULL) {
for (p = (filename + 2); *p; p++) {
if (*p == '/') {
if ((p[1] == '.') && (p[2] == '.') &&
(p[3] == '/' || p[3] == '\0')) {
/*
** Handle "/../" or "/..".
*/
for (q = (p - 1); (q >= filename) && (*q != '/'); q--)
/*
** Back up to previous slash or beginning of string.
*/
;
if ((q[0] == '/') && strncmp(q, "/../", 4) &&
!((q - 1) > filename && q[-1] == '/')) {
/*
** Not at beginning of string or in a
** host field, so remove the "/xxx/..".
*/
q1 = (p + 3);
p = q;
while (*q1 != '\0')
*p++ = *q1++;
*p = '\0'; /* terminate */
#ifdef NOTDEFINED
/*
** Make sure filename has at least one slash.
*/
if (*filename == '\0') {
*filename = '/';
*(filename + 1) = '\0';
}
#endif /* NOTDEFINED */
/*
** Start again with previous slash.
*/
p = (q - 1);
}
} else if (p[1] == '.' && p[2] == '/') {
/*
** Handle "./" by removing the characters.
*/
q = p;
q1 = (p + 2);
while (*q1 != '\0')
*q++ = *q1++;
*q = '\0'; /* terminate */
p--;
} else if (p[1] == '.' && p[2] == '\0') {
/*
** Handle terminal "." by removing the character.
*/
p[1] = '\0';
}
}
}
}
}
/* Make Relative Name. HTRelative()
** -------------------
**
** This function creates and returns a string which gives an expression of
** one address as related to another. Where there is no relation, an absolute
** address is retured.
**
** On entry,
** Both names must be absolute, fully qualified names of nodes
** (no anchor bits)
**
** On exit,
** The return result points to a newly allocated name which, if
** parsed by HTParse relative to relatedName, will yield aName.
** The caller is responsible for freeing the resulting name later.
**
*/
PUBLIC char * HTRelative ARGS2(
CONST char *, aName,
CONST char *, relatedName)
{
char * result = NULL;
CONST char *p = aName;
CONST char *q = relatedName;
CONST char * after_access = NULL;
CONST char * path = NULL;
CONST char * last_slash = NULL;
int slashes = 0;
for (; *p; p++, q++) { /* Find extent of match */
if (*p != *q)
break;
if (*p == ':')
after_access = p+1;
if (*p == '/') {
last_slash = p;
slashes++;
if (slashes == 3)
path=p;
}
}
/* q, p point to the first non-matching character or zero */
if (!after_access) { /* Different access */
StrAllocCopy(result, aName);
} else if (slashes < 3){ /* Different nodes */
StrAllocCopy(result, after_access);
} else if (slashes == 3){ /* Same node, different path */
StrAllocCopy(result, path);
} else { /* Some path in common */
int levels = 0;
for (; *q && (*q != '#'); q++)
if (*q == '/')
levels++;
result = (char *)malloc(3*levels + strlen(last_slash) + 1);
if (result == NULL)
outofmem(__FILE__, "HTRelative");
result[0] = '\0';
for (; levels; levels--)
strcat(result, "../");
strcat(result, last_slash+1);
}
if (TRACE)
fprintf(stderr, "HT: `%s' expressed relative to\n `%s' is\n `%s'.",
aName, relatedName, result);
return result;
}
/* Escape undesirable characters using % HTEscape()
** -------------------------------------
**
** This function takes a pointer to a string in which
** some characters may be unacceptable unescaped.
** It returns a string which has these characters
** represented by a '%' character followed by two hex digits.
**
** Unlike HTUnEscape(), this routine returns a malloced string.
*/
PRIVATE CONST unsigned char isAcceptable[96] =
/* Bit 0 xalpha -- see HTFile.h
** Bit 1 xpalpha -- as xalpha but with plus.
** Bit 3 ... path -- as xpalphas but with /
*/
/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
{ 0,0,0,0,0,0,0,0,0,0,7,6,0,7,7,4, /* 2x !"#$%&'()*+,-./ */
7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,0, /* 3x 0123456789:;<=>? */
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 4x @ABCDEFGHIJKLMNO */
7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,7, /* 5X PQRSTUVWXYZ[\]^_ */
0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 6x `abcdefghijklmno */
7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,0 }; /* 7X pqrstuvwxyz{\}~ DEL */
PRIVATE char *hex = "0123456789ABCDEF";
#define ACCEPTABLE(a) ( a>=32 && a<128 && ((isAcceptable[a-32]) & mask))
PUBLIC char * HTEscape ARGS2(
CONST char *, str,
unsigned char, mask)
{
CONST char * p;
char * q;
char * result;
int unacceptable = 0;
for (p = str; *p; p++)
if (!ACCEPTABLE((unsigned char)TOASCII(*p)))
unacceptable++;
result = (char *) malloc(p-str + unacceptable+ unacceptable + 1);
if (result == NULL)
outofmem(__FILE__, "HTEscape");
for (q = result, p = str; *p; p++) {
unsigned char a = TOASCII(*p);
if (!ACCEPTABLE(a)) {
*q++ = HEX_ESCAPE; /* Means hex commming */
*q++ = hex[a >> 4];
*q++ = hex[a & 15];
}
else *q++ = *p;
}
*q++ = '\0'; /* Terminate */
return result;
}
/* Escape undesirable characters using % but space to +. HTEscapeSP()
** -----------------------------------------------------
**
** This function takes a pointer to a string in which
** some characters may be unacceptable unescaped.
** It returns a string which has these characters
** represented by a '%' character followed by two hex digits,
** except that spaces are converted to '+' instead of %2B.
**
** Unlike HTUnEscape(), this routine returns a malloced string.
*/
PUBLIC char * HTEscapeSP ARGS2(
CONST char *, str,
unsigned char, mask)
{
CONST char * p;
char * q;
char * result;
int unacceptable = 0;
for (p = str; *p; p++)
if (!(*p == ' ' || ACCEPTABLE((unsigned char)TOASCII(*p))))
unacceptable++;
result = (char *) malloc(p-str + unacceptable+ unacceptable + 1);
if (result == NULL)
outofmem(__FILE__, "HTEscape");
for (q = result, p = str; *p; p++) {
unsigned char a = TOASCII(*p);
if (a == 32) {
*q++ = '+';
} else if (!ACCEPTABLE(a)) {
*q++ = HEX_ESCAPE; /* Means hex commming */
*q++ = hex[a >> 4];
*q++ = hex[a & 15];
} else {
*q++ = *p;
}
}
*q++ = '\0'; /* Terminate */
return result;
}
/* Decode %xx escaped characters. HTUnEscape()
** ------------------------------
**
** This function takes a pointer to a string in which some
** characters may have been encoded in %xy form, where xy is
** the acsii hex code for character 16x+y.
** The string is converted in place, as it will never grow.
*/
PRIVATE char from_hex ARGS1(
char, c)
{
return c >= '0' && c <= '9' ? c - '0'
: c >= 'A' && c <= 'F'? c - 'A' + 10
: c - 'a' + 10; /* accept small letters just in case */
}
PUBLIC char * HTUnEscape ARGS1(
char *, str)
{
char * p = str;
char * q = str;
if (!(p && *p))
return str;
while (*p != '\0') {
if (*p == HEX_ESCAPE) {
p++;
if (*p)
*q = from_hex(*p++) * 16;
if (*p)
*q = FROMASCII(*q + from_hex(*p++));
q++;
} else {
*q++ = *p++;
}
}
*q++ = '\0';
return str;
} /* HTUnEscape */
/* Decode some %xx escaped characters. HTUnEscapeSome()
** ----------------------------------- Klaus Weide
** (kweide@tezcat.com)
** This function takes a pointer to a string in which some
** characters may have been encoded in %xy form, where xy is
** the acsii hex code for character 16x+y, and a pointer to
** a second string containing one or more characters which
** should be unescaped if escaped in the first string.
** The first string is converted in place, as it will never grow.
*/
PUBLIC char * HTUnEscapeSome ARGS2(
char *, str,
CONST char *, do_trans)
{
char * p = str;
char * q = str;
char testcode;
if (p == NULL || *p == '\0' || do_trans == NULL || *do_trans == '\0')
return str;
while (*p != '\0') {
if (*p == HEX_ESCAPE &&
p[1] && p[2] && /* tests shouldn't be needed, but.. */
isxdigit((unsigned char)p[1]) &&
isxdigit((unsigned char)p[2]) &&
(testcode = from_hex(p[1])*16 + from_hex(p[2])) && /* %00 no good*/
strchr(do_trans, testcode)) { /* it's one of the ones we want */
*q++ = FROMASCII(testcode);
p += 3;
} else {
*q++ = *p++;
}
}
*q++ = '\0';
return str;
} /* HTUnEscapeSome */