tmp-objdir.con commit Merge branch 'da/difftool-dir-diff-fix' into da/t7800-cleanup (a83c2d2)
   1#include "cache.h"
   2#include "tmp-objdir.h"
   3#include "dir.h"
   4#include "sigchain.h"
   5#include "string-list.h"
   6#include "strbuf.h"
   7#include "argv-array.h"
   8
   9struct tmp_objdir {
  10        struct strbuf path;
  11        struct argv_array env;
  12};
  13
  14/*
  15 * Allow only one tmp_objdir at a time in a running process, which simplifies
  16 * our signal/atexit cleanup routines.  It's doubtful callers will ever need
  17 * more than one, and we can expand later if so.  You can have many such
  18 * tmp_objdirs simultaneously in many processes, of course.
  19 */
  20static struct tmp_objdir *the_tmp_objdir;
  21
  22static void tmp_objdir_free(struct tmp_objdir *t)
  23{
  24        strbuf_release(&t->path);
  25        argv_array_clear(&t->env);
  26        free(t);
  27}
  28
  29static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal)
  30{
  31        int err;
  32
  33        if (!t)
  34                return 0;
  35
  36        if (t == the_tmp_objdir)
  37                the_tmp_objdir = NULL;
  38
  39        /*
  40         * This may use malloc via strbuf_grow(), but we should
  41         * have pre-grown t->path sufficiently so that this
  42         * doesn't happen in practice.
  43         */
  44        err = remove_dir_recursively(&t->path, 0);
  45
  46        /*
  47         * When we are cleaning up due to a signal, we won't bother
  48         * freeing memory; it may cause a deadlock if the signal
  49         * arrived while libc's allocator lock is held.
  50         */
  51        if (!on_signal)
  52                tmp_objdir_free(t);
  53        return err;
  54}
  55
  56int tmp_objdir_destroy(struct tmp_objdir *t)
  57{
  58        return tmp_objdir_destroy_1(t, 0);
  59}
  60
  61static void remove_tmp_objdir(void)
  62{
  63        tmp_objdir_destroy(the_tmp_objdir);
  64}
  65
  66static void remove_tmp_objdir_on_signal(int signo)
  67{
  68        tmp_objdir_destroy_1(the_tmp_objdir, 1);
  69        sigchain_pop(signo);
  70        raise(signo);
  71}
  72
  73/*
  74 * These env_* functions are for setting up the child environment; the
  75 * "replace" variant overrides the value of any existing variable with that
  76 * "key". The "append" variant puts our new value at the end of a list,
  77 * separated by PATH_SEP (which is what separate values in
  78 * GIT_ALTERNATE_OBJECT_DIRECTORIES).
  79 */
  80static void env_append(struct argv_array *env, const char *key, const char *val)
  81{
  82        const char *old = getenv(key);
  83
  84        if (!old)
  85                argv_array_pushf(env, "%s=%s", key, val);
  86        else
  87                argv_array_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
  88}
  89
  90static void env_replace(struct argv_array *env, const char *key, const char *val)
  91{
  92        argv_array_pushf(env, "%s=%s", key, val);
  93}
  94
  95static int setup_tmp_objdir(const char *root)
  96{
  97        char *path;
  98        int ret = 0;
  99
 100        path = xstrfmt("%s/pack", root);
 101        ret = mkdir(path, 0777);
 102        free(path);
 103
 104        return ret;
 105}
 106
 107struct tmp_objdir *tmp_objdir_create(void)
 108{
 109        static int installed_handlers;
 110        struct tmp_objdir *t;
 111
 112        if (the_tmp_objdir)
 113                die("BUG: only one tmp_objdir can be used at a time");
 114
 115        t = xmalloc(sizeof(*t));
 116        strbuf_init(&t->path, 0);
 117        argv_array_init(&t->env);
 118
 119        strbuf_addf(&t->path, "%s/incoming-XXXXXX", get_object_directory());
 120
 121        /*
 122         * Grow the strbuf beyond any filename we expect to be placed in it.
 123         * If tmp_objdir_destroy() is called by a signal handler, then
 124         * we should be able to use the strbuf to remove files without
 125         * having to call malloc.
 126         */
 127        strbuf_grow(&t->path, 1024);
 128
 129        if (!mkdtemp(t->path.buf)) {
 130                /* free, not destroy, as we never touched the filesystem */
 131                tmp_objdir_free(t);
 132                return NULL;
 133        }
 134
 135        the_tmp_objdir = t;
 136        if (!installed_handlers) {
 137                atexit(remove_tmp_objdir);
 138                sigchain_push_common(remove_tmp_objdir_on_signal);
 139                installed_handlers++;
 140        }
 141
 142        if (setup_tmp_objdir(t->path.buf)) {
 143                tmp_objdir_destroy(t);
 144                return NULL;
 145        }
 146
 147        env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
 148                   absolute_path(get_object_directory()));
 149        env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
 150        env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
 151                    absolute_path(t->path.buf));
 152
 153        return t;
 154}
 155
 156/*
 157 * Make sure we copy packfiles and their associated metafiles in the correct
 158 * order. All of these ends_with checks are slightly expensive to do in
 159 * the midst of a sorting routine, but in practice it shouldn't matter.
 160 * We will have a relatively small number of packfiles to order, and loose
 161 * objects exit early in the first line.
 162 */
 163static int pack_copy_priority(const char *name)
 164{
 165        if (!starts_with(name, "pack"))
 166                return 0;
 167        if (ends_with(name, ".keep"))
 168                return 1;
 169        if (ends_with(name, ".pack"))
 170                return 2;
 171        if (ends_with(name, ".idx"))
 172                return 3;
 173        return 4;
 174}
 175
 176static int pack_copy_cmp(const char *a, const char *b)
 177{
 178        return pack_copy_priority(a) - pack_copy_priority(b);
 179}
 180
 181static int read_dir_paths(struct string_list *out, const char *path)
 182{
 183        DIR *dh;
 184        struct dirent *de;
 185
 186        dh = opendir(path);
 187        if (!dh)
 188                return -1;
 189
 190        while ((de = readdir(dh)))
 191                if (de->d_name[0] != '.')
 192                        string_list_append(out, de->d_name);
 193
 194        closedir(dh);
 195        return 0;
 196}
 197
 198static int migrate_paths(struct strbuf *src, struct strbuf *dst);
 199
 200static int migrate_one(struct strbuf *src, struct strbuf *dst)
 201{
 202        struct stat st;
 203
 204        if (stat(src->buf, &st) < 0)
 205                return -1;
 206        if (S_ISDIR(st.st_mode)) {
 207                if (!mkdir(dst->buf, 0777)) {
 208                        if (adjust_shared_perm(dst->buf))
 209                                return -1;
 210                } else if (errno != EEXIST)
 211                        return -1;
 212                return migrate_paths(src, dst);
 213        }
 214        return finalize_object_file(src->buf, dst->buf);
 215}
 216
 217static int migrate_paths(struct strbuf *src, struct strbuf *dst)
 218{
 219        size_t src_len = src->len, dst_len = dst->len;
 220        struct string_list paths = STRING_LIST_INIT_DUP;
 221        int i;
 222        int ret = 0;
 223
 224        if (read_dir_paths(&paths, src->buf) < 0)
 225                return -1;
 226        paths.cmp = pack_copy_cmp;
 227        string_list_sort(&paths);
 228
 229        for (i = 0; i < paths.nr; i++) {
 230                const char *name = paths.items[i].string;
 231
 232                strbuf_addf(src, "/%s", name);
 233                strbuf_addf(dst, "/%s", name);
 234
 235                ret |= migrate_one(src, dst);
 236
 237                strbuf_setlen(src, src_len);
 238                strbuf_setlen(dst, dst_len);
 239        }
 240
 241        string_list_clear(&paths, 0);
 242        return ret;
 243}
 244
 245int tmp_objdir_migrate(struct tmp_objdir *t)
 246{
 247        struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
 248        int ret;
 249
 250        if (!t)
 251                return 0;
 252
 253        strbuf_addbuf(&src, &t->path);
 254        strbuf_addstr(&dst, get_object_directory());
 255
 256        ret = migrate_paths(&src, &dst);
 257
 258        strbuf_release(&src);
 259        strbuf_release(&dst);
 260
 261        tmp_objdir_destroy(t);
 262        return ret;
 263}
 264
 265const char **tmp_objdir_env(const struct tmp_objdir *t)
 266{
 267        if (!t)
 268                return NULL;
 269        return t->env.argv;
 270}
 271
 272void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
 273{
 274        add_to_alternates_memory(t->path.buf);
 275}