ref: 1d891d163e814a93ee5346cf05b4fac297bf3a5c
dir: /sys/src/libhttpd/parse.c/
#include <u.h>
#include <libc.h>
#include <ctype.h>
#include <libsec.h>
#include <bin.h>
#include <httpd.h>
#include "escape.h"
typedef struct Hlex Hlex;
typedef struct MimeHead MimeHead;
enum
{
/*
* tokens
*/
Word = 1,
QString,
};
#define UlongMax 4294967295UL
struct Hlex
{
int tok;
int eoh;
int eol; /* end of header line encountered? */
uchar *hstart; /* start of header */
jmp_buf jmp; /* jmp here to parse header */
char wordval[HMaxWord];
HConnect *c;
};
struct MimeHead
{
char *name;
void (*parse)(Hlex*, char*);
uchar seen;
uchar ignore;
};
static void mimeaccept(Hlex*, char*);
static void mimeacceptchar(Hlex*, char*);
static void mimeacceptenc(Hlex*, char*);
static void mimeacceptlang(Hlex*, char*);
static void mimeagent(Hlex*, char*);
static void mimeauthorization(Hlex*, char*);
static void mimeconnection(Hlex*, char*);
static void mimecontlen(Hlex*, char*);
static void mimecookie(Hlex*, char*);
static void mimeexpect(Hlex*, char*);
static void mimefresh(Hlex*, char*);
static void mimefrom(Hlex*, char*);
static void mimehost(Hlex*, char*);
static void mimeifrange(Hlex*, char*);
static void mimeignore(Hlex*, char*);
static void mimematch(Hlex*, char*);
static void mimemodified(Hlex*, char*);
static void mimenomatch(Hlex*, char*);
static void mimerange(Hlex*, char*);
static void mimetransenc(Hlex*, char*);
static void mimeunmodified(Hlex*, char*);
/*
* headers seen also include
* allow cache-control chargeto
* content-encoding content-language content-location content-md5 content-range content-type
* date etag expires forwarded last-modified max-forwards pragma
* proxy-agent proxy-authorization proxy-connection
* ua-color ua-cpu ua-os ua-pixels
* upgrade via x-afs-tokens x-serial-number
*/
static MimeHead mimehead[] =
{
{"accept", mimeaccept},
{"accept-charset", mimeacceptchar},
{"accept-encoding", mimeacceptenc},
{"accept-language", mimeacceptlang},
{"authorization", mimeauthorization},
{"connection", mimeconnection},
{"content-length", mimecontlen},
{"cookie", mimecookie},
{"expect", mimeexpect},
{"fresh", mimefresh},
{"from", mimefrom},
{"host", mimehost},
{"if-match", mimematch},
{"if-modified-since", mimemodified},
{"if-none-match", mimenomatch},
{"if-range", mimeifrange},
{"if-unmodified-since", mimeunmodified},
{"range", mimerange},
{"transfer-encoding", mimetransenc},
{"user-agent", mimeagent},
};
char* hmydomain;
char* hversion = "HTTP/1.1";
static void lexhead(Hlex*);
static void parsejump(Hlex*, char*);
static int getc(Hlex*);
static void ungetc(Hlex*);
static int wordcr(Hlex*);
static int wordnl(Hlex*);
static void word(Hlex*, char*);
static int lex1(Hlex*, int);
static int lex(Hlex*);
static int lexbase64(Hlex*);
static ulong digtoul(char *s, char **e);
/*
* flush and clean up junk from a request
*/
void
hreqcleanup(HConnect *c)
{
int i;
hxferenc(&c->hout, 0);
memset(&c->req, 0, sizeof(c->req));
memset(&c->head, 0, sizeof(c->head));
c->hpos = c->header;
c->hstop = c->header;
binfree(&c->bin);
for(i = 0; i < nelem(mimehead); i++){
mimehead[i].seen = 0;
mimehead[i].ignore = 0;
}
}
/*
* list of tokens
* if the client is HTTP/1.0,
* ignore headers which match one of the tokens.
* restarts parsing if necessary.
*/
static void
mimeconnection(Hlex *h, char *)
{
char *u, *p;
int reparse, i;
reparse = 0;
for(;;){
while(lex(h) != Word)
if(h->tok != ',')
goto breakout;
if(cistrcmp(h->wordval, "keep-alive") == 0)
h->c->head.persist = 1;
else if(cistrcmp(h->wordval, "close") == 0)
h->c->head.closeit = 1;
else if(!http11(h->c)){
for(i = 0; i < nelem(mimehead); i++){
if(cistrcmp(mimehead[i].name, h->wordval) == 0){
reparse = mimehead[i].seen && !mimehead[i].ignore;
mimehead[i].ignore = 1;
if(cistrcmp(mimehead[i].name, "authorization") == 0){
h->c->head.authuser = nil;
h->c->head.authpass = nil;
}
}
}
}
if(lex(h) != ',')
break;
}
breakout:;
/*
* if need to ignore headers we've already parsed,
* reset & start over. need to save authorization
* info because it's written over when parsed.
*/
if(reparse){
u = h->c->head.authuser;
p = h->c->head.authpass;
memset(&h->c->head, 0, sizeof(h->c->head));
h->c->head.authuser = u;
h->c->head.authpass = p;
h->c->hpos = h->hstart;
longjmp(h->jmp, 1);
}
}
int
hparseheaders(HConnect *c, int timeout)
{
Hlex h;
c->head.fresh_thresh = 0;
c->head.fresh_have = 0;
c->head.persist = 0;
if(c->req.vermaj == 0){
c->head.host = hmydomain;
return 1;
}
memset(&h, 0, sizeof(h));
h.c = c;
if(timeout)
alarm(timeout);
if(hgethead(c, 1) < 0)
return -1;
if(timeout)
alarm(0);
h.hstart = c->hpos;
if(setjmp(h.jmp) == -1)
return -1;
h.eol = 0;
h.eoh = 0;
h.tok = '\n';
while(lex(&h) != '\n'){
if(h.tok == Word && lex(&h) == ':')
parsejump(&h, hstrdup(c, h.wordval));
while(h.tok != '\n')
lex(&h);
h.eol = h.eoh;
}
if(http11(c)){
/*
* according to the http/1.1 spec,
* these rules must be followed
*/
if(c->head.host == nil){
hfail(c, HBadReq, nil);
return -1;
}
if(c->req.urihost != nil)
c->head.host = c->req.urihost;
/*
* also need to check host is actually this one
*/
}else if(c->head.host == nil)
c->head.host = hmydomain;
return 1;
}
/*
* mimeparams : | mimeparams ";" mimepara
* mimeparam : token "=" token | token "=" qstring
*/
static HSPairs*
mimeparams(Hlex *h)
{
HSPairs *p;
char *s;
p = nil;
for(;;){
if(lex(h) != Word)
break;
s = hstrdup(h->c, h->wordval);
if(lex(h) != Word && h->tok != QString)
break;
p = hmkspairs(h->c, s, hstrdup(h->c, h->wordval), p);
}
return hrevspairs(p);
}
/*
* mimehfields : mimehfield | mimehfields commas mimehfield
* mimehfield : token mimeparams
* commas : "," | commas ","
*/
static HFields*
mimehfields(Hlex *h)
{
HFields *f;
f = nil;
for(;;){
while(lex(h) != Word)
if(h->tok != ',')
goto breakout;
f = hmkhfields(h->c, hstrdup(h->c, h->wordval), nil, f);
if(lex(h) == ';')
f->params = mimeparams(h);
if(h->tok != ',')
break;
}
breakout:;
return hrevhfields(f);
}
/*
* parse a list of acceptable types, encodings, languages, etc.
*/
static HContent*
mimeok(Hlex *h, char *name, int multipart, HContent *head)
{
char *generic, *specific, *s;
float v;
/*
* each type is separated by one or more commas
*/
while(lex(h) != Word)
if(h->tok != ',')
return head;
generic = hstrdup(h->c, h->wordval);
lex(h);
if(h->tok == '/' || multipart){
/*
* at one time, IE5 improperly said '*' for single types
*/
if(h->tok != '/')
return nil;
if(lex(h) != Word)
return head;
specific = hstrdup(h->c, h->wordval);
if(!multipart && strcmp(specific, "*") != 0)
return head;
lex(h);
}else
specific = nil;
head = hmkcontent(h->c, generic, specific, head);
for(;;){
switch(h->tok){
case ';':
/*
* should make a list of these params
* for accept, they fall into two classes:
* up to a q=..., they modify the media type.
* afterwards, they acceptance criteria
*/
if(lex(h) == Word){
s = hstrdup(h->c, h->wordval);
if(lex(h) != '=' || lex(h) != Word && h->tok != QString)
return head;
v = strtod(h->wordval, nil);
if(strcmp(s, "q") == 0)
head->q = v;
else if(strcmp(s, "mxb") == 0)
head->mxb = v;
else{
/* cope with accept: application/xhtml+xml; profile=http://www.wapforum.org/xhtml, */
while(lex(h) == Word || (h->tok != ',' && h->eol == 0) )
;
return mimeok(h, name, multipart, head);
}
}
break;
case ',':
return mimeok(h, name, multipart, head);
default:
return head;
}
lex(h);
}
}
/*
* parse a list of entity tags
* 1#entity-tag
* entity-tag = [weak] opaque-tag
* weak = "W/"
* opaque-tag = quoted-string
*/
static HETag*
mimeetag(Hlex *h, HETag *head)
{
HETag *e;
int weak;
for(;;){
while(lex(h) != Word && h->tok != QString)
if(h->tok != ',')
return head;
weak = 0;
if(h->tok == Word && strcmp(h->wordval, "*") != 0){
if(strcmp(h->wordval, "W") != 0)
return head;
if(lex(h) != '/' || lex(h) != QString)
return head;
weak = 1;
}
e = halloc(h->c, sizeof(HETag));
e->etag = hstrdup(h->c, h->wordval);
e->weak = weak;
e->next = head;
head = e;
if(lex(h) != ',')
return head;
}
}
/*
* ranges-specifier = byte-ranges-specifier
* byte-ranges-specifier = "bytes" "=" byte-range-set
* byte-range-set = 1#(byte-range-spec|suffix-byte-range-spec)
* byte-range-spec = byte-pos "-" [byte-pos]
* byte-pos = 1*DIGIT
* suffix-byte-range-spec = "-" suffix-length
* suffix-length = 1*DIGIT
*
* syntactically invalid range specifiers cause the
* entire header field to be ignored.
* it is syntactically incorrect for the second byte pos
* to be smaller than the first byte pos
*/
static HRange*
mimeranges(Hlex *h, HRange *head)
{
HRange *r, *rh, *tail;
char *w;
ulong start, stop;
int suf;
if(lex(h) != Word || strcmp(h->wordval, "bytes") != 0 || lex(h) != '=')
return head;
rh = nil;
tail = nil;
for(;;){
while(lex(h) != Word){
if(h->tok != ','){
if(h->tok == '\n')
goto breakout;
return head;
}
}
w = h->wordval;
start = 0;
suf = 1;
if(w[0] != '-'){
suf = 0;
start = digtoul(w, &w);
if(w[0] != '-')
return head;
}
w++;
stop = ~0UL;
if(w[0] != '\0'){
stop = digtoul(w, &w);
if(w[0] != '\0')
return head;
if(!suf && stop < start)
return head;
}
r = halloc(h->c, sizeof(HRange));
r->suffix = suf;
r->start = start;
r->stop = stop;
r->next = nil;
if(rh == nil)
rh = r;
else
tail->next = r;
tail = r;
if(lex(h) != ','){
if(h->tok == '\n')
break;
return head;
}
}
breakout:;
if(head == nil)
return rh;
for(tail = head; tail->next != nil; tail = tail->next)
;
tail->next = rh;
return head;
}
static void
mimeaccept(Hlex *h, char *name)
{
h->c->head.oktype = mimeok(h, name, 1, h->c->head.oktype);
}
static void
mimeacceptchar(Hlex *h, char *name)
{
h->c->head.okchar = mimeok(h, name, 0, h->c->head.okchar);
}
static void
mimeacceptenc(Hlex *h, char *name)
{
h->c->head.okencode = mimeok(h, name, 0, h->c->head.okencode);
}
static void
mimeacceptlang(Hlex *h, char *name)
{
h->c->head.oklang = mimeok(h, name, 0, h->c->head.oklang);
}
static void
mimemodified(Hlex *h, char *)
{
lexhead(h);
h->c->head.ifmodsince = hdate2sec(h->wordval);
}
static void
mimeunmodified(Hlex *h, char *)
{
lexhead(h);
h->c->head.ifunmodsince = hdate2sec(h->wordval);
}
static void
mimematch(Hlex *h, char *)
{
h->c->head.ifmatch = mimeetag(h, h->c->head.ifmatch);
}
static void
mimenomatch(Hlex *h, char *)
{
h->c->head.ifnomatch = mimeetag(h, h->c->head.ifnomatch);
}
/*
* argument is either etag or date
*/
static void
mimeifrange(Hlex *h, char *)
{
int c, d, et;
et = 0;
c = getc(h);
while(c == ' ' || c == '\t')
c = getc(h);
if(c == '"')
et = 1;
else if(c == 'W'){
d = getc(h);
if(d == '/')
et = 1;
ungetc(h);
}
ungetc(h);
if(et){
h->c->head.ifrangeetag = mimeetag(h, h->c->head.ifrangeetag);
}else{
lexhead(h);
h->c->head.ifrangedate = hdate2sec(h->wordval);
}
}
static void
mimerange(Hlex *h, char *)
{
h->c->head.range = mimeranges(h, h->c->head.range);
}
/*
* parse it like cookies
*/
static void
authdigest(Hlex *h, char *)
{
char *s;
HSPairs *p;
p = nil;
for(;;){
while(lex(h) != Word)
if(h->tok != ';' && h->tok != ',')
goto breakout;
s = hstrdup(h->c, h->wordval);
while (lex(h) != Word && h->tok != QString)
if (h->tok != '=')
goto breakout;
p = hmkspairs(h->c, s, hstrdup(h->c, h->wordval), p);
}
breakout:
h->c->head.authinfo = hrevspairs(p);
}
/*
* note: netscape and ie through versions 4.7 and 4
* support only basic authorization, so that is all that is supported here
*
* "Authorization" ":" "Basic" base64-user-pass
* where base64-user-pass is the base64 encoding of
* username ":" password
*/
static void
authbasic(Hlex *h, char *)
{
char *up, *p;
int n;
n = lexbase64(h);
if(!n)
return;
/*
* wipe out source for password, so it won't be logged.
* it is replaced by a single =,
* which is valid base64, but not ok for an auth reponse.
* therefore future parses of the header field will not overwrite
* authuser and authpass.
*/
memmove(h->c->hpos - (n - 1), h->c->hpos, h->c->hstop - h->c->hpos);
h->c->hstop -= n - 1;
*h->c->hstop = '\0';
h->c->hpos -= n - 1;
h->c->hpos[-1] = '=';
up = halloc(h->c, n + 1);
n = dec64((uchar*)up, n, h->wordval, n);
up[n] = '\0';
p = strchr(up, ':');
if(p != nil){
*p++ = '\0';
h->c->head.authuser = hstrdup(h->c, up);
h->c->head.authpass = hstrdup(h->c, p);
}
}
/*
* "Authorization" ":" "Basic" | "Digest" ...
*/
static void
mimeauthorization(Hlex *h, char *)
{
int i;
static MimeHead authparser[] = {
{ "basic", authbasic },
{ "digest", authdigest },
};
if(lex(h) != Word)
return;
for (i = 0; i < nelem(authparser); i++)
if (cistrcmp(h->wordval, authparser[i].name) == 0) {
(*authparser[i].parse)(h, nil);
break;
}
}
static void
mimeagent(Hlex *h, char *)
{
lexhead(h);
h->c->head.client = hstrdup(h->c, h->wordval);
}
static void
mimefrom(Hlex *h, char *)
{
lexhead(h);
}
static void
mimehost(Hlex *h, char *)
{
char *hd;
lexhead(h);
for(hd = h->wordval; *hd == ' ' || *hd == '\t'; hd++)
;
h->c->head.host = hlower(hstrdup(h->c, hd));
}
/*
* if present, implies that a message body follows the headers
* "content-length" ":" digits
*/
static void
mimecontlen(Hlex *h, char *)
{
char *e;
ulong v;
if(lex(h) != Word)
return;
e = h->wordval;
v = digtoul(e, &e);
if(v == ~0UL || *e != '\0')
return;
h->c->head.contlen = v;
}
/*
* mimexpect : "expect" ":" expects
* expects : | expects "," expect
* expect : "100-continue" | token | token "=" token expectparams | token "=" qstring expectparams
* expectparams : ";" token | ";" token "=" token | token "=" qstring
* for now, we merely parse "100-continue" or anything else.
*/
static void
mimeexpect(Hlex *h, char *)
{
if(lex(h) != Word || cistrcmp(h->wordval, "100-continue") != 0 || lex(h) != '\n')
h->c->head.expectother = 1;
h->c->head.expectcont = 1;
}
static void
mimetransenc(Hlex *h, char *)
{
h->c->head.transenc = mimehfields(h);
}
static void
mimecookie(Hlex *h, char *)
{
char *s;
HSPairs *p;
p = nil;
for(;;){
while(lex(h) != Word)
if(h->tok != ';' && h->tok != ',')
goto breakout;
s = hstrdup(h->c, h->wordval);
while (lex(h) != Word && h->tok != QString)
if (h->tok != '=')
goto breakout;
p = hmkspairs(h->c, s, hstrdup(h->c, h->wordval), p);
}
breakout:
h->c->head.cookie = hrevspairs(p);
}
static void
mimefresh(Hlex *h, char *)
{
char *s;
lexhead(h);
for(s = h->wordval; *s && (*s==' ' || *s=='\t'); s++)
;
if(strncmp(s, "pathstat/", 9) == 0)
h->c->head.fresh_thresh = atoi(s+9);
else if(strncmp(s, "have/", 5) == 0)
h->c->head.fresh_have = atoi(s+5);
}
static void
mimeignore(Hlex *h, char *)
{
lexhead(h);
}
static void
parsejump(Hlex *h, char *k)
{
int l, r, m;
l = 1;
r = nelem(mimehead) - 1;
while(l <= r){
m = (r + l) >> 1;
if(cistrcmp(mimehead[m].name, k) <= 0)
l = m + 1;
else
r = m - 1;
}
m = l - 1;
if(cistrcmp(mimehead[m].name, k) == 0 && !mimehead[m].ignore){
mimehead[m].seen = 1;
(*mimehead[m].parse)(h, k);
}else
mimeignore(h, k);
}
static int
lex(Hlex *h)
{
return h->tok = lex1(h, 0);
}
static int
lexbase64(Hlex *h)
{
int c, n;
n = 0;
lex1(h, 1);
while((c = getc(h)) >= 0){
if(!isalnum(c) && c != '+' && c != '/'){
ungetc(h);
break;
}
if(n < HMaxWord-1)
h->wordval[n++] = c;
}
h->wordval[n] = '\0';
return n;
}
/*
* rfc 822/rfc 1521 lexical analyzer
*/
static int
lex1(Hlex *h, int skipwhite)
{
int level, c;
if(h->eol)
return '\n';
top:
c = getc(h);
switch(c){
case '(':
level = 1;
while((c = getc(h)) >= 0){
if(c == '\\'){
c = getc(h);
if(c < 0)
return '\n';
continue;
}
if(c == '(')
level++;
else if(c == ')' && --level == 0)
break;
else if(c == '\n'){
c = getc(h);
if(c < 0)
return '\n';
if(c == ')' && --level == 0)
break;
if(c != ' ' && c != '\t'){
ungetc(h);
return '\n';
}
}
}
goto top;
case ' ': case '\t':
goto top;
case '\r':
c = getc(h);
if(c != '\n'){
ungetc(h);
goto top;
}
case '\n':
if(h->tok == '\n'){
h->eol = 1;
h->eoh = 1;
return '\n';
}
c = getc(h);
if(c < 0){
h->eol = 1;
return '\n';
}
if(c != ' ' && c != '\t'){
ungetc(h);
h->eol = 1;
return '\n';
}
goto top;
case ')':
case '<': case '>':
case '[': case ']':
case '@': case '/':
case ',': case ';': case ':': case '?': case '=':
if(skipwhite){
ungetc(h);
return c;
}
return c;
case '"':
if(skipwhite){
ungetc(h);
return c;
}
word(h, "\"");
getc(h); /* skip the closing quote */
return QString;
default:
ungetc(h);
if(skipwhite)
return c;
word(h, "\"(){}<>@,;:/[]?=\r\n \t");
if(h->wordval[0] == '\0'){
h->c->head.closeit = 1;
hfail(h->c, HSyntax);
longjmp(h->jmp, -1);
}
return Word;
}
/* not reached */
}
/*
* return the rest of an rfc 822, including \n
* do not map to lower case
*/
static void
lexhead(Hlex *h)
{
int c, n;
n = 0;
while((c = getc(h)) >= 0){
if(c == '\r')
c = wordcr(h);
else if(c == '\n')
c = wordnl(h);
if(c == '\n')
break;
if(c == '\\'){
c = getc(h);
if(c < 0)
break;
}
if(n < HMaxWord-1)
h->wordval[n++] = c;
}
h->tok = '\n';
h->eol = 1;
h->wordval[n] = '\0';
}
static void
word(Hlex *h, char *stop)
{
int c, n;
n = 0;
while((c = getc(h)) >= 0){
if(c == '\r')
c = wordcr(h);
else if(c == '\n')
c = wordnl(h);
if(c == '\\'){
c = getc(h);
if(c < 0)
break;
}else if(c < 32 || strchr(stop, c) != nil){
ungetc(h);
break;
}
if(n < HMaxWord-1)
h->wordval[n++] = c;
}
h->wordval[n] = '\0';
}
static int
wordcr(Hlex *h)
{
int c;
c = getc(h);
if(c == '\n')
return wordnl(h);
ungetc(h);
return ' ';
}
static int
wordnl(Hlex *h)
{
int c;
c = getc(h);
if(c == ' ' || c == '\t')
return c;
ungetc(h);
return '\n';
}
static int
getc(Hlex *h)
{
if(h->eoh)
return -1;
if(h->c->hpos < h->c->hstop)
return *h->c->hpos++;
h->eoh = 1;
h->eol = 1;
return -1;
}
static void
ungetc(Hlex *h)
{
if(h->eoh)
return;
h->c->hpos--;
}
static ulong
digtoul(char *s, char **e)
{
ulong v;
int c, ovfl;
v = 0;
ovfl = 0;
for(;;){
c = *s;
if(c < '0' || c > '9')
break;
s++;
c -= '0';
if(v > UlongMax/10 || v == UlongMax/10 && c >= UlongMax%10)
ovfl = 1;
v = v * 10 + c;
}
if(e)
*e = s;
if(ovfl)
return UlongMax;
return v;
}
int
http11(HConnect *c)
{
return c->req.vermaj > 1 || c->req.vermaj == 1 && c->req.vermin > 0;
}
char*
hmkmimeboundary(HConnect *c)
{
char buf[32];
int i;
srand((time(0)<<16)|getpid());
strcpy(buf, "upas-");
for(i = 5; i < sizeof(buf)-1; i++)
buf[i] = 'a' + nrand(26);
buf[i] = 0;
return hstrdup(c, buf);
}
HSPairs*
hmkspairs(HConnect *c, char *s, char *t, HSPairs *next)
{
HSPairs *sp;
sp = halloc(c, sizeof *sp);
sp->s = s;
sp->t = t;
sp->next = next;
return sp;
}
HSPairs*
hrevspairs(HSPairs *sp)
{
HSPairs *last, *next;
last = nil;
for(; sp != nil; sp = next){
next = sp->next;
sp->next = last;
last = sp;
}
return last;
}
HFields*
hmkhfields(HConnect *c, char *s, HSPairs *p, HFields *next)
{
HFields *hf;
hf = halloc(c, sizeof *hf);
hf->s = s;
hf->params = p;
hf->next = next;
return hf;
}
HFields*
hrevhfields(HFields *hf)
{
HFields *last, *next;
last = nil;
for(; hf != nil; hf = next){
next = hf->next;
hf->next = last;
last = hf;
}
return last;
}
HContent*
hmkcontent(HConnect *c, char *generic, char *specific, HContent *next)
{
HContent *ct;
ct = halloc(c, sizeof(HContent));
ct->generic = generic;
ct->specific = specific;
ct->next = next;
ct->q = 1;
ct->mxb = 0;
return ct;
}