Implemented support for restoring hardlinks in chpathtool.

svn path=/main/branches/prefix/; revision=9142

diff --git a/src/chpathtool.c b/src/chpathtool.c
index 0aa07c38193429a8ed804d25397f43498fbf18c0..d7af4bfd2d29fe0f71e73e69cd90c1774802b042 100644 (file)
--- a/src/chpathtool.c
+++ b/src/chpathtool.c
@@ -38,11 +38,19 @@
  * value, hoping it is enough */
 #define MAX_PATH 1024
 
+typedef struct _file_hlink {
+       dev_t    st_dev;            /* device inode resides on */
+       ino_t    st_ino;            /* inode's number */
+       char     path[MAX_PATH];    /* the file's path + name */
+       struct _file_hlink* next;   /* pointer to the next in the list */
+} file_hlink;
+
 static char *magic;
 static char *value;
 static size_t magiclen;
 static size_t valuelen;
 static char quiet;
+static file_hlink *hlinks = NULL;
 
 /**
  * Writes padding zero-bytes after the first encountered zero-byte.
@@ -238,8 +246,46 @@ int dirwalk(char *src, char *srcp, char *trg, char *trgp) {
                                S_ISREG(s.st_mode)
                                )
                {
-                       /* FIXME: handle hard links! (keep track of files with >1
-                        * refs, match those with a list of known files with count >1 */
+                       /* handle hard links, match each of them to a list of known
+                        * files (with st_nlink > 1), such that we only process each
+                        * file once, and are able to restore the hard link. */
+                       if (s.st_nlink > 1) {
+                               if (hlinks == NULL) {
+                                       hlinks = malloc(sizeof(file_hlink));
+                                       hlinks->st_dev = s.st_dev;
+                                       hlinks->st_ino = s.st_ino;
+                                       strcpy(hlinks->path, src);
+                                       hlinks->next = NULL;
+                               } else {
+                                       /* look for this file */
+                                       file_hlink *hl = NULL;
+                                       do {
+                                               hl = (hl == NULL ? hlinks : hl->next);
+                                               if (hl->st_dev == s.st_dev && hl->st_ino == s.st_ino) {
+                                                       /* this is the same file, make a hard link */
+                                                       if (link(hl->path, trg) != 0) {
+                                                               fprintf(stderr, "failed to create hard link "
+                                                                               "%s: %s\n", trg, strerror(errno));
+                                                               return(-1);
+                                                       }
+                                                       hl = NULL;
+                                                       break;
+                                               }
+                                       } while (hl->next != NULL);
+                                       /* we didn't know this one yet, add it */
+                                       if (hl != NULL) {
+                                               hl = hl->next = malloc(sizeof(file_hlink));
+                                               hl->st_dev = s.st_dev;
+                                               hl->st_ino = s.st_ino;
+                                               strcpy(hl->path, src);
+                                               hl->next = NULL;
+                                       } else {
+                                               /* don't "copy" the file, we already made a hard
+                                                * link to it */
+                                               continue;
+                                       }
+                               }
+                       }
 
                        /* copy */
                        if (chpath(src, trg) != 0) {