setuid & sticky bit

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# 1  
setuid & sticky bit

Can anyone explain me difference between setuid and sticky bit? and also between setuid and chown?
# 2  
Really need to know what Operating System and version you are running because the meaning of what used to be known as the "sticky bit" has changed in modern O/S.
There is no unix command called "setuid" - it is a system call in the "C" programming language. There is however an explanation of the sticky bit in "man chmod".
There are unix command called "chmod" and "chown" and there are also system calls called "chmod" and "chown" in the "C" programming language.
Not sure whether you are looking from the point of view of a writing "C" programs or some other angle.

# For "C" programming language
man 2 chmod
man 2 setuid
man 2 chown

# For unix commands
man chmod
man chown

# 3  
Originally Posted by kkalyan
Can anyone explain me difference between setuid and sticky bit?
It's the same bit. It just has different meanings in different places.

I don't think it means anything for an ordinary file.

For an executable file, it runs the program as the file's owner -- it sets the UID with the setuid() call,, hence you sometimes hear it called "setuid bit". setuid doesn't work for shell scripts.

For a library file, it means 'remember the contents of this file in swap space', a performance tweak to keep busy libraries closer to memory. Many systems don't honor this anymore.

For directories, it means "only a file's owner is allowed to delete files in this directory". The usual behavior is that anyone with write-permissions can delete files.
and also between setuid and chown?
setuid is a flag. chown is a program.
# 4  
setuid & sticky -- It cannot be the exact same bit.

sticky bit on a directory: chown 1777 [dirname]
No other setting really makes sense. The '1' is the sticky bit setting. Methyl is right - the sticky bit can mean different behavior in a few kinds of UNIX. The most common meaning is that, for a directory, every creator of a file in that directory is also the file
owner. /tmp is a common example.

setuid: chown 4nnn where 4 sets a regular file as setuid, and nnn is the other settings.

4 and 1 cannot be a single bit (2 & 3 are also used) since at least the number of bits required to represent 0, 1, 2, 3, 4 is required. How this is represented is filesystem dependent and OS dependent.
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