/* Make links relative after mirroring.

* For example, mirroring http://a.b/c/d.html gets "a.b/c/d.html",

* but the links in d.html need to be adjusted, so that in d.html,

* "/foo" becomes "../foo" */

#include <stralloc.h>

#include <buffer.h>

#include <errmsg.h>

#include <fmt.h>

#include <str.h>

#include <ctype.h>

#include <byte.h>

#include <scan.h>

#include <case.h>

#include <sys/stat.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/mman.h>

#include <utime.h>

#include <string.h>

#include "havealloca.h"

static int canonicalize(stralloc* url,const char* baseurl) {

/* for the comments, assume baseurl is "http://www.fefe.de/x/y.html" */

int l=strlen(baseurl);

char* dest=alloca(url->len+l+2);

char* x=dest;

if (stralloc_0(url)==0) return 0;

if (url->s[0]=='#') {

/* "#bar" -> "http://www.fefe.de/x/y.html#bar" */

l=str_chr(baseurl,'#');

byte_copy(x,l,baseurl);

byte_copy(x+l,url->len+1,url->s);

} else if (url->s[0]=='?') {

/* "?bar" -> "http://www.fefe.de/x/y.html?bar" */

for (l=0; baseurl[l]; ++l)

if (baseurl[l]=='?' || baseurl[l]=='#')

break;

byte_copy(x,l,baseurl);

byte_copy(x+l,url->len+1,url->s);

} else if (url->s[0]=='/') {

if (url->s[1]=='/') {

/* "//fnord.fefe.de/bla.html" -> "http://fnord.fefe.de/bla.html" */

l=str_chr(baseurl,':');

if (baseurl[l]==':') ++l;

byte_copy(x,l,baseurl);

byte_copy(x+l,url->len+1,url->s);

} else {

/* "/bla.html" -> "http://www.fefe.de/bla.html" */

l=str_chr(baseurl,':');

if (baseurl[l]==':' && baseurl[l+1]=='/' && baseurl[l+2]=='/')

l+=3;

l+=str_chr(baseurl+l,'/');

byte_copy(x,l,baseurl);

byte_copy(x+l,url->len+1,url->s);

}

} else if (strstr(url->s,"://")) {

/* "http://foo/bar" -> "http://foo/bar" */

byte_copy(x,url->len+1,url->s);

} else {

/* "z.html" -> "http://www.fefe.de/x/z.html" */

int k;

for (k=l=0; baseurl[k]; ++k) {

if (baseurl[k]=='/') l=k+1;

if (baseurl[k]=='?') break;

}

byte_copy(x,l,baseurl);

byte_copy(x+l,url->len+1,url->s);

}

return stralloc_copys(url,x);

}

static char* mmap_read_stat(const char* filename,struct stat* ss) {

int fd=open(filename,O_RDONLY);

char* map;

map=0;

if (fd>=0) {

if (fstat(fd,ss)==0) {

map=mmap(0,ss->st_size,PROT_READ,MAP_SHARED,fd,0);

if (map==(char*)-1)

map=0;

}

close(fd);

}

return map;

}

static int stralloc_istag(stralloc* sa,const char* in) {

char* a;

int l;

l=strlen(in);

a=sa->s;

if (sa->len<l+2) return 0;

if (*a != '<') return 0;

++a;

if (!case_equalb(a,l,in)) return 0;

a+=l;

if (*a==' ' || *a=='\t' || *a=='\n' || *a=='\r' || *a=='>') return 1;

return 0;

}

static int extractparam(stralloc* tag,const char* wanted,stralloc* before,stralloc* arg,stralloc* after) {

int l=strlen(wanted);

char* x,* max,* y;

if (tag->len<l+4) return 0;

max=tag->s+tag->len; y=0;

x=tag->s;

if (*x != '<') return 0;

++x;

for (; x<max && !isspace(*x); ++x) ;

for (; x<max && isspace(*x); ++x) ;

for (; x<max-l; ++x) {

if (max-x>l && case_equalb(x,l,wanted) && x[l]=='=') {

x+=l+1;

if (stralloc_copyb(before,tag->s,x-tag->s)==0) return 0;

if (*x=='"') {

++x;

y=x;

for (; x<max && *x!='"'; ++x) ;

if (stralloc_copyb(arg,y,x-y)==0) return 0;

++x;

} else {

y=x;

for (; x<max && !isspace(*x) && *x!='>'; ++x) ;

if (stralloc_copyb(arg,y,x-y)==0) return 0;

}

y=x;

if (stralloc_copyb(after,y,max-y)==0) return 0;

return 1;

}

}

return 0;

}

static int mangleurl(stralloc* tag,const char* baseurl) {

char* x;

const char* y;

static stralloc before,arg,after,tmp;

int found;

struct stat ss;

found=0;

if (stralloc_istag(tag,"a") || stralloc_istag(tag,"link"))

found=1;

else if (stralloc_istag(tag,"img") || stralloc_istag(tag,"frame"))

found=2;

if (!found) return 0;

if (extractparam(tag,found==1?"href":"src",&before,&arg,&after)) {

if (stralloc_starts(&arg,"/") ||

stralloc_starts(&arg,"http://") ||

stralloc_starts(&arg,"https://")) {

canonicalize(&arg,baseurl);

} else

return 0; /* url was already relative */

if (stralloc_0(&arg)==0) return -1;

stralloc_chop(&arg);

x=arg.s+7; if (*x=='/') ++x;

y=baseurl+7; if (*y=='/') ++y;

/* now x is something like

* "www.spiegel.de/img/0,1020,525770,00.jpg"

* and baseurl is something like

* "www.spiegel.de/panorama/0,1518,378421,00.html"

* and we want to change x into "../img/0,1020,525770,00.jpg" */

if (stat(x,&ss)!=0) return 0;

for (;;) {

int i=str_chr(x,'/');

int j=str_chr(y,'/');

if (i>0 && i==j && byte_equal(x,i,y)) {

x+=i+1;

y+=i+1;

while (*x=='/') ++x;

while (*y=='/') ++y;

} else

break;

}

stralloc_zero(&tmp);

for (;;) {

int i=str_chr(y,'/');

if (y[i]=='/') {

y+=i+1;

while (*y=='/') ++y;

if (stralloc_cats(&tmp,"../")==0) return -1;

} else

break;

}

{

int i,needquote;

for (i=needquote=0; x[i]; ++i)

if (!isalnum(x[i]) && x[i]!='/' && x[i]!='_' && x[i]!='.') needquote=1;

if (needquote) {

if (stralloc_cats(&before,"\"")==0 ||

stralloc_cat(&before,&tmp)==0 ||

stralloc_cats(&before,x)==0 ||

stralloc_cats(&before,"\"")==0) return -1;

} else

if (stralloc_cat(&before,&tmp)==0 ||

stralloc_cats(&before,x)==0) return -1;

}

if (stralloc_cat(&before,&after)==0) return -1;

if (stralloc_copy(tag,&before)==0) return -1;

}

return 0;

}

/* usage: rellink "http://www.nytimes.com/2005/10/06/international/middleeast/06cnd-prexy.html?ex=1129262400&en=30e300dafe83d0fc&ei=5065&partner=MYWAY" downloaded-data.html */

int main(int argc,char* argv[]) {

char* baseurl;

char* map,* max,* x;

struct stat ss;

static stralloc sa;

if (argc!=3)

die(0,"usage: rellink http://base/url downloaded-data.html");

errmsg_iam("rellink");

baseurl=argv[1];

map=mmap_read_stat(argv[2],&ss);

if (map==0)

diesys(111,"open \"",argv[2],"\" failed");

max=map+ss.st_size;

for (x=map; x<max; ) {

stralloc tag;

/* copy non-tag */

for (; x<max && *x!='<'; ++x)

if (stralloc_append(&sa,x)==0)

nomem:

die(111,"out of memory");

if (x>=max) break;

stralloc_copys(&tag,"");

{

int indq,insq,ok;

indq=insq=ok=0;

for (; x<max; ++x) {

if (*x == '\'') insq^=1; else

if (*x == '"') indq^=1;

if (stralloc_append(&tag,x)==0) goto nomem;

if (*x == '>' && !insq && !indq) { ok=1; ++x; break; }

}

if (ok)

if (mangleurl(&tag,baseurl)==-1) goto nomem;

}

if (stralloc_cat(&sa,&tag)==0) goto nomem;

}

if (sa.len == ss.st_size && byte_equal(sa.s,ss.st_size,map)) return 0;

munmap(map,ss.st_size);

{

struct utimbuf utb;

int fd=open(argv[2],O_WRONLY|O_TRUNC,0600);

if (fd==-1) die(111,"open(\"",argv[2],"\")");

write(fd,sa.s,sa.len);

close(fd);

utb.actime=ss.st_atime;

utb.modtime=ss.st_mtime;

utime(argv[2],&utb);

}

return 0;

}