release/src/router/nfs-utils/utils/statd/notlist.c

   1 /*
   2  * Copyright (C) 1995, 1997-1999 Jeffrey A. Uphoff
   3  * Modified by Olaf Kirch, 1996.
   4  * Modified by H.J. Lu, 1998.
   5  * Modified by Lon Hohberger, Oct. 2000.
   6  *   - Fixed memory leaks, run-off-end problems, etc.
   7  *
   8  * NSM for Linux.
   9  */
  10
  11 /*
  12  * Simple list management for notify list
  13  */
  14
  15 #ifdef HAVE_CONFIG_H
  16 #include <config.h>
  17 #endif
  18
  19 #include <string.h>
  20 #include "misc.h"
  21 #include "statd.h"
  22 #include "notlist.h"
  23
  24
  25 #ifdef DEBUG
  26 /*
  27  * LH - The linked list code had some bugs.  Used this to help debug
  28  * new code.
  29  */
  30 static void
  31 plist(notify_list *head, int en)
  32 {
  33         /* case where we ran off the end */
  34         if (!head) return;
  35
  36         printf("Entry %d: %s\n",en, NL_MON_NAME(head));
  37         plist(head->next, ++en);
  38 }
  39
  40 static void
  41 nlist_print(notify_list **head)
  42 {
  43         printf("--- Begin notify list dump ---\n");
  44         plist(*head,1);
  45         printf("--- End notify list dump ---\n");
  46 }
  47 #endif /* DEBUG */
  48
  49 /*
  50  * Allocate memory and set up a new notify list entry.
  51  */
  52 notify_list *
  53 nlist_new(char *my_name, char *mon_name, int state)
  54 {
  55         notify_list     *new;
  56
  57         new = (notify_list *) xmalloc(sizeof(notify_list));
  58         memset(new, 0, sizeof(*new));
  59
  60         NL_TIMES(new) = MAX_TRIES;
  61         NL_STATE(new) = state;
  62         NL_MY_NAME(new) = xstrdup(my_name);
  63         NL_MON_NAME(new) = xstrdup(mon_name);
  64
  65         return new;
  66 }
  67
  68 /*
  69  * Insert *entry into a notify list at the point specified by
  70  * **head.  This can be in the middle.  However, we do not handle
  71  * list _append_ in this function; rather, the only place we should
  72  * have to worry about this case is in nlist_insert_timer below.
  73  * - entry must not be NULL.
  74  */
  75 void
  76 nlist_insert(notify_list **head, notify_list *entry)
  77 {
  78         if (*head) {
  79                 /*
  80                  * Cases where we're prepending a non-empty list
  81                  * or inserting possibly in the middle somewhere (eg,
  82                  * nlist_insert_timer...)
  83                  */
  84                 entry->next = (*head);          /* Forward pointer */
  85                 entry->prev = (*head)->prev;    /* Back pointer */
  86                 (*head)->prev = entry;          /* head's new back pointer */
  87         }
  88
  89         /* Common to all cases, including new list creation */
  90         *head = entry;                  /* New head */
  91
  92 #ifdef DEBUG
  93         nlist_print(head);
  94 #endif
  95 }
  96
  97 /*
  98  * (re)insert *entry into notify_list **head.  This requires that
  99  * NL_WHEN(entry) has been set (usually, this is time() + 5 seconds).
 100  * - entry must not be NULL
 101  *
 102  * LH - This used to cause (a) a memory leak and (b) dropped notify-list
 103  * entries.  The pointer ran off the end of the list, and changed the
 104  * head-end to point to the new, one-entry list.  All other entries became garbage.
 105  *
 106  * FIXME: Optimize this function. (I'll work on it - LH)
 107  */
 108 void
 109 nlist_insert_timer(notify_list **head, notify_list *entry)
 110 {
 111         notify_list     *spot = *head,          /* Insertion location */
 112                                                 /* ...Start at head */
 113                         *back = NULL;           /* Back pointer */
 114
 115
 116         /* Find first entry with higher timeout value or end of list */
 117         while (spot && NL_WHEN(spot) <= NL_WHEN(entry)) {
 118                 /*
 119                  * Keep the back pointer in case we
 120                  * run off the end...  (see below)
 121                  */
 122                 back = spot;
 123                 spot = spot->next;
 124         }
 125
 126         if (spot == (*head)) {
 127                 /*
 128                  * case where we're prepending an empty or non-empty
 129                  * list or inserting in the middle somewhere.  Pass
 130                  * the real head of the list, since we'll be changing
 131                  * during the insert...
 132                  */
 133                 nlist_insert(head, entry);
 134         } else {
 135                 /* all other cases - don't move the real head pointer */
 136                 nlist_insert(&spot, entry);
 137
 138                 /*
 139                  * If spot == entry, then spot was NULL when we called
 140                  * nlist_insert.  This happened because we had run off
 141                  * the end of the list.  Append entry to original list.
 142                  */
 143                 if (spot == entry) {
 144                         back->next = entry;
 145                         entry->prev = back;
 146                 }
 147         }
 148 }
 149
 150 /*
 151  * Remove *entry from the list pointed to by **head.
 152  * Do not destroy *entry.  This is normally done before
 153  * a re-insertion with a timer, but can be done anywhere.
 154  * - entry must not be NULL.
 155  */
 156 void
 157 nlist_remove(notify_list **head, notify_list *entry)
 158 {
 159         notify_list     *prev = entry->prev,
 160                         *next = entry->next;
 161
 162         if (next) {
 163                 next->prev = prev;
 164         }
 165
 166         if (prev) {
 167                 /* Case(s) where entry isn't at the front */
 168                 prev->next = next;
 169         } else {
 170                 /* cases where entry is at the front */
 171                 *head = next;
 172         }
 173
 174         entry->next = entry->prev = NULL;
 175 #ifdef DEBUG
 176         nlist_print(head);
 177 #endif
 178 }
 179
 180 /*
 181  * Clone an entry in the notify list -
 182  * - entry must not be NULL
 183  */
 184 notify_list *
 185 nlist_clone(notify_list *entry)
 186 {
 187         notify_list     *new;
 188
 189         new = nlist_new(NL_MY_NAME(entry), NL_MON_NAME(entry), NL_STATE(entry));
 190         NL_MY_PROG(new) = NL_MY_PROG(entry);
 191         NL_MY_VERS(new) = NL_MY_VERS(entry);
 192         NL_MY_PROC(new) = NL_MY_PROC(entry);
 193         NL_ADDR(new)    = NL_ADDR(entry);
 194         memcpy(NL_PRIV(new), NL_PRIV(entry), SM_PRIV_SIZE);
 195
 196         return new;
 197 }
 198
 199 /*
 200  * Destroy an entry in a notify list and free the memory.
 201  * If *head is NULL, just free the entry.  This would be
 202  * done only when we know entry isn't in any list.
 203  * - entry must not be NULL.
 204  */
 205 void
 206 nlist_free(notify_list **head, notify_list *entry)
 207 {
 208         if (head && (*head))
 209                 nlist_remove(head, entry);
 210         if (NL_MY_NAME(entry))
 211                 free(NL_MY_NAME(entry));
 212         if (NL_MON_NAME(entry))
 213                 free(NL_MON_NAME(entry));
 214         free(entry->dns_name);
 215         free(entry);
 216 }
 217
 218 /*
 219  * Destroy an entire notify list
 220  */
 221 void
 222 nlist_kill(notify_list **head)
 223 {
 224         while (*head)
 225                 nlist_free(head, *head);
 226 }
 227
 228 /*
 229  * Walk a list looking for a matching name in the NL_MON_NAME field.
 230  */
 231 notify_list *
 232 nlist_gethost(notify_list *list, char *host, int myname)
 233 {
 234         notify_list     *lp;
 235
 236         for (lp = list; lp; lp = lp->next) {
 237                 if (matchhostname(host, myname? NL_MY_NAME(lp) : NL_MON_NAME(lp)))
 238                         return lp;
 239         }
 240
 241         return (notify_list *) NULL;
 242 }