server-info.c

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