diff options
Diffstat (limited to 'sha1_file.c')
-rw-r--r-- | sha1_file.c | 2440 |
1 files changed, 2440 insertions, 0 deletions
diff --git a/sha1_file.c b/sha1_file.c new file mode 100644 index 0000000000..66a4e00fa8 --- /dev/null +++ b/sha1_file.c @@ -0,0 +1,2440 @@ +/* + * GIT - The information manager from hell + * + * Copyright (C) Linus Torvalds, 2005 + * + * This handles basic git sha1 object files - packing, unpacking, + * creation etc. + */ +#include "cache.h" +#include "delta.h" +#include "pack.h" +#include "blob.h" +#include "commit.h" +#include "tag.h" +#include "tree.h" +#include "refs.h" + +#ifndef O_NOATIME +#if defined(__linux__) && (defined(__i386__) || defined(__PPC__)) +#define O_NOATIME 01000000 +#else +#define O_NOATIME 0 +#endif +#endif + +#ifdef NO_C99_FORMAT +#define SZ_FMT "lu" +static unsigned long sz_fmt(size_t s) { return (unsigned long)s; } +#else +#define SZ_FMT "zu" +static size_t sz_fmt(size_t s) { return s; } +#endif + +const unsigned char null_sha1[20]; + +static unsigned int sha1_file_open_flag = O_NOATIME; + +const signed char hexval_table[256] = { + -1, -1, -1, -1, -1, -1, -1, -1, /* 00-07 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 08-0f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 10-17 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 18-1f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 20-27 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 28-2f */ + 0, 1, 2, 3, 4, 5, 6, 7, /* 30-37 */ + 8, 9, -1, -1, -1, -1, -1, -1, /* 38-3f */ + -1, 10, 11, 12, 13, 14, 15, -1, /* 40-47 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 48-4f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 50-57 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 58-5f */ + -1, 10, 11, 12, 13, 14, 15, -1, /* 60-67 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 68-67 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 70-77 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 78-7f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 80-87 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 88-8f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 90-97 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* 98-9f */ + -1, -1, -1, -1, -1, -1, -1, -1, /* a0-a7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* a8-af */ + -1, -1, -1, -1, -1, -1, -1, -1, /* b0-b7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* b8-bf */ + -1, -1, -1, -1, -1, -1, -1, -1, /* c0-c7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* c8-cf */ + -1, -1, -1, -1, -1, -1, -1, -1, /* d0-d7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* d8-df */ + -1, -1, -1, -1, -1, -1, -1, -1, /* e0-e7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* e8-ef */ + -1, -1, -1, -1, -1, -1, -1, -1, /* f0-f7 */ + -1, -1, -1, -1, -1, -1, -1, -1, /* f8-ff */ +}; + +int get_sha1_hex(const char *hex, unsigned char *sha1) +{ + int i; + for (i = 0; i < 20; i++) { + unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]); + if (val & ~0xff) + return -1; + *sha1++ = val; + hex += 2; + } + return 0; +} + +int safe_create_leading_directories(char *path) +{ + char *pos = path; + struct stat st; + + if (is_absolute_path(path)) + pos++; + + while (pos) { + pos = strchr(pos, '/'); + if (!pos) + break; + *pos = 0; + if (!stat(path, &st)) { + /* path exists */ + if (!S_ISDIR(st.st_mode)) { + *pos = '/'; + return -3; + } + } + else if (mkdir(path, 0777)) { + *pos = '/'; + return -1; + } + else if (adjust_shared_perm(path)) { + *pos = '/'; + return -2; + } + *pos++ = '/'; + } + return 0; +} + +char * sha1_to_hex(const unsigned char *sha1) +{ + static int bufno; + static char hexbuffer[4][50]; + static const char hex[] = "0123456789abcdef"; + char *buffer = hexbuffer[3 & ++bufno], *buf = buffer; + int i; + + for (i = 0; i < 20; i++) { + unsigned int val = *sha1++; + *buf++ = hex[val >> 4]; + *buf++ = hex[val & 0xf]; + } + *buf = '\0'; + + return buffer; +} + +static void fill_sha1_path(char *pathbuf, const unsigned char *sha1) +{ + int i; + for (i = 0; i < 20; i++) { + static char hex[] = "0123456789abcdef"; + unsigned int val = sha1[i]; + char *pos = pathbuf + i*2 + (i > 0); + *pos++ = hex[val >> 4]; + *pos = hex[val & 0xf]; + } +} + +/* + * NOTE! This returns a statically allocated buffer, so you have to be + * careful about using it. Do an "xstrdup()" if you need to save the + * filename. + * + * Also note that this returns the location for creating. Reading + * SHA1 file can happen from any alternate directory listed in the + * DB_ENVIRONMENT environment variable if it is not found in + * the primary object database. + */ +char *sha1_file_name(const unsigned char *sha1) +{ + static char *name, *base; + + if (!base) { + const char *sha1_file_directory = get_object_directory(); + int len = strlen(sha1_file_directory); + base = xmalloc(len + 60); + memcpy(base, sha1_file_directory, len); + memset(base+len, 0, 60); + base[len] = '/'; + base[len+3] = '/'; + name = base + len + 1; + } + fill_sha1_path(name, sha1); + return base; +} + +char *sha1_pack_name(const unsigned char *sha1) +{ + static const char hex[] = "0123456789abcdef"; + static char *name, *base, *buf; + int i; + + if (!base) { + const char *sha1_file_directory = get_object_directory(); + int len = strlen(sha1_file_directory); + base = xmalloc(len + 60); + sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory); + name = base + len + 11; + } + + buf = name; + + for (i = 0; i < 20; i++) { + unsigned int val = *sha1++; + *buf++ = hex[val >> 4]; + *buf++ = hex[val & 0xf]; + } + + return base; +} + +char *sha1_pack_index_name(const unsigned char *sha1) +{ + static const char hex[] = "0123456789abcdef"; + static char *name, *base, *buf; + int i; + + if (!base) { + const char *sha1_file_directory = get_object_directory(); + int len = strlen(sha1_file_directory); + base = xmalloc(len + 60); + sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory); + name = base + len + 11; + } + + buf = name; + + for (i = 0; i < 20; i++) { + unsigned int val = *sha1++; + *buf++ = hex[val >> 4]; + *buf++ = hex[val & 0xf]; + } + + return base; +} + +struct alternate_object_database *alt_odb_list; +static struct alternate_object_database **alt_odb_tail; + +static void read_info_alternates(const char * alternates, int depth); + +/* + * Prepare alternate object database registry. + * + * The variable alt_odb_list points at the list of struct + * alternate_object_database. The elements on this list come from + * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT + * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates, + * whose contents is similar to that environment variable but can be + * LF separated. Its base points at a statically allocated buffer that + * contains "/the/directory/corresponding/to/.git/objects/...", while + * its name points just after the slash at the end of ".git/objects/" + * in the example above, and has enough space to hold 40-byte hex + * SHA1, an extra slash for the first level indirection, and the + * terminating NUL. + */ +static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth) +{ + struct stat st; + const char *objdir = get_object_directory(); + struct alternate_object_database *ent; + struct alternate_object_database *alt; + /* 43 = 40-byte + 2 '/' + terminating NUL */ + int pfxlen = len; + int entlen = pfxlen + 43; + int base_len = -1; + + if (!is_absolute_path(entry) && relative_base) { + /* Relative alt-odb */ + if (base_len < 0) + base_len = strlen(relative_base) + 1; + entlen += base_len; + pfxlen += base_len; + } + ent = xmalloc(sizeof(*ent) + entlen); + + if (!is_absolute_path(entry) && relative_base) { + memcpy(ent->base, relative_base, base_len - 1); + ent->base[base_len - 1] = '/'; + memcpy(ent->base + base_len, entry, len); + } + else + memcpy(ent->base, entry, pfxlen); + + ent->name = ent->base + pfxlen + 1; + ent->base[pfxlen + 3] = '/'; + ent->base[pfxlen] = ent->base[entlen-1] = 0; + + /* Detect cases where alternate disappeared */ + if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) { + error("object directory %s does not exist; " + "check .git/objects/info/alternates.", + ent->base); + free(ent); + return -1; + } + + /* Prevent the common mistake of listing the same + * thing twice, or object directory itself. + */ + for (alt = alt_odb_list; alt; alt = alt->next) { + if (!memcmp(ent->base, alt->base, pfxlen)) { + free(ent); + return -1; + } + } + if (!memcmp(ent->base, objdir, pfxlen)) { + free(ent); + return -1; + } + + /* add the alternate entry */ + *alt_odb_tail = ent; + alt_odb_tail = &(ent->next); + ent->next = NULL; + + /* recursively add alternates */ + read_info_alternates(ent->base, depth + 1); + + ent->base[pfxlen] = '/'; + + return 0; +} + +static void link_alt_odb_entries(const char *alt, const char *ep, int sep, + const char *relative_base, int depth) +{ + const char *cp, *last; + + if (depth > 5) { + error("%s: ignoring alternate object stores, nesting too deep.", + relative_base); + return; + } + + last = alt; + while (last < ep) { + cp = last; + if (cp < ep && *cp == '#') { + while (cp < ep && *cp != sep) + cp++; + last = cp + 1; + continue; + } + while (cp < ep && *cp != sep) + cp++; + if (last != cp) { + if (!is_absolute_path(last) && depth) { + error("%s: ignoring relative alternate object store %s", + relative_base, last); + } else { + link_alt_odb_entry(last, cp - last, + relative_base, depth); + } + } + while (cp < ep && *cp == sep) + cp++; + last = cp; + } +} + +static void read_info_alternates(const char * relative_base, int depth) +{ + char *map; + size_t mapsz; + struct stat st; + const char alt_file_name[] = "info/alternates"; + /* Given that relative_base is no longer than PATH_MAX, + ensure that "path" has enough space to append "/", the + file name, "info/alternates", and a trailing NUL. */ + char path[PATH_MAX + 1 + sizeof alt_file_name]; + int fd; + + sprintf(path, "%s/%s", relative_base, alt_file_name); + fd = open(path, O_RDONLY); + if (fd < 0) + return; + if (fstat(fd, &st) || (st.st_size == 0)) { + close(fd); + return; + } + mapsz = xsize_t(st.st_size); + map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + + link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth); + + munmap(map, mapsz); +} + +void prepare_alt_odb(void) +{ + const char *alt; + + if (alt_odb_tail) + return; + + alt = getenv(ALTERNATE_DB_ENVIRONMENT); + if (!alt) alt = ""; + + alt_odb_tail = &alt_odb_list; + link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0); + + read_info_alternates(get_object_directory(), 0); +} + +static char *find_sha1_file(const unsigned char *sha1, struct stat *st) +{ + char *name = sha1_file_name(sha1); + struct alternate_object_database *alt; + + if (!stat(name, st)) + return name; + prepare_alt_odb(); + for (alt = alt_odb_list; alt; alt = alt->next) { + name = alt->name; + fill_sha1_path(name, sha1); + if (!stat(alt->base, st)) + return alt->base; + } + return NULL; +} + +static unsigned int pack_used_ctr; +static unsigned int pack_mmap_calls; +static unsigned int peak_pack_open_windows; +static unsigned int pack_open_windows; +static size_t peak_pack_mapped; +static size_t pack_mapped; +struct packed_git *packed_git; + +void pack_report(void) +{ + fprintf(stderr, + "pack_report: getpagesize() = %10" SZ_FMT "\n" + "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n" + "pack_report: core.packedGitLimit = %10" SZ_FMT "\n", + sz_fmt(getpagesize()), + sz_fmt(packed_git_window_size), + sz_fmt(packed_git_limit)); + fprintf(stderr, + "pack_report: pack_used_ctr = %10u\n" + "pack_report: pack_mmap_calls = %10u\n" + "pack_report: pack_open_windows = %10u / %10u\n" + "pack_report: pack_mapped = " + "%10" SZ_FMT " / %10" SZ_FMT "\n", + pack_used_ctr, + pack_mmap_calls, + pack_open_windows, peak_pack_open_windows, + sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped)); +} + +static int check_packed_git_idx(const char *path, struct packed_git *p) +{ + void *idx_map; + struct pack_idx_header *hdr; + size_t idx_size; + uint32_t version, nr, i, *index; + int fd = open(path, O_RDONLY); + struct stat st; + + if (fd < 0) + return -1; + if (fstat(fd, &st)) { + close(fd); + return -1; + } + idx_size = xsize_t(st.st_size); + if (idx_size < 4 * 256 + 20 + 20) { + close(fd); + return error("index file %s is too small", path); + } + idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + + hdr = idx_map; + if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) { + version = ntohl(hdr->idx_version); + if (version < 2 || version > 2) { + munmap(idx_map, idx_size); + return error("index file %s is version %d" + " and is not supported by this binary" + " (try upgrading GIT to a newer version)", + path, version); + } + } else + version = 1; + + nr = 0; + index = idx_map; + if (version > 1) + index += 2; /* skip index header */ + for (i = 0; i < 256; i++) { + uint32_t n = ntohl(index[i]); + if (n < nr) { + munmap(idx_map, idx_size); + return error("non-monotonic index %s", path); + } + nr = n; + } + + if (version == 1) { + /* + * Total size: + * - 256 index entries 4 bytes each + * - 24-byte entries * nr (20-byte sha1 + 4-byte offset) + * - 20-byte SHA1 of the packfile + * - 20-byte SHA1 file checksum + */ + if (idx_size != 4*256 + nr * 24 + 20 + 20) { + munmap(idx_map, idx_size); + return error("wrong index v1 file size in %s", path); + } + } else if (version == 2) { + /* + * Minimum size: + * - 8 bytes of header + * - 256 index entries 4 bytes each + * - 20-byte sha1 entry * nr + * - 4-byte crc entry * nr + * - 4-byte offset entry * nr + * - 20-byte SHA1 of the packfile + * - 20-byte SHA1 file checksum + * And after the 4-byte offset table might be a + * variable sized table containing 8-byte entries + * for offsets larger than 2^31. + */ + unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20; + unsigned long max_size = min_size; + if (nr) + max_size += (nr - 1)*8; + if (idx_size < min_size || idx_size > max_size) { + munmap(idx_map, idx_size); + return error("wrong index v2 file size in %s", path); + } + if (idx_size != min_size && + /* + * make sure we can deal with large pack offsets. + * 31-bit signed offset won't be enough, neither + * 32-bit unsigned one will be. + */ + (sizeof(off_t) <= 4)) { + munmap(idx_map, idx_size); + return error("pack too large for current definition of off_t in %s", path); + } + } + + p->index_version = version; + p->index_data = idx_map; + p->index_size = idx_size; + p->num_objects = nr; + return 0; +} + +int open_pack_index(struct packed_git *p) +{ + char *idx_name; + int ret; + + if (p->index_data) + return 0; + + idx_name = xstrdup(p->pack_name); + strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx"); + ret = check_packed_git_idx(idx_name, p); + free(idx_name); + return ret; +} + +static void scan_windows(struct packed_git *p, + struct packed_git **lru_p, + struct pack_window **lru_w, + struct pack_window **lru_l) +{ + struct pack_window *w, *w_l; + + for (w_l = NULL, w = p->windows; w; w = w->next) { + if (!w->inuse_cnt) { + if (!*lru_w || w->last_used < (*lru_w)->last_used) { + *lru_p = p; + *lru_w = w; + *lru_l = w_l; + } + } + w_l = w; + } +} + +static int unuse_one_window(struct packed_git *current, int keep_fd) +{ + struct packed_git *p, *lru_p = NULL; + struct pack_window *lru_w = NULL, *lru_l = NULL; + + if (current) + scan_windows(current, &lru_p, &lru_w, &lru_l); + for (p = packed_git; p; p = p->next) + scan_windows(p, &lru_p, &lru_w, &lru_l); + if (lru_p) { + munmap(lru_w->base, lru_w->len); + pack_mapped -= lru_w->len; + if (lru_l) + lru_l->next = lru_w->next; + else { + lru_p->windows = lru_w->next; + if (!lru_p->windows && lru_p->pack_fd != keep_fd) { + close(lru_p->pack_fd); + lru_p->pack_fd = -1; + } + } + free(lru_w); + pack_open_windows--; + return 1; + } + return 0; +} + +void release_pack_memory(size_t need, int fd) +{ + size_t cur = pack_mapped; + while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd)) + ; /* nothing */ +} + +void close_pack_windows(struct packed_git *p) +{ + while (p->windows) { + struct pack_window *w = p->windows; + + if (w->inuse_cnt) + die("pack '%s' still has open windows to it", + p->pack_name); + munmap(w->base, w->len); + pack_mapped -= w->len; + pack_open_windows--; + p->windows = w->next; + free(w); + } +} + +void unuse_pack(struct pack_window **w_cursor) +{ + struct pack_window *w = *w_cursor; + if (w) { + w->inuse_cnt--; + *w_cursor = NULL; + } +} + +/* + * Do not call this directly as this leaks p->pack_fd on error return; + * call open_packed_git() instead. + */ +static int open_packed_git_1(struct packed_git *p) +{ + struct stat st; + struct pack_header hdr; + unsigned char sha1[20]; + unsigned char *idx_sha1; + long fd_flag; + + if (!p->index_data && open_pack_index(p)) + return error("packfile %s index unavailable", p->pack_name); + + p->pack_fd = open(p->pack_name, O_RDONLY); + if (p->pack_fd < 0 || fstat(p->pack_fd, &st)) + return -1; + + /* If we created the struct before we had the pack we lack size. */ + if (!p->pack_size) { + if (!S_ISREG(st.st_mode)) + return error("packfile %s not a regular file", p->pack_name); + p->pack_size = st.st_size; + } else if (p->pack_size != st.st_size) + return error("packfile %s size changed", p->pack_name); + + /* We leave these file descriptors open with sliding mmap; + * there is no point keeping them open across exec(), though. + */ + fd_flag = fcntl(p->pack_fd, F_GETFD, 0); + if (fd_flag < 0) + return error("cannot determine file descriptor flags"); + fd_flag |= FD_CLOEXEC; + if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1) + return error("cannot set FD_CLOEXEC"); + + /* Verify we recognize this pack file format. */ + if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr)) + return error("file %s is far too short to be a packfile", p->pack_name); + if (hdr.hdr_signature != htonl(PACK_SIGNATURE)) + return error("file %s is not a GIT packfile", p->pack_name); + if (!pack_version_ok(hdr.hdr_version)) + return error("packfile %s is version %u and not supported" + " (try upgrading GIT to a newer version)", + p->pack_name, ntohl(hdr.hdr_version)); + + /* Verify the pack matches its index. */ + if (p->num_objects != ntohl(hdr.hdr_entries)) + return error("packfile %s claims to have %u objects" + " while index indicates %u objects", + p->pack_name, ntohl(hdr.hdr_entries), + p->num_objects); + if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1) + return error("end of packfile %s is unavailable", p->pack_name); + if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1)) + return error("packfile %s signature is unavailable", p->pack_name); + idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40; + if (hashcmp(sha1, idx_sha1)) + return error("packfile %s does not match index", p->pack_name); + return 0; +} + +static int open_packed_git(struct packed_git *p) +{ + if (!open_packed_git_1(p)) + return 0; + if (p->pack_fd != -1) { + close(p->pack_fd); + p->pack_fd = -1; + } + return -1; +} + +static int in_window(struct pack_window *win, off_t offset) +{ + /* We must promise at least 20 bytes (one hash) after the + * offset is available from this window, otherwise the offset + * is not actually in this window and a different window (which + * has that one hash excess) must be used. This is to support + * the object header and delta base parsing routines below. + */ + off_t win_off = win->offset; + return win_off <= offset + && (offset + 20) <= (win_off + win->len); +} + +unsigned char* use_pack(struct packed_git *p, + struct pack_window **w_cursor, + off_t offset, + unsigned int *left) +{ + struct pack_window *win = *w_cursor; + + if (p->pack_fd == -1 && open_packed_git(p)) + die("packfile %s cannot be accessed", p->pack_name); + + /* Since packfiles end in a hash of their content and its + * pointless to ask for an offset into the middle of that + * hash, and the in_window function above wouldn't match + * don't allow an offset too close to the end of the file. + */ + if (offset > (p->pack_size - 20)) + die("offset beyond end of packfile (truncated pack?)"); + + if (!win || !in_window(win, offset)) { + if (win) + win->inuse_cnt--; + for (win = p->windows; win; win = win->next) { + if (in_window(win, offset)) + break; + } + if (!win) { + size_t window_align = packed_git_window_size / 2; + off_t len; + win = xcalloc(1, sizeof(*win)); + win->offset = (offset / window_align) * window_align; + len = p->pack_size - win->offset; + if (len > packed_git_window_size) + len = packed_git_window_size; + win->len = (size_t)len; + pack_mapped += win->len; + while (packed_git_limit < pack_mapped + && unuse_one_window(p, p->pack_fd)) + ; /* nothing */ + win->base = xmmap(NULL, win->len, + PROT_READ, MAP_PRIVATE, + p->pack_fd, win->offset); + if (win->base == MAP_FAILED) + die("packfile %s cannot be mapped: %s", + p->pack_name, + strerror(errno)); + pack_mmap_calls++; + pack_open_windows++; + if (pack_mapped > peak_pack_mapped) + peak_pack_mapped = pack_mapped; + if (pack_open_windows > peak_pack_open_windows) + peak_pack_open_windows = pack_open_windows; + win->next = p->windows; + p->windows = win; + } + } + if (win != *w_cursor) { + win->last_used = pack_used_ctr++; + win->inuse_cnt++; + *w_cursor = win; + } + offset -= win->offset; + if (left) + *left = win->len - xsize_t(offset); + return win->base + offset; +} + +struct packed_git *add_packed_git(const char *path, int path_len, int local) +{ + struct stat st; + struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2); + + /* + * Make sure a corresponding .pack file exists and that + * the index looks sane. + */ + path_len -= strlen(".idx"); + if (path_len < 1) + return NULL; + memcpy(p->pack_name, path, path_len); + strcpy(p->pack_name + path_len, ".pack"); + if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) { + free(p); + return NULL; + } + + /* ok, it looks sane as far as we can check without + * actually mapping the pack file. + */ + p->index_version = 0; + p->index_data = NULL; + p->index_size = 0; + p->num_objects = 0; + p->pack_size = st.st_size; + p->next = NULL; + p->windows = NULL; + p->pack_fd = -1; + p->pack_local = local; + p->mtime = st.st_mtime; + if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1)) + hashclr(p->sha1); + return p; +} + +struct packed_git *parse_pack_index(unsigned char *sha1) +{ + char *path = sha1_pack_index_name(sha1); + return parse_pack_index_file(sha1, path); +} + +struct packed_git *parse_pack_index_file(const unsigned char *sha1, + const char *idx_path) +{ + const char *path = sha1_pack_name(sha1); + struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2); + + if (check_packed_git_idx(idx_path, p)) { + free(p); + return NULL; + } + + strcpy(p->pack_name, path); + p->pack_size = 0; + p->next = NULL; + p->windows = NULL; + p->pack_fd = -1; + hashcpy(p->sha1, sha1); + return p; +} + +void install_packed_git(struct packed_git *pack) +{ + pack->next = packed_git; + packed_git = pack; +} + +static void prepare_packed_git_one(char *objdir, int local) +{ + /* Ensure that this buffer is large enough so that we can + append "/pack/" without clobbering the stack even if + strlen(objdir) were PATH_MAX. */ + char path[PATH_MAX + 1 + 4 + 1 + 1]; + int len; + DIR *dir; + struct dirent *de; + + sprintf(path, "%s/pack", objdir); + len = strlen(path); + dir = opendir(path); + if (!dir) { + if (errno != ENOENT) + error("unable to open object pack directory: %s: %s", + path, strerror(errno)); + return; + } + path[len++] = '/'; + while ((de = readdir(dir)) != NULL) { + int namelen = strlen(de->d_name); + struct packed_git *p; + + if (!has_extension(de->d_name, ".idx")) + continue; + + if (len + namelen + 1 > sizeof(path)) + continue; + + /* Don't reopen a pack we already have. */ + strcpy(path + len, de->d_name); + for (p = packed_git; p; p = p->next) { + if (!memcmp(path, p->pack_name, len + namelen - 4)) + break; + } + if (p) + continue; + /* See if it really is a valid .idx file with corresponding + * .pack file that we can map. + */ + p = add_packed_git(path, len + namelen, local); + if (!p) + continue; + install_packed_git(p); + } + closedir(dir); +} + +static int sort_pack(const void *a_, const void *b_) +{ + struct packed_git *a = *((struct packed_git **)a_); + struct packed_git *b = *((struct packed_git **)b_); + int st; + + /* + * Local packs tend to contain objects specific to our + * variant of the project than remote ones. In addition, + * remote ones could be on a network mounted filesystem. + * Favor local ones for these reasons. + */ + st = a->pack_local - b->pack_local; + if (st) + return -st; + + /* + * Younger packs tend to contain more recent objects, + * and more recent objects tend to get accessed more + * often. + */ + if (a->mtime < b->mtime) + return 1; + else if (a->mtime == b->mtime) + return 0; + return -1; +} + +static void rearrange_packed_git(void) +{ + struct packed_git **ary, *p; + int i, n; + + for (n = 0, p = packed_git; p; p = p->next) + n++; + if (n < 2) + return; + + /* prepare an array of packed_git for easier sorting */ + ary = xcalloc(n, sizeof(struct packed_git *)); + for (n = 0, p = packed_git; p; p = p->next) + ary[n++] = p; + + qsort(ary, n, sizeof(struct packed_git *), sort_pack); + + /* link them back again */ + for (i = 0; i < n - 1; i++) + ary[i]->next = ary[i + 1]; + ary[n - 1]->next = NULL; + packed_git = ary[0]; + + free(ary); +} + +static int prepare_packed_git_run_once = 0; +void prepare_packed_git(void) +{ + struct alternate_object_database *alt; + + if (prepare_packed_git_run_once) + return; + prepare_packed_git_one(get_object_directory(), 1); + prepare_alt_odb(); + for (alt = alt_odb_list; alt; alt = alt->next) { + alt->name[-1] = 0; + prepare_packed_git_one(alt->base, 0); + alt->name[-1] = '/'; + } + rearrange_packed_git(); + prepare_packed_git_run_once = 1; +} + +void reprepare_packed_git(void) +{ + prepare_packed_git_run_once = 0; + prepare_packed_git(); +} + +int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type) +{ + unsigned char real_sha1[20]; + hash_sha1_file(map, size, type, real_sha1); + return hashcmp(sha1, real_sha1) ? -1 : 0; +} + +static void *map_sha1_file(const unsigned char *sha1, unsigned long *size) +{ + struct stat st; + void *map; + int fd; + char *filename = find_sha1_file(sha1, &st); + + if (!filename) { + return NULL; + } + + fd = open(filename, O_RDONLY | sha1_file_open_flag); + if (fd < 0) { + /* See if it works without O_NOATIME */ + switch (sha1_file_open_flag) { + default: + fd = open(filename, O_RDONLY); + if (fd >= 0) + break; + /* Fallthrough */ + case 0: + return NULL; + } + + /* If it failed once, it will probably fail again. + * Stop using O_NOATIME + */ + sha1_file_open_flag = 0; + } + *size = xsize_t(st.st_size); + map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + return map; +} + +static int legacy_loose_object(unsigned char *map) +{ + unsigned int word; + + /* + * Is it a zlib-compressed buffer? If so, the first byte + * must be 0x78 (15-bit window size, deflated), and the + * first 16-bit word is evenly divisible by 31 + */ + word = (map[0] << 8) + map[1]; + if (map[0] == 0x78 && !(word % 31)) + return 1; + else + return 0; +} + +unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep) +{ + unsigned shift; + unsigned char c; + unsigned long size; + unsigned long used = 0; + + c = buf[used++]; + *type = (c >> 4) & 7; + size = c & 15; + shift = 4; + while (c & 0x80) { + if (len <= used) + return 0; + if (sizeof(long) * 8 <= shift) + return 0; + c = buf[used++]; + size += (c & 0x7f) << shift; + shift += 7; + } + *sizep = size; + return used; +} + +static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz) +{ + unsigned long size, used; + static const char valid_loose_object_type[8] = { + 0, /* OBJ_EXT */ + 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */ + 0, /* "delta" and others are invalid in a loose object */ + }; + enum object_type type; + + /* Get the data stream */ + memset(stream, 0, sizeof(*stream)); + stream->next_in = map; + stream->avail_in = mapsize; + stream->next_out = buffer; + stream->avail_out = bufsiz; + + if (legacy_loose_object(map)) { + inflateInit(stream); + return inflate(stream, 0); + } + + + /* + * There used to be a second loose object header format which + * was meant to mimic the in-pack format, allowing for direct + * copy of the object data. This format turned up not to be + * really worth it and we don't write it any longer. But we + * can still read it. + */ + used = unpack_object_header_gently(map, mapsize, &type, &size); + if (!used || !valid_loose_object_type[type]) + return -1; + map += used; + mapsize -= used; + + /* Set up the stream for the rest.. */ + stream->next_in = map; + stream->avail_in = mapsize; + inflateInit(stream); + + /* And generate the fake traditional header */ + stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", + typename(type), size); + return 0; +} + +static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1) +{ + int bytes = strlen(buffer) + 1; + unsigned char *buf = xmalloc(1+size); + unsigned long n; + int status = Z_OK; + + n = stream->total_out - bytes; + if (n > size) + n = size; + memcpy(buf, (char *) buffer + bytes, n); + bytes = n; + if (bytes <= size) { + /* + * The above condition must be (bytes <= size), not + * (bytes < size). In other words, even though we + * expect no more output and set avail_out to zer0, + * the input zlib stream may have bytes that express + * "this concludes the stream", and we *do* want to + * eat that input. + * + * Otherwise we would not be able to test that we + * consumed all the input to reach the expected size; + * we also want to check that zlib tells us that all + * went well with status == Z_STREAM_END at the end. + */ + stream->next_out = buf + bytes; + stream->avail_out = size - bytes; + while (status == Z_OK) + status = inflate(stream, Z_FINISH); + } + buf[size] = 0; + if (status == Z_STREAM_END && !stream->avail_in) { + inflateEnd(stream); + return buf; + } + + if (status < 0) + error("corrupt loose object '%s'", sha1_to_hex(sha1)); + else if (stream->avail_in) + error("garbage at end of loose object '%s'", + sha1_to_hex(sha1)); + free(buf); + return NULL; +} + +/* + * We used to just use "sscanf()", but that's actually way + * too permissive for what we want to check. So do an anal + * object header parse by hand. + */ +static int parse_sha1_header(const char *hdr, unsigned long *sizep) +{ + char type[10]; + int i; + unsigned long size; + + /* + * The type can be at most ten bytes (including the + * terminating '\0' that we add), and is followed by + * a space. + */ + i = 0; + for (;;) { + char c = *hdr++; + if (c == ' ') + break; + type[i++] = c; + if (i >= sizeof(type)) + return -1; + } + type[i] = 0; + + /* + * The length must follow immediately, and be in canonical + * decimal format (ie "010" is not valid). + */ + size = *hdr++ - '0'; + if (size > 9) + return -1; + if (size) { + for (;;) { + unsigned long c = *hdr - '0'; + if (c > 9) + break; + hdr++; + size = size * 10 + c; + } + } + *sizep = size; + + /* + * The length must be followed by a zero byte + */ + return *hdr ? -1 : type_from_string(type); +} + +static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1) +{ + int ret; + z_stream stream; + char hdr[8192]; + + ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)); + if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0) + return NULL; + + return unpack_sha1_rest(&stream, hdr, *size, sha1); +} + +unsigned long get_size_from_delta(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos) +{ + const unsigned char *data; + unsigned char delta_head[20], *in; + z_stream stream; + int st; + + memset(&stream, 0, sizeof(stream)); + stream.next_out = delta_head; + stream.avail_out = sizeof(delta_head); + + inflateInit(&stream); + do { + in = use_pack(p, w_curs, curpos, &stream.avail_in); + stream.next_in = in; + st = inflate(&stream, Z_FINISH); + curpos += stream.next_in - in; + } while ((st == Z_OK || st == Z_BUF_ERROR) && + stream.total_out < sizeof(delta_head)); + inflateEnd(&stream); + if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) + die("delta data unpack-initial failed"); + + /* Examine the initial part of the delta to figure out + * the result size. + */ + data = delta_head; + + /* ignore base size */ + get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); + + /* Read the result size */ + return get_delta_hdr_size(&data, delta_head+sizeof(delta_head)); +} + +static off_t get_delta_base(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + enum object_type type, + off_t delta_obj_offset) +{ + unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL); + off_t base_offset; + + /* use_pack() assured us we have [base_info, base_info + 20) + * as a range that we can look at without walking off the + * end of the mapped window. Its actually the hash size + * that is assured. An OFS_DELTA longer than the hash size + * is stupid, as then a REF_DELTA would be smaller to store. + */ + if (type == OBJ_OFS_DELTA) { + unsigned used = 0; + unsigned char c = base_info[used++]; + base_offset = c & 127; + while (c & 128) { + base_offset += 1; + if (!base_offset || MSB(base_offset, 7)) + die("offset value overflow for delta base object"); + c = base_info[used++]; + base_offset = (base_offset << 7) + (c & 127); + } + base_offset = delta_obj_offset - base_offset; + if (base_offset >= delta_obj_offset) + die("delta base offset out of bound"); + *curpos += used; + } else if (type == OBJ_REF_DELTA) { + /* The base entry _must_ be in the same pack */ + base_offset = find_pack_entry_one(base_info, p); + if (!base_offset) + die("failed to find delta-pack base object %s", + sha1_to_hex(base_info)); + *curpos += 20; + } else + die("I am totally screwed"); + return base_offset; +} + +/* forward declaration for a mutually recursive function */ +static int packed_object_info(struct packed_git *p, off_t offset, + unsigned long *sizep); + +static int packed_delta_info(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + enum object_type type, + off_t obj_offset, + unsigned long *sizep) +{ + off_t base_offset; + + base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset); + type = packed_object_info(p, base_offset, NULL); + + /* We choose to only get the type of the base object and + * ignore potentially corrupt pack file that expects the delta + * based on a base with a wrong size. This saves tons of + * inflate() calls. + */ + if (sizep) + *sizep = get_size_from_delta(p, w_curs, curpos); + + return type; +} + +static int unpack_object_header(struct packed_git *p, + struct pack_window **w_curs, + off_t *curpos, + unsigned long *sizep) +{ + unsigned char *base; + unsigned int left; + unsigned long used; + enum object_type type; + + /* use_pack() assures us we have [base, base + 20) available + * as a range that we can look at at. (Its actually the hash + * size that is assured.) With our object header encoding + * the maximum deflated object size is 2^137, which is just + * insane, so we know won't exceed what we have been given. + */ + base = use_pack(p, w_curs, *curpos, &left); + used = unpack_object_header_gently(base, left, &type, sizep); + if (!used) + die("object offset outside of pack file"); + *curpos += used; + + return type; +} + +const char *packed_object_info_detail(struct packed_git *p, + off_t obj_offset, + unsigned long *size, + unsigned long *store_size, + unsigned int *delta_chain_length, + unsigned char *base_sha1) +{ + struct pack_window *w_curs = NULL; + off_t curpos; + unsigned long dummy; + unsigned char *next_sha1; + enum object_type type; + + *delta_chain_length = 0; + curpos = obj_offset; + type = unpack_object_header(p, &w_curs, &curpos, size); + + for (;;) { + switch (type) { + default: + die("pack %s contains unknown object type %d", + p->pack_name, type); + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + *store_size = 0; /* notyet */ + unuse_pack(&w_curs); + return typename(type); + case OBJ_OFS_DELTA: + obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); + if (*delta_chain_length == 0) { + /* TODO: find base_sha1 as pointed by curpos */ + hashclr(base_sha1); + } + break; + case OBJ_REF_DELTA: + next_sha1 = use_pack(p, &w_curs, curpos, NULL); + if (*delta_chain_length == 0) + hashcpy(base_sha1, next_sha1); + obj_offset = find_pack_entry_one(next_sha1, p); + break; + } + (*delta_chain_length)++; + curpos = obj_offset; + type = unpack_object_header(p, &w_curs, &curpos, &dummy); + } +} + +static int packed_object_info(struct packed_git *p, off_t obj_offset, + unsigned long *sizep) +{ + struct pack_window *w_curs = NULL; + unsigned long size; + off_t curpos = obj_offset; + enum object_type type; + + type = unpack_object_header(p, &w_curs, &curpos, &size); + + switch (type) { + case OBJ_OFS_DELTA: + case OBJ_REF_DELTA: + type = packed_delta_info(p, &w_curs, curpos, + type, obj_offset, sizep); + break; + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + if (sizep) + *sizep = size; + break; + default: + die("pack %s contains unknown object type %d", + p->pack_name, type); + } + unuse_pack(&w_curs); + return type; +} + +static void *unpack_compressed_entry(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + unsigned long size) +{ + int st; + z_stream stream; + unsigned char *buffer, *in; + + buffer = xmalloc(size + 1); + buffer[size] = 0; + memset(&stream, 0, sizeof(stream)); + stream.next_out = buffer; + stream.avail_out = size; + + inflateInit(&stream); + do { + in = use_pack(p, w_curs, curpos, &stream.avail_in); + stream.next_in = in; + st = inflate(&stream, Z_FINISH); + curpos += stream.next_in - in; + } while (st == Z_OK || st == Z_BUF_ERROR); + inflateEnd(&stream); + if ((st != Z_STREAM_END) || stream.total_out != size) { + free(buffer); + return NULL; + } + + return buffer; +} + +#define MAX_DELTA_CACHE (256) + +static size_t delta_base_cached; + +static struct delta_base_cache_lru_list { + struct delta_base_cache_lru_list *prev; + struct delta_base_cache_lru_list *next; +} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru }; + +static struct delta_base_cache_entry { + struct delta_base_cache_lru_list lru; + void *data; + struct packed_git *p; + off_t base_offset; + unsigned long size; + enum object_type type; +} delta_base_cache[MAX_DELTA_CACHE]; + +static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset) +{ + unsigned long hash; + + hash = (unsigned long)p + (unsigned long)base_offset; + hash += (hash >> 8) + (hash >> 16); + return hash % MAX_DELTA_CACHE; +} + +static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset, + unsigned long *base_size, enum object_type *type, int keep_cache) +{ + void *ret; + unsigned long hash = pack_entry_hash(p, base_offset); + struct delta_base_cache_entry *ent = delta_base_cache + hash; + + ret = ent->data; + if (ret && ent->p == p && ent->base_offset == base_offset) + goto found_cache_entry; + return unpack_entry(p, base_offset, type, base_size); + +found_cache_entry: + if (!keep_cache) { + ent->data = NULL; + ent->lru.next->prev = ent->lru.prev; + ent->lru.prev->next = ent->lru.next; + delta_base_cached -= ent->size; + } else { + ret = xmemdupz(ent->data, ent->size); + } + *type = ent->type; + *base_size = ent->size; + return ret; +} + +static inline void release_delta_base_cache(struct delta_base_cache_entry *ent) +{ + if (ent->data) { + free(ent->data); + ent->data = NULL; + ent->lru.next->prev = ent->lru.prev; + ent->lru.prev->next = ent->lru.next; + delta_base_cached -= ent->size; + } +} + +static void add_delta_base_cache(struct packed_git *p, off_t base_offset, + void *base, unsigned long base_size, enum object_type type) +{ + unsigned long hash = pack_entry_hash(p, base_offset); + struct delta_base_cache_entry *ent = delta_base_cache + hash; + struct delta_base_cache_lru_list *lru; + + release_delta_base_cache(ent); + delta_base_cached += base_size; + + for (lru = delta_base_cache_lru.next; + delta_base_cached > delta_base_cache_limit + && lru != &delta_base_cache_lru; + lru = lru->next) { + struct delta_base_cache_entry *f = (void *)lru; + if (f->type == OBJ_BLOB) + release_delta_base_cache(f); + } + for (lru = delta_base_cache_lru.next; + delta_base_cached > delta_base_cache_limit + && lru != &delta_base_cache_lru; + lru = lru->next) { + struct delta_base_cache_entry *f = (void *)lru; + release_delta_base_cache(f); + } + + ent->p = p; + ent->base_offset = base_offset; + ent->type = type; + ent->data = base; + ent->size = base_size; + ent->lru.next = &delta_base_cache_lru; + ent->lru.prev = delta_base_cache_lru.prev; + delta_base_cache_lru.prev->next = &ent->lru; + delta_base_cache_lru.prev = &ent->lru; +} + +static void *unpack_delta_entry(struct packed_git *p, + struct pack_window **w_curs, + off_t curpos, + unsigned long delta_size, + off_t obj_offset, + enum object_type *type, + unsigned long *sizep) +{ + void *delta_data, *result, *base; + unsigned long base_size; + off_t base_offset; + + base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset); + base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0); + if (!base) + die("failed to read delta base object" + " at %"PRIuMAX" from %s", + (uintmax_t)base_offset, p->pack_name); + + delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size); + if (!delta_data) + die("failed to unpack compressed delta" + " at %"PRIuMAX" from %s", + (uintmax_t)curpos, p->pack_name); + result = patch_delta(base, base_size, + delta_data, delta_size, + sizep); + if (!result) + die("failed to apply delta"); + free(delta_data); + add_delta_base_cache(p, base_offset, base, base_size, *type); + return result; +} + +void *unpack_entry(struct packed_git *p, off_t obj_offset, + enum object_type *type, unsigned long *sizep) +{ + struct pack_window *w_curs = NULL; + off_t curpos = obj_offset; + void *data; + + *type = unpack_object_header(p, &w_curs, &curpos, sizep); + switch (*type) { + case OBJ_OFS_DELTA: + case OBJ_REF_DELTA: + data = unpack_delta_entry(p, &w_curs, curpos, *sizep, + obj_offset, type, sizep); + break; + case OBJ_COMMIT: + case OBJ_TREE: + case OBJ_BLOB: + case OBJ_TAG: + data = unpack_compressed_entry(p, &w_curs, curpos, *sizep); + break; + default: + die("unknown object type %i in %s", *type, p->pack_name); + } + unuse_pack(&w_curs); + return data; +} + +const unsigned char *nth_packed_object_sha1(struct packed_git *p, + uint32_t n) +{ + const unsigned char *index = p->index_data; + if (!index) { + if (open_pack_index(p)) + return NULL; + index = p->index_data; + } + if (n >= p->num_objects) + return NULL; + index += 4 * 256; + if (p->index_version == 1) { + return index + 24 * n + 4; + } else { + index += 8; + return index + 20 * n; + } +} + +static off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n) +{ + const unsigned char *index = p->index_data; + index += 4 * 256; + if (p->index_version == 1) { + return ntohl(*((uint32_t *)(index + 24 * n))); + } else { + uint32_t off; + index += 8 + p->num_objects * (20 + 4); + off = ntohl(*((uint32_t *)(index + 4 * n))); + if (!(off & 0x80000000)) + return off; + index += p->num_objects * 4 + (off & 0x7fffffff) * 8; + return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) | + ntohl(*((uint32_t *)(index + 4))); + } +} + +off_t find_pack_entry_one(const unsigned char *sha1, + struct packed_git *p) +{ + const uint32_t *level1_ofs = p->index_data; + const unsigned char *index = p->index_data; + unsigned hi, lo; + + if (!index) { + if (open_pack_index(p)) + return 0; + level1_ofs = p->index_data; + index = p->index_data; + } + if (p->index_version > 1) { + level1_ofs += 2; + index += 8; + } + index += 4 * 256; + hi = ntohl(level1_ofs[*sha1]); + lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1])); + + do { + unsigned mi = (lo + hi) / 2; + unsigned x = (p->index_version > 1) ? (mi * 20) : (mi * 24 + 4); + int cmp = hashcmp(index + x, sha1); + if (!cmp) + return nth_packed_object_offset(p, mi); + if (cmp > 0) + hi = mi; + else + lo = mi+1; + } while (lo < hi); + return 0; +} + +int matches_pack_name(struct packed_git *p, const char *name) +{ + const char *last_c, *c; + + if (!strcmp(p->pack_name, name)) + return 1; + + for (c = p->pack_name, last_c = c; *c;) + if (*c == '/') + last_c = ++c; + else + ++c; + if (!strcmp(last_c, name)) + return 1; + + return 0; +} + +static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed) +{ + static struct packed_git *last_found = (void *)1; + struct packed_git *p; + off_t offset; + + prepare_packed_git(); + if (!packed_git) + return 0; + p = (last_found == (void *)1) ? packed_git : last_found; + + do { + if (ignore_packed) { + const char **ig; + for (ig = ignore_packed; *ig; ig++) + if (matches_pack_name(p, *ig)) + break; + if (*ig) + goto next; + } + + offset = find_pack_entry_one(sha1, p); + if (offset) { + /* + * We are about to tell the caller where they can + * locate the requested object. We better make + * sure the packfile is still here and can be + * accessed before supplying that answer, as + * it may have been deleted since the index + * was loaded! + */ + if (p->pack_fd == -1 && open_packed_git(p)) { + error("packfile %s cannot be accessed", p->pack_name); + goto next; + } + e->offset = offset; + e->p = p; + hashcpy(e->sha1, sha1); + last_found = p; + return 1; + } + + next: + if (p == last_found) + p = packed_git; + else + p = p->next; + if (p == last_found) + p = p->next; + } while (p); + return 0; +} + +struct packed_git *find_sha1_pack(const unsigned char *sha1, + struct packed_git *packs) +{ + struct packed_git *p; + + for (p = packs; p; p = p->next) { + if (find_pack_entry_one(sha1, p)) + return p; + } + return NULL; + +} + +static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep) +{ + int status; + unsigned long mapsize, size; + void *map; + z_stream stream; + char hdr[32]; + + map = map_sha1_file(sha1, &mapsize); + if (!map) + return error("unable to find %s", sha1_to_hex(sha1)); + if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) + status = error("unable to unpack %s header", + sha1_to_hex(sha1)); + else if ((status = parse_sha1_header(hdr, &size)) < 0) + status = error("unable to parse %s header", sha1_to_hex(sha1)); + else if (sizep) + *sizep = size; + inflateEnd(&stream); + munmap(map, mapsize); + return status; +} + +int sha1_object_info(const unsigned char *sha1, unsigned long *sizep) +{ + struct pack_entry e; + + if (!find_pack_entry(sha1, &e, NULL)) { + reprepare_packed_git(); + if (!find_pack_entry(sha1, &e, NULL)) + return sha1_loose_object_info(sha1, sizep); + } + return packed_object_info(e.p, e.offset, sizep); +} + +static void *read_packed_sha1(const unsigned char *sha1, + enum object_type *type, unsigned long *size) +{ + struct pack_entry e; + + if (!find_pack_entry(sha1, &e, NULL)) + return NULL; + else + return cache_or_unpack_entry(e.p, e.offset, size, type, 1); +} + +/* + * This is meant to hold a *small* number of objects that you would + * want read_sha1_file() to be able to return, but yet you do not want + * to write them into the object store (e.g. a browse-only + * application). + */ +static struct cached_object { + unsigned char sha1[20]; + enum object_type type; + void *buf; + unsigned long size; +} *cached_objects; +static int cached_object_nr, cached_object_alloc; + +static struct cached_object *find_cached_object(const unsigned char *sha1) +{ + int i; + struct cached_object *co = cached_objects; + + for (i = 0; i < cached_object_nr; i++, co++) { + if (!hashcmp(co->sha1, sha1)) + return co; + } + return NULL; +} + +int pretend_sha1_file(void *buf, unsigned long len, enum object_type type, + unsigned char *sha1) +{ + struct cached_object *co; + + hash_sha1_file(buf, len, typename(type), sha1); + if (has_sha1_file(sha1) || find_cached_object(sha1)) + return 0; + if (cached_object_alloc <= cached_object_nr) { + cached_object_alloc = alloc_nr(cached_object_alloc); + cached_objects = xrealloc(cached_objects, + sizeof(*cached_objects) * + cached_object_alloc); + } + co = &cached_objects[cached_object_nr++]; + co->size = len; + co->type = type; + co->buf = xmalloc(len); + memcpy(co->buf, buf, len); + hashcpy(co->sha1, sha1); + return 0; +} + +void *read_sha1_file(const unsigned char *sha1, enum object_type *type, + unsigned long *size) +{ + unsigned long mapsize; + void *map, *buf; + struct cached_object *co; + + co = find_cached_object(sha1); + if (co) { + *type = co->type; + *size = co->size; + return xmemdupz(co->buf, co->size); + } + + buf = read_packed_sha1(sha1, type, size); + if (buf) + return buf; + map = map_sha1_file(sha1, &mapsize); + if (map) { + buf = unpack_sha1_file(map, mapsize, type, size, sha1); + munmap(map, mapsize); + return buf; + } + reprepare_packed_git(); + return read_packed_sha1(sha1, type, size); +} + +void *read_object_with_reference(const unsigned char *sha1, + const char *required_type_name, + unsigned long *size, + unsigned char *actual_sha1_return) +{ + enum object_type type, required_type; + void *buffer; + unsigned long isize; + unsigned char actual_sha1[20]; + + required_type = type_from_string(required_type_name); + hashcpy(actual_sha1, sha1); + while (1) { + int ref_length = -1; + const char *ref_type = NULL; + + buffer = read_sha1_file(actual_sha1, &type, &isize); + if (!buffer) + return NULL; + if (type == required_type) { + *size = isize; + if (actual_sha1_return) + hashcpy(actual_sha1_return, actual_sha1); + return buffer; + } + /* Handle references */ + else if (type == OBJ_COMMIT) + ref_type = "tree "; + else if (type == OBJ_TAG) + ref_type = "object "; + else { + free(buffer); + return NULL; + } + ref_length = strlen(ref_type); + + if (memcmp(buffer, ref_type, ref_length) || + get_sha1_hex((char *) buffer + ref_length, actual_sha1)) { + free(buffer); + return NULL; + } + free(buffer); + /* Now we have the ID of the referred-to object in + * actual_sha1. Check again. */ + } +} + +static void write_sha1_file_prepare(const void *buf, unsigned long len, + const char *type, unsigned char *sha1, + char *hdr, int *hdrlen) +{ + SHA_CTX c; + + /* Generate the header */ + *hdrlen = sprintf(hdr, "%s %lu", type, len)+1; + + /* Sha1.. */ + SHA1_Init(&c); + SHA1_Update(&c, hdr, *hdrlen); + SHA1_Update(&c, buf, len); + SHA1_Final(sha1, &c); +} + +/* + * Link the tempfile to the final place, possibly creating the + * last directory level as you do so. + * + * Returns the errno on failure, 0 on success. + */ +static int link_temp_to_file(const char *tmpfile, const char *filename) +{ + int ret; + char *dir; + + if (!link(tmpfile, filename)) + return 0; + + /* + * Try to mkdir the last path component if that failed. + * + * Re-try the "link()" regardless of whether the mkdir + * succeeds, since a race might mean that somebody + * else succeeded. + */ + ret = errno; + dir = strrchr(filename, '/'); + if (dir) { + *dir = 0; + if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) { + *dir = '/'; + return -2; + } + *dir = '/'; + if (!link(tmpfile, filename)) + return 0; + ret = errno; + } + return ret; +} + +/* + * Move the just written object into its final resting place + */ +int move_temp_to_file(const char *tmpfile, const char *filename) +{ + int ret = link_temp_to_file(tmpfile, filename); + + /* + * Coda hack - coda doesn't like cross-directory links, + * so we fall back to a rename, which will mean that it + * won't be able to check collisions, but that's not a + * big deal. + * + * The same holds for FAT formatted media. + * + * When this succeeds, we just return 0. We have nothing + * left to unlink. + */ + if (ret && ret != EEXIST) { + if (!rename(tmpfile, filename)) + return 0; + ret = errno; + } + unlink(tmpfile); + if (ret) { + if (ret != EEXIST) { + return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret)); + } + /* FIXME!!! Collision check here ? */ + } + + return 0; +} + +static int write_buffer(int fd, const void *buf, size_t len) +{ + if (write_in_full(fd, buf, len) < 0) + return error("file write error (%s)", strerror(errno)); + return 0; +} + +int hash_sha1_file(const void *buf, unsigned long len, const char *type, + unsigned char *sha1) +{ + char hdr[32]; + int hdrlen; + write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen); + return 0; +} + +int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1) +{ + int size, ret; + unsigned char *compressed; + z_stream stream; + unsigned char sha1[20]; + char *filename; + static char tmpfile[PATH_MAX]; + char hdr[32]; + int fd, hdrlen; + + /* Normally if we have it in the pack then we do not bother writing + * it out into .git/objects/??/?{38} file. + */ + write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen); + filename = sha1_file_name(sha1); + if (returnsha1) + hashcpy(returnsha1, sha1); + if (has_sha1_file(sha1)) + return 0; + fd = open(filename, O_RDONLY); + if (fd >= 0) { + /* + * FIXME!!! We might do collision checking here, but we'd + * need to uncompress the old file and check it. Later. + */ + close(fd); + return 0; + } + + if (errno != ENOENT) { + return error("sha1 file %s: %s\n", filename, strerror(errno)); + } + + snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory()); + + fd = mkstemp(tmpfile); + if (fd < 0) { + if (errno == EPERM) + return error("insufficient permission for adding an object to repository database %s\n", get_object_directory()); + else + return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno)); + } + + /* Set it up */ + memset(&stream, 0, sizeof(stream)); + deflateInit(&stream, zlib_compression_level); + size = 8 + deflateBound(&stream, len+hdrlen); + compressed = xmalloc(size); + + /* Compress it */ + stream.next_out = compressed; + stream.avail_out = size; + + /* First header.. */ + stream.next_in = (unsigned char *)hdr; + stream.avail_in = hdrlen; + while (deflate(&stream, 0) == Z_OK) + /* nothing */; + + /* Then the data itself.. */ + stream.next_in = buf; + stream.avail_in = len; + ret = deflate(&stream, Z_FINISH); + if (ret != Z_STREAM_END) + die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret); + + ret = deflateEnd(&stream); + if (ret != Z_OK) + die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret); + + size = stream.total_out; + + if (write_buffer(fd, compressed, size) < 0) + die("unable to write sha1 file"); + fchmod(fd, 0444); + if (close(fd)) + die("unable to write sha1 file"); + free(compressed); + + return move_temp_to_file(tmpfile, filename); +} + +/* + * We need to unpack and recompress the object for writing + * it out to a different file. + */ +static void *repack_object(const unsigned char *sha1, unsigned long *objsize) +{ + size_t size; + z_stream stream; + unsigned char *unpacked; + unsigned long len; + enum object_type type; + char hdr[32]; + int hdrlen; + void *buf; + + /* need to unpack and recompress it by itself */ + unpacked = read_packed_sha1(sha1, &type, &len); + if (!unpacked) + error("cannot read sha1_file for %s", sha1_to_hex(sha1)); + + hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1; + + /* Set it up */ + memset(&stream, 0, sizeof(stream)); + deflateInit(&stream, zlib_compression_level); + size = deflateBound(&stream, len + hdrlen); + buf = xmalloc(size); + + /* Compress it */ + stream.next_out = buf; + stream.avail_out = size; + + /* First header.. */ + stream.next_in = (void *)hdr; + stream.avail_in = hdrlen; + while (deflate(&stream, 0) == Z_OK) + /* nothing */; + + /* Then the data itself.. */ + stream.next_in = unpacked; + stream.avail_in = len; + while (deflate(&stream, Z_FINISH) == Z_OK) + /* nothing */; + deflateEnd(&stream); + free(unpacked); + + *objsize = stream.total_out; + return buf; +} + +int write_sha1_to_fd(int fd, const unsigned char *sha1) +{ + int retval; + unsigned long objsize; + void *buf = map_sha1_file(sha1, &objsize); + + if (buf) { + retval = write_buffer(fd, buf, objsize); + munmap(buf, objsize); + return retval; + } + + buf = repack_object(sha1, &objsize); + retval = write_buffer(fd, buf, objsize); + free(buf); + return retval; +} + +int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer, + size_t bufsize, size_t *bufposn) +{ + char tmpfile[PATH_MAX]; + int local; + z_stream stream; + unsigned char real_sha1[20]; + unsigned char discard[4096]; + int ret; + SHA_CTX c; + + snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory()); + + local = mkstemp(tmpfile); + if (local < 0) { + if (errno == EPERM) + return error("insufficient permission for adding an object to repository database %s\n", get_object_directory()); + else + return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno)); + } + + memset(&stream, 0, sizeof(stream)); + + inflateInit(&stream); + + SHA1_Init(&c); + + do { + ssize_t size; + if (*bufposn) { + stream.avail_in = *bufposn; + stream.next_in = (unsigned char *) buffer; + do { + stream.next_out = discard; + stream.avail_out = sizeof(discard); + ret = inflate(&stream, Z_SYNC_FLUSH); + SHA1_Update(&c, discard, sizeof(discard) - + stream.avail_out); + } while (stream.avail_in && ret == Z_OK); + if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0) + die("unable to write sha1 file"); + memmove(buffer, buffer + *bufposn - stream.avail_in, + stream.avail_in); + *bufposn = stream.avail_in; + if (ret != Z_OK) + break; + } + size = xread(fd, buffer + *bufposn, bufsize - *bufposn); + if (size <= 0) { + close(local); + unlink(tmpfile); + if (!size) + return error("Connection closed?"); + perror("Reading from connection"); + return -1; + } + *bufposn += size; + } while (1); + inflateEnd(&stream); + + fchmod(local, 0444); + if (close(local) != 0) + die("unable to write sha1 file"); + SHA1_Final(real_sha1, &c); + if (ret != Z_STREAM_END) { + unlink(tmpfile); + return error("File %s corrupted", sha1_to_hex(sha1)); + } + if (hashcmp(sha1, real_sha1)) { + unlink(tmpfile); + return error("File %s has bad hash", sha1_to_hex(sha1)); + } + + return move_temp_to_file(tmpfile, sha1_file_name(sha1)); +} + +int has_pack_index(const unsigned char *sha1) +{ + struct stat st; + if (stat(sha1_pack_index_name(sha1), &st)) + return 0; + return 1; +} + +int has_pack_file(const unsigned char *sha1) +{ + struct stat st; + if (stat(sha1_pack_name(sha1), &st)) + return 0; + return 1; +} + +int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed) +{ + struct pack_entry e; + return find_pack_entry(sha1, &e, ignore_packed); +} + +int has_sha1_file(const unsigned char *sha1) +{ + struct stat st; + struct pack_entry e; + + if (find_pack_entry(sha1, &e, NULL)) + return 1; + return find_sha1_file(sha1, &st) ? 1 : 0; +} + +int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object) +{ + struct strbuf buf; + int ret; + + strbuf_init(&buf, 0); + if (strbuf_read(&buf, fd, 4096) < 0) { + strbuf_release(&buf); + return -1; + } + + if (!type) + type = blob_type; + if (write_object) + ret = write_sha1_file(buf.buf, buf.len, type, sha1); + else + ret = hash_sha1_file(buf.buf, buf.len, type, sha1); + strbuf_release(&buf); + + return ret; +} + +int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, + enum object_type type, const char *path) +{ + size_t size = xsize_t(st->st_size); + void *buf = NULL; + int ret, re_allocated = 0; + + if (size) + buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + + if (!type) + type = OBJ_BLOB; + + /* + * Convert blobs to git internal format + */ + if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) { + struct strbuf nbuf; + strbuf_init(&nbuf, 0); + if (convert_to_git(path, buf, size, &nbuf)) { + munmap(buf, size); + buf = strbuf_detach(&nbuf, &size); + re_allocated = 1; + } + } + + if (write_object) + ret = write_sha1_file(buf, size, typename(type), sha1); + else + ret = hash_sha1_file(buf, size, typename(type), sha1); + if (re_allocated) { + free(buf); + return ret; + } + if (size) + munmap(buf, size); + return ret; +} + +int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object) +{ + int fd; + char *target; + size_t len; + + switch (st->st_mode & S_IFMT) { + case S_IFREG: + fd = open(path, O_RDONLY); + if (fd < 0) + return error("open(\"%s\"): %s", path, + strerror(errno)); + if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0) + return error("%s: failed to insert into database", + path); + break; + case S_IFLNK: + len = xsize_t(st->st_size); + target = xmalloc(len + 1); + if (readlink(path, target, len + 1) != st->st_size) { + char *errstr = strerror(errno); + free(target); + return error("readlink(\"%s\"): %s", path, + errstr); + } + if (!write_object) + hash_sha1_file(target, len, blob_type, sha1); + else if (write_sha1_file(target, len, blob_type, sha1)) + return error("%s: failed to insert into database", + path); + free(target); + break; + case S_IFDIR: + return resolve_gitlink_ref(path, "HEAD", sha1); + default: + return error("%s: unsupported file type", path); + } + return 0; +} + +int read_pack_header(int fd, struct pack_header *header) +{ + char *c = (char*)header; + ssize_t remaining = sizeof(struct pack_header); + do { + ssize_t r = xread(fd, c, remaining); + if (r <= 0) + /* "eof before pack header was fully read" */ + return PH_ERROR_EOF; + remaining -= r; + c += r; + } while (remaining > 0); + if (header->hdr_signature != htonl(PACK_SIGNATURE)) + /* "protocol error (pack signature mismatch detected)" */ + return PH_ERROR_PACK_SIGNATURE; + if (!pack_version_ok(header->hdr_version)) + /* "protocol error (pack version unsupported)" */ + return PH_ERROR_PROTOCOL; + return 0; +} |