Cannot manually update database for locate?
I've been trying to update the databases used by locate on my Macbook (10.6.3 Snow Leopard) but even following the commands shown in this thread hasn't gotten me anywhere. I just get an error from it - if I try to use it via sudo, I get some racket about permission denied for such-n-such directory. I tried running it as root (sudo su, then the command) and that didn't work either. Quit back to my regular terminal prompt, and now I just get
macbook:~ monte$ sudo /usr/libexec/locate.updatedb
find: .: Permission denied
macbook:~ monte$
I'm thoroughly confused, and half afraid that I may have hosed something in the process. Any help or suggestions would be greatly appreciated!
Monte
Solution 1:
The solution for your problem is very simple. But if you want to know better why the error is occurring and why the proposed solution works, you can read the entire answer.
Otherwise, if you only want to get the answer, go straight to the "How to update your locate db?" session.
What exactly locate.updatedb does?
This is the current behavior of locate.updatedb
:
- If you are running the script as
root
, the script calls itself with the usernobody
. Then, when the children returns, it updates the final locale database with the database saved by the children process (nobody
user) in a temporary location, and then exits;
Code (/usr/libexec/locate.updatedb
, line 31, with additional comments added by me):
if [ "$(id -u)" = "0" ]; then ## IF ROOT USER
rc=0
export FCODES=`mktemp -t updatedb` ## CREATE A TEMP FILE
chown nobody $FCODES # TEMP FILE OWNED BY THE NOBODY USER
tmpdb=`su -fm nobody -c "$0"` || rc=1 ## CALL ITSELF AS USER NOBODY
if [ $rc = 0 ]; then
install -m 0444 -o nobody -g wheel $FCODES \
/var/db/locate.database ## INSTALL THE LOCATE DATABASE SAVED \
## BY THE CHILDREN IN THE TEMP FILE
fi
rm $FCODES
exit $rc ## EXIT
fi
- When running with another user (it is, the user
nobody
), the script indexes your system (ignoring the paths which it doesn't have permission) and then saves the result in a temporary file (actually, the previously temp file created by its father).
Some considerations:
- Part of the logic is executed as root, and other part as nobody;
- If the script is called without
sudo
, it won't work (onlyroot
has permission in the/var/db
directory). It is, you must really run the script asroot
; - As a result,
locate.updatedb
can't index files inside your home directory (thenobody
user doesn't have permission to access it);- I think
locate.updatedb
indexes this way because it will be impossible to an user to discover name of files that belongs to another user (in another home directory); - If you want to locate files inside your home, you can use
mdfind
, as proposed by @ted-naleid.
- I think
Some code (/usr/libexec/locate.updatedb
, line 93, with additional comments):
if $find -s $SEARCHPATHS $excludes -or -print 2>/dev/null | ## SEARCH
$mklocatedb -presort > $tmp ## CREATE LOCALEDB
then
case X"`$find $tmp -size -257c -print`" in
X) cat $tmp > $FCODES;; ## SAVE LOCALEDB IN THE TEMP FILE
[...]
Why are you getting "Permission Denied" errors?
As I said, locale.updatedb
launchs a new instance of itself as the nobody
user. However, you cannot start a script inside a workdir in which the script has no permissions.
Probably, you are getting "Permission denied" errors because you're running locale.updatedb
inside your home.
I'm creating a simple script to show this fact:
#!/bin/bash
if [ $(id -un) != "nobody" ]; then
sudo -u nobody "$0"
exit 0
fi
find / -mindepth 1 -maxdepth 1 | wc -l
If you put this script inside /tmp/test.sh
and set execution permission to it (chmod +x /tmp/test.sh
), depending of your workdir, it can show or not errors:
$ cd /tmp
$ ./test.sh
29
$ cd ~
$ /tmp/test.sh
shell-init: error retrieving current directory: getcwd: cannot access parent directories: Permission denied
job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: Permission denied
find: .: Permission denied
0
How to update your locate db?
Now, it's simple! Only change your workdir to a place where nobody
has permission before executing locale.updatedb
:
cd /
sudo /usr/libexec/locate.updatedb
Solution 2:
You might want to try to repair file permissions (in the Disk Utility application). Sounds like it might be an issue with that.
Also, not directly related to locate, but I've found that on the mac that mdfind actually does what I want quite a bit better than locate does. It's the command line interface to spotlight, and it lets you find just by file name if you want to mimic locate:
mdfind -name <filename>
Just using "mdfind " will find both file names and look inside files (sort of grep/find put together).
No need to manually update the database for it as OSX maintains the spotlight information for you.
Solution 3:
launchctl load -wF /System/Library/LaunchDaemons/com.apple.locate.plist
If it doesn't help, try:
launchctl stop com.apple.locate
launchctl start com.apple.locate