--- /dev/null
+CFLAGS=-g
+CC=gcc
+
+PROG=update-cache show-diff init-db write-tree read-tree commit-tree cat-file
+
+all: $(PROG)
+
+install: $(PROG)
+ install $(PROG) $(HOME)/bin/
+
+LIBS= -lssl
+
+init-db: init-db.o
+
+update-cache: update-cache.o read-cache.o
+ $(CC) $(CFLAGS) -o update-cache update-cache.o read-cache.o $(LIBS)
+
+show-diff: show-diff.o read-cache.o
+ $(CC) $(CFLAGS) -o show-diff show-diff.o read-cache.o $(LIBS)
+
+write-tree: write-tree.o read-cache.o
+ $(CC) $(CFLAGS) -o write-tree write-tree.o read-cache.o $(LIBS)
+
+read-tree: read-tree.o read-cache.o
+ $(CC) $(CFLAGS) -o read-tree read-tree.o read-cache.o $(LIBS)
+
+commit-tree: commit-tree.o read-cache.o
+ $(CC) $(CFLAGS) -o commit-tree commit-tree.o read-cache.o $(LIBS)
+
+cat-file: cat-file.o read-cache.o
+ $(CC) $(CFLAGS) -o cat-file cat-file.o read-cache.o $(LIBS)
+
+read-cache.o: cache.h
+show-diff.o: cache.h
+
+clean:
+ rm -f *.o $(PROG) temp_git_file_*
+
+backup: clean
+ cd .. ; tar czvf dircache.tar.gz dir-cache
--- /dev/null
+
+ GIT - the stupid content tracker
+
+"git" can mean anything, depending on your mood.
+
+ - random three-letter combination that is pronounceable, and not
+ actually used by any common UNIX command. The fact that it is a
+ mispronounciation of "get" may or may not be relevant.
+ - stupid. contemptible and despicable. simple. Take your pick from the
+ dictionary of slang.
+ - "global information tracker": you're in a good mood, and it actually
+ works for you. Angels sing, and a light suddenly fills the room.
+ - "goddamn idiotic truckload of sh*t": when it breaks
+
+This is a stupid (but extremely fast) directory content manager. It
+doesn't do a whole lot, but what it _does_ do is track directory
+contents efficiently.
+
+There are two object abstractions: the "object database", and the
+"current directory cache".
+
+ The Object Database (SHA1_FILE_DIRECTORY)
+
+The object database is literally just a content-addressable collection
+of objects. All objects are named by their content, which is
+approximated by the SHA1 hash of the object itself. Objects may refer
+to other objects (by referencing their SHA1 hash), and so you can build
+up a hierarchy of objects.
+
+There are several kinds of objects in the content-addressable collection
+database. They are all in deflated with zlib, and start off with a tag
+of their type, and size information about the data. The SHA1 hash is
+always the hash of the _compressed_ object, not the original one.
+
+In particular, the consistency of an object can always be tested
+independently of the contents or the type of the object: all objects can
+be validated by verifying that (a) their hashes match the content of the
+file and (b) the object successfully inflates to a stream of bytes that
+forms a sequence of <ascii tag without space> + <space> + <ascii decimal
+size> + <byte\0> + <binary object data>.
+
+BLOB: A "blob" object is nothing but a binary blob of data, and doesn't
+refer to anything else. There is no signature or any other verification
+of the data, so while the object is consistent (it _is_ indexed by its
+sha1 hash, so the data itself is certainly correct), it has absolutely
+no other attributes. No name associations, no permissions. It is
+purely a blob of data (ie normally "file contents").
+
+TREE: The next hierarchical object type is the "tree" object. A tree
+object is a list of permission/name/blob data, sorted by name. In other
+words the tree object is uniquely determined by the set contents, and so
+two separate but identical trees will always share the exact same
+object.
+
+Again, a "tree" object is just a pure data abstraction: it has no
+history, no signatures, no verification of validity, except that the
+contents are again protected by the hash itself. So you can trust the
+contents of a tree, the same way you can trust the contents of a blob,
+but you don't know where those contents _came_ from.
+
+Side note on trees: since a "tree" object is a sorted list of
+"filename+content", you can create a diff between two trees without
+actually having to unpack two trees. Just ignore all common parts, and
+your diff will look right. In other words, you can effectively (and
+efficiently) tell the difference between any two random trees by O(n)
+where "n" is the size of the difference, rather than the size of the
+tree.
+
+Side note 2 on trees: since the name of a "blob" depends entirely and
+exclusively on its contents (ie there are no names or permissions
+involved), you can see trivial renames or permission changes by noticing
+that the blob stayed the same. However, renames with data changes need
+a smarter "diff" implementation.
+
+CHANGESET: The "changeset" object is an object that introduces the
+notion of history into the picture. In contrast to the other objects,
+it doesn't just describe the physical state of a tree, it describes how
+we got there, and why.
+
+A "changeset" is defined by the tree-object that it results in, the
+parent changesets (zero, one or more) that led up to that point, and a
+comment on what happened. Again, a changeset is not trusted per se:
+the contents are well-defined and "safe" due to the cryptographically
+strong signatures at all levels, but there is no reason to believe that
+the tree is "good" or that the merge information makes sense. The
+parents do not have to actually have any relationship with the result,
+for example.
+
+Note on changesets: unlike real SCM's, changesets do not contain rename
+information or file mode chane information. All of that is implicit in
+the trees involved (the result tree, and the result trees of the
+parents), and describing that makes no sense in this idiotic file
+manager.
+
+TRUST: The notion of "trust" is really outside the scope of "git", but
+it's worth noting a few things. First off, since everything is hashed
+with SHA1, you _can_ trust that an object is intact and has not been
+messed with by external sources. So the name of an object uniquely
+identifies a known state - just not a state that you may want to trust.
+
+Furthermore, since the SHA1 signature of a changeset refers to the
+SHA1 signatures of the tree it is associated with and the signatures
+of the parent, a single named changeset specifies uniquely a whole
+set of history, with full contents. You can't later fake any step of
+the way once you have the name of a changeset.
+
+So to introduce some real trust in the system, the only thing you need
+to do is to digitally sign just _one_ special note, which includes the
+name of a top-level changeset. Your digital signature shows others that
+you trust that changeset, and the immutability of the history of
+changesets tells others that they can trust the whole history.
+
+In other words, you can easily validate a whole archive by just sending
+out a single email that tells the people the name (SHA1 hash) of the top
+changeset, and digitally sign that email using something like GPG/PGP.
+
+In particular, you can also have a separate archive of "trust points" or
+tags, which document your (and other peoples) trust. You may, of
+course, archive these "certificates of trust" using "git" itself, but
+it's not something "git" does for you.
+
+Another way of saying the same thing: "git" itself only handles content
+integrity, the trust has to come from outside.
+
+ Current Directory Cache (".dircache/index")
+
+The "current directory cache" is a simple binary file, which contains an
+efficient representation of a virtual directory content at some random
+time. It does so by a simple array that associates a set of names,
+dates, permissions and content (aka "blob") objects together. The cache
+is always kept ordered by name, and names are unique at any point in
+time, but the cache has no long-term meaning, and can be partially
+updated at any time.
+
+In particular, the "current directory cache" certainly does not need to
+be consistent with the current directory contents, but it has two very
+important attributes:
+
+ (a) it can re-generate the full state it caches (not just the directory
+ structure: through the "blob" object it can regenerate the data too)
+
+ As a special case, there is a clear and unambiguous one-way mapping
+ from a current directory cache to a "tree object", which can be
+ efficiently created from just the current directory cache without
+ actually looking at any other data. So a directory cache at any
+ one time uniquely specifies one and only one "tree" object (but
+ has additional data to make it easy to match up that tree object
+ with what has happened in the directory)
+
+
+and
+
+ (b) it has efficient methods for finding inconsistencies between that
+ cached state ("tree object waiting to be instantiated") and the
+ current state.
+
+Those are the two ONLY things that the directory cache does. It's a
+cache, and the normal operation is to re-generate it completely from a
+known tree object, or update/compare it with a live tree that is being
+developed. If you blow the directory cache away entirely, you haven't
+lost any information as long as you have the name of the tree that it
+described.
+
+(But directory caches can also have real information in them: in
+particular, they can have the representation of an intermediate tree
+that has not yet been instantiated. So they do have meaning and usage
+outside of caching - in one sense you can think of the current directory
+cache as being the "work in progress" towards a tree commit).
--- /dev/null
+#ifndef CACHE_H
+#define CACHE_H
+
+#include <stdio.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+#include <openssl/sha.h>
+#include <zlib.h>
+
+/*
+ * Basic data structures for the directory cache
+ *
+ * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
+ * not even trying to be portable. It's trying to be efficient. It's
+ * just a cache, after all.
+ */
+
+#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
+struct cache_header {
+ unsigned int signature;
+ unsigned int version;
+ unsigned int entries;
+ unsigned char sha1[20];
+};
+
+/*
+ * The "cache_time" is just the low 32 bits of the
+ * time. It doesn't matter if it overflows - we only
+ * check it for equality in the 32 bits we save.
+ */
+struct cache_time {
+ unsigned int sec;
+ unsigned int nsec;
+};
+
+/*
+ * dev/ino/uid/gid/size are also just tracked to the low 32 bits
+ * Again - this is just a (very strong in practice) heuristic that
+ * the inode hasn't changed.
+ */
+struct cache_entry {
+ struct cache_time ctime;
+ struct cache_time mtime;
+ unsigned int st_dev;
+ unsigned int st_ino;
+ unsigned int st_mode;
+ unsigned int st_uid;
+ unsigned int st_gid;
+ unsigned int st_size;
+ unsigned char sha1[20];
+ unsigned short namelen;
+ unsigned char name[0];
+};
+
+const char *sha1_file_directory;
+struct cache_entry **active_cache;
+unsigned int active_nr, active_alloc;
+
+#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
+#define DEFAULT_DB_ENVIRONMENT ".dircache/objects"
+
+#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
+#define ce_size(ce) cache_entry_size((ce)->namelen)
+
+#define alloc_nr(x) (((x)+16)*3/2)
+
+/* Initialize the cache information */
+extern int read_cache(void);
+
+/* Return a statically allocated filename matching the sha1 signature */
+extern char *sha1_file_name(unsigned char *sha1);
+
+/* Write a memory buffer out to the sha file */
+extern int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size);
+
+/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
+extern void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size);
+extern int write_sha1_file(char *buf, unsigned len);
+
+/* Convert to/from hex/sha1 representation */
+extern int get_sha1_hex(char *hex, unsigned char *sha1);
+extern char *sha1_to_hex(unsigned char *sha1); /* static buffer! */
+
+/* General helper functions */
+extern void usage(const char *err);
+
+#endif /* CACHE_H */
--- /dev/null
+#include "cache.h"
+
+int main(int argc, char **argv)
+{
+ unsigned char sha1[20];
+ char type[20];
+ void *buf;
+ unsigned long size;
+ char template[] = "temp_git_file_XXXXXX";
+ int fd;
+
+ if (argc != 2 || get_sha1_hex(argv[1], sha1))
+ usage("cat-file: cat-file <sha1>");
+ buf = read_sha1_file(sha1, type, &size);
+ if (!buf)
+ exit(1);
+ fd = mkstemp(template);
+ if (fd < 0)
+ usage("unable to create tempfile");
+ if (write(fd, buf, size) != size)
+ strcpy(type, "bad");
+ printf("%s: %s\n", template, type);
+}
--- /dev/null
+#include "cache.h"
+
+#include <pwd.h>
+#include <time.h>
+
+#define BLOCKING (1ul << 14)
+#define ORIG_OFFSET (40)
+
+/*
+ * Leave space at the beginning to insert the tag
+ * once we know how big things are.
+ *
+ * FIXME! Share the code with "write-tree.c"
+ */
+static void init_buffer(char **bufp, unsigned int *sizep)
+{
+ char *buf = malloc(BLOCKING);
+ memset(buf, 0, ORIG_OFFSET);
+ *sizep = ORIG_OFFSET;
+ *bufp = buf;
+}
+
+static void add_buffer(char **bufp, unsigned int *sizep, const char *fmt, ...)
+{
+ char one_line[2048];
+ va_list args;
+ int len;
+ unsigned long alloc, size, newsize;
+ char *buf;
+
+ va_start(args, fmt);
+ len = vsnprintf(one_line, sizeof(one_line), fmt, args);
+ va_end(args);
+ size = *sizep;
+ newsize = size + len;
+ alloc = (size + 32767) & ~32767;
+ buf = *bufp;
+ if (newsize > alloc) {
+ alloc = (newsize + 32767) & ~32767;
+ buf = realloc(buf, alloc);
+ *bufp = buf;
+ }
+ *sizep = newsize;
+ memcpy(buf + size, one_line, len);
+}
+
+static int prepend_integer(char *buffer, unsigned val, int i)
+{
+ buffer[--i] = '\0';
+ do {
+ buffer[--i] = '0' + (val % 10);
+ val /= 10;
+ } while (val);
+ return i;
+}
+
+static void finish_buffer(char *tag, char **bufp, unsigned int *sizep)
+{
+ int taglen;
+ int offset;
+ char *buf = *bufp;
+ unsigned int size = *sizep;
+
+ offset = prepend_integer(buf, size - ORIG_OFFSET, ORIG_OFFSET);
+ taglen = strlen(tag);
+ offset -= taglen;
+ buf += offset;
+ size -= offset;
+ memcpy(buf, tag, taglen);
+
+ *bufp = buf;
+ *sizep = size;
+}
+
+static void remove_special(char *p)
+{
+ char c;
+ char *dst = p;
+
+ for (;;) {
+ c = *p;
+ p++;
+ switch(c) {
+ case '\n': case '<': case '>':
+ continue;
+ }
+ *dst++ = c;
+ if (!c)
+ break;
+ }
+}
+
+/*
+ * Having more than two parents may be strange, but hey, there's
+ * no conceptual reason why the file format couldn't accept multi-way
+ * merges. It might be the "union" of several packages, for example.
+ *
+ * I don't really expect that to happen, but this is here to make
+ * it clear that _conceptually_ it's ok..
+ */
+#define MAXPARENT (16)
+
+int main(int argc, char **argv)
+{
+ int i, len;
+ int parents = 0;
+ unsigned char tree_sha1[20];
+ unsigned char parent_sha1[MAXPARENT][20];
+ char *gecos, *realgecos;
+ char *email, realemail[1000];
+ char *date, *realdate;
+ char comment[1000];
+ struct passwd *pw;
+ time_t now;
+ char *buffer;
+ unsigned int size;
+
+ if (argc < 2 || get_sha1_hex(argv[1], tree_sha1) < 0)
+ usage("commit-tree <sha1> [-p <sha1>]* < changelog");
+
+ for (i = 2; i < argc; i += 2) {
+ char *a, *b;
+ a = argv[i]; b = argv[i+1];
+ if (!b || strcmp(a, "-p") || get_sha1_hex(b, parent_sha1[parents]))
+ usage("commit-tree <sha1> [-p <sha1>]* < changelog");
+ parents++;
+ }
+ if (!parents)
+ fprintf(stderr, "Committing initial tree %s\n", argv[1]);
+ pw = getpwuid(getuid());
+ if (!pw)
+ usage("You don't exist. Go away!");
+ realgecos = pw->pw_gecos;
+ len = strlen(pw->pw_name);
+ memcpy(realemail, pw->pw_name, len);
+ realemail[len] = '@';
+ gethostname(realemail+len+1, sizeof(realemail)-len-1);
+ time(&now);
+ realdate = ctime(&now);
+
+ gecos = getenv("COMMITTER_NAME") ? : realgecos;
+ email = getenv("COMMITTER_EMAIL") ? : realemail;
+ date = getenv("COMMITTER_DATE") ? : realdate;
+
+ remove_special(gecos); remove_special(realgecos);
+ remove_special(email); remove_special(realemail);
+ remove_special(date); remove_special(realdate);
+
+ init_buffer(&buffer, &size);
+ add_buffer(&buffer, &size, "tree %s\n", sha1_to_hex(tree_sha1));
+
+ /*
+ * NOTE! This ordering means that the same exact tree merged with a
+ * different order of parents will be a _different_ changeset even
+ * if everything else stays the same.
+ */
+ for (i = 0; i < parents; i++)
+ add_buffer(&buffer, &size, "parent %s\n", sha1_to_hex(parent_sha1[i]));
+
+ /* Person/date information */
+ add_buffer(&buffer, &size, "author %s <%s> %s\n", gecos, email, date);
+ add_buffer(&buffer, &size, "committer %s <%s> %s\n\n", realgecos, realemail, realdate);
+
+ /* And add the comment */
+ while (fgets(comment, sizeof(comment), stdin) != NULL)
+ add_buffer(&buffer, &size, "%s", comment);
+
+ finish_buffer("commit ", &buffer, &size);
+
+ write_sha1_file(buffer, size);
+ return 0;
+}
--- /dev/null
+#include "cache.h"
+
+int main(int argc, char **argv)
+{
+ char *sha1_dir = getenv(DB_ENVIRONMENT), *path;
+ int len, i, fd;
+
+ if (mkdir(".dircache", 0700) < 0) {
+ perror("unable to create .dircache");
+ exit(1);
+ }
+
+ /*
+ * If you want to, you can share the DB area with any number of branches.
+ * That has advantages: you can save space by sharing all the SHA1 objects.
+ * On the other hand, it might just make lookup slower and messier. You
+ * be the judge.
+ */
+ sha1_dir = getenv(DB_ENVIRONMENT);
+ if (sha1_dir) {
+ struct stat st;
+ if (!stat(sha1_dir, &st) < 0 && S_ISDIR(st.st_mode))
+ return;
+ fprintf(stderr, "DB_ENVIRONMENT set to bad directory %s: ", sha1_dir);
+ }
+
+ /*
+ * The default case is to have a DB per managed directory.
+ */
+ sha1_dir = DEFAULT_DB_ENVIRONMENT;
+ fprintf(stderr, "defaulting to private storage area\n");
+ len = strlen(sha1_dir);
+ if (mkdir(sha1_dir, 0700) < 0) {
+ if (errno != EEXIST) {
+ perror(sha1_dir);
+ exit(1);
+ }
+ }
+ path = malloc(len + 40);
+ memcpy(path, sha1_dir, len);
+ for (i = 0; i < 256; i++) {
+ sprintf(path+len, "/%02x", i);
+ if (mkdir(path, 0700) < 0) {
+ if (errno != EEXIST) {
+ perror(path);
+ exit(1);
+ }
+ }
+ }
+ return 0;
+}
--- /dev/null
+#include "cache.h"
+
+const char *sha1_file_directory = NULL;
+struct cache_entry **active_cache = NULL;
+unsigned int active_nr = 0, active_alloc = 0;
+
+void usage(const char *err)
+{
+ fprintf(stderr, "read-tree: %s\n", err);
+ exit(1);
+}
+
+static unsigned hexval(char c)
+{
+ if (c >= '0' && c <= '9')
+ return c - '0';
+ if (c >= 'a' && c <= 'f')
+ return c - 'a' + 10;
+ if (c >= 'A' && c <= 'F')
+ return c - 'A' + 10;
+ return ~0;
+}
+
+int get_sha1_hex(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;
+}
+
+char * sha1_to_hex(unsigned char *sha1)
+{
+ static char buffer[50];
+ static const char hex[] = "0123456789abcdef";
+ char *buf = buffer;
+ int i;
+
+ for (i = 0; i < 20; i++) {
+ unsigned int val = *sha1++;
+ *buf++ = hex[val >> 4];
+ *buf++ = hex[val & 0xf];
+ }
+ return buffer;
+}
+
+/*
+ * 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.
+ */
+char *sha1_file_name(unsigned char *sha1)
+{
+ int i;
+ static char *name, *base;
+
+ if (!base) {
+ char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
+ int len = strlen(sha1_file_directory);
+ base = malloc(len + 60);
+ memcpy(base, sha1_file_directory, len);
+ memset(base+len, 0, 60);
+ base[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];
+ }
+ return base;
+}
+
+void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
+{
+ z_stream stream;
+ char buffer[8192];
+ struct stat st;
+ int i, fd, ret, bytes;
+ void *map, *buf;
+ char *filename = sha1_file_name(sha1);
+
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ perror(filename);
+ return NULL;
+ }
+ 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 NULL;
+
+ /* Get the data stream */
+ memset(&stream, 0, sizeof(stream));
+ stream.next_in = map;
+ stream.avail_in = st.st_size;
+ stream.next_out = buffer;
+ stream.avail_out = sizeof(buffer);
+
+ inflateInit(&stream);
+ ret = inflate(&stream, 0);
+ if (sscanf(buffer, "%10s %lu", type, size) != 2)
+ return NULL;
+ bytes = strlen(buffer) + 1;
+ buf = malloc(*size);
+ if (!buf)
+ return NULL;
+
+ 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 */;
+ }
+ inflateEnd(&stream);
+ return buf;
+}
+
+int write_sha1_file(char *buf, unsigned len)
+{
+ int size;
+ char *compressed;
+ z_stream stream;
+ unsigned char sha1[20];
+ SHA_CTX c;
+
+ /* Set it up */
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_BEST_COMPRESSION);
+ size = deflateBound(&stream, len);
+ compressed = malloc(size);
+
+ /* Compress it */
+ stream.next_in = buf;
+ stream.avail_in = len;
+ stream.next_out = compressed;
+ stream.avail_out = size;
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ deflateEnd(&stream);
+ size = stream.total_out;
+
+ /* Sha1.. */
+ SHA1_Init(&c);
+ SHA1_Update(&c, compressed, size);
+ SHA1_Final(sha1, &c);
+
+ if (write_sha1_buffer(sha1, compressed, size) < 0)
+ return -1;
+ printf("%s\n", sha1_to_hex(sha1));
+ return 0;
+}
+
+int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
+{
+ char *filename = sha1_file_name(sha1);
+ int i, fd;
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+ if (fd < 0)
+ return (errno == EEXIST) ? 0 : -1;
+ write(fd, buf, size);
+ close(fd);
+ return 0;
+}
+
+static int error(const char * string)
+{
+ fprintf(stderr, "error: %s\n", string);
+ return -1;
+}
+
+static int verify_hdr(struct cache_header *hdr, unsigned long size)
+{
+ SHA_CTX c;
+ unsigned char sha1[20];
+
+ if (hdr->signature != CACHE_SIGNATURE)
+ return error("bad signature");
+ if (hdr->version != 1)
+ return error("bad version");
+ SHA1_Init(&c);
+ SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
+ SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
+ SHA1_Final(sha1, &c);
+ if (memcmp(sha1, hdr->sha1, 20))
+ return error("bad header sha1");
+ return 0;
+}
+
+int read_cache(void)
+{
+ int fd, i;
+ struct stat st;
+ unsigned long size, offset;
+ void *map;
+ struct cache_header *hdr;
+
+ errno = EBUSY;
+ if (active_cache)
+ return error("more than one cachefile");
+ errno = ENOENT;
+ sha1_file_directory = getenv(DB_ENVIRONMENT);
+ if (!sha1_file_directory)
+ sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
+ if (access(sha1_file_directory, X_OK) < 0)
+ return error("no access to SHA1 file directory");
+ fd = open(".dircache/index", O_RDONLY);
+ if (fd < 0)
+ return (errno == ENOENT) ? 0 : error("open failed");
+
+ map = (void *)-1;
+ if (!fstat(fd, &st)) {
+ map = NULL;
+ size = st.st_size;
+ errno = EINVAL;
+ if (size > sizeof(struct cache_header))
+ map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ }
+ close(fd);
+ if (-1 == (int)(long)map)
+ return error("mmap failed");
+
+ hdr = map;
+ if (verify_hdr(hdr, size) < 0)
+ goto unmap;
+
+ active_nr = hdr->entries;
+ active_alloc = alloc_nr(active_nr);
+ active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
+
+ offset = sizeof(*hdr);
+ for (i = 0; i < hdr->entries; i++) {
+ struct cache_entry *ce = map + offset;
+ offset = offset + ce_size(ce);
+ active_cache[i] = ce;
+ }
+ return active_nr;
+
+unmap:
+ munmap(map, size);
+ errno = EINVAL;
+ return error("verify header failed");
+}
+
--- /dev/null
+#include "cache.h"
+
+static int unpack(unsigned char *sha1)
+{
+ void *buffer;
+ unsigned long size;
+ char type[20];
+
+ buffer = read_sha1_file(sha1, type, &size);
+ if (!buffer)
+ usage("unable to read sha1 file");
+ if (strcmp(type, "tree"))
+ usage("expected a 'tree' node");
+ while (size) {
+ int len = strlen(buffer)+1;
+ unsigned char *sha1 = buffer + len;
+ char *path = strchr(buffer, ' ')+1;
+ unsigned int mode;
+ if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
+ usage("corrupt 'tree' file");
+ buffer = sha1 + 20;
+ size -= len + 20;
+ printf("%o %s (%s)\n", mode, path, sha1_to_hex(sha1));
+ }
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int fd;
+ unsigned char sha1[20];
+
+ if (argc != 2)
+ usage("read-tree <key>");
+ if (get_sha1_hex(argv[1], sha1) < 0)
+ usage("read-tree <key>");
+ sha1_file_directory = getenv(DB_ENVIRONMENT);
+ if (!sha1_file_directory)
+ sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
+ if (unpack(sha1) < 0)
+ usage("unpack failed");
+ return 0;
+}
--- /dev/null
+#include "cache.h"
+
+#define MTIME_CHANGED 0x0001
+#define CTIME_CHANGED 0x0002
+#define OWNER_CHANGED 0x0004
+#define MODE_CHANGED 0x0008
+#define INODE_CHANGED 0x0010
+#define DATA_CHANGED 0x0020
+
+static int match_stat(struct cache_entry *ce, struct stat *st)
+{
+ unsigned int changed = 0;
+
+ if (ce->mtime.sec != (unsigned int)st->st_mtim.tv_sec ||
+ ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
+ changed |= MTIME_CHANGED;
+ if (ce->ctime.sec != (unsigned int)st->st_ctim.tv_sec ||
+ ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
+ changed |= CTIME_CHANGED;
+ if (ce->st_uid != (unsigned int)st->st_uid ||
+ ce->st_gid != (unsigned int)st->st_gid)
+ changed |= OWNER_CHANGED;
+ if (ce->st_mode != (unsigned int)st->st_mode)
+ changed |= MODE_CHANGED;
+ if (ce->st_dev != (unsigned int)st->st_dev ||
+ ce->st_ino != (unsigned int)st->st_ino)
+ changed |= INODE_CHANGED;
+ if (ce->st_size != (unsigned int)st->st_size)
+ changed |= DATA_CHANGED;
+ return changed;
+}
+
+static void show_differences(struct cache_entry *ce, struct stat *cur,
+ void *old_contents, unsigned long long old_size)
+{
+ static char cmd[1000];
+ FILE *f;
+
+ snprintf(cmd, sizeof(cmd), "diff -u - %s", ce->name);
+ f = popen(cmd, "w");
+ fwrite(old_contents, old_size, 1, f);
+ pclose(f);
+}
+
+int main(int argc, char **argv)
+{
+ int entries = read_cache();
+ int i;
+
+ if (entries < 0) {
+ perror("read_cache");
+ exit(1);
+ }
+ for (i = 0; i < entries; i++) {
+ struct stat st;
+ struct cache_entry *ce = active_cache[i];
+ int n, changed;
+ unsigned int mode;
+ unsigned long size;
+ char type[20];
+ void *new;
+
+ if (stat(ce->name, &st) < 0) {
+ printf("%s: %s\n", ce->name, strerror(errno));
+ continue;
+ }
+ changed = match_stat(ce, &st);
+ if (!changed) {
+ printf("%s: ok\n", ce->name);
+ continue;
+ }
+ printf("%.*s: ", ce->namelen, ce->name);
+ for (n = 0; n < 20; n++)
+ printf("%02x", ce->sha1[n]);
+ printf("\n");
+ new = read_sha1_file(ce->sha1, type, &size);
+ show_differences(ce, &st, new, size);
+ free(new);
+ }
+ return 0;
+}
--- /dev/null
+#include "cache.h"
+
+static int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
+{
+ int len = len1 < len2 ? len1 : len2;
+ int cmp;
+
+ cmp = memcmp(name1, name2, len);
+ if (cmp)
+ return cmp;
+ if (len1 < len2)
+ return -1;
+ if (len1 > len2)
+ return 1;
+ return 0;
+}
+
+static int cache_name_pos(const char *name, int namelen)
+{
+ int first, last;
+
+ first = 0;
+ last = active_nr;
+ while (last > first) {
+ int next = (last + first) >> 1;
+ struct cache_entry *ce = active_cache[next];
+ int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
+ if (!cmp)
+ return -next-1;
+ if (cmp < 0) {
+ last = next;
+ continue;
+ }
+ first = next+1;
+ }
+ return first;
+}
+
+static int remove_file_from_cache(char *path)
+{
+ int pos = cache_name_pos(path, strlen(path));
+ if (pos < 0) {
+ pos = -pos-1;
+ active_nr--;
+ if (pos < active_nr)
+ memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
+ }
+}
+
+static int add_cache_entry(struct cache_entry *ce)
+{
+ int pos;
+
+ pos = cache_name_pos(ce->name, ce->namelen);
+
+ /* existing match? Just replace it */
+ if (pos < 0) {
+ active_cache[-pos-1] = ce;
+ return 0;
+ }
+
+ /* Make sure the array is big enough .. */
+ if (active_nr == active_alloc) {
+ active_alloc = alloc_nr(active_alloc);
+ active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
+ }
+
+ /* Add it in.. */
+ active_nr++;
+ if (active_nr > pos)
+ memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
+ active_cache[pos] = ce;
+ return 0;
+}
+
+static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
+{
+ z_stream stream;
+ int max_out_bytes = namelen + st->st_size + 200;
+ void *out = malloc(max_out_bytes);
+ void *metadata = malloc(namelen + 200);
+ void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ SHA_CTX c;
+
+ close(fd);
+ if (!out || (int)(long)in == -1)
+ return -1;
+
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_BEST_COMPRESSION);
+
+ /*
+ * ASCII size + nul byte
+ */
+ stream.next_in = metadata;
+ stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
+ stream.next_out = out;
+ stream.avail_out = max_out_bytes;
+ while (deflate(&stream, 0) == Z_OK)
+ /* nothing */;
+
+ /*
+ * File content
+ */
+ stream.next_in = in;
+ stream.avail_in = st->st_size;
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ /*nothing */;
+
+ deflateEnd(&stream);
+
+ SHA1_Init(&c);
+ SHA1_Update(&c, out, stream.total_out);
+ SHA1_Final(ce->sha1, &c);
+
+ return write_sha1_buffer(ce->sha1, out, stream.total_out);
+}
+
+static int add_file_to_cache(char *path)
+{
+ int size, namelen;
+ struct cache_entry *ce;
+ struct stat st;
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ return remove_file_from_cache(path);
+ return -1;
+ }
+ if (fstat(fd, &st) < 0) {
+ close(fd);
+ return -1;
+ }
+ namelen = strlen(path);
+ size = cache_entry_size(namelen);
+ ce = malloc(size);
+ memset(ce, 0, size);
+ memcpy(ce->name, path, namelen);
+ ce->ctime.sec = st.st_ctime;
+ ce->ctime.nsec = st.st_ctim.tv_nsec;
+ ce->mtime.sec = st.st_mtime;
+ ce->mtime.nsec = st.st_mtim.tv_nsec;
+ ce->st_dev = st.st_dev;
+ ce->st_ino = st.st_ino;
+ ce->st_mode = st.st_mode;
+ ce->st_uid = st.st_uid;
+ ce->st_gid = st.st_gid;
+ ce->st_size = st.st_size;
+ ce->namelen = namelen;
+
+ if (index_fd(path, namelen, ce, fd, &st) < 0)
+ return -1;
+
+ return add_cache_entry(ce);
+}
+
+static int write_cache(int newfd, struct cache_entry **cache, int entries)
+{
+ SHA_CTX c;
+ struct cache_header hdr;
+ int i;
+
+ hdr.signature = CACHE_SIGNATURE;
+ hdr.version = 1;
+ hdr.entries = entries;
+
+ SHA1_Init(&c);
+ SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
+ for (i = 0; i < entries; i++) {
+ struct cache_entry *ce = cache[i];
+ int size = ce_size(ce);
+ SHA1_Update(&c, ce, size);
+ }
+ SHA1_Final(hdr.sha1, &c);
+
+ if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
+ return -1;
+
+ for (i = 0; i < entries; i++) {
+ struct cache_entry *ce = cache[i];
+ int size = ce_size(ce);
+ if (write(newfd, ce, size) != size)
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * We fundamentally don't like some paths: we don't want
+ * dot or dot-dot anywhere, and in fact, we don't even want
+ * any other dot-files (.dircache or anything else). They
+ * are hidden, for chist sake.
+ *
+ * Also, we don't want double slashes or slashes at the
+ * end that can make pathnames ambiguous.
+ */
+static int verify_path(char *path)
+{
+ char c;
+
+ goto inside;
+ for (;;) {
+ if (!c)
+ return 1;
+ if (c == '/') {
+inside:
+ c = *path++;
+ if (c != '/' && c != '.' && c != '\0')
+ continue;
+ return 0;
+ }
+ c = *path++;
+ }
+}
+
+int main(int argc, char **argv)
+{
+ int i, newfd, entries;
+
+ entries = read_cache();
+ if (entries < 0) {
+ perror("cache corrupted");
+ return -1;
+ }
+
+ newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
+ if (newfd < 0) {
+ perror("unable to create new cachefile");
+ return -1;
+ }
+ for (i = 1 ; i < argc; i++) {
+ char *path = argv[i];
+ if (!verify_path(path)) {
+ fprintf(stderr, "Ignoring path %s\n", argv[i]);
+ continue;
+ }
+ if (add_file_to_cache(path)) {
+ fprintf(stderr, "Unable to add %s to database\n", path);
+ goto out;
+ }
+ }
+ if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
+ return 0;
+out:
+ unlink(".dircache/index.lock");
+}
--- /dev/null
+#include "cache.h"
+
+static int check_valid_sha1(unsigned char *sha1)
+{
+ char *filename = sha1_file_name(sha1);
+ int ret;
+
+ /* If we were anal, we'd check that the sha1 of the contents actually matches */
+ ret = access(filename, R_OK);
+ if (ret)
+ perror(filename);
+ return ret;
+}
+
+static int prepend_integer(char *buffer, unsigned val, int i)
+{
+ buffer[--i] = '\0';
+ do {
+ buffer[--i] = '0' + (val % 10);
+ val /= 10;
+ } while (val);
+ return i;
+}
+
+#define ORIG_OFFSET (40) /* Enough space to add the header of "tree <size>\0" */
+
+int main(int argc, char **argv)
+{
+ unsigned long size, offset, val;
+ int i, entries = read_cache();
+ char *buffer;
+
+ if (entries <= 0) {
+ fprintf(stderr, "No file-cache to create a tree of\n");
+ exit(1);
+ }
+
+ /* Guess at an initial size */
+ size = entries * 40 + 400;
+ buffer = malloc(size);
+ offset = ORIG_OFFSET;
+
+ for (i = 0; i < entries; i++) {
+ struct cache_entry *ce = active_cache[i];
+ if (check_valid_sha1(ce->sha1) < 0)
+ exit(1);
+ if (offset + ce->namelen + 60 > size) {
+ size = alloc_nr(offset + ce->namelen + 60);
+ buffer = realloc(buffer, size);
+ }
+ offset += sprintf(buffer + offset, "%o %s", ce->st_mode, ce->name);
+ buffer[offset++] = 0;
+ memcpy(buffer + offset, ce->sha1, 20);
+ offset += 20;
+ }
+
+ i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
+ i -= 5;
+ memcpy(buffer+i, "tree ", 5);
+
+ buffer += i;
+ offset -= i;
+
+ write_sha1_file(buffer, offset);
+ return 0;
+}