eris/fnord.c

/* simple httpd to be started from tcpserver */
#define _FILE_OFFSET_BITS 64
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
//#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
#include <grp.h>
#include <errno.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <dirent.h>
#include <sys/mman.h>
#include <limits.h>
#include "fmt.h"
#include "buffer.h"
#include "byte.h"
#include "scan.h"

/* Some things I use for debugging */
#ifdef DUMP
#  include <stdio.h>
#  define DUMPf(fmt, args...) fprintf(stderr, "%s:%s:%d " fmt "\n", __FILE__, __FUNCTION__, __LINE__, ##args)
#else
#  define DUMPf(fmt, args...)
#endif
#define DUMP() DUMPf("")
#define DUMP_d(v) DUMPf("%s = %d", #v, v)
#define DUMP_x(v) DUMPf("%s = 0x%x", #v, v)
#define DUMP_s(v) DUMPf("%s = %s", #v, v)
#define DUMP_c(v) DUMPf("%s = %c", #v, v)
#define DUMP_p(v) DUMPf("%s = %p", #v, v)

/* uncomment the following line to enable support for CGI */
// #define CGI

#ifdef CGI
/* uncomment the following line to enable support for "index.cgi"
 * That is: if "index.html" is not present then look for "index.cgi" */
#define INDEX_CGI
#endif

/* the following switch will make fnord normalize the Host: HTTP header
 * from "foo" to "foo:80" */
#define NORMALIZE_HOST

/* uncomment the following line to enable support for autogenerated
 * directory-listings for directories without index */
/* #define DIR_LIST */

#ifdef DIR_LIST
/* uncomment the following line to enable support for system symlink
 * dereferencingr.
 * HOPE YOU KNOW WHAT YOU'RE LINKING !
 *
 * e.g.: if a file foo is a symlink to /etc/passwd and you don't have a
 * chroot enviroment then the system-wide /etc/passwd is provided !!!
 *
 * If the symlink is dangling OR this option is not active the symlink is
 * provided as a new http-uri.
 *
 * e.g.: is foo a symlink to /etc/passwd than the clinet gets a href to
 * http://<vhost>/etc/passwd */
/* #define SYSTEM_SYMLINK_DEREF */
#endif

/* uncomment the following line to get full-host redirection.
 * If a file is not found locally, and $REDIRECT_HOST is set, fnord will
 * issue a redirect to strcat($REDIRECT_HOST,uri).  Otherwise, if
 * $REDIRECT_URI is set, fnord will issue a redirect to $REDIRECT_URI.
 * Only if those fail will a 404 error be returned. */
#define OLD_STYLE_REDIRECT

/* uncomment the following line to get full-host redirection.
 * if the virtual host directory/symlink is a broken symlink, fnord will
 * issue a redirect.  If the contents of the symlink starts with an
 * equal sign ('='), fnord will throw away the URI part. */
#define REDIRECT

/* uncomment the following line to make fnord chroot to the current
 * working directory and drop privileges */
#define CHROOT

/* uncomment the following line to make fnord support connection
 * keep-alive */
#define KEEPALIVE

/* the following is the time in seconds that fnord should wait for a
 * valid HTTP request */
#define READTIMEOUT 20

/* the following is the time in seconds that fnord should wait before
 * aborting a request when trying to write the answer */
#define WRITETIMEOUT 20

#define CGI_TIMEOUT	(5*60)	/* 5 minutes time-out for CGI to complete */

/* defining USE_SENDFILE enables zero-copy TCP on Linux for static
 * files.  I measured over 320 meg per second with apache bench over
 * localhost with sendfile and keep-alive.  However, sendfile does not
 * work with large files and may be considered cheating ;-)
 * Also, sendfile is a blocking operation.  Thus, no timeout handling. */
#define USE_SENDFILE

#ifndef __linux__
#undef USE_SENDFILE
#endif

#ifdef USE_SENDFILE
#include <sys/sendfile.h>
#endif

#ifndef O_NDELAY
#define O_NDELAY O_NONBLOCK
#endif

#define USE_MMAP
#ifndef _POSIX_MAPPED_FILES
#undef USE_MMAP
#endif

enum { UNKNOWN, GET, HEAD, POST } method;

#ifdef TCP_CORK
static int corked;
#endif
static long retcode=404;	/* used for logging code */
char *host="?";			/* Host: header */
char *port;			/* also Host: header, :80 part */
char *args;			/* URL behind ? (for CGIs) */
char *url;			/* string between GET and HTTP/1.0, demangled */
char *ua="?";			/* user-agent */
char *refer;			/* Referrer: header */
char *accept_enc;		/* Accept-Encoding */
int httpversion;		/* 0 == 1.0, 1 == 1.1 */
#ifdef KEEPALIVE
int keepalive=0;		/* should we keep the connection alive? */
int rootdir;	/* fd of root directory, so we can fchdir back for keep-alive */
#endif
#ifdef CGI
char *cookie;			/* Referrer: header */
char *uri;			/* copy of url before demangling */
char *content_type;
char *content_len;
char *auth_type;
char *post_miss;
unsigned long post_mlen;
unsigned long post_len=0;
#endif

#if _FILE_OFFSET_BITS == 64
static unsigned long long rangestart, rangeend;	/* for ranged queries */
#define scan_range scan_ulonglong
#define buffer_putrange buffer_putulonglong
#include "scan_ulonglong.c"
#include "fmt_ulonglong.c"
#include "buffer_putulonglong.c"
#else
static unsigned long rangestart, rangeend;	/* for ranged queries */
#define scan_range scan_ulong
#define buffer_putrange buffer_putulong
#endif

static const char days[] = "SunMonTueWedThuFriSat";
static const char months[] = "JanFebMarAprMayJunJulAugSepOctNovDec";

#define MAXHEADERLEN 8192

char* remote_ip;
#ifdef CGI
char* remote_port;
char* remote_ident;
#endif

static void sanitize(char* ua) {	/* replace strings with underscores for logging */
  int j;
  for (j=0; ua[j]; ++j) if (isspace(ua[j])) ua[j]='_';
}

static int buffer_put2digits(buffer* b,unsigned int i) {
  char x[2];
  x[0]=(i/10)+'0';
  x[1]=(i%10)+'0';
  return buffer_put(b,x,2);
}

static void dolog(off_t len) {	/* write a log line to stderr */
#ifdef COLF
  time_t t=time(0);
  struct tm* x=localtime(&t);
  int l=-(timezone/60);
  buffer_puts(buffer_2,remote_ip?remote_ip:"0.0.0.0");
  buffer_puts(buffer_2," - - [");

  buffer_put2digits(buffer_2,x->tm_mday);
  buffer_puts(buffer_2,"/");
  buffer_put(buffer_2,months+3*x->tm_mon,3);
  buffer_puts(buffer_2,"/");
  buffer_put2digits(buffer_2,(x->tm_year+1900)/100);
  buffer_put2digits(buffer_2,(x->tm_year+1900)%100);
  buffer_puts(buffer_2,":");
  buffer_put2digits(buffer_2,x->tm_hour);
  buffer_puts(buffer_2,":");
  buffer_put2digits(buffer_2,x->tm_min);
  buffer_puts(buffer_2,":");
  buffer_put2digits(buffer_2,x->tm_sec);
  buffer_puts(buffer_2,l>=0?" +":" -");
  if (l<0) l=-l;
  buffer_put2digits(buffer_2,l/60);
  buffer_put2digits(buffer_2,l%60);
  buffer_puts(buffer_2,"] \"");
  switch (method) {
  case GET: buffer_puts(buffer_2,"GET "); break;
  case POST: buffer_puts(buffer_2,"POST "); break;
  case HEAD: buffer_puts(buffer_2,"HEAD "); break;
  default: buffer_puts(buffer_2,"? "); break;
  }
  buffer_puts(buffer_2,url);
  buffer_puts(buffer_2,httpversion?" HTTP/1.1\" ":" HTTP/1.0\" ");
  buffer_putulong(buffer_2,retcode);
  buffer_putspace(buffer_2);
  buffer_putrange(buffer_2,len);

#else
  buffer_puts(buffer_2,remote_ip?remote_ip:"0.0.0.0");
  buffer_putspace(buffer_2);
  buffer_putulong(buffer_2,retcode);
  buffer_putspace(buffer_2);
  buffer_putrange(buffer_2,len);
  buffer_putspace(buffer_2);
  sanitize(host);
  buffer_puts(buffer_2,host);
  buffer_putspace(buffer_2);
  sanitize(ua);
  buffer_puts(buffer_2,ua);
  buffer_putspace(buffer_2);
  if (!refer) refer="none";
  sanitize(refer);
  buffer_puts(buffer_2,refer);
  buffer_putspace(buffer_2);
  if (url)
    buffer_puts(buffer_2,url);
  else
    buffer_puts(buffer_2,"(null)");
#endif
  buffer_puts(buffer_2,"\n");
  buffer_flush(buffer_2);
}

/* output an error message and exit */
static void badrequest(long code,const char *httpcomment,const char *message) {
  retcode=code;
  dolog(0);
  buffer_puts(buffer_1,"HTTP/1.0 ");
  buffer_putulong(buffer_1,code);
  buffer_putspace(buffer_1);
  buffer_puts(buffer_1,httpcomment);
  buffer_puts(buffer_1, "\r\nConnection: close\r\n");
  if (message[0]) {
    buffer_puts(buffer_1,"Content-Length: ");
    buffer_putulong(buffer_1,strlen(message));
    buffer_puts(buffer_1,"\r\nContent-Type: text/html\r\n\r\n");
    buffer_puts(buffer_1,message);
  } else {
    buffer_puts(buffer_1,"\r\n");
  }
  buffer_flush(buffer_1);
  exit(0);
}

#ifdef CGI
#define CGIENVLEN 21

static const char *cgivars[CGIENVLEN] = {
  "GATEWAY_INTERFACE=",
  "SERVER_PROTOCOL=",
  "SERVER_SOFTWARE=",
  "SERVER_NAME=",
  "SERVER_PORT=",
  "REQUEST_METHOD=",
  "REQUEST_URI=",
  "SCRIPT_NAME=",
  "REMOTE_ADDR=",
  "REMOTE_PORT=",
  "REMOTE_IDENT=",
  "HTTP_USER_AGENT=",
  "HTTP_COOKIE=",
  "HTTP_REFERER=",
  "HTTP_ACCEPT_ENCODING=",
  "AUTH_TYPE=",
  "CONTENT_TYPE=",
  "CONTENT_LENGTH=",
  "QUERY_STRING=",
  "PATH_INFO=",
  "PATH_TRANSLATED="
};

static int iscgivar(const char *s) {
  register unsigned int i=0;
  for (;i<CGIENVLEN;i++)
    if (str_start(s, cgivars[i])) return 1;
  return 0;
}

static unsigned int elen(register const char *const *e) {
  register unsigned int i=0;
  while (e[i]) i++;
  return i;
}

static void do_cgi(const char* pathinfo,const char* const* envp) {
  const char *method_name[]={ "?", "GET", "HEAD", "POST"};
  char cgi_env_buf[MAXHEADERLEN*2+PATH_MAX+200];
  register unsigned int en=elen(envp);
  char *tmp=cgi_env_buf;
  char **cgi_arg;
  register int i;
  char **cgi_env=(char **)alloca((CGIENVLEN+en+1)*sizeof(char *)) ;

  cgi_env[0]="GATEWAY_INTERFACE=CGI/1.1";
  cgi_env[1]="SERVER_PROTOCOL=HTTP/1.0";
  cgi_env[2]="SERVER_SOFTWARE="FNORD;

  cgi_env[3]=tmp;
  tmp+=str_copy(tmp,"SERVER_NAME=");
  tmp+=str_copy(tmp,host);
  *tmp=0; ++tmp;

  cgi_env[4]=tmp;
  tmp+=str_copy(tmp,"SERVER_PORT=");
  tmp+=str_copy(tmp,port);
  *tmp=0; ++tmp;

  cgi_env[5]=tmp;
  tmp+=str_copy(tmp,"REQUEST_METHOD=");
  tmp+=str_copy(tmp,method_name[method]);
  *tmp=0; ++tmp;

  cgi_env[6]=tmp;
  tmp+=str_copy(tmp,"REQUEST_URI=");
  tmp+=str_copy(tmp,uri);
  *tmp=0; ++tmp;

  cgi_env[7]=tmp;
  tmp+=str_copy(tmp,"SCRIPT_NAME=");
  tmp+=str_copy(tmp,url);
  *tmp=0; ++tmp;

  i=7;
  if (remote_ip) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"REMOTE_ADDR=");
    tmp+=str_copy(tmp,remote_ip);
    *tmp=0; ++tmp;
  }

  if (remote_port) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"REMOTE_PORT=");
    tmp+=str_copy(tmp,remote_port);
    *tmp=0; ++tmp;
  }

  if (remote_ident) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"REMOTE_IDENT=");
    tmp+=str_copy(tmp,remote_ident);
    *tmp=0; ++tmp;
  }

  if (ua) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"HTTP_USER_AGENT=");
    tmp+=str_copy(tmp,ua);
    *tmp=0; ++tmp;
  }

  if (cookie) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"HTTP_COOKIE=");
    tmp+=str_copy(tmp,cookie);
    *tmp=0; ++tmp;
  }

  if (refer) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"HTTP_REFERER=");
    tmp+=str_copy(tmp,refer);
    *tmp=0; ++tmp;
  }

  if (accept_enc) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"HTTP_ACCEPT_ENCODING=");
    tmp+=str_copy(tmp,accept_enc);
    *tmp=0; ++tmp;
  }

  if (auth_type) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"AUTH_TYPE=");
    tmp+=str_copy(tmp,auth_type);
    *tmp=0; ++tmp;
  }

  if (content_type) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"CONTENT_TYPE=");
    tmp+=str_copy(tmp,content_type);
    *tmp=0; ++tmp;
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"CONTENT_LENGTH=");
    DUMP_s(content_len);
    tmp+=str_copy(tmp,content_len);
    *tmp=0; ++tmp;
  }

  if (args) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"QUERY_STRING=");
    tmp+=str_copy(tmp,args);
    *tmp=0; ++tmp;
  }

  if (pathinfo) {
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"PATH_INFO=");
    tmp+=str_copy(tmp,pathinfo);
    *tmp=0; ++tmp;
    cgi_env[++i]=tmp;
    tmp+=str_copy(tmp,"PATH_TRANSLATED=");
    tmp+=realpath(pathinfo,tmp)?str_len(tmp):str_copy(tmp,pathinfo);
    ++tmp;
  }

  {
    unsigned int j=0;
    for (;j<en;j++)
      if (!iscgivar(envp[j])) cgi_env[++i]=(char*)envp[j];
  }
  cgi_env[++i]=0;

  /* argv */
  if (args && (args[str_chr(args,'=')]==0)) {
    int n=3;
    for (i=0;args[i];++i) if (args[i]=='+') ++n;
    cgi_arg=alloca(n*sizeof(char*));
    cgi_arg[n=1]=args;
    for (i=0;args[i];++i) {
      if (args[i]=='+') {
	args[i]=0;
	++i;
	cgi_arg[++n]=args+i;
      }
    }
    cgi_arg[++n]=0;
  } else {
    cgi_arg=alloca(2*sizeof(char*));
    cgi_arg[1]=0;
  }

  i=strrchr(url,'/')-url;
  strncpy(tmp,url+1,i);
  tmp[i]=0;
  chdir(tmp);

  /* program name */
  cgi_arg[0]=tmp;
  tmp[0]='.';
  tmp[str_copy(tmp+1,url+i)+1]=0;

  /* start cgi */
  execve(cgi_arg[0],cgi_arg,cgi_env);
  raise(SIGQUIT);	/* gateway unavailable. */
}

static void cgi_child(int sig) {
  int n,pid=waitpid(0,&n,WNOHANG);
  if (pid>0) {
    if (WIFSIGNALED(n)) {
      if (WTERMSIG(n)==SIGALRM)
	badrequest(504,"Gateway Time-out","Gateway has hit the Time-out.");
      else
	badrequest(502,"Bad Gateway","Gateway broken or unavailable.");
    }
  }
  signal(SIGCHLD,cgi_child);
}

static void cgi_send_correct_http(const char*s,unsigned int sl) {
  unsigned int i;
  char ch=0;
  for (i=0;i<sl;++i) {
    if ((s[i]=='\r')&&(s[i+1]=='\n')) {
      ++i; goto out_nl;
    }
    else {
      if (s[i]!='\n') buffer_put(buffer_1,s+i,1);
      else {
out_nl: buffer_put(buffer_1,"\r\n",2);
	if (ch=='\n') { ++i; break; }
      }
    }
    ch=s[i];
  }
  buffer_put(buffer_1,s+i,sl-i);
}

static void start_cgi(int nph,const char* pathinfo,const char *const *envp) {
  size_t size=0;
  int n;
  int pid;
  char ibuf[8192],obuf[8192];
  int fd[2],df[2];

  if (pipe(fd)||pipe(df)) {
    badrequest(500,"Internal Server Error","Server Resource problem.");
  }

  if ((pid=fork())) {
    if (pid>0) {
      struct pollfd pfd[2];
      int nr=1;
      int startup=1;

      signal(SIGCHLD,cgi_child);
      signal(SIGPIPE,SIG_IGN);		/* NO! no signal! */

      close(df[0]);
      close(fd[1]);

      pfd[0].fd=fd[0];
      pfd[0].events=POLLIN;
      pfd[0].revents=0;

      pfd[1].fd=df[1];
      pfd[1].events=POLLOUT;
      pfd[1].revents=0;

      if (post_len) ++nr;	/* have post data */
      else close(df[1]);	/* no post data */

      while(poll(pfd,nr,-1)!=-1) {
	/* read from cgi */
	if (pfd[0].revents&POLLIN) {
	  if (!(n=read(fd[0],ibuf,sizeof(ibuf)))) break;
	  if (n<0) goto cgi_500;
	  /* startup */
	  if (startup) {
	    startup=0;
	    if (nph) {	/* NPH-CGI */
	      buffer_put(buffer_1,ibuf,n);
	      scan_ulong(ibuf+9,&retcode); /* only get error code / str_len("HTTP/x.x ")==9 */
	    }
	    else {	/* CGI */
	      if (byte_diff(ibuf,10,"Location: ")==0) {
		retcode=302;
		buffer_puts(buffer_1,"HTTP/1.0 302 CGI-Redirect\r\nConnection: close\r\n");
		signal(SIGCHLD,SIG_IGN);
		cgi_send_correct_http(ibuf,n);
		buffer_flush(buffer_1);
		dolog(0);
		exit(0);
	      }
	      else {
		retcode=200;
		buffer_puts(buffer_1,"HTTP/1.0 200 OK\r\nServer: "FNORD"\r\nPragma: no-cache\r\nConnection: close\r\n");
		signal(SIGCHLD,SIG_IGN);
		cgi_send_correct_http(ibuf,n);
	      }
	    }
	  }
	  /* non startup */
	  else {
	    buffer_put(buffer_1,ibuf,n);
	  }
	  size+=n;
	  if (pfd[0].revents&POLLHUP) break;
	}
	/* write to cgi the post data */
	else if (nr>1 && pfd[1].revents&POLLOUT) {
	  if (post_miss) {
	    write(df[1],post_miss,post_mlen);
	    post_miss=0;
	  }
	  else if (post_mlen<post_len) {
	    n=read(0,obuf,sizeof(obuf));
	    if (n<1) goto cgi_500;
	    post_mlen+=n;
	    write(df[1],obuf,n);
	  }
	  else {
	    --nr;
	    close(df[1]);
	  }
	}
	else if (pfd[0].revents&POLLHUP) break;
	else {
cgi_500:  if (startup)
	    badrequest(500,"Internal Server Error","Looks like the CGI crashed.");
	  else {
	    buffer_puts(buffer_1,"\n\n");
	    buffer_puts(buffer_1,"Looks like the CGI crashed.");
	    buffer_puts(buffer_1,"\n\n");
	    break;
	  }
	}
      }

      buffer_flush(buffer_1);
      dolog(size);
#ifdef TCP_CORK
      {
	int zero=0;
	setsockopt(1,IPPROTO_TCP,TCP_CORK,&zero,sizeof(zero));
      }
#endif
    }
  }
  else {
    close(df[1]);
    close(fd[0]);

    dup2(df[0],0);
    dup2(fd[1],1);

    close(df[0]);
    close(fd[1]);

    alarm(CGI_TIMEOUT);
    do_cgi(pathinfo,envp);
  }
  exit(0);
}
#endif

static int fromhex(int c) {
  if (c>='0' && c<='9') return c-'0';
  else { c|=' ';
    if (c>='a' && c<='f') return c-'a'+10;
  }
  return -1;
}

/* header(buf,buflen,"User-Agent")="Mozilla" */
static char* header(char* buf,int buflen,const char* hname) {
  int slen=str_len(hname);
  int i;
  char* c;

  DUMPf("buflen %d, slen %d",buflen,slen);
  for (i=0; i<buflen-slen-2; ++i) {
    DUMPf("[%.*s] [%s]",slen,buf+i,hname);
    if (!strncasecmp(buf+i,hname,slen)) {
      DUMP();
      if (i && (buf[i-1] && buf[i-1]!='\n')) continue;
      DUMP();
      if (buf[i+slen]!=':' || buf[i+slen+1]!=' ') continue;
      DUMP();
      c=buf+i+slen+2;
      i+=slen+2;
      for (; i<buflen; ++i) {
        DUMP_c(buf[i]);
	if (buf[i]==0 || buf[i]=='\n' || buf[i]=='\r') {
	  buf[i]=0;
	  break;
	}
      }
      while (*c==' ' || *c=='\t') ++c;
      return c;
    }
  }
  return 0;
}

static char* encoding=0;
static char* mimetype="application/octet-stream";

static struct mimeentry { const char* name, *type; } mimetab[] = {
  { "html",	"text/html; charset=UTF-8" },
  { "htm",	"text/html; charset=UTF-8" },
  { "txt",	"text/plain; charset=UTF-8" },
  { "css",	"text/css" },
  { "ps",	"application/postscript" },
  { "pdf",	"application/pdf" },
  { "js",	"application/javascript" },
  { "gif",	"image/gif" },
  { "png",	"image/png" },
  { "jpeg",	"image/jpeg" },
  { "jpg",	"image/jpeg" },
  { "svg",  "image/svg+xml" },
  { "mpeg",	"video/mpeg" },
  { "mpg",	"video/mpeg" },
  { "avi",	"video/x-msvideo" },
  { "mov",	"video/quicktime" },
  { "qt",	"video/quicktime" },
  { "mp3",	"audio/mpeg" },
  { "ogg",	"audio/ogg" },
  { "wav",	"audio/x-wav" },
  { "epub", "application/epub+zip" },
  { "dvi",	"application/x-dvi" },
  { "pac",	"application/x-ns-proxy-autoconfig" },
  { "sig",	"application/pgp-signature" },
  { "swf",  "application/x-shockwave-flash" },
  { "torrent",	"application/x-bittorrent" },
  { "tar",	"application/x-tar" },
  { "zip",	"application/zip" },
  { "dtd",	"text/xml" },
  { "xml",	"text/xml" },
  { "xbm",	"image/x-xbitmap" },
  { "xpm",	"image/x-xpixmap" },
  { "xwd",	"image/x-xwindowdump" },
  { "ico",  "image/x-icon" },
  { 0 } };

/* try to find out MIME type and content encoding.
 * This is called twice, once for the actual URL and once for URL.gz.
 * If the actual URL already ende with .gz, return
 * application/octet-stream to make sure the client can download the
 * file even if he does not support gzip encoding */
static void getmimetype(char* url,int explicit) {
  char save;
  int ext;
  ext=str_len(url);
  while (ext>0 && url[ext]!='.' && url[ext]!='/') --ext;
  if (url[ext]=='.') {
    ++ext;
    if (str_equal(url+ext,"bz2")) goto octetstream;
    if (str_equal(url+ext,"gz")) {
      if (!encoding) {
	if (explicit) goto octetstream;
	encoding="gzip";
	save=url[ext-1];
	url[ext-1]=0;
	getmimetype(url,explicit);
	url[ext-1]=save;
      } else
octetstream:
	mimetype="application/octet-stream";
    } else {
      int i;
      for (i=0; mimetab[i].name; ++i)
	if (str_equal(mimetab[i].name,url+ext)) {
	  mimetype=(char*)mimetab[i].type;
	  break;
	}
    }
  }
}

static int matchcommalist(const char* needle,const char* haystack) {
  /* needle: "text/html",
   * haystack: the accept header, "text/html, text/plain\r\n" */
  /* return nonzero if match was found */
  int len=str_len(needle);
  if (!byte_equal(needle,len,haystack)) return 0;
  switch (haystack[len]) {
  case ';': case ',': case '\r': case '\n': case 0: return 1;
  }
  return 0;
}

static int findincommalist(const char* needle,const char* haystack) {
  const char* accept;
  for (accept=haystack; accept;) {
    /* format: foo/bar, */
    const char *tmp=accept;
    int final;
    while (*tmp) {
      if (*tmp==';') break; else
      if (*tmp==',') break;
      ++tmp;
    }
    final=(*tmp==0 || *tmp==';');
    if (matchcommalist("*/*",accept)) break;
    if (matchcommalist(haystack,accept)) break;
    accept=tmp+1;
    if (final) return 0;
  }
  return 1;
}

/*
 *   timerfc function Copyright 1996, Michiel Boland.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or
 *   without modification, are permitted provided that the following
 *   conditions are met:
 *
 *   1. Redistributions of source code must retain the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials
 *      provided with the distribution.
 *
 *   3. The name of the author may not be used to endorse or promote
 *      products derived from this software without specific prior
 *      written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
 *   EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 *   THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 *   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR
 *   BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 *   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 *   IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 *   THE POSSIBILITY OF SUCH DAMAGE.
 */
static time_t timerfc(const char *s)
{
	static const int daytab[2][12] = {
		{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
		{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
	};
	unsigned sec, min, hour, day, mon, year;
	char month[3];
	int c;
	unsigned n;
	char flag;
	char state;
	char isctime;
	enum { D_START, D_END, D_MON, D_DAY, D_YEAR, D_HOUR, D_MIN, D_SEC };

	sec = 60;
	min = 60;
	hour = 24;
	day = 32;
	year = 1969;
	isctime = 0;
	month[0] = 0;
	state = D_START;
	n = 0;
	flag = 1;
	do {
		c = *s++;
		switch (state) {
		case D_START:
			if (c == ' ') {
				state = D_MON;
				isctime = 1;
			} else if (c == ',')
				state = D_DAY;
			break;
		case D_MON:
			if (isalpha(c)) {
				if (n < 3)
					month[n++] = c;
			} else {
				if (n < 3)
					return -1;
				n = 0;
				state = isctime ? D_DAY : D_YEAR;
			}
			break;
		case D_DAY:
			if (c == ' ' && flag)
				;
			else if (isdigit(c)) {
				flag = 0;
				n = 10 * n + (c - '0');
			} else {
				day = n;
				n = 0;
				state = isctime ? D_HOUR : D_MON;
			}
			break;
		case D_YEAR:
			if (isdigit(c))
				n = 10 * n + (c - '0');
			else {
				year = n;
				n = 0;
				state = isctime ? D_END : D_HOUR;
			}
			break;
		case D_HOUR:
			if (isdigit(c))
				n = 10 * n + (c - '0');
			else {
				hour = n;
				n = 0;
				state = D_MIN;
			}
			break;
		case D_MIN:
			if (isdigit(c))
				n = 10 * n + (c - '0');
			else {
				min = n;
				n = 0;
				state = D_SEC;
			}
			break;
		case D_SEC:
			if (isdigit(c))
				n = 10 * n + (c - '0');
			else {
				sec = n;
				n = 0;
				state = isctime ? D_YEAR : D_END;
			}
			break;
		}
	} while (state != D_END && c);
	switch (month[0]) {
	case 'A':
		mon = (month[1] == 'p') ? 4 : 8;
		break;
	case 'D':
		mon = 12;
		break;
	case 'F':
		mon = 2;
		break;
	case 'J':
		mon = (month[1] == 'a') ? 1 : ((month[2] == 'l') ? 7 : 6);
		break;
	case 'M':
		mon = (month[2] == 'r') ? 3 : 5;
		break;
	case 'N':
		mon = 11;
		break;
	case 'O':
		mon = 10;
		break;
	case 'S':
		mon = 9;
		break;
	default:
		return -1;
	}
	if (year <= 100)
		year += (year < 70) ? 2000 : 1900;
	--mon;
	--day;
	if (sec >= 60 || min >= 60 || hour >= 60 || day >= 31)
		return -1;
	if (year < 1970)
		return 0;
	return sec + 60L * (min + 60L * (hour + 24L * ( day +
	    daytab[year % 4 == 0 && (year % 100 || year % 400 == 0)][mon] +
	    365L * (year - 1970L) + ((year - 1969L) >> 2))));
}

static struct stat st;

/* try to return a file */
static int doit(char* buf,int buflen,char* url,int explicit) {
  int fd=-1;
  char* accept;
  while (url[0]=='/') ++url;
  getmimetype(url,explicit);
  {
    char *b=buf;
    int l=buflen;
    for (;;) {
      char *h=header(b,l,"Accept");
      if (!h) goto ok;
      if (findincommalist(mimetype,h)) goto ok;
      l-=(h-b)+1;
      b=h+1;
    }
    retcode=406; goto bad;
  }
ok:
  if (encoding) {	/* see if client accepts the encoding */
    char *tmp=header(buf,buflen,"Accept-Encoding");
    if (!tmp || !strstr(tmp,"gzip"))
      { retcode=406; goto bad; }
  }
  if ((fd=open(url,O_RDONLY))>=0) {
    if (fstat(fd,&st)) goto bad;
    /* no directories */
    if (S_ISDIR(st.st_mode)) goto bad;
    /* see if the peer accepts MIME type */
    /* see if the document has been changed */
    {
      char *field = header(buf,buflen,"If-Modified-Since");

      if (field) {
        time_t ims;
        
        ims = timerfc(field);
        if ((ims!=(time_t)-1) && (st.st_mtime<=ims)) { retcode=304; goto bad; }
      }
    }
    rangestart=0; rangeend=st.st_size;
    if ((accept=header(buf,buflen,"Range"))) {
      /* format: "bytes=17-23", "bytes=23-" */
      if (!strncmp(accept,"bytes=",6)) {
	int i;
	accept+=6;
	i=scan_range(accept,&rangestart);
	if (i) {
	  accept+=i;
	  if (*accept=='-') {
	    ++accept;
	    if (*accept) {
	      i=scan_range(accept,&rangeend);
	      if (!i) rangeend=st.st_size; else ++rangeend;
	    }
	  }
	}
      }
      if (rangestart>rangeend || rangeend>st.st_size) { retcode=416; goto bad; }
    }
    return fd;
bad:
    if (fd>=0) close(fd);
  }
  return -1;
}

static void redirectboilerplate() {
  buffer_puts(buffer_1,"HTTP/1.0 301 Go Away\r\nConnection: close\r\nContent-Length: 0\r\nLocation: ");
}

static void handleredirect(const char *url,const char* origurl) {
  char symlink[1024];
  int len;
#ifdef OLD_STYLE_REDIRECT
  char* env;
#endif
  while (*url=='/') ++url;
  if ((len=readlink(url,symlink,1023))>0) {
    /* el-cheapo redirection */
    redirectboilerplate();
    buffer_put(buffer_1,symlink,len);
#ifdef OLD_STYLE_REDIRECT
fini:
#endif
    retcode=301;
    buffer_puts(buffer_1,"\r\n\r\n");
    dolog(0);
    buffer_flush(buffer_1);
    exit(0);
  }
#ifdef OLD_STYLE_REDIRECT
  if ((env=getenv("REDIRECT_HOST"))) {
    redirectboilerplate();
    buffer_puts(buffer_1,env);
    while (*origurl=='/') ++origurl;
    buffer_puts(buffer_1,origurl);
    goto fini;
  } else if ((env=getenv("REDIRECT_URI"))) {
    redirectboilerplate();
    buffer_puts(buffer_1,env);
    goto fini;
  }
#endif
}

#ifdef DIR_LIST
static void hdl_encode_html(const char*s,unsigned int sl) {
  int i;
  for (i=0;i<sl;++i) {
    unsigned char ch=s[i];
    if (ch>159) {
encode_dec:
      buffer_puts(buffer_1,"&#");
      buffer_putulong(buffer_1,ch);
      buffer_puts(buffer_1,";");
    }
    else if ((ch>128)||(ch<32)) {
      buffer_put(buffer_1," ",1);
    }
    else if (ch=='"') buffer_puts(buffer_1,"&quot;");
    else if (ch=='&') buffer_puts(buffer_1,"&amp;");
    else if (ch=='<') buffer_puts(buffer_1,"&lt;");
    else if (ch=='>') buffer_puts(buffer_1,"&gt;");
    else buffer_put(buffer_1,&ch,1);
  }
}
static int buffer_puthex(unsigned int i) {
  unsigned int t;
  char x[4];
  t='0'|(i>>4)&0xf;