Make fsck reachability avoid doing unnecessary work for
[git/git.git] / fsck-cache.c
CommitLineData
20222118
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1#include "cache.h"
2
3#include <sys/types.h>
4#include <dirent.h>
5
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6/*
7 * The low 16 bits of the "flags" field shows whether
8 * a commit is part of the path to the root for that
9 * parent.
10 *
11 * Bit 16 is an internal flag that we've seen the
12 * definition for this rev, and not just seen it as
13 * a parent target.
14 */
15#define MAX_COMMITS (16)
16#define marked(rev) ((rev)->flags & 0xffff)
17#define SEEN 0x10000
18#define USED 0x20000
19#define REACHABLE 0x40000
20
21static int show_unreachable = 0;
22static int head_supplied = 0;
23static unsigned char head_sha1[20];
24
25struct parent {
26 struct revision *parent;
27 struct parent *next;
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28};
29
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30struct revision {
31 unsigned int flags;
8ba0bbb2 32 unsigned char sha1[20];
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33 unsigned long date;
34 struct parent *parent;
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35};
36
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37static struct revision **revs;
38static int nr_revs, rev_allocs;
8ba0bbb2 39
d9839e03 40static int find_rev(unsigned char *sha1)
8ba0bbb2 41{
d9839e03 42 int first = 0, last = nr_revs;
8ba0bbb2 43
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44 while (first < last) {
45 int next = (first + last) / 2;
46 struct revision *rev = revs[next];
47 int cmp;
8ba0bbb2 48
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49 cmp = memcmp(sha1, rev->sha1, 20);
50 if (!cmp)
51 return next;
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52 if (cmp < 0) {
53 last = next;
54 continue;
55 }
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56 first = next+1;
57 }
58 return -first-1;
59}
60
61static struct revision *lookup_rev(unsigned char *sha1)
62{
63 int pos = find_rev(sha1);
64 struct revision *n;
65
66 if (pos >= 0)
67 return revs[pos];
68
69 pos = -pos-1;
70
71 if (rev_allocs == nr_revs) {
72 rev_allocs = alloc_nr(rev_allocs);
73 revs = realloc(revs, rev_allocs * sizeof(struct revision *));
74 }
75 n = malloc(sizeof(struct revision));
76
77 n->flags = 0;
78 memcpy(n->sha1, sha1, 20);
79 n->parent = NULL;
80
81 /* Insert it into the right place */
82 memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
83 revs[pos] = n;
84 nr_revs++;
85
86 return n;
87}
88
89static struct revision *add_relationship(struct revision *rev, unsigned char *needs)
90{
91 struct revision *parent_rev = lookup_rev(needs);
92 struct parent **pp = &rev->parent, *p;
93
94 while ((p = *pp) != NULL) {
95 if (p->parent == parent_rev)
96 return parent_rev;
97 pp = &p->next;
98 }
99
100 p = malloc(sizeof(*p));
101 p->parent = parent_rev;
102 p->next = NULL;
103 *pp = p;
104 return parent_rev;
105}
106
107static void mark_reachable(struct revision *rev)
108{
109 struct parent *p = rev->parent;
110
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111 /* If we've been here already, don't bother */
112 if (rev->flags & REACHABLE)
113 return;
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114 rev->flags |= REACHABLE | USED;
115 while (p) {
116 mark_reachable(p->parent);
117 p = p->next;
8ba0bbb2 118 }
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119}
120
121static void check_connectivity(void)
122{
123 int i;
124
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125 if (head_supplied)
126 mark_reachable(lookup_rev(head_sha1));
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127
128 /* Look up all the requirements, warn about missing objects.. */
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129 for (i = 0; i < nr_revs; i++) {
130 struct revision *rev = revs[i];
8ba0bbb2 131
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132 if (show_unreachable && !(rev->flags & REACHABLE)) {
133 printf("unreachable %s\n", sha1_to_hex(rev->sha1));
8ba0bbb2 134 continue;
d9839e03 135 }
8ba0bbb2 136
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137 switch (rev->flags & (SEEN | USED)) {
138 case 0:
139 printf("bad %s\n", sha1_to_hex(rev->sha1));
140 break;
141 case USED:
142 printf("missing %s\n", sha1_to_hex(rev->sha1));
143 break;
144 case SEEN:
145 printf("dangling %s\n", sha1_to_hex(rev->sha1));
146 break;
147 }
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148 }
149}
150
151static void mark_needs_sha1(unsigned char *parent, const char * tag, unsigned char *child)
20222118 152{
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153 struct revision * child_rev = add_relationship(lookup_rev(parent), child);
154 child_rev->flags |= USED;
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155}
156
1ea34e36 157static int mark_sha1_seen(unsigned char *sha1, char *tag)
20222118 158{
d9839e03 159 struct revision *rev = lookup_rev(sha1);
8ba0bbb2 160
d9839e03 161 rev->flags |= SEEN;
1ea34e36 162 return 0;
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163}
164
1ea34e36 165static int fsck_tree(unsigned char *sha1, void *data, unsigned long size)
20222118 166{
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167 int warn_old_tree = 1;
168
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169 while (size) {
170 int len = 1+strlen(data);
171 unsigned char *file_sha1 = data + len;
172 char *path = strchr(data, ' ');
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173 unsigned int mode;
174 if (size < len + 20 || !path || sscanf(data, "%o", &mode) != 1)
1ea34e36 175 return -1;
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176
177 /* Warn about trees that don't do the recursive thing.. */
178 if (warn_old_tree && strchr(path, '/')) {
179 fprintf(stderr, "warning: fsck-cache: tree %s has full pathnames in it\n", sha1_to_hex(sha1));
180 warn_old_tree = 0;
181 }
182
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183 data += len + 20;
184 size -= len + 20;
f768846e 185 mark_needs_sha1(sha1, S_ISDIR(mode) ? "tree" : "blob", file_sha1);
1ea34e36 186 }
59c1e249 187 return 0;
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188}
189
190static int fsck_commit(unsigned char *sha1, void *data, unsigned long size)
191{
16d4d1ba 192 int parents;
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193 unsigned char tree_sha1[20];
194 unsigned char parent_sha1[20];
195
196 if (memcmp(data, "tree ", 5))
197 return -1;
198 if (get_sha1_hex(data + 5, tree_sha1) < 0)
199 return -1;
200 mark_needs_sha1(sha1, "tree", tree_sha1);
201 data += 5 + 40 + 1; /* "tree " + <hex sha1> + '\n' */
16d4d1ba 202 parents = 0;
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203 while (!memcmp(data, "parent ", 7)) {
204 if (get_sha1_hex(data + 7, parent_sha1) < 0)
205 return -1;
206 mark_needs_sha1(sha1, "commit", parent_sha1);
207 data += 7 + 40 + 1; /* "parent " + <hex sha1> + '\n' */
16d4d1ba 208 parents++;
1ea34e36 209 }
16d4d1ba 210 if (!parents)
d9839e03 211 printf("root %s\n", sha1_to_hex(sha1));
59c1e249 212 return 0;
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213}
214
215static int fsck_entry(unsigned char *sha1, char *tag, void *data, unsigned long size)
216{
1ea34e36 217 if (!strcmp(tag, "blob")) {
20222118 218 /* Nothing to check */;
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219 } else if (!strcmp(tag, "tree")) {
220 if (fsck_tree(sha1, data, size) < 0)
221 return -1;
222 } else if (!strcmp(tag, "commit")) {
223 if (fsck_commit(sha1, data, size) < 0)
224 return -1;
225 } else
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226 return -1;
227 return mark_sha1_seen(sha1, tag);
228}
229
230static int fsck_name(char *hex)
231{
232 unsigned char sha1[20];
233 if (!get_sha1_hex(hex, sha1)) {
234 unsigned long mapsize;
235 void *map = map_sha1_file(sha1, &mapsize);
236 if (map) {
237 char type[100];
238 unsigned long size;
239 void *buffer = NULL;
240 if (!check_sha1_signature(sha1, map, mapsize))
241 buffer = unpack_sha1_file(map, mapsize, type, &size);
242 munmap(map, mapsize);
243 if (buffer && !fsck_entry(sha1, type, buffer, size))
244 return 0;
245 }
246 }
247 return -1;
248}
249
250static int fsck_dir(int i, char *path)
251{
252 DIR *dir = opendir(path);
253 struct dirent *de;
254
255 if (!dir) {
2de381f9 256 return error("missing sha1 directory '%s'", path);
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257 }
258
259 while ((de = readdir(dir)) != NULL) {
260 char name[100];
261 int len = strlen(de->d_name);
262
263 switch (len) {
264 case 2:
265 if (de->d_name[1] != '.')
266 break;
267 case 1:
268 if (de->d_name[0] != '.')
269 break;
270 continue;
271 case 38:
272 sprintf(name, "%02x", i);
273 memcpy(name+2, de->d_name, len+1);
274 if (!fsck_name(name))
275 continue;
276 }
277 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
278 }
279 closedir(dir);
280 return 0;
281}
282
283int main(int argc, char **argv)
284{
285 int i;
286 char *sha1_dir;
287
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288 for (i = 1; i < argc; i++) {
289 if (!strcmp(argv[i], "--unreachable")) {
290 show_unreachable = 1;
291 continue;
292 }
293 if (!get_sha1_hex(argv[i], head_sha1)) {
294 head_supplied = 1;
295 continue;
296 }
297 usage("fsck-cache [[--unreachable] <head-sha1>]");
298 }
299 if (show_unreachable && !head_supplied)
300 usage("unable to do reachability checks without a head");
301
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302 sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
303 for (i = 0; i < 256; i++) {
304 static char dir[4096];
305 sprintf(dir, "%s/%02x", sha1_dir, i);
306 fsck_dir(i, dir);
307 }
8ba0bbb2 308 check_connectivity();
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LT
309 return 0;
310}