Path: utzoo!mnetor!uunet!husc6!rutgers!rochester!cornell!uw-beaver!tektronix!tekgen!teksce!johnhi From: johnhi@teksce.SCE.TEK.COM (John Higley) Newsgroups: comp.unix.questions Subject: Why am I getting this failure? Message-ID: <897@teksce.SCE.TEK.COM> Date: 12 Dec 87 01:00:08 GMT Reply-To: johnhi@teksce.UUCP (John Higley) Organization: Tektronix, Inc., Beaverton, OR. Lines: 43 Keywords: A short C program is included Given the following code segment and two unrelated users: ---------------------------cut--------------------------------- #includeextern int errno; extern char *sys_errlist[]; main() { FILE *testfile; if ((testfile=fopen("junkfile","r")) == NULL) fprintf(stderr,"Unable to open file - %s\n",sys_errlist[errno]); } ---------------------------cut--------------------------------- User 1 owns the program sets it up with the mode 4755 (-rwsr-xr-x) User 2 creates a directory (junkdir) and a file (junkdir/junkfile) The mode on junkdir is 700 junkfile is 644 User 2 goes into junkdir and executes the program. The program should fail with Permission denied User 2 changes mode on junkdir to 701 (o+x), and executes the program again. The program fails with Permission denied. (Why?) User 2 changes mode on junkdir to 710 or 711 (g+x) and executes again. The program succeeds. (Why does fopen need group execute on the directory when the two users are not in the same group????) John Higley johnhi@teksce.SCE.TEK.COM.UUCP