server-info.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6
   7 /*
   8  * Create the file "path" by writing to a temporary file and renaming
   9  * it into place. The contents of the file come from "generate", which
  10  * should return non-zero if it encounters an error.
  11  */
  12 static int update_info_file(char *path, int (*generate)(FILE *))
  13 {
  14         char *tmp = mkpathdup("%s_XXXXXX", path);
  15         int ret = -1;
  16         int fd = -1;
  17         FILE *fp = NULL, *to_close;
  18
  19         safe_create_leading_directories(path);
  20         fd = git_mkstemp_mode(tmp, 0666);
  21         if (fd < 0)
  22                 goto out;
  23         to_close = fp = fdopen(fd, "w");
  24         if (!fp)
  25                 goto out;
  26         fd = -1;
  27         ret = generate(fp);
  28         if (ret)
  29                 goto out;
  30         fp = NULL;
  31         if (fclose(to_close))
  32                 goto out;
  33         if (adjust_shared_perm(tmp) < 0)
  34                 goto out;
  35         if (rename(tmp, path) < 0)
  36                 goto out;
  37         ret = 0;
  38
  39 out:
  40         if (ret) {
  41                 error_errno("unable to update %s", path);
  42                 if (fp)
  43                         fclose(fp);
  44                 else if (fd >= 0)
  45                         close(fd);
  46                 unlink(tmp);
  47         }
  48         free(tmp);
  49         return ret;
  50 }
  51
  52 static int add_info_ref(const char *path, const struct object_id *oid,
  53                         int flag, void *cb_data)
  54 {
  55         FILE *fp = cb_data;
  56         struct object *o = parse_object(oid);
  57         if (!o)
  58                 return -1;
  59
  60         if (fprintf(fp, "%s     %s\n", oid_to_hex(oid), path) < 0)
  61                 return -1;
  62
  63         if (o->type == OBJ_TAG) {
  64                 o = deref_tag(o, path, 0);
  65                 if (o)
  66                         if (fprintf(fp, "%s     %s^{}\n",
  67                                 oid_to_hex(&o->oid), path) < 0)
  68                                 return -1;
  69         }
  70         return 0;
  71 }
  72
  73 static int generate_info_refs(FILE *fp)
  74 {
  75         return for_each_ref(add_info_ref, fp);
  76 }
  77
  78 static int update_info_refs(int force)
  79 {
  80         char *path = git_pathdup("info/refs");
  81         int ret = update_info_file(path, generate_info_refs);
  82         free(path);
  83         return ret;
  84 }
  85
  86 /* packs */
  87 static struct pack_info {
  88         struct packed_git *p;
  89         int old_num;
  90         int new_num;
  91         int nr_alloc;
  92         int nr_heads;
  93         unsigned char (*head)[20];
  94 } **info;
  95 static int num_pack;
  96 static const char *objdir;
  97 static int objdirlen;
  98
  99 static struct pack_info *find_pack_by_name(const char *name)
 100 {
 101         int i;
 102         for (i = 0; i < num_pack; i++) {
 103                 struct packed_git *p = info[i]->p;
 104                 /* skip "/pack/" after ".git/objects" */
 105                 if (!strcmp(p->pack_name + objdirlen + 6, name))
 106                         return info[i];
 107         }
 108         return NULL;
 109 }
 110
 111 /* Returns non-zero when we detect that the info in the
 112  * old file is useless.
 113  */
 114 static int parse_pack_def(const char *line, int old_cnt)
 115 {
 116         struct pack_info *i = find_pack_by_name(line + 2);
 117         if (i) {
 118                 i->old_num = old_cnt;
 119                 return 0;
 120         }
 121         else {
 122                 /* The file describes a pack that is no longer here */
 123                 return 1;
 124         }
 125 }
 126
 127 /* Returns non-zero when we detect that the info in the
 128  * old file is useless.
 129  */
 130 static int read_pack_info_file(const char *infofile)
 131 {
 132         FILE *fp;
 133         char line[1000];
 134         int old_cnt = 0;
 135
 136         fp = fopen(infofile, "r");
 137         if (!fp)
 138                 return 1; /* nonexistent is not an error. */
 139
 140         while (fgets(line, sizeof(line), fp)) {
 141                 int len = strlen(line);
 142                 if (len && line[len-1] == '\n')
 143                         line[--len] = 0;
 144
 145                 if (!len)
 146                         continue;
 147
 148                 switch (line[0]) {
 149                 case 'P': /* P name */
 150                         if (parse_pack_def(line, old_cnt++))
 151                                 goto out_stale;
 152                         break;
 153                 case 'D': /* we used to emit D but that was misguided. */
 154                 case 'T': /* we used to emit T but nobody uses it. */
 155                         goto out_stale;
 156                 default:
 157                         error("unrecognized: %s", line);
 158                         break;
 159                 }
 160         }
 161         fclose(fp);
 162         return 0;
 163  out_stale:
 164         fclose(fp);
 165         return 1;
 166 }
 167
 168 static int compare_info(const void *a_, const void *b_)
 169 {
 170         struct pack_info *const *a = a_;
 171         struct pack_info *const *b = b_;
 172
 173         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 174                 /* Keep the order in the original */
 175                 return (*a)->old_num - (*b)->old_num;
 176         else if (0 <= (*a)->old_num)
 177                 /* Only A existed in the original so B is obviously newer */
 178                 return -1;
 179         else if (0 <= (*b)->old_num)
 180                 /* The other way around. */
 181                 return 1;
 182
 183         /* then it does not matter but at least keep the comparison stable */
 184         if ((*a)->p == (*b)->p)
 185                 return 0;
 186         else if ((*a)->p < (*b)->p)
 187                 return -1;
 188         else
 189                 return 1;
 190 }
 191
 192 static void init_pack_info(const char *infofile, int force)
 193 {
 194         struct packed_git *p;
 195         int stale;
 196         int i = 0;
 197
 198         objdir = get_object_directory();
 199         objdirlen = strlen(objdir);
 200
 201         prepare_packed_git();
 202         for (p = packed_git; p; p = p->next) {
 203                 /* we ignore things on alternate path since they are
 204                  * not available to the pullers in general.
 205                  */
 206                 if (!p->pack_local)
 207                         continue;
 208                 i++;
 209         }
 210         num_pack = i;
 211         info = xcalloc(num_pack, sizeof(struct pack_info *));
 212         for (i = 0, p = packed_git; p; p = p->next) {
 213                 if (!p->pack_local)
 214                         continue;
 215                 info[i] = xcalloc(1, sizeof(struct pack_info));
 216                 info[i]->p = p;
 217                 info[i]->old_num = -1;
 218                 i++;
 219         }
 220
 221         if (infofile && !force)
 222                 stale = read_pack_info_file(infofile);
 223         else
 224                 stale = 1;
 225
 226         for (i = 0; i < num_pack; i++) {
 227                 if (stale) {
 228                         info[i]->old_num = -1;
 229                         info[i]->nr_heads = 0;
 230                 }
 231         }
 232
 233         /* renumber them */
 234         QSORT(info, num_pack, compare_info);
 235         for (i = 0; i < num_pack; i++)
 236                 info[i]->new_num = i;
 237 }
 238
 239 static void free_pack_info(void)
 240 {
 241         int i;
 242         for (i = 0; i < num_pack; i++)
 243                 free(info[i]);
 244         free(info);
 245 }
 246
 247 static int write_pack_info_file(FILE *fp)
 248 {
 249         int i;
 250         for (i = 0; i < num_pack; i++) {
 251                 if (fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6) < 0)
 252                         return -1;
 253         }
 254         if (fputc('\n', fp) == EOF)
 255                 return -1;
 256         return 0;
 257 }
 258
 259 static int update_info_packs(int force)
 260 {
 261         char *infofile = mkpathdup("%s/info/packs", get_object_directory());
 262         int ret;
 263
 264         init_pack_info(infofile, force);
 265         ret = update_info_file(infofile, write_pack_info_file);
 266         free_pack_info();
 267         free(infofile);
 268         return ret;
 269 }
 270
 271 /* public */
 272 int update_server_info(int force)
 273 {
 274         /* We would add more dumb-server support files later,
 275          * including index of available pack files and their
 276          * intended audiences.
 277          */
 278         int errs = 0;
 279
 280         errs = errs | update_info_refs(force);
 281         errs = errs | update_info_packs(force);
 282
 283         /* remove leftover rev-cache file if there is any */
 284         unlink_or_warn(git_path("info/rev-cache"));
 285
 286         return errs;
 287 }