Problem with libmod-1.5

[antonio.fonseca@xxxxx]

While running SMSLink, a sms to email gateway, in AXIS devboard 82 I get an
unusual problem while connecting to the gsm modem. The package SMSLink uses
libmodem-1.5 and i'm monitoring ttyS2 with sermon. Everything works fine
with the the first initialization string.

>sermon /dev/ttyS2 9600
sniffing /dev/ttyS2 at 9600baud
ATZ0  (the initialization string)
OK    (the response from the modem)

---

after that I get an error from libmodem-1.5 routines:

lopen_mdm_line():FD was not set when select returned (timeout)

examining the code in libmodem-1.5 I see:

#define EMDMNOFDSET	23   /* FD was not set when select returned
(timeout) */

that returns from this piece of code

		cfm = '\0';
		FD_ZERO(&readfds);
		FD_SET(fd, &readfds);
		tmout.tv_sec = device->dl;
		tmout.tv_usec = 0;

		ret = select(FD_SETSIZE, &readfds, NULL, NULL, &tmout);

		if (ret < 0) {
			mdmfree(cmdbuffer);
			mdmfree(cmdmodem);
			return (mdmerrno = -EMDMSEL);
		}

		if (!FD_ISSET(fd, &readfds)) {
			mdmfree(cmdbuffer);
			mdmfree(cmdmodem);
			return (mdmerrno = -EMDMNOFDSET);
		}

From the man pages for UNIX:


     FD_ZERO(&fdset)
           Initializes the file descriptor set fdset to have zero
           bits for all file descriptors.

     FD_SET(fd, &fdset)
           Sets the bit for the file descriptor fd  in  the  file
           descriptor set fdset.

     FD_ISSET(fd, &fdset)
           Returns a non-zero value  if  the  bit  for  the  file
           descriptor  fd  is  set  in  the  file  descriptor set
           pointed to by fdset, and 0 otherwise.

For the purpose of this program I think the file descriptor is /dev/ttyS2
wich I am using to communicate with the modem. Since the /dev tree is
read-only, the probable cause is that the program tries to write in a
filesystem which is read-only.

I have no way of redirecting the modem port in config file of libmodem
(modems) to other directory since libmodem-1.5 config files assume all
devices are in /dev tree.

Is there any way of making this directory also writable?

Thank You