curl/src/tool_cb_rea.c
Daniel Stenberg a55256cfb2
curl: timeout in the read callback
The read callback can timeout if there's nothing to read within the
given maximum period. Example use case is when doing "curl -m 3
telnet://example.com" or anything else that expects input on stdin or
similar that otherwise would "hang" until something happens and then not
respect the timeout.

This fixes KNOWN_BUG 8.1, first filed in July 2009.

Bug: https://sourceforge.net/p/curl/bugs/846/

Closes #9815
2022-10-28 17:57:14 +02:00

117 lines
3.2 KiB
C

/***************************************************************************
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* Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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***************************************************************************/
#include "tool_setup.h"
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#define ENABLE_CURLX_PRINTF
/* use our own printf() functions */
#include "curlx.h"
#include "tool_cfgable.h"
#include "tool_cb_rea.h"
#include "tool_operate.h"
#include "tool_util.h"
#include "memdebug.h" /* keep this as LAST include */
/*
** callback for CURLOPT_READFUNCTION
*/
size_t tool_read_cb(char *buffer, size_t sz, size_t nmemb, void *userdata)
{
ssize_t rc = 0;
struct InStruct *in = userdata;
struct OperationConfig *config = in->config;
if(config->timeout_ms) {
struct timeval now = tvnow();
long msdelta = tvdiff(now, in->per->start);
if(msdelta > config->timeout_ms)
/* timeout */
return 0;
#ifndef WIN32
/* this logic waits on read activity on a file descriptor that is not a
socket which makes it not work with select() on Windows */
else {
fd_set bits;
struct timeval timeout;
long wait = config->timeout_ms - msdelta;
/* wait this long at the most */
timeout.tv_sec = wait/1000;
timeout.tv_usec = (wait%1000)*1000;
FD_ZERO(&bits);
FD_SET(in->fd, &bits);
if(!select(in->fd + 1, &bits, NULL, NULL, &timeout))
return 0; /* timeout */
}
#endif
}
rc = read(in->fd, buffer, sz*nmemb);
if(rc < 0) {
if(errno == EAGAIN) {
errno = 0;
in->config->readbusy = TRUE;
return CURL_READFUNC_PAUSE;
}
/* since size_t is unsigned we can't return negative values fine */
rc = 0;
}
in->config->readbusy = FALSE;
/* when select() rerturned zero here, it timed out */
return (size_t)rc;
}
/*
** callback for CURLOPT_XFERINFOFUNCTION used to unpause busy reads
*/
int tool_readbusy_cb(void *clientp,
curl_off_t dltotal, curl_off_t dlnow,
curl_off_t ultotal, curl_off_t ulnow)
{
struct per_transfer *per = clientp;
struct OperationConfig *config = per->config;
(void)dltotal; /* unused */
(void)dlnow; /* unused */
(void)ultotal; /* unused */
(void)ulnow; /* unused */
if(config->readbusy) {
config->readbusy = FALSE;
curl_easy_pause(per->curl, CURLPAUSE_CONT);
}
return per->noprogress? 0 : CURL_PROGRESSFUNC_CONTINUE;
}