Split "git-pull-script" into two parts
[gitweb.git] / sha1_file.c
index bb44a01746cb08863fde8a320bee40bcb3806fcf..e6ce455ae90bd430f2128f454bdb6e0575412486 100644 (file)
 
 const char *sha1_file_directory = NULL;
 
+#ifndef O_NOATIME
+#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
+#define O_NOATIME 01000000
+#else
+#define O_NOATIME 0
+#endif
+#endif
+
+static unsigned int sha1_file_open_flag = O_NOATIME;
+
 static unsigned hexval(char c)
 {
        if (c >= '0' && c <= '9')
@@ -35,6 +45,48 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
        return 0;
 }
 
+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);
+}
+
+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 *gitdir;
+       const char **p;
+
+       if (!get_sha1_hex(str, sha1))
+               return 0;
+
+       gitdir = ".git";
+       for (p = prefix; *p; p++) {
+               snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str);
+               if (!get_sha1_file(pathname, sha1))
+                       return 0;
+       }
+
+       return -1;
+}
+
 char * sha1_to_hex(const unsigned char *sha1)
 {
        static char buffer[50];
@@ -63,7 +115,7 @@ char *sha1_file_name(const unsigned char *sha1)
        if (!base) {
                char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
                int len = strlen(sha1_file_directory);
-               base = malloc(len + 60);
+               base = xmalloc(len + 60);
                memcpy(base, sha1_file_directory, len);
                memset(base+len, 0, 60);
                base[len] = '/';
@@ -80,12 +132,14 @@ char *sha1_file_name(const unsigned char *sha1)
        return base;
 }
 
-int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
+int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
 {
+       char header[100];
        unsigned char real_sha1[20];
        SHA_CTX c;
 
        SHA1_Init(&c);
+       SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
        SHA1_Update(&c, map, size);
        SHA1_Final(real_sha1, &c);
        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
@@ -94,13 +148,26 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
        char *filename = sha1_file_name(sha1);
-       int fd = open(filename, O_RDONLY);
        struct stat st;
        void *map;
+       int fd;
 
+       fd = open(filename, O_RDONLY | sha1_file_open_flag);
        if (fd < 0) {
-               perror(filename);
-               return NULL;
+               /* 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:
+                       perror(filename);
+                       return NULL;
+               }
+
+               /* 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);
@@ -130,13 +197,13 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
 
        inflateInit(&stream);
        ret = inflate(&stream, 0);
+       if (ret < Z_OK)
+               return NULL;
        if (sscanf(buffer, "%10s %lu", type, size) != 2)
                return NULL;
 
        bytes = strlen(buffer) + 1;
-       buf = malloc(*size);
-       if (!buf)
-               return NULL;
+       buf = xmalloc(*size);
 
        memcpy(buf, buffer + bytes, stream.total_out - bytes);
        bytes = stream.total_out - bytes;
@@ -164,84 +231,242 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
        return NULL;
 }
 
-int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
+void *read_object_with_reference(const unsigned char *sha1,
+                                const unsigned char *required_type,
+                                unsigned long *size,
+                                unsigned char *actual_sha1_return)
+{
+       char type[20];
+       void *buffer;
+       unsigned long isize;
+       unsigned char actual_sha1[20];
+
+       memcpy(actual_sha1, sha1, 20);
+       while (1) {
+               int ref_length = -1;
+               const char *ref_type = NULL;
+
+               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);
+
+               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. */
+       }
+}
+
+int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
        int size;
        char *compressed;
        z_stream stream;
        unsigned char sha1[20];
        SHA_CTX c;
+       char *filename;
+       static char tmpfile[PATH_MAX];
+       char hdr[50];
+       int fd, hdrlen, ret;
+
+       /* 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);
+
+       if (returnsha1)
+               memcpy(returnsha1, sha1, 20);
+
+       filename = sha1_file_name(sha1);
+       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) {
+               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);
-       size = deflateBound(&stream, len);
-       compressed = malloc(size);
+       size = deflateBound(&stream, len+hdrlen);
+       compressed = xmalloc(size);
 
        /* Compress it */
-       stream.next_in = buf;
-       stream.avail_in = len;
        stream.next_out = compressed;
        stream.avail_out = size;
+
+       /* First header.. */
+       stream.next_in = hdr;
+       stream.avail_in = hdrlen;
+       while (deflate(&stream, 0) == Z_OK)
+               /* nothing */
+
+       /* Then the data itself.. */
+       stream.next_in = buf;
+       stream.avail_in = len;
        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(fd, compressed, size) != size)
+               die("unable to write file");
+       fchmod(fd, 0444);
+       close(fd);
+
+       ret = link(tmpfile, filename);
+       if (ret < 0) {
+               ret = errno;
+
+               /*
+                * 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;
+               }
+               /* FIXME!!! Collision check here ? */
+       }
 
-       if (write_sha1_buffer(sha1, compressed, size) < 0)
-               return -1;
-       if (returnsha1)
-               memcpy(returnsha1, sha1, 20);
        return 0;
 }
 
-static inline int collision_check(char *filename, void *buf, unsigned int size)
+int write_sha1_from_fd(const unsigned char *sha1, int fd)
 {
-#ifdef COLLISION_CHECK
-       void *map;
-       int fd = open(filename, O_RDONLY);
-       struct stat st;
-       int cmp;
+       char *filename = sha1_file_name(sha1);
 
-       /* Unreadable object, or object went away? Strange. */
-       if (fd < 0)
-               return -1;
+       int local;
+       z_stream stream;
+       unsigned char real_sha1[20];
+       char buf[4096];
+       char discard[4096];
+       int ret;
+       SHA_CTX c;
 
-       if (fstat(fd, &st) < 0 || size != st.st_size)
-               return -1;
+       local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 
-       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
+       if (local < 0)
+               return error("Couldn't open %s\n", filename);
+
+       memset(&stream, 0, sizeof(stream));
+
+       inflateInit(&stream);
+
+       SHA1_Init(&c);
+
+       do {
+               ssize_t size;
+               size = read(fd, buf, 4096);
+               if (size <= 0) {
+                       close(local);
+                       unlink(filename);
+                       if (!size)
+                               return error("Connection closed?");
+                       perror("Reading from connection");
+                       return -1;
+               }
+               write(local, buf, size);
+               stream.avail_in = size;
+               stream.next_in = buf;
+               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);
+               
+       } while (ret == Z_OK);
+       inflateEnd(&stream);
+
+       close(local);
+       SHA1_Final(real_sha1, &c);
+       if (ret != Z_STREAM_END) {
+               unlink(filename);
+               return error("File %s corrupted", sha1_to_hex(sha1));
+       }
+       if (memcmp(sha1, real_sha1, 20)) {
+               unlink(filename);
+               return error("File %s has bad hash\n", sha1_to_hex(sha1));
+       }
+       
        return 0;
 }
 
-int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
+int has_sha1_file(const unsigned char *sha1)
 {
        char *filename = sha1_file_name(sha1);
-       int fd;
+       struct stat st;
 
-       fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0) {
-               if (errno != EEXIST)
-                       return -1;
-               if (collision_check(filename, buf, size))
-                       return error("SHA1 collision detected!"
-                                       " This is bad, bad, BAD!\a\n");
-               return 0;
-       }
-       write(fd, buf, size);
-       close(fd);
+       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;
+}