tmp-objdir.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2
   3 #include "git-compat-util.h"
   4 #include "tmp-objdir.h"
   5 #include "abspath.h"
   6 #include "chdir-notify.h"
   7 #include "dir.h"
   8 #include "environment.h"
   9 #include "object-file.h"
  10 #include "path.h"
  11 #include "string-list.h"
  12 #include "strbuf.h"
  13 #include "strvec.h"
  14 #include "quote.h"
  15 #include "object-store-ll.h"
  16
  17 struct tmp_objdir {
  18         struct strbuf path;
  19         struct strvec env;
  20         struct object_directory *prev_odb;
  21         int will_destroy;
  22 };
  23
  24 /*
  25  * Allow only one tmp_objdir at a time in a running process, which simplifies
  26  * our atexit cleanup routines.  It's doubtful callers will ever need
  27  * more than one, and we can expand later if so.  You can have many such
  28  * tmp_objdirs simultaneously in many processes, of course.
  29  */
  30 static struct tmp_objdir *the_tmp_objdir;
  31
  32 static void tmp_objdir_free(struct tmp_objdir *t)
  33 {
  34         strbuf_release(&t->path);
  35         strvec_clear(&t->env);
  36         free(t);
  37 }
  38
  39 int tmp_objdir_destroy(struct tmp_objdir *t)
  40 {
  41         int err;
  42
  43         if (!t)
  44                 return 0;
  45
  46         if (t == the_tmp_objdir)
  47                 the_tmp_objdir = NULL;
  48
  49         if (t->prev_odb)
  50                 restore_primary_odb(t->prev_odb, t->path.buf);
  51
  52         err = remove_dir_recursively(&t->path, 0);
  53
  54         tmp_objdir_free(t);
  55
  56         return err;
  57 }
  58
  59 static void remove_tmp_objdir(void)
  60 {
  61         tmp_objdir_destroy(the_tmp_objdir);
  62 }
  63
  64 void tmp_objdir_discard_objects(struct tmp_objdir *t)
  65 {
  66         remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL);
  67 }
  68
  69 /*
  70  * These env_* functions are for setting up the child environment; the
  71  * "replace" variant overrides the value of any existing variable with that
  72  * "key". The "append" variant puts our new value at the end of a list,
  73  * separated by PATH_SEP (which is what separate values in
  74  * GIT_ALTERNATE_OBJECT_DIRECTORIES).
  75  */
  76 static void env_append(struct strvec *env, const char *key, const char *val)
  77 {
  78         struct strbuf quoted = STRBUF_INIT;
  79         const char *old;
  80
  81         /*
  82          * Avoid quoting if it's not necessary, for maximum compatibility
  83          * with older parsers which don't understand the quoting.
  84          */
  85         if (*val == '"' || strchr(val, PATH_SEP)) {
  86                 strbuf_addch(&quoted, '"');
  87                 quote_c_style(val, &quoted, NULL, 1);
  88                 strbuf_addch(&quoted, '"');
  89                 val = quoted.buf;
  90         }
  91
  92         old = getenv(key);
  93         if (!old)
  94                 strvec_pushf(env, "%s=%s", key, val);
  95         else
  96                 strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
  97
  98         strbuf_release(&quoted);
  99 }
 100
 101 static void env_replace(struct strvec *env, const char *key, const char *val)
 102 {
 103         strvec_pushf(env, "%s=%s", key, val);
 104 }
 105
 106 static int setup_tmp_objdir(const char *root)
 107 {
 108         char *path;
 109         int ret = 0;
 110
 111         path = xstrfmt("%s/pack", root);
 112         ret = mkdir(path, 0777);
 113         free(path);
 114
 115         return ret;
 116 }
 117
 118 struct tmp_objdir *tmp_objdir_create(const char *prefix)
 119 {
 120         static int installed_handlers;
 121         struct tmp_objdir *t;
 122
 123         if (the_tmp_objdir)
 124                 BUG("only one tmp_objdir can be used at a time");
 125
 126         t = xcalloc(1, sizeof(*t));
 127         strbuf_init(&t->path, 0);
 128         strvec_init(&t->env);
 129
 130         /*
 131          * Use a string starting with tmp_ so that the builtin/prune.c code
 132          * can recognize any stale objdirs left behind by a crash and delete
 133          * them.
 134          */
 135         strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX", get_object_directory(), prefix);
 136
 137         if (!mkdtemp(t->path.buf)) {
 138                 /* free, not destroy, as we never touched the filesystem */
 139                 tmp_objdir_free(t);
 140                 return NULL;
 141         }
 142
 143         the_tmp_objdir = t;
 144         if (!installed_handlers) {
 145                 atexit(remove_tmp_objdir);
 146                 installed_handlers++;
 147         }
 148
 149         if (setup_tmp_objdir(t->path.buf)) {
 150                 tmp_objdir_destroy(t);
 151                 return NULL;
 152         }
 153
 154         env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
 155                    absolute_path(get_object_directory()));
 156         env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
 157         env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
 158                     absolute_path(t->path.buf));
 159
 160         return t;
 161 }
 162
 163 /*
 164  * Make sure we copy packfiles and their associated metafiles in the correct
 165  * order. All of these ends_with checks are slightly expensive to do in
 166  * the midst of a sorting routine, but in practice it shouldn't matter.
 167  * We will have a relatively small number of packfiles to order, and loose
 168  * objects exit early in the first line.
 169  */
 170 static int pack_copy_priority(const char *name)
 171 {
 172         if (!starts_with(name, "pack"))
 173                 return 0;
 174         if (ends_with(name, ".keep"))
 175                 return 1;
 176         if (ends_with(name, ".pack"))
 177                 return 2;
 178         if (ends_with(name, ".rev"))
 179                 return 3;
 180         if (ends_with(name, ".idx"))
 181                 return 4;
 182         return 5;
 183 }
 184
 185 static int pack_copy_cmp(const char *a, const char *b)
 186 {
 187         return pack_copy_priority(a) - pack_copy_priority(b);
 188 }
 189
 190 static int read_dir_paths(struct string_list *out, const char *path)
 191 {
 192         DIR *dh;
 193         struct dirent *de;
 194
 195         dh = opendir(path);
 196         if (!dh)
 197                 return -1;
 198
 199         while ((de = readdir(dh)))
 200                 if (de->d_name[0] != '.')
 201                         string_list_append(out, de->d_name);
 202
 203         closedir(dh);
 204         return 0;
 205 }
 206
 207 static int migrate_paths(struct strbuf *src, struct strbuf *dst);
 208
 209 static int migrate_one(struct strbuf *src, struct strbuf *dst)
 210 {
 211         struct stat st;
 212
 213         if (stat(src->buf, &st) < 0)
 214                 return -1;
 215         if (S_ISDIR(st.st_mode)) {
 216                 if (!mkdir(dst->buf, 0777)) {
 217                         if (adjust_shared_perm(dst->buf))
 218                                 return -1;
 219                 } else if (errno != EEXIST)
 220                         return -1;
 221                 return migrate_paths(src, dst);
 222         }
 223         return finalize_object_file(src->buf, dst->buf);
 224 }
 225
 226 static int migrate_paths(struct strbuf *src, struct strbuf *dst)
 227 {
 228         size_t src_len = src->len, dst_len = dst->len;
 229         struct string_list paths = STRING_LIST_INIT_DUP;
 230         int i;
 231         int ret = 0;
 232
 233         if (read_dir_paths(&paths, src->buf) < 0)
 234                 return -1;
 235         paths.cmp = pack_copy_cmp;
 236         string_list_sort(&paths);
 237
 238         for (i = 0; i < paths.nr; i++) {
 239                 const char *name = paths.items[i].string;
 240
 241                 strbuf_addf(src, "/%s", name);
 242                 strbuf_addf(dst, "/%s", name);
 243
 244                 ret |= migrate_one(src, dst);
 245
 246                 strbuf_setlen(src, src_len);
 247                 strbuf_setlen(dst, dst_len);
 248         }
 249
 250         string_list_clear(&paths, 0);
 251         return ret;
 252 }
 253
 254 int tmp_objdir_migrate(struct tmp_objdir *t)
 255 {
 256         struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
 257         int ret;
 258
 259         if (!t)
 260                 return 0;
 261
 262         if (t->prev_odb) {
 263                 if (the_repository->objects->odb->will_destroy)
 264                         BUG("migrating an ODB that was marked for destruction");
 265                 restore_primary_odb(t->prev_odb, t->path.buf);
 266                 t->prev_odb = NULL;
 267         }
 268
 269         strbuf_addbuf(&src, &t->path);
 270         strbuf_addstr(&dst, get_object_directory());
 271
 272         ret = migrate_paths(&src, &dst);
 273
 274         strbuf_release(&src);
 275         strbuf_release(&dst);
 276
 277         tmp_objdir_destroy(t);
 278         return ret;
 279 }
 280
 281 const char **tmp_objdir_env(const struct tmp_objdir *t)
 282 {
 283         if (!t)
 284                 return NULL;
 285         return t->env.v;
 286 }
 287
 288 void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
 289 {
 290         add_to_alternates_memory(t->path.buf);
 291 }
 292
 293 void tmp_objdir_replace_primary_odb(struct tmp_objdir *t, int will_destroy)
 294 {
 295         if (t->prev_odb)
 296                 BUG("the primary object database is already replaced");
 297         t->prev_odb = set_temporary_primary_odb(t->path.buf, will_destroy);
 298         t->will_destroy = will_destroy;
 299 }
 300
 301 struct tmp_objdir *tmp_objdir_unapply_primary_odb(void)
 302 {
 303         if (!the_tmp_objdir || !the_tmp_objdir->prev_odb)
 304                 return NULL;
 305
 306         restore_primary_odb(the_tmp_objdir->prev_odb, the_tmp_objdir->path.buf);
 307         the_tmp_objdir->prev_odb = NULL;
 308         return the_tmp_objdir;
 309 }
 310
 311 void tmp_objdir_reapply_primary_odb(struct tmp_objdir *t, const char *old_cwd,
 312                 const char *new_cwd)
 313 {
 314         char *path;
 315
 316         path = reparent_relative_path(old_cwd, new_cwd, t->path.buf);
 317         strbuf_reset(&t->path);
 318         strbuf_addstr(&t->path, path);
 319         free(path);
 320         tmp_objdir_replace_primary_odb(t, t->will_destroy);
 321 }