Test suite: reset TERM to its previous value after testing.
[git] / pack-write.c
1 #include "cache.h"
2 #include "pack.h"
3 #include "csum-file.h"
4
5 uint32_t pack_idx_default_version = 1;
6 uint32_t pack_idx_off32_limit = 0x7fffffff;
7
8 static int sha1_compare(const void *_a, const void *_b)
9 {
10         struct pack_idx_entry *a = *(struct pack_idx_entry **)_a;
11         struct pack_idx_entry *b = *(struct pack_idx_entry **)_b;
12         return hashcmp(a->sha1, b->sha1);
13 }
14
15 /*
16  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
17  * the SHA1 hash of sorted object names. The objects array passed in
18  * will be sorted by SHA1 on exit.
19  */
20 const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, unsigned char *sha1)
21 {
22         struct sha1file *f;
23         struct pack_idx_entry **sorted_by_sha, **list, **last;
24         off_t last_obj_offset = 0;
25         uint32_t array[256];
26         int i, fd;
27         SHA_CTX ctx;
28         uint32_t index_version;
29
30         if (nr_objects) {
31                 sorted_by_sha = objects;
32                 list = sorted_by_sha;
33                 last = sorted_by_sha + nr_objects;
34                 for (i = 0; i < nr_objects; ++i) {
35                         if (objects[i]->offset > last_obj_offset)
36                                 last_obj_offset = objects[i]->offset;
37                 }
38                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
39                       sha1_compare);
40         }
41         else
42                 sorted_by_sha = list = last = NULL;
43
44         if (!index_name) {
45                 static char tmpfile[PATH_MAX];
46                 snprintf(tmpfile, sizeof(tmpfile),
47                          "%s/tmp_idx_XXXXXX", get_object_directory());
48                 fd = xmkstemp(tmpfile);
49                 index_name = xstrdup(tmpfile);
50         } else {
51                 unlink(index_name);
52                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
53         }
54         if (fd < 0)
55                 die("unable to create %s: %s", index_name, strerror(errno));
56         f = sha1fd(fd, index_name);
57
58         /* if last object's offset is >= 2^31 we should use index V2 */
59         index_version = (last_obj_offset >> 31) ? 2 : pack_idx_default_version;
60
61         /* index versions 2 and above need a header */
62         if (index_version >= 2) {
63                 struct pack_idx_header hdr;
64                 hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
65                 hdr.idx_version = htonl(index_version);
66                 sha1write(f, &hdr, sizeof(hdr));
67         }
68
69         /*
70          * Write the first-level table (the list is sorted,
71          * but we use a 256-entry lookup to be able to avoid
72          * having to do eight extra binary search iterations).
73          */
74         for (i = 0; i < 256; i++) {
75                 struct pack_idx_entry **next = list;
76                 while (next < last) {
77                         struct pack_idx_entry *obj = *next;
78                         if (obj->sha1[0] != i)
79                                 break;
80                         next++;
81                 }
82                 array[i] = htonl(next - sorted_by_sha);
83                 list = next;
84         }
85         sha1write(f, array, 256 * 4);
86
87         /* compute the SHA1 hash of sorted object names. */
88         SHA1_Init(&ctx);
89
90         /*
91          * Write the actual SHA1 entries..
92          */
93         list = sorted_by_sha;
94         for (i = 0; i < nr_objects; i++) {
95                 struct pack_idx_entry *obj = *list++;
96                 if (index_version < 2) {
97                         uint32_t offset = htonl(obj->offset);
98                         sha1write(f, &offset, 4);
99                 }
100                 sha1write(f, obj->sha1, 20);
101                 SHA1_Update(&ctx, obj->sha1, 20);
102         }
103
104         if (index_version >= 2) {
105                 unsigned int nr_large_offset = 0;
106
107                 /* write the crc32 table */
108                 list = sorted_by_sha;
109                 for (i = 0; i < nr_objects; i++) {
110                         struct pack_idx_entry *obj = *list++;
111                         uint32_t crc32_val = htonl(obj->crc32);
112                         sha1write(f, &crc32_val, 4);
113                 }
114
115                 /* write the 32-bit offset table */
116                 list = sorted_by_sha;
117                 for (i = 0; i < nr_objects; i++) {
118                         struct pack_idx_entry *obj = *list++;
119                         uint32_t offset = (obj->offset <= pack_idx_off32_limit) ?
120                                 obj->offset : (0x80000000 | nr_large_offset++);
121                         offset = htonl(offset);
122                         sha1write(f, &offset, 4);
123                 }
124
125                 /* write the large offset table */
126                 list = sorted_by_sha;
127                 while (nr_large_offset) {
128                         struct pack_idx_entry *obj = *list++;
129                         uint64_t offset = obj->offset;
130                         if (offset > pack_idx_off32_limit) {
131                                 uint32_t split[2];
132                                 split[0] = htonl(offset >> 32);
133                                 split[1] = htonl(offset & 0xffffffff);
134                                 sha1write(f, split, 8);
135                                 nr_large_offset--;
136                         }
137                 }
138         }
139
140         sha1write(f, sha1, 20);
141         sha1close(f, NULL, 1);
142         SHA1_Final(sha1, &ctx);
143         return index_name;
144 }
145
146 void fixup_pack_header_footer(int pack_fd,
147                          unsigned char *pack_file_sha1,
148                          const char *pack_name,
149                          uint32_t object_count)
150 {
151         static const int buf_sz = 128 * 1024;
152         SHA_CTX c;
153         struct pack_header hdr;
154         char *buf;
155
156         if (lseek(pack_fd, 0, SEEK_SET) != 0)
157                 die("Failed seeking to start: %s", strerror(errno));
158         if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
159                 die("Unable to reread header of %s: %s", pack_name, strerror(errno));
160         if (lseek(pack_fd, 0, SEEK_SET) != 0)
161                 die("Failed seeking to start: %s", strerror(errno));
162         hdr.hdr_entries = htonl(object_count);
163         write_or_die(pack_fd, &hdr, sizeof(hdr));
164
165         SHA1_Init(&c);
166         SHA1_Update(&c, &hdr, sizeof(hdr));
167
168         buf = xmalloc(buf_sz);
169         for (;;) {
170                 ssize_t n = xread(pack_fd, buf, buf_sz);
171                 if (!n)
172                         break;
173                 if (n < 0)
174                         die("Failed to checksum %s: %s", pack_name, strerror(errno));
175                 SHA1_Update(&c, buf, n);
176         }
177         free(buf);
178
179         SHA1_Final(pack_file_sha1, &c);
180         write_or_die(pack_fd, pack_file_sha1, 20);
181 }
182
183 char *index_pack_lockfile(int ip_out)
184 {
185         int len, s;
186         char packname[46];
187
188         /*
189          * The first thing we expects from index-pack's output
190          * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
191          * %40s is the newly created pack SHA1 name.  In the "keep"
192          * case, we need it to remove the corresponding .keep file
193          * later on.  If we don't get that then tough luck with it.
194          */
195         for (len = 0;
196                  len < 46 && (s = xread(ip_out, packname+len, 46-len)) > 0;
197                  len += s);
198         if (len == 46 && packname[45] == '\n' &&
199                 memcmp(packname, "keep\t", 5) == 0) {
200                 char path[PATH_MAX];
201                 packname[45] = 0;
202                 snprintf(path, sizeof(path), "%s/pack/pack-%s.keep",
203                          get_object_directory(), packname + 5);
204                 return xstrdup(path);
205         }
206         return NULL;
207 }