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;
  18
  19         safe_create_leading_directories(path);
  20         fd = git_mkstemp_mode(tmp, 0666);
  21         if (fd < 0)
  22                 goto out;
  23         fp = fdopen(fd, "w");
  24         if (!fp)
  25                 goto out;
  26         ret = generate(fp);
  27         if (ret)
  28                 goto out;
  29         if (fclose(fp))
  30                 goto out;
  31         if (adjust_shared_perm(tmp) < 0)
  32                 goto out;
  33         if (rename(tmp, path) < 0)
  34                 goto out;
  35         ret = 0;
  36
  37 out:
  38         if (ret) {
  39                 error_errno("unable to update %s", path);
  40                 if (fp)
  41                         fclose(fp);
  42                 else if (fd >= 0)
  43                         close(fd);
  44                 unlink(tmp);
  45         }
  46         free(tmp);
  47         return ret;
  48 }
  49
  50 static int add_info_ref(const char *path, const struct object_id *oid,
  51                         int flag, void *cb_data)
  52 {
  53         FILE *fp = cb_data;
  54         struct object *o = parse_object(oid->hash);
  55         if (!o)
  56                 return -1;
  57
  58         if (fprintf(fp, "%s     %s\n", oid_to_hex(oid), path) < 0)
  59                 return -1;
  60
  61         if (o->type == OBJ_TAG) {
  62                 o = deref_tag(o, path, 0);
  63                 if (o)
  64                         if (fprintf(fp, "%s     %s^{}\n",
  65                                 oid_to_hex(&o->oid), path) < 0)
  66                                 return -1;
  67         }
  68         return 0;
  69 }
  70
  71 static int generate_info_refs(FILE *fp)
  72 {
  73         return for_each_ref(add_info_ref, fp);
  74 }
  75
  76 static int update_info_refs(int force)
  77 {
  78         char *path = git_pathdup("info/refs");
  79         int ret = update_info_file(path, generate_info_refs);
  80         free(path);
  81         return ret;
  82 }
  83
  84 /* packs */
  85 static struct pack_info {
  86         struct packed_git *p;
  87         int old_num;
  88         int new_num;
  89         int nr_alloc;
  90         int nr_heads;
  91         unsigned char (*head)[20];
  92 } **info;
  93 static int num_pack;
  94 static const char *objdir;
  95 static int objdirlen;
  96
  97 static struct pack_info *find_pack_by_name(const char *name)
  98 {
  99         int i;
 100         for (i = 0; i < num_pack; i++) {
 101                 struct packed_git *p = info[i]->p;
 102                 /* skip "/pack/" after ".git/objects" */
 103                 if (!strcmp(p->pack_name + objdirlen + 6, 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 *line, int old_cnt)
 113 {
 114         struct pack_info *i = find_pack_by_name(line + 2);
 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         char line[1000];
 132         int old_cnt = 0;
 133
 134         fp = fopen(infofile, "r");
 135         if (!fp)
 136                 return 1; /* nonexistent is not an error. */
 137
 138         while (fgets(line, sizeof(line), fp)) {
 139                 int len = strlen(line);
 140                 if (len && line[len-1] == '\n')
 141                         line[--len] = 0;
 142
 143                 if (!len)
 144                         continue;
 145
 146                 switch (line[0]) {
 147                 case 'P': /* P name */
 148                         if (parse_pack_def(line, old_cnt++))
 149                                 goto out_stale;
 150                         break;
 151                 case 'D': /* we used to emit D but that was misguided. */
 152                 case 'T': /* we used to emit T but nobody uses it. */
 153                         goto out_stale;
 154                 default:
 155                         error("unrecognized: %s", line);
 156                         break;
 157                 }
 158         }
 159         fclose(fp);
 160         return 0;
 161  out_stale:
 162         fclose(fp);
 163         return 1;
 164 }
 165
 166 static int compare_info(const void *a_, const void *b_)
 167 {
 168         struct pack_info *const *a = a_;
 169         struct pack_info *const *b = b_;
 170
 171         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 172                 /* Keep the order in the original */
 173                 return (*a)->old_num - (*b)->old_num;
 174         else if (0 <= (*a)->old_num)
 175                 /* Only A existed in the original so B is obviously newer */
 176                 return -1;
 177         else if (0 <= (*b)->old_num)
 178                 /* The other way around. */
 179                 return 1;
 180
 181         /* then it does not matter but at least keep the comparison stable */
 182         if ((*a)->p == (*b)->p)
 183                 return 0;
 184         else if ((*a)->p < (*b)->p)
 185                 return -1;
 186         else
 187                 return 1;
 188 }
 189
 190 static void init_pack_info(const char *infofile, int force)
 191 {
 192         struct packed_git *p;
 193         int stale;
 194         int i = 0;
 195
 196         objdir = get_object_directory();
 197         objdirlen = strlen(objdir);
 198
 199         prepare_packed_git();
 200         for (p = packed_git; p; p = p->next) {
 201                 /* we ignore things on alternate path since they are
 202                  * not available to the pullers in general.
 203                  */
 204                 if (!p->pack_local)
 205                         continue;
 206                 i++;
 207         }
 208         num_pack = i;
 209         info = xcalloc(num_pack, sizeof(struct pack_info *));
 210         for (i = 0, p = packed_git; p; p = p->next) {
 211                 if (!p->pack_local)
 212                         continue;
 213                 info[i] = xcalloc(1, sizeof(struct pack_info));
 214                 info[i]->p = p;
 215                 info[i]->old_num = -1;
 216                 i++;
 217         }
 218
 219         if (infofile && !force)
 220                 stale = read_pack_info_file(infofile);
 221         else
 222                 stale = 1;
 223
 224         for (i = 0; i < num_pack; i++) {
 225                 if (stale) {
 226                         info[i]->old_num = -1;
 227                         info[i]->nr_heads = 0;
 228                 }
 229         }
 230
 231         /* renumber them */
 232         QSORT(info, num_pack, compare_info);
 233         for (i = 0; i < num_pack; i++)
 234                 info[i]->new_num = i;
 235 }
 236
 237 static void free_pack_info(void)
 238 {
 239         int i;
 240         for (i = 0; i < num_pack; i++)
 241                 free(info[i]);
 242         free(info);
 243 }
 244
 245 static int write_pack_info_file(FILE *fp)
 246 {
 247         int i;
 248         for (i = 0; i < num_pack; i++) {
 249                 if (fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6) < 0)
 250                         return -1;
 251         }
 252         if (fputc('\n', fp) == EOF)
 253                 return -1;
 254         return 0;
 255 }
 256
 257 static int update_info_packs(int force)
 258 {
 259         char *infofile = mkpathdup("%s/info/packs", get_object_directory());
 260         int ret;
 261
 262         init_pack_info(infofile, force);
 263         ret = update_info_file(infofile, write_pack_info_file);
 264         free_pack_info();
 265         free(infofile);
 266         return ret;
 267 }
 268
 269 /* public */
 270 int update_server_info(int force)
 271 {
 272         /* We would add more dumb-server support files later,
 273          * including index of available pack files and their
 274          * intended audiences.
 275          */
 276         int errs = 0;
 277
 278         errs = errs | update_info_refs(force);
 279         errs = errs | update_info_packs(force);
 280
 281         /* remove leftover rev-cache file if there is any */
 282         unlink_or_warn(git_path("info/rev-cache"));
 283
 284         return errs;
 285 }