Re: [Nautilus-list] Cache getpwuid results

[Maciej Stachowiak <mjs noisehavoc org>]

On 14Aug2001 09:13PM (-0400), Alex Larsson wrote:
> Here is a patch that caches the getpwuid results in 
> nautilus_file_denies_access_permission() which seems to be called for 
> every file in a scanned directory.
> 

Hi Alex,

Maybe it would be useful to split the getpwuid caching code into one
or more separate functions in case anything else ever needs it.

Regards,

Maciej

> / Alex
> 
> Index: nautilus-file.c
> ===================================================================
> RCS file: /cvs/gnome/nautilus/libnautilus-private/nautilus-file.c,v
> retrieving revision 1.249.2.4
> diff -u -p -r1.249.2.4 nautilus-file.c
> --- nautilus-file.c	2001/07/31 21:59:28	1.249.2.4
> +++ nautilus-file.c	2001/08/15 01:11:30
> @@ -60,7 +60,11 @@
>  #include <pwd.h>
>  #include <stdlib.h>
>  #include <unistd.h>
> +#include <sys/time.h>
>  
> +/* Time in seconds to cache getpwuid results */
> +#define GETPWUID_CACHE_TIME (5*60)
> +
>  #undef NAUTILUS_FILE_DEBUG_REF
>  
>  #ifdef NAUTILUS_FILE_DEBUG_REF
> @@ -582,10 +586,13 @@ nautilus_file_denies_access_permission (
>  				        GnomeVFSFilePermissions group_permission,
>  				        GnomeVFSFilePermissions other_permission)
>  {
> -	uid_t user_id;
> -	struct passwd *password_info;
> -	gid_t supplementary_groups[NGROUPS_MAX];
> -	int num_supplementary_groups;
> +	struct timeval now;
> +	static struct timeval cached_time = {0,0};
> +	static struct passwd *password_info;
> +	static uid_t user_id;
> +	static gid_t primary_group;
> +	static gid_t supplementary_groups[NGROUPS_MAX];
> +	static int num_supplementary_groups;
>  	int i;
>  
>  	g_assert (NAUTILUS_IS_FILE (file));
> @@ -602,9 +609,23 @@ nautilus_file_denies_access_permission (
>  		return FALSE;
>  	}
>  
> -	/* Check the user. */
> -	user_id = geteuid ();
> +	/* This is called often. Cache the user information for five minutes */
> +	
> +	gettimeofday (&now, NULL);
> +	
> +	if (cached_time.tv_sec == 0 ||
> +	    (now.tv_sec - cached_time.tv_sec) > GETPWUID_CACHE_TIME) {
> +		cached_time = now;
> +		user_id = geteuid ();
> +		/* No need to free result of getpwuid. */
> +		password_info = getpwuid (user_id);
> +		if (password_info)
> +			primary_group = password_info->pw_gid;
> +		num_supplementary_groups = getgroups (NGROUPS_MAX, supplementary_groups);
> +	}
>  
> +	/* Check the user. */
> +	
>  	/* Root is not forbidden to do anything. */
>  	if (user_id == 0) {
>  		return FALSE;
> @@ -619,8 +640,6 @@ nautilus_file_denies_access_permission (
>  		return (file->details->info->permissions & owner_permission) == 0;
>  	}
>  
> -	/* No need to free result of getpwuid. */
> -	password_info = getpwuid (user_id);
>  
>  	/* Group member's access is governed by the group bits. */
>  	/* FIXME bugzilla.eazel.com 644: 
> @@ -628,11 +647,10 @@ nautilus_file_denies_access_permission (
>  	 * there be garbage there? What will it do for non-local files?
>  	 */
>  	if (password_info != NULL
> -	    && password_info->pw_gid == (gid_t) file->details->info->gid) {
> +	    && primary_group == (gid_t) file->details->info->gid) {
>  		return (file->details->info->permissions & group_permission) == 0;
>  	}
>  	/* Check supplementary groups */
> -	num_supplementary_groups = getgroups (NGROUPS_MAX, supplementary_groups);
>  	for (i = 0; i < num_supplementary_groups; i++) {
>  		if ((gid_t) file->details->info->gid == supplementary_groups[i]) {
>  			return (file->details->info->permissions & group_permission) == 0;
> 
> 
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