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. */
15 #ifdef PRESERVE_PERMISSIONS_SUPPORT
16 # include "hardlink.h"
18 /* The structure currently used to manage hardlink info is a list.
19 Therefore, most of the functions which manipulate hardlink data
20 are walklist procedures. This is not a very efficient implementation;
21 if someone decides to use a real hash table (for instance), then
22 much of this code can be rewritten to be a little less arcane.
24 Each element of `hardlist' represents an inode. It is keyed on the
25 inode number, and points to a list of files. This is to make it
26 easy to find out what files are linked to a given file FOO: find
27 FOO's inode, look it up in hardlist, and retrieve the list of files
28 associated with that inode.
30 Each file node, in turn, is represented by a `hardlink_info' struct,
31 which includes `status' and `links' fields. The `status' field should
32 be used by a procedure like commit_fileproc or update_fileproc to
33 record each file's status; that way, after all file links have been
34 recorded, CVS can check the linkage of files which are in doubt
35 (i.e. T_NEEDS_MERGE files).
37 TODO: a diagram of an example hardlist would help here. */
39 /* TODO: change this to something with a marginal degree of
40 efficiency, like maybe a hash table. Yeah. */
42 List *hardlist; /* Record hardlink information for working files */
43 char *working_dir; /* The top-level working directory, used for
44 constructing full pathnames. */
46 /* Return a pointer to FILEPATH's node in the hardlist. This means
47 looking up its inode, retrieving the list of files linked to that
48 inode, and then looking up FILE in that list. If the file doesn't
49 seem to exist, return NULL. */
51 lookup_file_by_inode (filepath)
54 char *inodestr, *file;
58 /* Get file's basename, so that we can stat it. */
59 file = strrchr (filepath, '/');
63 file = (char *) filepath;
65 /* inodestr contains the hexadecimal representation of an
66 inode, so it requires two bytes of text to represent
67 each byte of the inode number. */
68 inodestr = (char *) xmalloc (2*sizeof(ino_t) + 1);
69 if (stat (file, &sb) < 0)
71 if (existence_error (errno))
73 /* The file doesn't exist; we may be doing an update on a
74 file that's been removed. A nonexistent file has no
75 link information, so return without changing hardlist. */
79 error (1, errno, "cannot stat %s", file);
82 sprintf (inodestr, "%lx", (unsigned long) sb.st_ino);
84 /* Find out if this inode is already in the hardlist, adding
85 a new entry to the list if not. */
86 hp = findnode (hardlist, inodestr);
90 hp->type = NT_UNKNOWN;
93 hp->delproc = dellist;
94 (void) addnode (hardlist, hp);
101 p = findnode (hp->data, filepath);
105 p->type = NT_UNKNOWN;
106 p->key = xstrdup (filepath);
108 (void) addnode (hp->data, p);
114 /* After a file has been checked out, add a node for it to the hardlist
115 (if necessary) and mark it as checked out. */
117 update_hardlink_info (file)
122 struct hardlink_info *hlinfo;
126 path = xstrdup (file);
130 /* file is a relative pathname; assume it's from the current
131 working directory. */
132 char *dir = xgetwd();
133 path = xmalloc (strlen(dir) + strlen(file) + 2);
134 sprintf (path, "%s/%s", dir, file);
138 n = lookup_file_by_inode (path);
141 /* Something is *really* wrong if the file doesn't exist here;
142 update_hardlink_info should be called only when a file has
143 just been checked out to a working directory. */
144 error (1, 0, "lost hardlink info for %s", file);
148 n->data = xmalloc (sizeof (struct hardlink_info));
150 hlinfo->status = T_UPTODATE;
151 hlinfo->checked_out = 1;
154 /* Return a List with all the files known to be linked to FILE in
155 the working directory. Used by special_file_mismatch, to determine
156 whether it is safe to merge two files.
158 FIXME: What is the memory allocation for the return value? We seem
159 to sometimes allocate a new list (getlist() call below) and sometimes
160 return an existing list (where we return n->data). */
162 list_linked_files_on_disk (file)
165 char *inodestr, *path;
169 /* If hardlist is NULL, we have not been doing an operation that
170 would permit us to know anything about the file's hardlinks
171 (cvs update, cvs commit, etc). Return an empty list. */
172 if (hardlist == NULL)
175 /* Get the full pathname of file (assuming the working directory) */
177 path = xstrdup (file);
180 char *dir = xgetwd();
181 path = (char *) xmalloc (strlen(dir) + strlen(file) + 2);
182 sprintf (path, "%s/%s", dir, file);
186 /* We do an extra lookup_file here just to make sure that there
187 is a node for `path' in the hardlist. If that were not so,
188 comparing the working directory linkage against the repository
189 linkage for a file would always fail. */
190 (void) lookup_file_by_inode (path);
192 if (stat (path, &sb) < 0)
193 error (1, errno, "cannot stat %s", file);
194 /* inodestr contains the hexadecimal representation of an
195 inode, so it requires two bytes of text to represent
196 each byte of the inode number. */
197 inodestr = (char *) xmalloc (2*sizeof(ino_t) + 1);
198 sprintf (inodestr, "%lx", (unsigned long) sb.st_ino);
200 /* Make sure the files linked to this inode are sorted. */
201 n = findnode (hardlist, inodestr);
202 sortlist (n->data, fsortcmp);
208 /* Compare the files in the `key' fields of two lists, returning 1 if
209 the lists are equivalent and 0 otherwise.
211 Only the basenames of each file are compared. This is an awful hack
212 that exists because list_linked_files_on_disk returns full paths
213 and the `hardlinks' structure of a RCSVers node contains only
214 basenames. That in turn is a result of the awful hack that only
215 basenames are stored in the RCS file. If anyone ever solves the
216 problem of correctly managing cross-directory hardlinks, this
217 function (along with most functions in this file) must be fixed. */
220 compare_linkage_lists (links1, links2)
227 sortlist (links1, fsortcmp);
228 sortlist (links2, fsortcmp);
230 n1 = links1->list->next;
231 n2 = links2->list->next;
233 while (n1 != links1->list && n2 != links2->list)
235 /* Get the basenames of both files. */
236 p1 = strrchr (n1->key, '/');
242 p2 = strrchr (n2->key, '/');
248 /* Compare the files' basenames. */
249 if (strcmp (p1, p2) != 0)
256 /* At this point we should be at the end of both lists; if not,
257 one file has more links than the other, and return 1. */
258 return (n1 == links1->list && n2 == links2->list);
261 /* Find a checked-out file in a list of filenames. Used by RCS_checkout
262 when checking out a new hardlinked file, to decide whether this file
263 can be linked to any others that already exist. The return value
264 is not currently used. */
267 find_checkedout_proc (node, data)
271 Node **uptodate = (Node **) data;
273 char *dir = xgetwd();
275 struct hardlink_info *hlinfo;
277 /* If we have already found a file, don't do anything. */
278 if (*uptodate != NULL)
281 /* Look at this file in the hardlist and see whether the checked_out
282 field is 1, meaning that it has been checked out during this CVS run. */
284 xmalloc (strlen (dir) + strlen (node->key) + 2);
285 sprintf (path, "%s/%s", dir, node->key);
286 link = lookup_file_by_inode (path);
292 /* We haven't seen this file -- maybe it hasn't been checked
298 if (hlinfo->checked_out)
300 /* This file has been checked out recently, so it's safe to
307 #endif /* PRESERVE_PERMISSIONS_SUPPORT */