| itsme86 |
09-27-2004 03:49 PM |
open() file creation weirdness
I think I'm losing my mind. Someone please tell me why "testfile" is being created with such an insane mode. If I specifically pass something like 0644 as the mode to open() it creates the file as expected, but shouldn't that be the default? And the same thing happens on my other linux box too!
(This is a little test program I wrote since I was having a similar problem in a different program that was creating files with mode -------r-- )
Code:
itsme@itsme:~/C/testdir$ cat opentest.c
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
int main(void)
{
int fd;
fd = open("testfile", O_WRONLY|O_TRUNC|O_CREAT);
close(fd);
return 0;
}
Code:
itsme@itsme:~/C/testdir$ gcc -Wall opentest.c -o opentest
itsme@itsme:~/C/testdir$ ls -al
total 24
drwxr-xr-x 2 itsme users 4096 2004-09-27 13:20 ./
drwxr-xr-x 5 itsme users 4096 2004-09-27 13:19 ../
-rwxr-xr-x 1 itsme users 10690 2004-09-27 13:20 opentest*
-rw------- 1 itsme users 211 2004-09-27 13:19 opentest.c
itsme@itsme:~/C/testdir$ ./opentest
itsme@itsme:~/C/testdir$ ls -al
total 24
drwxr-xr-x 2 itsme users 4096 2004-09-27 13:20 ./
drwxr-xr-x 5 itsme users 4096 2004-09-27 13:19 ../
-rwxr-xr-x 1 itsme users 10690 2004-09-27 13:20 opentest*
-rw------- 1 itsme users 211 2004-09-27 13:19 opentest.c
-r-x--s--T 1 itsme users 0 2004-09-27 13:20 testfile*
itsme@itsme:~/C/testdir$ umask
0022
itsme@itsme:~/C/testdir$ touch foo
itsme@itsme:~/C/testdir$ ls -al
total 24
drwxr-xr-x 2 itsme users 4096 2004-09-27 13:22 ./
drwxr-xr-x 5 itsme users 4096 2004-09-27 13:19 ../
-rw-r--r-- 1 itsme users 0 2004-09-27 13:22 foo
-rwxr-xr-x 1 itsme users 10690 2004-09-27 13:20 opentest*
-rw------- 1 itsme users 211 2004-09-27 13:19 opentest.c
-r-x--s--T 1 itsme users 0 2004-09-27 13:20 testfile*
itsme@itsme:~/C/testdir$
This is what's making me think it should have a sane mode if I leave it unspecified in my program:
Code:
O_CREAT
If the file does not exist it will be created. The
owner (user ID) of the file is set to the effective
user ID of the process. The group ownership (group
ID) is set either to the effective group ID of the
process or to the group ID of the parent directory
(depending on filesystem type and mount options,
and the mode of the parent directory, see, e.g.,
the mount options bsdgroups and sysvgroups of the
ext2 filesystem, as described in mount(8)).
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