server-info.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "refs.h"
   4 #include "object.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "packfile.h"
   8 #include "object-store.h"
   9
  10 /*
  11  * Create the file "path" by writing to a temporary file and renaming
  12  * it into place. The contents of the file come from "generate", which
  13  * should return non-zero if it encounters an error.
  14  */
  15 static int update_info_file(char *path, int (*generate)(FILE *))
  16 {
  17         char *tmp = mkpathdup("%s_XXXXXX", path);
  18         int ret = -1;
  19         int fd = -1;
  20         FILE *fp = NULL, *to_close;
  21
  22         safe_create_leading_directories(path);
  23         fd = git_mkstemp_mode(tmp, 0666);
  24         if (fd < 0)
  25                 goto out;
  26         to_close = fp = fdopen(fd, "w");
  27         if (!fp)
  28                 goto out;
  29         fd = -1;
  30         ret = generate(fp);
  31         if (ret)
  32                 goto out;
  33         fp = NULL;
  34         if (fclose(to_close))
  35                 goto out;
  36         if (adjust_shared_perm(tmp) < 0)
  37                 goto out;
  38         if (rename(tmp, path) < 0)
  39                 goto out;
  40         ret = 0;
  41
  42 out:
  43         if (ret) {
  44                 error_errno("unable to update %s", path);
  45                 if (fp)
  46                         fclose(fp);
  47                 else if (fd >= 0)
  48                         close(fd);
  49                 unlink(tmp);
  50         }
  51         free(tmp);
  52         return ret;
  53 }
  54
  55 static int add_info_ref(const char *path, const struct object_id *oid,
  56                         int flag, void *cb_data)
  57 {
  58         FILE *fp = cb_data;
  59         struct object *o = parse_object(oid);
  60         if (!o)
  61                 return -1;
  62
  63         if (fprintf(fp, "%s     %s\n", oid_to_hex(oid), path) < 0)
  64                 return -1;
  65
  66         if (o->type == OBJ_TAG) {
  67                 o = deref_tag(o, path, 0);
  68                 if (o)
  69                         if (fprintf(fp, "%s     %s^{}\n",
  70                                 oid_to_hex(&o->oid), path) < 0)
  71                                 return -1;
  72         }
  73         return 0;
  74 }
  75
  76 static int generate_info_refs(FILE *fp)
  77 {
  78         return for_each_ref(add_info_ref, fp);
  79 }
  80
  81 static int update_info_refs(int force)
  82 {
  83         char *path = git_pathdup("info/refs");
  84         int ret = update_info_file(path, generate_info_refs);
  85         free(path);
  86         return ret;
  87 }
  88
  89 /* packs */
  90 static struct pack_info {
  91         struct packed_git *p;
  92         int old_num;
  93         int new_num;
  94         int nr_alloc;
  95         int nr_heads;
  96         unsigned char (*head)[20];
  97 } **info;
  98 static int num_pack;
  99 static const char *objdir;
 100 static int objdirlen;
 101
 102 static struct pack_info *find_pack_by_name(const char *name)
 103 {
 104         int i;
 105         for (i = 0; i < num_pack; i++) {
 106                 struct packed_git *p = info[i]->p;
 107                 /* skip "/pack/" after ".git/objects" */
 108                 if (!strcmp(p->pack_name + objdirlen + 6, name))
 109                         return info[i];
 110         }
 111         return NULL;
 112 }
 113
 114 /* Returns non-zero when we detect that the info in the
 115  * old file is useless.
 116  */
 117 static int parse_pack_def(const char *line, int old_cnt)
 118 {
 119         struct pack_info *i = find_pack_by_name(line + 2);
 120         if (i) {
 121                 i->old_num = old_cnt;
 122                 return 0;
 123         }
 124         else {
 125                 /* The file describes a pack that is no longer here */
 126                 return 1;
 127         }
 128 }
 129
 130 /* Returns non-zero when we detect that the info in the
 131  * old file is useless.
 132  */
 133 static int read_pack_info_file(const char *infofile)
 134 {
 135         FILE *fp;
 136         char line[1000];
 137         int old_cnt = 0;
 138
 139         fp = fopen_or_warn(infofile, "r");
 140         if (!fp)
 141                 return 1; /* nonexistent is not an error. */
 142
 143         while (fgets(line, sizeof(line), fp)) {
 144                 int len = strlen(line);
 145                 if (len && line[len-1] == '\n')
 146                         line[--len] = 0;
 147
 148                 if (!len)
 149                         continue;
 150
 151                 switch (line[0]) {
 152                 case 'P': /* P name */
 153                         if (parse_pack_def(line, old_cnt++))
 154                                 goto out_stale;
 155                         break;
 156                 case 'D': /* we used to emit D but that was misguided. */
 157                 case 'T': /* we used to emit T but nobody uses it. */
 158                         goto out_stale;
 159                 default:
 160                         error("unrecognized: %s", line);
 161                         break;
 162                 }
 163         }
 164         fclose(fp);
 165         return 0;
 166  out_stale:
 167         fclose(fp);
 168         return 1;
 169 }
 170
 171 static int compare_info(const void *a_, const void *b_)
 172 {
 173         struct pack_info *const *a = a_;
 174         struct pack_info *const *b = b_;
 175
 176         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 177                 /* Keep the order in the original */
 178                 return (*a)->old_num - (*b)->old_num;
 179         else if (0 <= (*a)->old_num)
 180                 /* Only A existed in the original so B is obviously newer */
 181                 return -1;
 182         else if (0 <= (*b)->old_num)
 183                 /* The other way around. */
 184                 return 1;
 185
 186         /* then it does not matter but at least keep the comparison stable */
 187         if ((*a)->p == (*b)->p)
 188                 return 0;
 189         else if ((*a)->p < (*b)->p)
 190                 return -1;
 191         else
 192                 return 1;
 193 }
 194
 195 static void init_pack_info(const char *infofile, int force)
 196 {
 197         struct packed_git *p;
 198         int stale;
 199         int i = 0;
 200
 201         objdir = get_object_directory();
 202         objdirlen = strlen(objdir);
 203
 204         prepare_packed_git();
 205         for (p = get_packed_git(the_repository); p; p = p->next) {
 206                 /* we ignore things on alternate path since they are
 207                  * not available to the pullers in general.
 208                  */
 209                 if (!p->pack_local)
 210                         continue;
 211                 i++;
 212         }
 213         num_pack = i;
 214         info = xcalloc(num_pack, sizeof(struct pack_info *));
 215         for (i = 0, p = get_packed_git(the_repository); p; p = p->next) {
 216                 if (!p->pack_local)
 217                         continue;
 218                 info[i] = xcalloc(1, sizeof(struct pack_info));
 219                 info[i]->p = p;
 220                 info[i]->old_num = -1;
 221                 i++;
 222         }
 223
 224         if (infofile && !force)
 225                 stale = read_pack_info_file(infofile);
 226         else
 227                 stale = 1;
 228
 229         for (i = 0; i < num_pack; i++) {
 230                 if (stale) {
 231                         info[i]->old_num = -1;
 232                         info[i]->nr_heads = 0;
 233                 }
 234         }
 235
 236         /* renumber them */
 237         QSORT(info, num_pack, compare_info);
 238         for (i = 0; i < num_pack; i++)
 239                 info[i]->new_num = i;
 240 }
 241
 242 static void free_pack_info(void)
 243 {
 244         int i;
 245         for (i = 0; i < num_pack; i++)
 246                 free(info[i]);
 247         free(info);
 248 }
 249
 250 static int write_pack_info_file(FILE *fp)
 251 {
 252         int i;
 253         for (i = 0; i < num_pack; i++) {
 254                 if (fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6) < 0)
 255                         return -1;
 256         }
 257         if (fputc('\n', fp) == EOF)
 258                 return -1;
 259         return 0;
 260 }
 261
 262 static int update_info_packs(int force)
 263 {
 264         char *infofile = mkpathdup("%s/info/packs", get_object_directory());
 265         int ret;
 266
 267         init_pack_info(infofile, force);
 268         ret = update_info_file(infofile, write_pack_info_file);
 269         free_pack_info();
 270         free(infofile);
 271         return ret;
 272 }
 273
 274 /* public */
 275 int update_server_info(int force)
 276 {
 277         /* We would add more dumb-server support files later,
 278          * including index of available pack files and their
 279          * intended audiences.
 280          */
 281         int errs = 0;
 282
 283         errs = errs | update_info_refs(force);
 284         errs = errs | update_info_packs(force);
 285
 286         /* remove leftover rev-cache file if there is any */
 287         unlink_or_warn(git_path("info/rev-cache"));
 288
 289         return errs;
 290 }