repository: introduce raw object store field
[git/git.git] / tmp-objdir.c
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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"
aae2ae4f 8#include "quote.h"
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9
10struct tmp_objdir {
11 struct strbuf path;
12 struct argv_array env;
13};
14
15/*
16 * Allow only one tmp_objdir at a time in a running process, which simplifies
17 * our signal/atexit cleanup routines. It's doubtful callers will ever need
18 * more than one, and we can expand later if so. You can have many such
19 * tmp_objdirs simultaneously in many processes, of course.
20 */
21static struct tmp_objdir *the_tmp_objdir;
22
23static void tmp_objdir_free(struct tmp_objdir *t)
24{
25 strbuf_release(&t->path);
26 argv_array_clear(&t->env);
27 free(t);
28}
29
30static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal)
31{
32 int err;
33
34 if (!t)
35 return 0;
36
37 if (t == the_tmp_objdir)
38 the_tmp_objdir = NULL;
39
40 /*
41 * This may use malloc via strbuf_grow(), but we should
42 * have pre-grown t->path sufficiently so that this
43 * doesn't happen in practice.
44 */
45 err = remove_dir_recursively(&t->path, 0);
46
47 /*
48 * When we are cleaning up due to a signal, we won't bother
49 * freeing memory; it may cause a deadlock if the signal
50 * arrived while libc's allocator lock is held.
51 */
52 if (!on_signal)
53 tmp_objdir_free(t);
54 return err;
55}
56
57int tmp_objdir_destroy(struct tmp_objdir *t)
58{
59 return tmp_objdir_destroy_1(t, 0);
60}
61
62static void remove_tmp_objdir(void)
63{
64 tmp_objdir_destroy(the_tmp_objdir);
65}
66
67static void remove_tmp_objdir_on_signal(int signo)
68{
69 tmp_objdir_destroy_1(the_tmp_objdir, 1);
70 sigchain_pop(signo);
71 raise(signo);
72}
73
74/*
75 * These env_* functions are for setting up the child environment; the
76 * "replace" variant overrides the value of any existing variable with that
77 * "key". The "append" variant puts our new value at the end of a list,
78 * separated by PATH_SEP (which is what separate values in
79 * GIT_ALTERNATE_OBJECT_DIRECTORIES).
80 */
81static void env_append(struct argv_array *env, const char *key, const char *val)
82{
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83 struct strbuf quoted = STRBUF_INIT;
84 const char *old;
2564d994 85
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86 /*
87 * Avoid quoting if it's not necessary, for maximum compatibility
88 * with older parsers which don't understand the quoting.
89 */
90 if (*val == '"' || strchr(val, PATH_SEP)) {
91 strbuf_addch(&quoted, '"');
92 quote_c_style(val, &quoted, NULL, 1);
93 strbuf_addch(&quoted, '"');
94 val = quoted.buf;
95 }
96
97 old = getenv(key);
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98 if (!old)
99 argv_array_pushf(env, "%s=%s", key, val);
100 else
101 argv_array_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
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102
103 strbuf_release(&quoted);
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104}
105
106static void env_replace(struct argv_array *env, const char *key, const char *val)
107{
108 argv_array_pushf(env, "%s=%s", key, val);
109}
110
111static int setup_tmp_objdir(const char *root)
112{
113 char *path;
114 int ret = 0;
115
116 path = xstrfmt("%s/pack", root);
117 ret = mkdir(path, 0777);
118 free(path);
119
120 return ret;
121}
122
123struct tmp_objdir *tmp_objdir_create(void)
124{
125 static int installed_handlers;
126 struct tmp_objdir *t;
127
128 if (the_tmp_objdir)
129 die("BUG: only one tmp_objdir can be used at a time");
130
131 t = xmalloc(sizeof(*t));
132 strbuf_init(&t->path, 0);
133 argv_array_init(&t->env);
134
135 strbuf_addf(&t->path, "%s/incoming-XXXXXX", get_object_directory());
136
137 /*
138 * Grow the strbuf beyond any filename we expect to be placed in it.
139 * If tmp_objdir_destroy() is called by a signal handler, then
140 * we should be able to use the strbuf to remove files without
141 * having to call malloc.
142 */
143 strbuf_grow(&t->path, 1024);
144
145 if (!mkdtemp(t->path.buf)) {
146 /* free, not destroy, as we never touched the filesystem */
147 tmp_objdir_free(t);
148 return NULL;
149 }
150
151 the_tmp_objdir = t;
152 if (!installed_handlers) {
153 atexit(remove_tmp_objdir);
154 sigchain_push_common(remove_tmp_objdir_on_signal);
155 installed_handlers++;
156 }
157
158 if (setup_tmp_objdir(t->path.buf)) {
159 tmp_objdir_destroy(t);
160 return NULL;
161 }
162
163 env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
164 absolute_path(get_object_directory()));
165 env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
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166 env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
167 absolute_path(t->path.buf));
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168
169 return t;
170}
171
172/*
173 * Make sure we copy packfiles and their associated metafiles in the correct
174 * order. All of these ends_with checks are slightly expensive to do in
175 * the midst of a sorting routine, but in practice it shouldn't matter.
176 * We will have a relatively small number of packfiles to order, and loose
177 * objects exit early in the first line.
178 */
179static int pack_copy_priority(const char *name)
180{
181 if (!starts_with(name, "pack"))
182 return 0;
183 if (ends_with(name, ".keep"))
184 return 1;
185 if (ends_with(name, ".pack"))
186 return 2;
187 if (ends_with(name, ".idx"))
188 return 3;
189 return 4;
190}
191
192static int pack_copy_cmp(const char *a, const char *b)
193{
194 return pack_copy_priority(a) - pack_copy_priority(b);
195}
196
197static int read_dir_paths(struct string_list *out, const char *path)
198{
199 DIR *dh;
200 struct dirent *de;
201
202 dh = opendir(path);
203 if (!dh)
204 return -1;
205
206 while ((de = readdir(dh)))
62fe0eb4 207 if (de->d_name[0] != '.')
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208 string_list_append(out, de->d_name);
209
210 closedir(dh);
211 return 0;
212}
213
214static int migrate_paths(struct strbuf *src, struct strbuf *dst);
215
216static int migrate_one(struct strbuf *src, struct strbuf *dst)
217{
218 struct stat st;
219
220 if (stat(src->buf, &st) < 0)
221 return -1;
222 if (S_ISDIR(st.st_mode)) {
223 if (!mkdir(dst->buf, 0777)) {
224 if (adjust_shared_perm(dst->buf))
225 return -1;
226 } else if (errno != EEXIST)
227 return -1;
228 return migrate_paths(src, dst);
229 }
230 return finalize_object_file(src->buf, dst->buf);
231}
232
233static int migrate_paths(struct strbuf *src, struct strbuf *dst)
234{
235 size_t src_len = src->len, dst_len = dst->len;
236 struct string_list paths = STRING_LIST_INIT_DUP;
237 int i;
238 int ret = 0;
239
240 if (read_dir_paths(&paths, src->buf) < 0)
241 return -1;
242 paths.cmp = pack_copy_cmp;
243 string_list_sort(&paths);
244
245 for (i = 0; i < paths.nr; i++) {
246 const char *name = paths.items[i].string;
247
248 strbuf_addf(src, "/%s", name);
249 strbuf_addf(dst, "/%s", name);
250
251 ret |= migrate_one(src, dst);
252
253 strbuf_setlen(src, src_len);
254 strbuf_setlen(dst, dst_len);
255 }
256
257 string_list_clear(&paths, 0);
258 return ret;
259}
260
261int tmp_objdir_migrate(struct tmp_objdir *t)
262{
263 struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
264 int ret;
265
266 if (!t)
267 return 0;
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
281const char **tmp_objdir_env(const struct tmp_objdir *t)
282{
283 if (!t)
284 return NULL;
285 return t->env.argv;
286}
287
288void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
289{
290 add_to_alternates_memory(t->path.buf);
291}