1 /* This program is free software; you can redistribute it and/or modify
2 it under the terms of the GNU General Public License as published by
3 the Free Software Foundation; either version 2, or (at your option)
6 This program is distributed in the hope that it will be useful,
7 but WITHOUT ANY WARRANTY; without even the implied warranty of
8 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 GNU General Public License for more details. */
11 /* Collect and manage hardlink info associated with a particular file. */
16 /* The structure currently used to manage hardlink info is a list.
17 Therefore, most of the functions which manipulate hardlink data
18 are walklist procedures. This is not a very efficient implementation;
19 if someone decides to use a real hash table (for instance), then
20 much of this code can be rewritten to be a little less arcane.
22 Each element of `hardlist' represents an inode. It is keyed on the
23 inode number, and points to a list of files. This is to make it
24 easy to find out what files are linked to a given file FOO: find
25 FOO's inode, look it up in hardlist, and retrieve the list of files
26 associated with that inode.
28 Each file node, in turn, is represented by a `hardlink_info' struct,
29 which includes `status' and `links' fields. The `status' field should
30 be used by a procedure like commit_fileproc or update_fileproc to
31 record each file's status; that way, after all file links have been
32 recorded, CVS can check the linkage of files which are in doubt
33 (i.e. T_NEEDS_MERGE files).
35 TODO: a diagram of an example hardlist would help here. */
37 /* TODO: change this to something with a marginal degree of
38 efficiency, like maybe a hash table. Yeah. */
40 List *hardlist; /* Record hardlink information for working files */
41 char *working_dir; /* The top-level working directory, used for
42 constructing full pathnames. */
44 /* Return a pointer to FILEPATH's node in the hardlist. This means
45 looking up its inode, retrieving the list of files linked to that
46 inode, and then looking up FILE in that list. If the file doesn't
47 seem to exist, return NULL. */
49 lookup_file_by_inode (filepath)
52 char *inodestr, *file;
56 /* Get file's basename, so that we can stat it. */
57 file = strrchr (filepath, '/');
61 file = (char *) filepath;
63 /* inodestr contains the hexadecimal representation of an
64 inode, so it requires two bytes of text to represent
65 each byte of the inode number. */
66 inodestr = (char *) xmalloc (2*sizeof(ino_t)*sizeof(char) + 1);
67 if (stat (file, &sb) < 0)
71 /* The file doesn't exist; we may be doing an update on a
72 file that's been removed. A nonexistent file has no
73 link information, so return without changing hardlist. */
77 error (1, errno, "cannot stat %s", file);
80 sprintf (inodestr, "%lx", (unsigned long) sb.st_ino);
82 /* Find out if this inode is already in the hardlist, adding
83 a new entry to the list if not. */
84 hp = findnode (hardlist, inodestr);
90 hp->data = (char *) getlist();
91 hp->delproc = dellist;
92 (void) addnode (hardlist, hp);
99 p = findnode ((List *) hp->data, filepath);
104 p->key = xstrdup (filepath);
106 (void) addnode ((List *) hp->data, p);
112 /* After a file has been checked out, add a node for it to the hardlist
113 (if necessary) and mark it as checked out. */
115 update_hardlink_info (file)
120 struct hardlink_info *hlinfo;
124 path = xstrdup (file);
128 /* file is a relative pathname; assume it's from the current
129 working directory. */
130 char *dir = xgetwd();
131 path = xmalloc (sizeof(char) * (strlen(dir) + strlen(file) + 2));
132 sprintf (path, "%s/%s", dir, file);
136 n = lookup_file_by_inode (path);
139 /* Something is *really* wrong if the file doesn't exist here;
140 update_hardlink_info should be called only when a file has
141 just been checked out to a working directory. */
142 error (1, 0, "lost hardlink info for %s", file);
146 n->data = (char *) xmalloc (sizeof (struct hardlink_info));
147 hlinfo = (struct hardlink_info *) n->data;
148 hlinfo->status = T_UPTODATE;
149 hlinfo->checked_out = 1;
152 /* Return a List with all the files known to be linked to FILE in
153 the working directory. Used by special_file_mismatch, to determine
154 whether it is safe to merge two files.
156 FIXME: What is the memory allocation for the return value? We seem
157 to sometimes allocate a new list (getlist() call below) and sometimes
158 return an existing list (where we return n->data). */
160 list_linked_files_on_disk (file)
163 char *inodestr, *path;
167 /* If hardlist is NULL, we have not been doing an operation that
168 would permit us to know anything about the file's hardlinks
169 (cvs update, cvs commit, etc). Return an empty list. */
170 if (hardlist == NULL)
173 /* Get the full pathname of file (assuming the working directory) */
175 path = xstrdup (file);
178 char *dir = xgetwd();
179 path = (char *) xmalloc (sizeof(char) *
180 (strlen(dir) + strlen(file) + 2));
181 sprintf (path, "%s/%s", dir, file);
185 /* We do an extra lookup_file here just to make sure that there
186 is a node for `path' in the hardlist. If that were not so,
187 comparing the working directory linkage against the repository
188 linkage for a file would always fail. */
189 (void) lookup_file_by_inode (path);
191 if (stat (path, &sb) < 0)
192 error (1, errno, "cannot stat %s", file);
193 /* inodestr contains the hexadecimal representation of an
194 inode, so it requires two bytes of text to represent
195 each byte of the inode number. */
196 inodestr = (char *) xmalloc (2*sizeof(ino_t)*sizeof(char) + 1);
197 sprintf (inodestr, "%lx", (unsigned long) sb.st_ino);
199 /* Make sure the files linked to this inode are sorted. */
200 n = findnode (hardlist, inodestr);
201 sortlist ((List *) n->data, fsortcmp);
204 return (List *) n->data;
207 /* Compare the files in the `key' fields of two lists, returning 1 if
208 the lists are equivalent and 0 otherwise.
210 Only the basenames of each file are compared. This is an awful hack
211 that exists because list_linked_files_on_disk returns full paths
212 and the `hardlinks' structure of a RCSVers node contains only
213 basenames. That in turn is a result of the awful hack that only
214 basenames are stored in the RCS file. If anyone ever solves the
215 problem of correctly managing cross-directory hardlinks, this
216 function (along with most functions in this file) must be fixed. */
219 compare_linkage_lists (links1, links2)
226 sortlist (links1, fsortcmp);
227 sortlist (links2, fsortcmp);
229 n1 = links1->list->next;
230 n2 = links2->list->next;
232 while (n1 != links1->list && n2 != links2->list)
234 /* Get the basenames of both files. */
235 p1 = strrchr (n1->key, '/');
241 p2 = strrchr (n2->key, '/');
247 /* Compare the files' basenames. */
248 if (strcmp (p1, p2) != 0)
255 /* At this point we should be at the end of both lists; if not,
256 one file has more links than the other, and return 1. */
257 return (n1 == links1->list && n2 == links2->list);
260 /* Find a checked-out file in a list of filenames. Used by RCS_checkout
261 when checking out a new hardlinked file, to decide whether this file
262 can be linked to any others that already exist. The return value
263 is not currently used. */
266 find_checkedout_proc (node, data)
270 Node **uptodate = (Node **) data;
272 char *dir = xgetwd();
274 struct hardlink_info *hlinfo;
276 /* If we have already found a file, don't do anything. */
277 if (*uptodate != NULL)
280 /* Look at this file in the hardlist and see whether the checked_out
281 field is 1, meaning that it has been checked out during this CVS run. */
283 xmalloc (sizeof(char) * (strlen (dir) + strlen (node->key) + 2));
284 sprintf (path, "%s/%s", dir, node->key);
285 link = lookup_file_by_inode (path);
291 /* We haven't seen this file -- maybe it hasn't been checked
296 hlinfo = (struct hardlink_info *) link->data;
297 if (hlinfo->checked_out)
299 /* This file has been checked out recently, so it's safe to