staff@cadlab.sublink.ORG (Alex Martelli) (04/07/90)
> get by the carrier detect problem but I cannot get into a O_RDWR mode with the > /dev/tty** file that the modem is hooked up to, because it is "-rw--w--w-" > character file. This has to be able to be done because CU can get into a > read-write mode > (terminal mode) with the modem. CU is generally owned by user uucp, as is /dev/ttywhatever, and CU is a setuid program, so that anybody running it will have effective-userid of uucp, thus "own" the port... you MIGHT be able to get your program chown'ed to uucp and setuid as well (you'll have to talk with your sysadm), or a softer solution might be to make the port -rw-rw--w-, owned by some group, and let your executable be setgid to that. A very kludgey solution, which works in some cases, is to fork-and-exec good old CU itself, piping its I/O to/from your program as appropriate... maybe OK to read/write an S-register or two, but definitely not a general solution! The kludge is the only thing that might avoid dealing with the sysadm, however (me, I'm having trouble enough with serial comms under Unix even though I can su, chown and chmod all I want...!). Good luck. -- Alex Martelli - CAD.LAB s.p.a., v. Stalingrado 45, Bologna, Italia Email: (work:) staff@cadlab.sublink.org, (home:) alex@am.sublink.org Phone: (work:) ++39 (51) 371099, (home:) ++39 (51) 250434; Fax: ++39 (51) 366964 (work only; any time of day or night).