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jeremyevans / aqualung

Advanced music player
http://aqualung.jeremyevans.net
GNU General Public License v2.0
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Fix error creating config dirs #25

Closed sswam closed 3 years ago

sswam commented 3 years ago

dirname modifies its argument, so it would try to create ~/.config twice, giving an error.

jeremyevans commented 3 years ago

The behavior is operating system dependent, I'm guessing you are running on Linux, as looking at a Linux dirname(3) man page:

Bugs

In the glibc implementation of the POSIX versions of these functions they modify their argument

At least this is correctly recognized as a bug in glibc. Your patch looks good, and should still work in cases where dirname(3) doesn't modify the argument. I'll test and merge shortly.

sswam commented 3 years ago

There's no good way to implement dirname with that API. I looked it up, POSIX suggests and allows two bad alternatives:

RETURN VALUE
The dirname( ) function shall return a pointer to a string that is the parent directory of path. If
path is a null pointer or points to an empty string, a pointer to a string "." is returned.
The dirname( ) function may modify the string pointed to by path, and may return a pointer to
static storage that may then be overwritten by subsequent calls to dirname( ).

NetBSD for example does it the other way, returning a pointer to static storage (that may be overwritten). GNU is complaining that the POSIX definitions of dirname and basename are bad because they lead to bugs. It's a bug in POSIX, not a bug in glibc.