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 "strvec.h"
8 #include "quote.h"
9 #include "object-store.h"
10
11 struct tmp_objdir {
12 struct strbuf path;
13 struct strvec env;
14 };
15
16 /*
17 * Allow only one tmp_objdir at a time in a running process, which simplifies
18 * our signal/atexit cleanup routines. It's doubtful callers will ever need
19 * more than one, and we can expand later if so. You can have many such
20 * tmp_objdirs simultaneously in many processes, of course.
21 */
22 static struct tmp_objdir *the_tmp_objdir;
23
tmp_objdir_free(struct tmp_objdir * t)24 static void tmp_objdir_free(struct tmp_objdir *t)
25 {
26 strbuf_release(&t->path);
27 strvec_clear(&t->env);
28 free(t);
29 }
30
tmp_objdir_destroy_1(struct tmp_objdir * t,int on_signal)31 static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal)
32 {
33 int err;
34
35 if (!t)
36 return 0;
37
38 if (t == the_tmp_objdir)
39 the_tmp_objdir = NULL;
40
41 /*
42 * This may use malloc via strbuf_grow(), but we should
43 * have pre-grown t->path sufficiently so that this
44 * doesn't happen in practice.
45 */
46 err = remove_dir_recursively(&t->path, 0);
47
48 /*
49 * When we are cleaning up due to a signal, we won't bother
50 * freeing memory; it may cause a deadlock if the signal
51 * arrived while libc's allocator lock is held.
52 */
53 if (!on_signal)
54 tmp_objdir_free(t);
55 return err;
56 }
57
tmp_objdir_destroy(struct tmp_objdir * t)58 int tmp_objdir_destroy(struct tmp_objdir *t)
59 {
60 return tmp_objdir_destroy_1(t, 0);
61 }
62
remove_tmp_objdir(void)63 static void remove_tmp_objdir(void)
64 {
65 tmp_objdir_destroy(the_tmp_objdir);
66 }
67
remove_tmp_objdir_on_signal(int signo)68 static void remove_tmp_objdir_on_signal(int signo)
69 {
70 tmp_objdir_destroy_1(the_tmp_objdir, 1);
71 sigchain_pop(signo);
72 raise(signo);
73 }
74
75 /*
76 * These env_* functions are for setting up the child environment; the
77 * "replace" variant overrides the value of any existing variable with that
78 * "key". The "append" variant puts our new value at the end of a list,
79 * separated by PATH_SEP (which is what separate values in
80 * GIT_ALTERNATE_OBJECT_DIRECTORIES).
81 */
env_append(struct strvec * env,const char * key,const char * val)82 static void env_append(struct strvec *env, const char *key, const char *val)
83 {
84 struct strbuf quoted = STRBUF_INIT;
85 const char *old;
86
87 /*
88 * Avoid quoting if it's not necessary, for maximum compatibility
89 * with older parsers which don't understand the quoting.
90 */
91 if (*val == '"' || strchr(val, PATH_SEP)) {
92 strbuf_addch("ed, '"');
93 quote_c_style(val, "ed, NULL, 1);
94 strbuf_addch("ed, '"');
95 val = quoted.buf;
96 }
97
98 old = getenv(key);
99 if (!old)
100 strvec_pushf(env, "%s=%s", key, val);
101 else
102 strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
103
104 strbuf_release("ed);
105 }
106
env_replace(struct strvec * env,const char * key,const char * val)107 static void env_replace(struct strvec *env, const char *key, const char *val)
108 {
109 strvec_pushf(env, "%s=%s", key, val);
110 }
111
setup_tmp_objdir(const char * root)112 static int setup_tmp_objdir(const char *root)
113 {
114 char *path;
115 int ret = 0;
116
117 path = xstrfmt("%s/pack", root);
118 ret = mkdir(path, 0777);
119 free(path);
120
121 return ret;
122 }
123
tmp_objdir_create(void)124 struct tmp_objdir *tmp_objdir_create(void)
125 {
126 static int installed_handlers;
127 struct tmp_objdir *t;
128
129 if (the_tmp_objdir)
130 BUG("only one tmp_objdir can be used at a time");
131
132 t = xmalloc(sizeof(*t));
133 strbuf_init(&t->path, 0);
134 strvec_init(&t->env);
135
136 strbuf_addf(&t->path, "%s/incoming-XXXXXX", get_object_directory());
137
138 /*
139 * Grow the strbuf beyond any filename we expect to be placed in it.
140 * If tmp_objdir_destroy() is called by a signal handler, then
141 * we should be able to use the strbuf to remove files without
142 * having to call malloc.
143 */
144 strbuf_grow(&t->path, 1024);
145
146 if (!mkdtemp(t->path.buf)) {
147 /* free, not destroy, as we never touched the filesystem */
148 tmp_objdir_free(t);
149 return NULL;
150 }
151
152 the_tmp_objdir = t;
153 if (!installed_handlers) {
154 atexit(remove_tmp_objdir);
155 sigchain_push_common(remove_tmp_objdir_on_signal);
156 installed_handlers++;
157 }
158
159 if (setup_tmp_objdir(t->path.buf)) {
160 tmp_objdir_destroy(t);
161 return NULL;
162 }
163
164 env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
165 absolute_path(get_object_directory()));
166 env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
167 env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
168 absolute_path(t->path.buf));
169
170 return t;
171 }
172
173 /*
174 * Make sure we copy packfiles and their associated metafiles in the correct
175 * order. All of these ends_with checks are slightly expensive to do in
176 * the midst of a sorting routine, but in practice it shouldn't matter.
177 * We will have a relatively small number of packfiles to order, and loose
178 * objects exit early in the first line.
179 */
pack_copy_priority(const char * name)180 static int pack_copy_priority(const char *name)
181 {
182 if (!starts_with(name, "pack"))
183 return 0;
184 if (ends_with(name, ".keep"))
185 return 1;
186 if (ends_with(name, ".pack"))
187 return 2;
188 if (ends_with(name, ".rev"))
189 return 3;
190 if (ends_with(name, ".idx"))
191 return 4;
192 return 5;
193 }
194
pack_copy_cmp(const char * a,const char * b)195 static int pack_copy_cmp(const char *a, const char *b)
196 {
197 return pack_copy_priority(a) - pack_copy_priority(b);
198 }
199
read_dir_paths(struct string_list * out,const char * path)200 static int read_dir_paths(struct string_list *out, const char *path)
201 {
202 DIR *dh;
203 struct dirent *de;
204
205 dh = opendir(path);
206 if (!dh)
207 return -1;
208
209 while ((de = readdir(dh)))
210 if (de->d_name[0] != '.')
211 string_list_append(out, de->d_name);
212
213 closedir(dh);
214 return 0;
215 }
216
217 static int migrate_paths(struct strbuf *src, struct strbuf *dst);
218
migrate_one(struct strbuf * src,struct strbuf * dst)219 static int migrate_one(struct strbuf *src, struct strbuf *dst)
220 {
221 struct stat st;
222
223 if (stat(src->buf, &st) < 0)
224 return -1;
225 if (S_ISDIR(st.st_mode)) {
226 if (!mkdir(dst->buf, 0777)) {
227 if (adjust_shared_perm(dst->buf))
228 return -1;
229 } else if (errno != EEXIST)
230 return -1;
231 return migrate_paths(src, dst);
232 }
233 return finalize_object_file(src->buf, dst->buf);
234 }
235
migrate_paths(struct strbuf * src,struct strbuf * dst)236 static int migrate_paths(struct strbuf *src, struct strbuf *dst)
237 {
238 size_t src_len = src->len, dst_len = dst->len;
239 struct string_list paths = STRING_LIST_INIT_DUP;
240 int i;
241 int ret = 0;
242
243 if (read_dir_paths(&paths, src->buf) < 0)
244 return -1;
245 paths.cmp = pack_copy_cmp;
246 string_list_sort(&paths);
247
248 for (i = 0; i < paths.nr; i++) {
249 const char *name = paths.items[i].string;
250
251 strbuf_addf(src, "/%s", name);
252 strbuf_addf(dst, "/%s", name);
253
254 ret |= migrate_one(src, dst);
255
256 strbuf_setlen(src, src_len);
257 strbuf_setlen(dst, dst_len);
258 }
259
260 string_list_clear(&paths, 0);
261 return ret;
262 }
263
tmp_objdir_migrate(struct tmp_objdir * t)264 int tmp_objdir_migrate(struct tmp_objdir *t)
265 {
266 struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
267 int ret;
268
269 if (!t)
270 return 0;
271
272 strbuf_addbuf(&src, &t->path);
273 strbuf_addstr(&dst, get_object_directory());
274
275 ret = migrate_paths(&src, &dst);
276
277 strbuf_release(&src);
278 strbuf_release(&dst);
279
280 tmp_objdir_destroy(t);
281 return ret;
282 }
283
tmp_objdir_env(const struct tmp_objdir * t)284 const char **tmp_objdir_env(const struct tmp_objdir *t)
285 {
286 if (!t)
287 return NULL;
288 return t->env.v;
289 }
290
tmp_objdir_add_as_alternate(const struct tmp_objdir * t)291 void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
292 {
293 add_to_alternates_memory(t->path.buf);
294 }
295