Commit 38d2afce authored by Ben Greear's avatar Ben Greear Committed by Daniel Stenberg
Browse files

telnet: Allow programatic use of telnet. 

The main change is to allow input from user-specified methods,
when they are specified with CURLOPT_READFUNCTION.
All calls to fflush(stdout) in telnet.c were removed, which makes
using 'curl telnet://foo.com' painful since prompts and other data
are not always returned to the user promptly.  Use
'curl --no-buffer telnet://foo.com

' instead.  In general,
the user should have their CURLOPT_WRITEFUNCTION do a fflush
for interactive use.

Also fix assumption that reading from stdin never returns < 0.
Old code could crash in that case.

Call progress functions in telnet main loop.

Signed-off-by: default avatarBen Greear <greearb@candelatech.com>
parent 7f616eb5

lib/telnet.c

+69 −27
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ 
#include "sendf.h"

#include "telnet.h"

#include "connect.h"

#include "progress.h"



#define _MPRINTF_REPLACE /* use our functions only */

#include <curl/mprintf.h>
@@ -1206,6 +1207,7 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
#else

  int interval_ms;

  struct pollfd pfd[2];

  int poll_cnt;

#endif

  int ret;

  ssize_t nread;
@@ -1213,6 +1215,8 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
  bool keepon = TRUE;

  char *buf = data->state.buffer;

  struct TELNET *tn;

  curl_off_t total_dl = 0;

  curl_off_t total_ul = 0;



  *done = TRUE; /* unconditionally */
@@ -1402,8 +1406,6 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
          break;

        }



        fflush(stdout);



        /* Negotiate if the peer has started negotiating,

           otherwise don't. We don't want to speak telnet with

           non-telnet servers, like POP or SMTP. */
@@ -1446,27 +1448,28 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
#else

  pfd[0].fd = sockfd;

  pfd[0].events = POLLIN;



  if (data->set.is_fread_set) {

    poll_cnt = 1;

    interval_ms = 100; /* poll user-supplied read function */

  }

  else {

    pfd[1].fd = 0;

    pfd[1].events = POLLIN;

    poll_cnt = 2;

    interval_ms = 1 * 1000;

  }



  while(keepon) {

    switch (Curl_poll(pfd, 2, interval_ms)) {

    switch (Curl_poll(pfd, poll_cnt, interval_ms)) {

    case -1:                    /* error, stop reading */

      keepon = FALSE;

      continue;

    case 0:                     /* timeout */

      break;

      pfd[0].revents = 0;

      pfd[1].revents = 0;

      /* fall through */

    default:                    /* read! */

      if(pfd[1].revents & POLLIN) { /* read from stdin */

        nread = read(0, buf, 255);

        code = send_telnet_data(conn, buf, nread);

        if(code) {

          keepon = FALSE;

          break;

        }

      }



      if(pfd[0].revents & POLLIN) {

        /* read data from network */

        ret = Curl_read(conn, sockfd, buf, BUFSIZE - 1, &nread);
@@ -1486,6 +1489,8 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
          break;

        }



        total_dl += nread;

        Curl_pgrsSetDownloadCounter(data, total_dl);

        code = telrcv(conn, (unsigned char *)buf, nread);

        if(code) {

          keepon = FALSE;
@@ -1500,7 +1505,39 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
          tn->already_negotiated = 1;

        }

      }



      nread = 0;

      if (poll_cnt == 2) {

        if(pfd[1].revents & POLLIN) { /* read from stdin */

          nread = read(0, buf, BUFSIZE - 1);

        }

      }

      else {

        /* read from user-supplied method */

        nread = (int)conn->fread_func(buf, 1, BUFSIZE - 1, conn->fread_in);

        if (nread == CURL_READFUNC_ABORT) {

          keepon = FALSE;

          break;

        }

        if (nread == CURL_READFUNC_PAUSE)

          break;

      }



      if (nread > 0) {

        code = send_telnet_data(conn, buf, nread);

        if(code) {

          keepon = FALSE;

          break;

        }

        total_ul += nread;

        Curl_pgrsSetUploadCounter(data, total_ul);

      }

      else if (nread < 0)

        keepon = FALSE;



      break;

    } /* poll switch statement */



    if(data->set.timeout) {

      now = Curl_tvnow();

      if(Curl_tvdiff(now, conn->created) >= data->set.timeout) {
@@ -1509,6 +1546,11 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done) 
        keepon = FALSE;

      }

    }



    if(Curl_pgrsUpdate(conn)) {

       code = CURLE_ABORTED_BY_CALLBACK;

       break;

    }

  }

#endif

  /* mark this as "no further transfer wanted" */

lib/url.c

+12 −2
Original line number Diff line number Diff line
@@ -690,6 +690,8 @@ CURLcode Curl_init_userdefined(struct UserDefined *set) 


  /* use fread as default function to read input */

  set->fread_func = (curl_read_callback)fread;

  set->is_fread_set = 0;

  set->is_fwrite_set = 0;



  set->seek_func = ZERO_NULL;

  set->seek_client = ZERO_NULL;
@@ -1825,18 +1827,26 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, 
     * Set data write callback

     */

    data->set.fwrite_func = va_arg(param, curl_write_callback);

    if(!data->set.fwrite_func)

    if(!data->set.fwrite_func) {

      data->set.is_fwrite_set = 0;

      /* When set to NULL, reset to our internal default function */

      data->set.fwrite_func = (curl_write_callback)fwrite;

    }

    else

      data->set.is_fwrite_set = 0;

    break;

  case CURLOPT_READFUNCTION:

    /*

     * Read data callback

     */

    data->set.fread_func = va_arg(param, curl_read_callback);

    if(!data->set.fread_func)

    if(!data->set.fread_func) {

      data->set.is_fread_set = 0;

      /* When set to NULL, reset to our internal default function */

      data->set.fread_func = (curl_read_callback)fread;

    }

    else

      data->set.is_fread_set = 1;

    break;

  case CURLOPT_SEEKFUNCTION:

    /*

lib/urldata.h

+2 −0
Original line number Diff line number Diff line
@@ -1235,6 +1235,8 @@ struct UserDefined { 
  curl_write_callback fwrite_header; /* function that stores headers */

  curl_write_callback fwrite_rtp;    /* function that stores interleaved RTP */

  curl_read_callback fread_func;     /* function that reads the input */

  int is_fread_set; /* boolean, has read callback been set to non-NULL? */

  int is_fwrite_set; /* boolean, has write callback been set to non-NULL? */

  curl_progress_callback fprogress;  /* function for progress information */

  curl_debug_callback fdebug;      /* function that write informational data */

  curl_ioctl_callback ioctl_func;  /* function for I/O control */

src/main.c

+3 −1
Original line number Diff line number Diff line
@@ -4987,6 +4987,8 @@ operate(struct Configurable *config, int argc, argv_item_t argv[]) 
        input.config = config;

        my_setopt(curl, CURLOPT_READDATA, &input);

        /* what call to read */

        if ((outfile && !curlx_strequal("-", outfile)) ||

            !curlx_strnequal(url, "telnet:", 7))

          my_setopt(curl, CURLOPT_READFUNCTION, my_fread);



        /* in 7.18.0, the CURLOPT_SEEKFUNCTION/DATA pair is taking over what