"Mark Senior" <Mark.Senior (at) gov.ab (dot) ca [email concealed]> writes:

>
>
>> From: Derek Martin [mailto:code (at) pizzashack (dot) org [email concealed]]
>> Sent: April 13, 2005 08:50
>>
>>
>> The open() call is at fault here. If instead of being called
>> with a mode of RW_USER, it is called with the final intended
>> access mode, there is no need to later call chmod(), and the
>> problem is averted.
>
> One wrinkle - if the file is not intended to have user write permission
> on it, and gzip (unzip/cpio/pax...) initially created it with the
> intended permissions, there would be no way to then write the file.

In a quick test, this seems not to be true, at least on my Linux
system. It may be true over NFS.

[gifford@gifford tmp]$ ls -ld testfile
ls: testfile: No such file or directory
[gifford@gifford tmp]$ cat t.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

void die(char *msg)
{
perror(msg);
exit(1);
}

int main()
{
int fd;

if ((fd = open("testfile",O_CREAT|O_WRONLY,0)) < 0)
die("open failed");
if (write(fd,"output\n",7) < 0)
die("write failed");
if (close(fd) < 0)
die("close failed");

return 0;
}
[gifford@gifford tmp]$ gcc -Wall t.c
[gifford@gifford tmp]$ ./a.out
[gifford@gifford tmp]$ ls -ld testfile
---------- 1 gifford gifford 7 Apr 15 01:28 testfile
[gifford@gifford tmp]$ chmod +r testfile
[gifford@gifford tmp]$ cat testfile
output
[gifford@gifford tmp]$

----ScottG.

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