fsck-cache.c

   1 #include "cache.h"
   2
   3 #include <sys/types.h>
   4 #include <dirent.h>
   5
   6 /*
   7  * The low 16 bits of the "flags" field shows whether
   8  * a commit is part of the path to the root for that
   9  * parent.
  10  *
  11  * Bit 16 is an internal flag that we've seen the
  12  * definition for this rev, and not just seen it as
  13  * a parent target.
  14  */
  15 #define MAX_COMMITS (16)
  16 #define marked(rev)     ((rev)->flags & 0xffff)
  17 #define SEEN 0x10000
  18 #define USED 0x20000
  19 #define REACHABLE 0x40000
  20
  21 static int show_unreachable = 0;
  22 static int head_supplied = 0;
  23 static unsigned char head_sha1[20];
  24
  25 struct parent {
  26         struct revision *parent;
  27         struct parent *next;
  28 };
  29
  30 struct revision {
  31         unsigned int flags;
  32         unsigned char sha1[20];
  33         unsigned long date;
  34         struct parent *parent;
  35 };
  36
  37 static struct revision **revs;
  38 static int nr_revs, rev_allocs;
  39
  40 static int find_rev(unsigned char *sha1)
  41 {
  42         int first = 0, last = nr_revs;
  43
  44         while (first < last) {
  45                 int next = (first + last) / 2;
  46                 struct revision *rev = revs[next];
  47                 int cmp;
  48
  49                 cmp = memcmp(sha1, rev->sha1, 20);
  50                 if (!cmp)
  51                         return next;
  52                 if (cmp < 0) {
  53                         last = next;
  54                         continue;
  55                 }
  56                 first = next+1;
  57         }
  58         return -first-1;
  59 }
  60
  61 static struct revision *lookup_rev(unsigned char *sha1)
  62 {
  63         int pos = find_rev(sha1);
  64         struct revision *n;
  65
  66         if (pos >= 0)
  67                 return revs[pos];
  68
  69         pos = -pos-1;
  70
  71         if (rev_allocs == nr_revs) {
  72                 rev_allocs = alloc_nr(rev_allocs);
  73                 revs = realloc(revs, rev_allocs * sizeof(struct revision *));
  74         }
  75         n = malloc(sizeof(struct revision));
  76
  77         n->flags = 0;
  78         memcpy(n->sha1, sha1, 20);
  79         n->parent = NULL;
  80
  81         /* Insert it into the right place */
  82         memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
  83         revs[pos] = n;
  84         nr_revs++;
  85
  86         return n;
  87 }
  88
  89 static struct revision *add_relationship(struct revision *rev, unsigned char *needs)
  90 {
  91         struct revision *parent_rev = lookup_rev(needs);
  92         struct parent **pp = &rev->parent, *p;
  93
  94         while ((p = *pp) != NULL) {
  95                 if (p->parent == parent_rev)
  96                         return parent_rev;
  97                 pp = &p->next;
  98         }
  99
 100         p = malloc(sizeof(*p));
 101         p->parent = parent_rev;
 102         p->next = NULL;
 103         *pp = p;
 104         return parent_rev;
 105 }
 106
 107 static void mark_reachable(struct revision *rev)
 108 {
 109         struct parent *p = rev->parent;
 110
 111         /* If we've been here already, don't bother */
 112         if (rev->flags & REACHABLE)
 113                 return;
 114         rev->flags |= REACHABLE | USED;
 115         while (p) {
 116                 mark_reachable(p->parent);
 117                 p = p->next;
 118         }
 119 }
 120
 121 static void check_connectivity(void)
 122 {
 123         int i;
 124
 125         if (head_supplied)
 126                 mark_reachable(lookup_rev(head_sha1));
 127
 128         /* Look up all the requirements, warn about missing objects.. */
 129         for (i = 0; i < nr_revs; i++) {
 130                 struct revision *rev = revs[i];
 131
 132                 if (show_unreachable && !(rev->flags & REACHABLE)) {
 133                         printf("unreachable %s\n", sha1_to_hex(rev->sha1));
 134                         continue;
 135                 }
 136
 137                 switch (rev->flags & (SEEN | USED)) {
 138                 case 0:
 139                         printf("bad %s\n", sha1_to_hex(rev->sha1));
 140                         break;
 141                 case USED:
 142                         printf("missing %s\n", sha1_to_hex(rev->sha1));
 143                         break;
 144                 case SEEN:
 145                         printf("dangling %s\n", sha1_to_hex(rev->sha1));
 146                         break;
 147                 }
 148         }
 149 }
 150
 151 static void mark_needs_sha1(unsigned char *parent, const char * tag, unsigned char *child)
 152 {
 153         struct revision * child_rev = add_relationship(lookup_rev(parent), child);
 154         child_rev->flags |= USED;
 155 }
 156
 157 static int mark_sha1_seen(unsigned char *sha1, char *tag)
 158 {
 159         struct revision *rev = lookup_rev(sha1);
 160
 161         rev->flags |= SEEN;
 162         return 0;
 163 }
 164
 165 static int fsck_tree(unsigned char *sha1, void *data, unsigned long size)
 166 {
 167         int warn_old_tree = 1;
 168
 169         while (size) {
 170                 int len = 1+strlen(data);
 171                 unsigned char *file_sha1 = data + len;
 172                 char *path = strchr(data, ' ');
 173                 unsigned int mode;
 174                 if (size < len + 20 || !path || sscanf(data, "%o", &mode) != 1)
 175                         return -1;
 176
 177                 /* Warn about trees that don't do the recursive thing.. */
 178                 if (warn_old_tree && strchr(path, '/')) {
 179                         fprintf(stderr, "warning: fsck-cache: tree %s has full pathnames in it\n", sha1_to_hex(sha1));
 180                         warn_old_tree = 0;
 181                 }
 182
 183                 data += len + 20;
 184                 size -= len + 20;
 185                 mark_needs_sha1(sha1, S_ISDIR(mode) ? "tree" : "blob", file_sha1);
 186         }
 187         return 0;
 188 }
 189
 190 static int fsck_commit(unsigned char *sha1, void *data, unsigned long size)
 191 {
 192         int parents;
 193         unsigned char tree_sha1[20];
 194         unsigned char parent_sha1[20];
 195
 196         if (memcmp(data, "tree ", 5))
 197                 return -1;
 198         if (get_sha1_hex(data + 5, tree_sha1) < 0)
 199                 return -1;
 200         mark_needs_sha1(sha1, "tree", tree_sha1);
 201         data += 5 + 40 + 1;     /* "tree " + <hex sha1> + '\n' */
 202         parents = 0;
 203         while (!memcmp(data, "parent ", 7)) {
 204                 if (get_sha1_hex(data + 7, parent_sha1) < 0)
 205                         return -1;
 206                 mark_needs_sha1(sha1, "commit", parent_sha1);
 207                 data += 7 + 40 + 1;     /* "parent " + <hex sha1> + '\n' */
 208                 parents++;
 209         }
 210         if (!parents)
 211                 printf("root %s\n", sha1_to_hex(sha1));
 212         return 0;
 213 }
 214
 215 static int fsck_entry(unsigned char *sha1, char *tag, void *data, unsigned long size)
 216 {
 217         if (!strcmp(tag, "blob")) {
 218                 /* Nothing to check */;
 219         } else if (!strcmp(tag, "tree")) {
 220                 if (fsck_tree(sha1, data, size) < 0)
 221                         return -1;
 222         } else if (!strcmp(tag, "commit")) {
 223                 if (fsck_commit(sha1, data, size) < 0)
 224                         return -1;
 225         } else
 226                 return -1;
 227         return mark_sha1_seen(sha1, tag);
 228 }
 229
 230 static int fsck_name(char *hex)
 231 {
 232         unsigned char sha1[20];
 233         if (!get_sha1_hex(hex, sha1)) {
 234                 unsigned long mapsize;
 235                 void *map = map_sha1_file(sha1, &mapsize);
 236                 if (map) {
 237                         char type[100];
 238                         unsigned long size;
 239                         void *buffer = NULL;
 240                         if (!check_sha1_signature(sha1, map, mapsize))
 241                                 buffer = unpack_sha1_file(map, mapsize, type, &size);
 242                         munmap(map, mapsize);
 243                         if (buffer && !fsck_entry(sha1, type, buffer, size))
 244                                 return 0;
 245                 }
 246         }
 247         return -1;
 248 }
 249
 250 static int fsck_dir(int i, char *path)
 251 {
 252         DIR *dir = opendir(path);
 253         struct dirent *de;
 254
 255         if (!dir) {
 256                 return error("missing sha1 directory '%s'", path);
 257         }
 258
 259         while ((de = readdir(dir)) != NULL) {
 260                 char name[100];
 261                 int len = strlen(de->d_name);
 262
 263                 switch (len) {
 264                 case 2:
 265                         if (de->d_name[1] != '.')
 266                                 break;
 267                 case 1:
 268                         if (de->d_name[0] != '.')
 269                                 break;
 270                         continue;
 271                 case 38:
 272                         sprintf(name, "%02x", i);
 273                         memcpy(name+2, de->d_name, len+1);
 274                         if (!fsck_name(name))
 275                                 continue;
 276                 }
 277                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 278         }
 279         closedir(dir);
 280         return 0;
 281 }
 282
 283 int main(int argc, char **argv)
 284 {
 285         int i;
 286         char *sha1_dir;
 287
 288         for (i = 1; i < argc; i++) {
 289                 if (!strcmp(argv[i], "--unreachable")) {
 290                         show_unreachable = 1;
 291                         continue;
 292                 }
 293                 if (!get_sha1_hex(argv[i], head_sha1)) {
 294                         head_supplied = 1;
 295                         continue;
 296                 }
 297                 usage("fsck-cache [[--unreachable] <head-sha1>]");
 298         }
 299         if (show_unreachable && !head_supplied)
 300                 usage("unable to do reachability checks without a head");
 301
 302         sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
 303         for (i = 0; i < 256; i++) {
 304                 static char dir[4096];
 305                 sprintf(dir, "%s/%02x", sha1_dir, i);
 306                 fsck_dir(i, dir);
 307         }
 308         check_connectivity();
 309         return 0;
 310 }