server-info.c

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