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(the_repository, 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(the_repository, 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 } **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 *packname, int old_cnt)
 115 {
 116         struct pack_info *i = find_pack_by_name(packname);
 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         struct strbuf line = STRBUF_INIT;
 134         int old_cnt = 0;
 135         int stale = 1;
 136
 137         fp = fopen_or_warn(infofile, "r");
 138         if (!fp)
 139                 return 1; /* nonexistent is not an error. */
 140
 141         while (strbuf_getline(&line, fp) != EOF) {
 142                 const char *arg;
 143
 144                 if (!line.len)
 145                         continue;
 146
 147                 if (skip_prefix(line.buf, "P ", &arg)) {
 148                         /* P name */
 149                         if (parse_pack_def(arg, old_cnt++))
 150                                 goto out_stale;
 151                 } else if (line.buf[0] == 'D') {
 152                         /* we used to emit D but that was misguided. */
 153                         goto out_stale;
 154                 } else if (line.buf[0] == 'T') {
 155                         /* we used to emit T but nobody uses it. */
 156                         goto out_stale;
 157                 } else {
 158                         error("unrecognized: %s", line.buf);
 159                 }
 160         }
 161         stale = 0;
 162
 163  out_stale:
 164         strbuf_release(&line);
 165         fclose(fp);
 166         return stale;
 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         for (p = get_all_packs(the_repository); 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 = get_all_packs(the_repository); p; p = p->next) {
 213                 if (!p->pack_local)
 214                         continue;
 215                 assert(i < num_pack);
 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
 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 }