* This handles basic git sha1 object files - packing, unpacking,
* creation etc.
*/
-#include <stdarg.h>
#include "cache.h"
-
-const char *sha1_file_directory = NULL;
+#include "delta.h"
#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
return 0;
}
+static int get_sha1_file(const char *path, unsigned char *result)
+{
+ char buffer[60];
+ int fd = open(path, O_RDONLY);
+ int len;
+
+ if (fd < 0)
+ return -1;
+ len = read(fd, buffer, sizeof(buffer));
+ close(fd);
+ if (len < 40)
+ return -1;
+ return get_sha1_hex(buffer, result);
+}
+
+static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
+static void setup_git_env(void)
+{
+ git_dir = gitenv(GIT_DIR_ENVIRONMENT);
+ if (!git_dir)
+ git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
+ git_object_dir = gitenv(DB_ENVIRONMENT);
+ if (!git_object_dir) {
+ git_object_dir = xmalloc(strlen(git_dir) + 9);
+ sprintf(git_object_dir, "%s/objects", git_dir);
+ }
+ git_refs_dir = xmalloc(strlen(git_dir) + 6);
+ sprintf(git_refs_dir, "%s/refs", git_dir);
+ git_index_file = gitenv(INDEX_ENVIRONMENT);
+ if (!git_index_file) {
+ git_index_file = xmalloc(strlen(git_dir) + 7);
+ sprintf(git_index_file, "%s/index", git_dir);
+ }
+}
+
+char *get_object_directory(void)
+{
+ if (!git_object_dir)
+ setup_git_env();
+ return git_object_dir;
+}
+
+char *get_refs_directory(void)
+{
+ if (!git_refs_dir)
+ setup_git_env();
+ return git_refs_dir;
+}
+
+char *get_index_file(void)
+{
+ if (!git_index_file)
+ setup_git_env();
+ return git_index_file;
+}
+
+int get_sha1(const char *str, unsigned char *sha1)
+{
+ static char pathname[PATH_MAX];
+ static const char *prefix[] = {
+ "",
+ "refs",
+ "refs/tags",
+ "refs/heads",
+ "refs/snap",
+ NULL
+ };
+ const char **p;
+
+ if (!get_sha1_hex(str, sha1))
+ return 0;
+
+ if (!git_dir)
+ setup_git_env();
+ for (p = prefix; *p; p++) {
+ snprintf(pathname, sizeof(pathname), "%s/%s/%s",
+ git_dir, *p, str);
+ if (!get_sha1_file(pathname, sha1))
+ return 0;
+ }
+
+ return -1;
+}
+
char * sha1_to_hex(const unsigned char *sha1)
{
static char buffer[50];
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 a "strdup()" 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)
{
- int i;
static char *name, *base;
if (!base) {
- char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
+ const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
memcpy(base, sha1_file_directory, len);
base[len+3] = '/';
name = base + len + 1;
}
- for (i = 0; i < 20; i++) {
- static char hex[] = "0123456789abcdef";
- unsigned int val = sha1[i];
- char *pos = name + i*2 + (i > 0);
- *pos++ = hex[val >> 4];
- *pos = hex[val & 0xf];
- }
+ fill_sha1_path(name, sha1);
return base;
}
-int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
+static struct alternate_object_database {
+ char *base;
+ char *name;
+} *alt_odb;
+
+/*
+ * Prepare alternate object database registry.
+ * alt_odb points at an array of struct alternate_object_database.
+ * This array is terminated with an element that has both its base
+ * and name set to NULL. alt_odb[n] comes from n'th non-empty
+ * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
+ * variable, and 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.
+ * This function allocates the alt_odb array and all the strings
+ * pointed by base fields of the array elements with one xmalloc();
+ * the string pool immediately follows the array.
+ */
+static void prepare_alt_odb(void)
+{
+ int pass, totlen, i;
+ const char *cp, *last;
+ char *op = NULL;
+ const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
+
+ /* The first pass counts how large an area to allocate to
+ * hold the entire alt_odb structure, including array of
+ * structs and path buffers for them. The second pass fills
+ * the structure and prepares the path buffers for use by
+ * fill_sha1_path().
+ */
+ for (totlen = pass = 0; pass < 2; pass++) {
+ last = alt;
+ i = 0;
+ do {
+ cp = strchr(last, ':') ? : last + strlen(last);
+ if (last != cp) {
+ /* 43 = 40-byte + 2 '/' + terminating NUL */
+ int pfxlen = cp - last;
+ int entlen = pfxlen + 43;
+ if (pass == 0)
+ totlen += entlen;
+ else {
+ alt_odb[i].base = op;
+ alt_odb[i].name = op + pfxlen + 1;
+ memcpy(op, last, pfxlen);
+ op[pfxlen] = op[pfxlen + 3] = '/';
+ op[entlen-1] = 0;
+ op += entlen;
+ }
+ i++;
+ }
+ while (*cp && *cp == ':')
+ cp++;
+ last = cp;
+ } while (*cp);
+ if (pass)
+ break;
+ alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
+ alt_odb[i].base = alt_odb[i].name = NULL;
+ op = (char*)(&alt_odb[i+1]);
+ }
+}
+
+static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
+{
+ int i;
+ char *name = sha1_file_name(sha1);
+
+ if (!stat(name, st))
+ return name;
+ if (!alt_odb)
+ prepare_alt_odb();
+ for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
+ fill_sha1_path(name, sha1);
+ if (!stat(alt_odb[i].base, st))
+ return alt_odb[i].base;
+ }
+ return NULL;
+}
+
+int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
{
char header[100];
unsigned char real_sha1[20];
void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
{
- char *filename = sha1_file_name(sha1);
struct stat st;
void *map;
int fd;
+ char *filename = find_sha1_file(sha1, &st);
+
+ if (!filename) {
+ error("cannot map sha1 file %s", sha1_to_hex(sha1));
+ return NULL;
+ }
fd = open(filename, O_RDONLY | sha1_file_open_flag);
if (fd < 0) {
/* If it failed once, it will probably fail again. Stop using O_NOATIME */
sha1_file_open_flag = 0;
}
- if (fstat(fd, &st) < 0) {
- close(fd);
- return NULL;
- }
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (-1 == (int)(long)map)
return map;
}
+int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
+{
+ /* Get the data stream */
+ memset(stream, 0, sizeof(*stream));
+ stream->next_in = map;
+ stream->avail_in = mapsize;
+ stream->next_out = buffer;
+ stream->avail_out = size;
+
+ inflateInit(stream);
+ return inflate(stream, 0);
+}
+
+void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
+{
+ int bytes = strlen(buffer) + 1;
+ char *buf = xmalloc(1+size);
+
+ memcpy(buf, buffer + bytes, stream->total_out - bytes);
+ bytes = stream->total_out - bytes;
+ if (bytes < size) {
+ stream->next_out = buf + bytes;
+ stream->avail_out = size - bytes;
+ while (inflate(stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ }
+ buf[size] = 0;
+ inflateEnd(stream);
+ return buf;
+}
+
+/*
+ * 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.
+ */
+int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
+{
+ 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 = 10;
+ for (;;) {
+ char c = *hdr++;
+ if (c == ' ')
+ break;
+ if (!--i)
+ return -1;
+ *type++ = c;
+ }
+ *type = 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 : 0;
+}
+
void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
{
- int ret, bytes;
+ int ret;
z_stream stream;
- char buffer[8192];
- char *buf;
-
- /* Get the data stream */
- memset(&stream, 0, sizeof(stream));
- stream.next_in = map;
- stream.avail_in = mapsize;
- stream.next_out = buffer;
- stream.avail_out = sizeof(buffer);
+ char hdr[8192];
- inflateInit(&stream);
- ret = inflate(&stream, 0);
- if (ret < Z_OK)
- return NULL;
- if (sscanf(buffer, "%10s %lu", type, size) != 2)
+ ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
+ if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
return NULL;
- bytes = strlen(buffer) + 1;
- buf = xmalloc(*size);
+ return unpack_sha1_rest(&stream, hdr, *size);
+}
- memcpy(buf, buffer + bytes, stream.total_out - bytes);
- bytes = stream.total_out - bytes;
- if (bytes < *size && ret == Z_OK) {
- stream.next_out = buf + bytes;
- stream.avail_out = *size - bytes;
- while (inflate(&stream, Z_FINISH) == Z_OK)
- /* nothing */;
+int sha1_delta_base(const unsigned char *sha1, unsigned char *base_sha1)
+{
+ int ret;
+ unsigned long mapsize, size;
+ void *map;
+ z_stream stream;
+ char hdr[64], type[20];
+ void *delta_data_head;
+
+ map = map_sha1_file(sha1, &mapsize);
+ if (!map)
+ return -1;
+ ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
+ if (ret < Z_OK || parse_sha1_header(hdr, type, &size) < 0) {
+ ret = -1;
+ goto out;
}
+ if (strcmp(type, "delta")) {
+ ret = 0;
+ goto out;
+ }
+
+ delta_data_head = hdr + strlen(hdr) + 1;
+ ret = 1;
+ memcpy(base_sha1, delta_data_head, 20);
+ out:
inflateEnd(&stream);
- return buf;
+ munmap(map, mapsize);
+ return ret;
+}
+
+int sha1_file_size(const unsigned char *sha1, unsigned long *sizep)
+{
+ int ret, status;
+ unsigned long mapsize, size;
+ void *map;
+ z_stream stream;
+ char hdr[64], type[20];
+ const unsigned char *data;
+ unsigned char cmd;
+ int i;
+
+ map = map_sha1_file(sha1, &mapsize);
+ if (!map)
+ return -1;
+ ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
+ status = -1;
+ if (ret < Z_OK || parse_sha1_header(hdr, type, &size) < 0)
+ goto out;
+ if (strcmp(type, "delta")) {
+ *sizep = size;
+ status = 0;
+ goto out;
+ }
+
+ /* We are dealing with a delta object. Inflated, the first
+ * 20 bytes hold the base object SHA1, and delta data follows
+ * immediately after it.
+ *
+ * The initial part of the delta starts at delta_data_head +
+ * 20. Borrow code from patch-delta to read the result size.
+ */
+ data = hdr + strlen(hdr) + 1 + 20;
+
+ /* Skip over the source size; we are not interested in
+ * it and we cannot verify it because we do not want
+ * to read the base object.
+ */
+ cmd = *data++;
+ while (cmd) {
+ if (cmd & 1)
+ data++;
+ cmd >>= 1;
+ }
+ /* Read the result size */
+ size = i = 0;
+ cmd = *data++;
+ while (cmd) {
+ if (cmd & 1)
+ size |= *data++ << i;
+ i += 8;
+ cmd >>= 1;
+ }
+ *sizep = size;
+ status = 0;
+ out:
+ inflateEnd(&stream);
+ munmap(map, mapsize);
+ return status;
}
void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
if (map) {
buf = unpack_sha1_file(map, mapsize, type, size);
munmap(map, mapsize);
+ if (buf && !strcmp(type, "delta")) {
+ void *ref = NULL, *delta = buf;
+ unsigned long ref_size, delta_size = *size;
+ buf = NULL;
+ if (delta_size > 20)
+ ref = read_sha1_file(delta, type, &ref_size);
+ if (ref)
+ buf = patch_delta(ref, ref_size,
+ delta+20, delta_size-20,
+ size);
+ free(delta);
+ free(ref);
+ }
return buf;
}
return NULL;
}
-void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
- unsigned long *size,
- unsigned char *tree_sha1_return)
+void *read_object_with_reference(const unsigned char *sha1,
+ const char *required_type,
+ unsigned long *size,
+ unsigned char *actual_sha1_return)
{
char type[20];
void *buffer;
unsigned long isize;
- int was_commit = 0;
- unsigned char tree_sha1[20];
+ unsigned char actual_sha1[20];
- buffer = read_sha1_file(sha1, type, &isize);
+ memcpy(actual_sha1, sha1, 20);
+ while (1) {
+ int ref_length = -1;
+ const char *ref_type = NULL;
- /*
- * We might have read a commit instead of a tree, in which case
- * we parse out the tree_sha1 and attempt to read from there.
- * (buffer + 5) is because the tree sha1 is always at offset 5
- * in a commit record ("tree ").
- */
- if (buffer &&
- !strcmp(type, "commit") &&
- !get_sha1_hex(buffer + 5, tree_sha1)) {
- free(buffer);
- buffer = read_sha1_file(tree_sha1, type, &isize);
- was_commit = 1;
- }
+ buffer = read_sha1_file(actual_sha1, type, &isize);
+ if (!buffer)
+ return NULL;
+ if (!strcmp(type, required_type)) {
+ *size = isize;
+ if (actual_sha1_return)
+ memcpy(actual_sha1_return, actual_sha1, 20);
+ return buffer;
+ }
+ /* Handle references */
+ else if (!strcmp(type, "commit"))
+ ref_type = "tree ";
+ else if (!strcmp(type, "tag"))
+ ref_type = "object ";
+ else {
+ free(buffer);
+ return NULL;
+ }
+ ref_length = strlen(ref_type);
- /*
- * Now do we have something and if so is it a tree?
- */
- if (!buffer || strcmp(type, "tree")) {
- free(buffer);
- return NULL;
+ if (memcmp(buffer, ref_type, ref_length) ||
+ get_sha1_hex(buffer + ref_length, actual_sha1)) {
+ free(buffer);
+ return NULL;
+ }
+ /* Now we have the ID of the referred-to object in
+ * actual_sha1. Check again. */
}
-
- *size = isize;
- if (tree_sha1_return)
- memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20);
- return buffer;
}
-int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1)
+int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
{
int size;
- char *compressed;
+ unsigned char *compressed;
z_stream stream;
unsigned char sha1[20];
SHA_CTX c;
char *filename;
- char hdr[50];
- int fd, hdrlen;
+ static char tmpfile[PATH_MAX];
+ unsigned char hdr[50];
+ int fd, hdrlen, ret;
/* Generate the header */
- hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
+ hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
/* Sha1.. */
SHA1_Init(&c);
memcpy(returnsha1, sha1, 20);
filename = sha1_file_name(sha1);
- fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
- if (fd < 0) {
- if (errno != EEXIST)
- return -1;
-
+ fd = open(filename, O_RDONLY);
+ if (fd >= 0) {
/*
- * We might do collision checking here, but we'd need to
- * uncompress the old file and check it. Later.
+ * 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) {
+ fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
+ return -1;
+ }
+
+ snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
+
+ fd = mkstemp(tmpfile);
+ if (fd < 0) {
+ fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
+ return -1;
+ }
+
/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, Z_BEST_COMPRESSION);
stream.next_in = hdr;
stream.avail_in = hdrlen;
while (deflate(&stream, 0) == Z_OK)
- /* nothing */
+ /* nothing */;
/* Then the data itself.. */
stream.next_in = buf;
if (write(fd, compressed, size) != size)
die("unable to write file");
+ fchmod(fd, 0444);
close(fd);
-
- return 0;
-}
-
-static inline int collision_check(char *filename, void *buf, unsigned int size)
-{
-#ifdef COLLISION_CHECK
- void *map;
- int fd = open(filename, O_RDONLY);
- struct stat st;
- int cmp;
-
- /* Unreadable object, or object went away? Strange. */
- if (fd < 0)
- return -1;
-
- if (fstat(fd, &st) < 0 || size != st.st_size)
- return -1;
-
- map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
- close(fd);
- if (map == MAP_FAILED)
- return -1;
- cmp = memcmp(buf, map, size);
- munmap(map, size);
- if (cmp)
- return -1;
-#endif
- return 0;
-}
+ free(compressed);
-int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
-{
- char *filename = sha1_file_name(sha1);
- int fd;
+ ret = link(tmpfile, filename);
+ if (ret < 0) {
+ ret = errno;
- fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
- if (fd < 0) {
- if (errno != EEXIST)
+ /*
+ * 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.
+ *
+ * When this succeeds, we just return 0. We have nothing
+ * left to unlink.
+ */
+ if (ret == EXDEV && !rename(tmpfile, filename))
+ return 0;
+ }
+ unlink(tmpfile);
+ if (ret) {
+ if (ret != EEXIST) {
+ fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
return -1;
- if (collision_check(filename, buf, size))
- return error("SHA1 collision detected!"
- " This is bad, bad, BAD!\a\n");
- return 0;
+ }
+ /* FIXME!!! Collision check here ? */
}
- write(fd, buf, size);
- close(fd);
+
return 0;
}
int local;
z_stream stream;
unsigned char real_sha1[20];
- char buf[4096];
- char discard[4096];
+ unsigned char buf[4096];
+ unsigned char discard[4096];
int ret;
SHA_CTX c;
int has_sha1_file(const unsigned char *sha1)
{
- char *filename = sha1_file_name(sha1);
struct stat st;
+ return !!find_sha1_file(sha1, &st);
+}
- if (!stat(filename, &st))
- return 1;
- return 0;
+int index_fd(unsigned char *sha1, int fd, struct stat *st)
+{
+ unsigned long size = st->st_size;
+ void *buf;
+ int ret;
+
+ buf = "";
+ if (size)
+ buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ close(fd);
+ if ((int)(long)buf == -1)
+ return -1;
+
+ ret = write_sha1_file(buf, size, "blob", sha1);
+ if (size)
+ munmap(buf, size);
+ return ret;
}