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/* |
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* Hydra, an http server |
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* Copyright (C) 1995 Paul Phillips <paulp@go2net.com> |
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* Some changes Copyright (C) 1996 Larry Doolittle <ldoolitt@boa.org> |
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* Some changes Copyright (C) 1997 Jon Nelson <jnelson@boa.org> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 1, or (at your option) |
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* any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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* |
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*/ |
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|
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/* $Id: hash.c,v 1.2 2002/09/28 16:04:01 nmav Exp $*/ |
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|
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#include "boa.h" |
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#include "parse.h" |
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|
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/* |
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* There are two hash tables used, each with a key/value pair |
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* stored in a hash_struct. They are: |
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* |
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* mime_hashtable: |
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* key = file extension |
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* value = mime type |
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* |
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* passwd_hashtable: |
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* key = username |
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* value = home directory |
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* |
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*/ |
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|
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struct _hash_struct_ { |
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char *key; |
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char *value; |
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struct _hash_struct_ *next; |
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}; |
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|
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typedef struct _hash_struct_ hash_struct; |
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|
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static hash_struct *mime_hashtable[MIME_HASHTABLE_SIZE]; |
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static hash_struct *passwd_hashtable[PASSWD_HASHTABLE_SIZE]; |
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|
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#ifdef WANT_ICKY_HASH |
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static unsigned four_char_hash(char *buf); |
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#define boa_hash four_char_hash |
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#else |
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#ifdef WANT_SDBM_HASH |
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static unsigned sdbm_hash(char *str); |
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#define boa_hash sdbm_hash |
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#else |
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static unsigned djb2_hash(char *str); |
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#define boa_hash djb2_hash |
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#endif |
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#endif |
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|
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#ifdef WANT_ICKY_HASH |
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static unsigned four_char_hash(char *buf) |
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{ |
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unsigned int hash = (buf[0] + |
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(buf[1] ? buf[1] : 241 + |
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(buf[2] ? buf[2] : 251 + |
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(buf[3] ? buf[3] : 257)))); |
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#ifdef DEBUG_HASH |
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log_error_time(); |
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fprintf(stderr, "four_char_hash(%s) = %u\n", buf, hash); |
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#endif |
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return hash; |
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} |
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|
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/* The next two hashes taken from |
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* http://www.cs.yorku.ca/~oz/hash.html |
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* |
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* In my (admittedly) very brief testing, djb2_hash performed |
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* very slightly better than sdbm_hash. |
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*/ |
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|
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#else |
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#define MAX_HASH_LENGTH 4 |
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#ifdef WANT_SDBM_HASH |
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static unsigned sdbm_hash(char *str) |
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{ |
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unsigned hash = 0; |
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int c; |
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short count = MAX_HASH_LENGTH; |
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|
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#ifdef DEBUG_HASH |
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log_error_time(); |
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fprintf(stderr, "sdbm_hash(%s) = ", str); |
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#endif |
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|
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while ((c = *str++) && count--) |
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hash = c + (hash << 6) + (hash << 16) - hash; |
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|
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#ifdef DEBUG_HASH |
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fprintf(stderr, "%u\n", hash); |
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#endif |
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return hash; |
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} |
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#else |
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|
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static unsigned djb2_hash(char *str) |
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{ |
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unsigned hash = 5381; |
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int c; |
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short count = MAX_HASH_LENGTH; |
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|
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#ifdef DEBUG_HASH |
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log_error_time(); |
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fprintf(stderr, "djb2_hash(%s) = ", str); |
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#endif |
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|
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while ((c = *(str++)) && count--) |
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hash = ((hash << 5) + hash) + c; /* hash * 33 + c */ |
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|
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#ifdef DEBUG_HASH |
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fprintf(stderr, "%u\n", hash); |
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#endif |
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return hash; |
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} |
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#endif |
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#endif |
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|
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/* |
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* Name: add_mime_type |
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* Description: Adds a key/value pair to the mime_hashtable |
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*/ |
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|
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void add_mime_type(char *extension, char *type) |
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{ |
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unsigned int hash; |
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hash_struct *current, *next; |
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|
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if (!extension) |
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return; |
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|
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hash = get_mime_hash_value(extension); |
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|
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current = mime_hashtable[hash]; |
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|
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while (current) { |
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if (!strcmp(current->key, extension)) |
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return; /* don't add extension twice */ |
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if (current->next) |
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current = current->next; |
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else |
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break; |
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} |
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|
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/* if here, we need to add a new one */ |
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next = (hash_struct *) malloc(sizeof (hash_struct)); |
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if (!next) { |
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DIE("malloc of hash_struct failed!"); |
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} |
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next->key = strdup(extension); |
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if (!next->key) |
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DIE("malloc of hash_struct->key failed!"); |
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next->value = strdup(type); |
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if (!next->value) |
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DIE("malloc of hash_struct->value failed!"); |
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next->next = NULL; |
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|
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if (!current) { |
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mime_hashtable[hash] = next; |
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} else { |
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current->next = next; |
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} |
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} |
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|
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/* |
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* Name: get_mime_hash_value |
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* |
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* Description: adds the ASCII values of the file extension letters |
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* and mods by the hashtable size to get the hash value |
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*/ |
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|
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unsigned get_mime_hash_value(char *extension) |
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{ |
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unsigned int hash = 0; |
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|
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if (extension == NULL || extension[0] == '\0') { |
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/* FIXME */ |
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log_error_time(); |
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fprintf(stderr, "Attempt to hash NULL or empty string!\n"); |
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return 0; |
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} |
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|
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hash = boa_hash(extension); |
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hash %= MIME_HASHTABLE_SIZE; |
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|
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return hash; |
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} |
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|
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/* |
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* Name: get_mime_type |
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* |
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* Description: Returns the mime type for a supplied filename. |
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* Returns default type if not found. |
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*/ |
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|
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char *get_mime_type(const char *filename) |
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{ |
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char *extension; |
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hash_struct *current; |
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|
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unsigned int hash; |
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|
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extension = strrchr(filename, '.'); |
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|
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if (!extension || *extension++ == '\0') |
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return default_type; |
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|
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hash = get_mime_hash_value(extension); |
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current = mime_hashtable[hash]; |
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|
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while (current) { |
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if (!strcmp(current->key, extension)) /* hit */ |
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return current->value; |
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current = current->next; |
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} |
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|
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return default_type; |
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} |
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|
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/* |
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* Name: get_homedir_hash_value |
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* |
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* Description: adds the ASCII values of the username letters |
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* and mods by the hashtable size to get the hash value |
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*/ |
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|
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unsigned get_homedir_hash_value(char *name) |
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{ |
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unsigned int hash = 0; |
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|
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if (name == NULL || name[0] == '\0') { |
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/* FIXME */ |
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log_error_time(); |
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fprintf(stderr, "Attempt to hash NULL or empty string!\n"); |
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return 0; |
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} |
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|
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hash = boa_hash(name); |
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hash %= PASSWD_HASHTABLE_SIZE; |
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|
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return hash; |
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} |
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|
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|
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/* |
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* Name: get_home_dir |
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* |
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* Description: Returns a point to the supplied user's home directory. |
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* Adds to the hashtable if it's not already present. |
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* |
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*/ |
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|
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char *get_home_dir(char *name) |
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{ |
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struct passwd *passwdbuf; |
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|
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hash_struct *current, *next; |
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unsigned int hash; |
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|
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/* first check hash table -- if username is less than four characters, |
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just hash to zero (this should be very rare) */ |
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|
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hash = get_homedir_hash_value(name); |
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|
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for(current = passwd_hashtable[hash];current;current = current->next) { |
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if (!strcmp(current->key, name)) /* hit */ |
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return current->value; |
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if (!current->next) |
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break; |
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} |
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|
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/* if here, we have to add a new one */ |
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|
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passwdbuf = getpwnam(name); |
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|
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if (!passwdbuf) /* does not exist */ |
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return NULL; |
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|
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next = (hash_struct *) malloc(sizeof (hash_struct)); |
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if (!next) { |
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WARN("malloc of hash_struct for passwd_hashtable failed!"); |
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return NULL; |
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} |
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|
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next->key = strdup(name); |
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if (!next->key) { |
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WARN("malloc of passwd_hashtable[hash]->key failed!"); |
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free(next); |
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return NULL; |
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} |
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next->value = strdup(passwdbuf->pw_dir); |
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if (!next->value) { |
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WARN("malloc of passwd_hashtable[hash]->value failed!"); |
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free(next->key); |
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free(next); |
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return NULL; |
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} |
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next->next = NULL; |
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|
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if (!current) { |
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passwd_hashtable[hash] = next; |
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} else { |
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current->next = next; |
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} |
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return next->value; |
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} |
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|
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void dump_mime(void) |
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{ |
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int i; |
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hash_struct *temp; |
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for (i = 0; i < MIME_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
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temp = mime_hashtable[i]; |
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while (temp) { |
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hash_struct *temp_next; |
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|
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temp_next = temp->next; |
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free(temp->key); |
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free(temp->value); |
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free(temp); |
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|
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temp = temp_next; |
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} |
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mime_hashtable[i] = NULL; |
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} |
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} |
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|
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void dump_passwd(void) |
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{ |
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int i; |
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hash_struct *temp; |
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for (i = 0; i < PASSWD_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
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temp = passwd_hashtable[i]; |
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while (temp) { |
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hash_struct *temp_next; |
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|
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temp_next = temp->next; |
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free(temp->key); |
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free(temp->value); |
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free(temp); |
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|
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temp = temp_next; |
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} |
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passwd_hashtable[i] = NULL; |
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} |
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} |
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|
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extern int mmap_list_entries_used; |
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|
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void show_hash_stats(void) |
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{ |
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int i; |
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hash_struct *temp; |
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int total = 0; |
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int count; |
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|
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log_error_time(); |
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fprintf(stderr, "mmap_hashtable has %d entries\n", mmap_list_entries_used); |
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|
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for (i = 0; i < MIME_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
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if (mime_hashtable[i]) { |
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count = 0; |
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temp = mime_hashtable[i]; |
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while (temp) { |
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temp = temp->next; |
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++count; |
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} |
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#ifdef NOISY_SIGALRM |
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log_error_time(); |
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fprintf(stderr, "mime_hashtable[%d] has %d entries\n", |
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i, count); |
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#endif |
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total += count; |
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} |
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} |
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log_error_time(); |
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fprintf(stderr, "mime_hashtable has %d total entries\n", |
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total); |
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|
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total = 0; |
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for (i = 0; i < PASSWD_HASHTABLE_SIZE; ++i) { /* these limits OK? */ |
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if (passwd_hashtable[i]) { |
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temp = passwd_hashtable[i]; |
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count = 0; |
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while (temp) { |
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temp = temp->next; |
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++count; |
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} |
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#ifdef NOISY_SIGALRM |
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log_error_time(); |
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fprintf(stderr, "passwd_hashtable[%d] has %d entries\n", |
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i, count); |
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#endif |
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total += count; |
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} |
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} |
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|
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log_error_time(); |
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fprintf(stderr, "passwd_hashtable has %d total entries\n", |
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total); |
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|
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} |