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