path: root/dpip/dpip.c

/*
 * File: dpip.c
 *
 * Copyright 2005-2007 Jorge Arellano Cid <jcid@dillo.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>   /* for close */
#include <fcntl.h>    /* for fcntl */

#include "dpip.h"
#include "d_size.h"

#define DPIP_TAG_END            " '>"
#define DPIP_MODE_SWITCH_TAG    "cmd='start_send_page' "
#define MSG_ERR(...)            fprintf(stderr, "[dpip]: " __VA_ARGS__)

/*
 * Local variables
 */
static const char Quote = '\'';
static const int DpipTag = 1;

/*
 * Basically the syntax of a dpip tag is:
 *
 *  "<"[*alpha] *(<name>"="Quote<escaped_value>Quote) " "Quote">"
 *
 *   1.- No space is allowed around the "=" sign between a name and its value.
 *   2.- The Quote character is not allowed in <name>.
 *   3.- Attribute values stuff Quote as QuoteQuote.
 *
 * e.g. (with ' as Quote):
 *
 *   <a='b' b='c' '>                 OK
 *   <dpi a='b i' b='12' '>          OK
 *   <a='>' '>                       OK
 *   <a='ain''t no doubt' '>         OK
 *   <a='ain''t b=''no'' b='' doubt' '>    OK
 *   <a = '>' '>                     Wrong
 *
 * Notes:
 *
 *   Restriction #1 is for easy finding of end of tag (EOT=Space+Quote+>).
 *   Restriction #2 can be removed, but what for? ;)
 *   The functions here provide for this functionality.
 */

typedef enum {
   SEEK_NAME,
   MATCH_NAME,
   SKIP_VALUE,
   SKIP_QUOTE,
   FOUND
} DpipTagParsingState;

/* ------------------------------------------------------------------------- */

/*
 * Printf like function for building dpip commands.
 * It takes care of dpip escaping of its arguments.
 * NOTE : It ONLY accepts string parameters, and
 *        only one %s per parameter.
 */
char *a_Dpip_build_cmd(const char *format, ...)
{
   va_list argp;
   char *p, *q, *s;
   Dstr *cmd;

   /* Don't allow Quote characters in attribute names */
   if (strchr(format, Quote))
      return NULL;

   cmd = dStr_sized_new(64);
   dStr_append_c(cmd, '<');
   va_start(argp, format);
   for (p = q = (char*)format; *q;  ) {
      p = strstr(q, "%s");
      if (!p) {
         dStr_append(cmd, q);
         break;
      } else {
         /* Copy format's part */
         while (q != p)
            dStr_append_c(cmd, *q++);
         q += 2;

         dStr_append_c(cmd, Quote);
         /* Stuff-copy of argument */
         s = va_arg (argp, char *);
         for (  ; *s; ++s) {
            dStr_append_c(cmd, *s);
            if (*s == Quote)
               dStr_append_c(cmd, *s);
         }
         dStr_append_c(cmd, Quote);
      }
   }
   va_end(argp);
   dStr_append_c(cmd, ' ');
   dStr_append_c(cmd, Quote);
   dStr_append_c(cmd, '>');

   p = cmd->str;
   dStr_free(cmd, FALSE);
   return p;
}

/*
 * Task: given a tag, its size and an attribute name, return the
 * attribute value (stuffing of ' is removed here).
 *
 * Return value: the attribute value, or NULL if not present or malformed.
 */
char *a_Dpip_get_attr_l(char *tag, size_t tagsize, const char *attrname)
{
   uint_t i, n = 0, found = 0;
   char *p, *q, *start, *val = NULL;
   DpipTagParsingState state = SEEK_NAME;

   if (!tag || !tagsize || !attrname || !*attrname)
      return NULL;

   for (i = 1; i < tagsize && !found; ++i) {
      switch (state) {
      case SEEK_NAME:
         if (tag[i] == attrname[0] && (tag[i-1] == ' ' || tag[i-1] == '<')) {
            n = 1;
            state = MATCH_NAME;
         } else if (tag[i] == Quote && tag[i-1] == '=')
            state = SKIP_VALUE;
         break;
      case MATCH_NAME:
         if (tag[i] == attrname[n])
            ++n;
         else if (tag[i] == '=' && !attrname[n])
            state = FOUND;
         else
            state = SEEK_NAME;
         break;
      case SKIP_VALUE:
         if (tag[i] == Quote)
            state = (tag[i+1] == Quote) ? SKIP_QUOTE : SEEK_NAME;
         break;
      case SKIP_QUOTE:
         state = SKIP_VALUE;
         break;
      case FOUND:
         found = 1;
         break;
      }
   }

   if (found) {
      p = start = tag + i;
      while ((q = strchr(p, Quote)) && q[1] == Quote)
         p = q + 2;
      if (q && q[1] == ' ') {
         val = dStrndup(start, (uint_t)(q - start));
         for (p = q = val; (*q = *p); ++p, ++q)
            if (*p == Quote && p[1] == p[0])
               ++p;
      }
   }
   return val;
}

/*
 * Task: given a tag and an attribute name, return its value.
 * Return value: the attribute value, or NULL if not present or malformed.
 */
char *a_Dpip_get_attr(char *tag, const char *attrname)
{
   return (tag ? a_Dpip_get_attr_l(tag, strlen(tag), attrname) : NULL);
}

/*
 * Check whether the given 'auth' string equals what dpid saved.
 * Return value: 1 if equal, -1 otherwise
 */
int a_Dpip_check_auth(const char *auth)
{
   char SharedSecret[32];
   FILE *In;
   char *fname, *rcline = NULL, *tail;
   int i, port, ret = -1;

   dReturn_val_if (auth == NULL, -1);

   fname = dStrconcat(dGethomedir(), "/.dillo/dpid_comm_keys", NULL);
   if ((In = fopen(fname, "r")) == NULL) {
      MSG_ERR("[a_Dpip_check_auth] %s\n", dStrerror(errno));
   } else if ((rcline = dGetline(In)) == NULL) {
      MSG_ERR("[a_Dpip_check_auth] empty file: %s\n", fname);
   } else {
      port = strtol(rcline, &tail, 10);
      for (i = 0; *tail && isxdigit(tail[i+1]); ++i)
         SharedSecret[i] = tail[i+1];
      SharedSecret[i] = 0;
      if (strcmp(auth, SharedSecret) == 0)
         ret = 1;
   }
   dFree(rcline);
   dFree(fname);

   return ret;
}

/* --------------------------------------------------------------------------
 * Dpip socket API ----------------------------------------------------------
 */

/*
 * Create and initialize a dpip socket handler
 */
Dsh *a_Dpip_dsh_new(int fd_in, int fd_out, int flush_sz)
{
   Dsh *dsh = dNew(Dsh, 1);

   /* init descriptors and streams */
   dsh->fd_in  = fd_in;
   dsh->fd_out = fd_out;
   dsh->out = fdopen(fd_out, "w");

   /* init buffer */
   dsh->dbuf = dStr_sized_new(8 *1024);
   dsh->rd_dbuf = dStr_sized_new(8 *1024);
   dsh->flush_sz = flush_sz;
   dsh->mode = DPIP_TAG;
   if (fcntl(dsh->fd_in, F_GETFL) & O_NONBLOCK)
      dsh->mode |= DPIP_NONBLOCK;
   dsh->status = 0;

   return dsh;
}

/*
 * Streamed write to socket
 * Return: 0 on success, 1 on error.
 */
int a_Dpip_dsh_write(Dsh *dsh, int flush, const char *Data, int DataSize)
{
   int ret = 1;

   /* append to buf */
   dStr_append_l(dsh->dbuf, Data, DataSize);

   /* flush data if necessary */
   if (flush || dsh->dbuf->len >= dsh->flush_sz) {
      if (dsh->dbuf->len &&
          fwrite (dsh->dbuf->str, dsh->dbuf->len, 1, dsh->out) != 1) {
         MSG_ERR("[a_Dpip_dsh_write] %s\n", dStrerror(errno));
      } else {
         fflush(dsh->out);
         dStr_truncate(dsh->dbuf, 0);
         ret = 0;
      }

   } else {
      ret = 0;
   }

   return ret;
}

/*
 * Convenience function.
 */
int a_Dpip_dsh_write_str(Dsh *dsh, int flush, const char *str)
{
   return a_Dpip_dsh_write(dsh, flush, str, (int)strlen(str));
}

/*
 * Read new data from the socket into our buffer.
 * Used by both blocking and non-blocking IO.
 */
static void Dpip_dsh_read(Dsh *dsh)
{
//#define LBUF_SZ 16384
#define LBUF_SZ 1

   ssize_t st;
   int old_flags, blocking;
   char buf[LBUF_SZ];

   blocking = !(dsh->mode & DPIP_NONBLOCK);
   if (blocking) {
      old_flags = fcntl(dsh->fd_in, F_GETFL);
   }

   while (1) {
      /* can't use fread() */
      do
         st = read(dsh->fd_in, buf, LBUF_SZ);
      while (st < 0 && errno == EINTR);

      if (st < 0) {
         if (errno == EAGAIN) {
            /* no problem, return what we've got so far... */
            dsh->status = DPIP_EAGAIN;
         } else {
            MSG_ERR("[Dpip_dsh_read] %s\n", dStrerror(errno));
            dsh->status = DPIP_ERROR;
         }
         break;
      } else if (st == 0) {
         dsh->status = DPIP_EOF;
         break;
      } else {
         /* append to buf */
         dStr_append_l(dsh->rd_dbuf, buf, st);
         if (blocking) {
            /* set NONBLOCKING temporarily... */
            fcntl(dsh->fd_in, F_SETFL, O_NONBLOCK | old_flags);
         }
      }
   }

   if (blocking) {
      /* restore blocking mode */
      fcntl(dsh->fd_in, F_SETFL, old_flags);
   }
}

/*
 * Return a newlly allocated string with the next dpip token in the socket.
 * Return value: token string on success, NULL otherwise
 */
char *a_Dpip_dsh_read_token(Dsh *dsh)
{
   char *p, *ret = NULL;

   /* switch mode upon request */
   if (dsh->mode & DPIP_LAST_TAG)
      dsh->mode = DPIP_RAW;

   /* Only read from socket when there's no data in buffer or
    * the tag is incomplete */
   if (dsh->rd_dbuf->len == 0 ||
       (dsh->mode & DPIP_TAG &&
        !(p = strstr(dsh->rd_dbuf->str, DPIP_TAG_END)))) {
      Dpip_dsh_read(dsh);
   }

   if (dsh->mode & DPIP_TAG) {
      /* return a full tag */
      if ((p = strstr(dsh->rd_dbuf->str, DPIP_TAG_END))) {
         ret = dStrndup(dsh->rd_dbuf->str, p - dsh->rd_dbuf->str + 3);
         dStr_erase(dsh->rd_dbuf, 0, p - dsh->rd_dbuf->str + 3);
         if (strstr(ret, DPIP_MODE_SWITCH_TAG))
            dsh->mode |= DPIP_LAST_TAG;
      }
   } else {
      /* raw mode, return what we have "as is" */
      if (dsh->rd_dbuf->len > 0) {
         ret = dStrndup(dsh->rd_dbuf->str, dsh->rd_dbuf->len);
         dStr_truncate(dsh->rd_dbuf, 0);
      }
   }

   return ret;
}

/*
 * Close this socket for reading and writing.
 */
void a_Dpip_dsh_close(Dsh *dsh)
{
   fclose(dsh->out);
   close(dsh->fd_out);
}

/*
 * Free the SockHandler structure
 */
void a_Dpip_dsh_free(Dsh *dsh)
{
   dStr_free(dsh->dbuf, 1);
   dStr_free(dsh->rd_dbuf, 1);
   dFree(dsh);
}