bash: Hide git-fast-import.
[gitweb.git] / sha1_file.c
index 63123cc47be29430565f594340374271248f01bc..0d4bf80e74b16aa089acd06c24ad1b1a039e65b5 100644 (file)
 #endif
 #endif
 
+#ifdef NO_C99_FORMAT
+#define SZ_FMT "lu"
+#else
+#define SZ_FMT "zu"
+#endif
+
 const unsigned char null_sha1[20];
 
 static unsigned int sha1_file_open_flag = O_NOATIME;
@@ -355,10 +361,8 @@ static void read_info_alternates(const char * relative_base, int depth)
                close(fd);
                return;
        }
-       map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       if (map == MAP_FAILED)
-               return;
 
        link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 
@@ -398,15 +402,40 @@ static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 }
 
 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;
 static size_t page_size;
 struct packed_git *packed_git;
 
+void pack_report()
+{
+       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",
+               page_size,
+               packed_git_window_size,
+               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,
+               pack_mapped, peak_pack_mapped);
+}
+
 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
                                void **idx_map_)
 {
        void *idx_map;
-       unsigned int *index;
+       uint32_t *index;
        unsigned long idx_size;
        int nr, i;
        int fd = open(path, O_RDONLY);
@@ -418,10 +447,8 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
                return -1;
        }
        idx_size = st.st_size;
-       idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       if (idx_map == MAP_FAILED)
-               return -1;
 
        index = idx_map;
        *idx_map_ = idx_map;
@@ -429,12 +456,23 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 
        /* check index map */
        if (idx_size < 4*256 + 20 + 20)
-               return error("index file too small");
+               return error("index file %s is too small", path);
+
+       /* a future index format would start with this, as older git
+        * binaries would fail the non-monotonic index check below.
+        * give a nicer warning to the user if we can.
+        */
+       if (index[0] == htonl(PACK_IDX_SIGNATURE))
+               return error("index file %s is a newer version"
+                       " and is not supported by this binary"
+                       " (try upgrading GIT to a newer version)",
+                       path);
+
        nr = 0;
        for (i = 0; i < 256; i++) {
                unsigned int n = ntohl(index[i]);
                if (n < nr)
-                       return error("non-monotonic index");
+                       return error("non-monotonic index %s", path);
                nr = n;
        }
 
@@ -446,28 +484,39 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
         *  - 20-byte SHA1 file checksum
         */
        if (idx_size != 4*256 + nr * 24 + 20 + 20)
-               return error("wrong index file size");
+               return error("wrong index file size in %s", path);
 
        return 0;
 }
 
-static int unuse_one_window(void)
+static void scan_windows(struct packed_git *p,
+       struct packed_git **lru_p,
+       struct pack_window **lru_w,
+       struct pack_window **lru_l)
 {
-       struct packed_git *p, *lru_p = NULL;
-       struct pack_window *w, *w_l, *lru_w = NULL, *lru_l = NULL;
+       struct pack_window *w, *w_l;
 
-       for (p = packed_git; p; p = p->next) {
-               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;
-                               }
+       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;
                }
+               w_l = w;
        }
+}
+
+static int unuse_one_window(struct packed_git *current)
+{
+       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;
@@ -475,17 +524,25 @@ static int unuse_one_window(void)
                        lru_l->next = lru_w->next;
                else {
                        lru_p->windows = lru_w->next;
-                       if (!lru_p->windows) {
+                       if (!lru_p->windows && lru_p != current) {
                                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)
+{
+       size_t cur = pack_mapped;
+       while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
+               ; /* nothing */
+}
+
 void unuse_pack(struct pack_window **w_cursor)
 {
        struct pack_window *w = *w_cursor;
@@ -495,46 +552,75 @@ void unuse_pack(struct pack_window **w_cursor)
        }
 }
 
-static void open_packed_git(struct packed_git *p)
+/*
+ * 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;
 
        p->pack_fd = open(p->pack_name, O_RDONLY);
        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
-               die("packfile %s cannot be opened", p->pack_name);
+               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))
-                       die("packfile %s not a regular file", p->pack_name);
+                       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)
-               die("packfile %s size changed", p->pack_name);
+               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. */
-       read_or_die(p->pack_fd, &hdr, sizeof(hdr));
+       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))
-               die("file %s is not a GIT packfile", p->pack_name);
+               return error("file %s is not a GIT packfile", p->pack_name);
        if (!pack_version_ok(hdr.hdr_version))
-               die("packfile %s is version %u and not supported"
+               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 (num_packed_objects(p) != ntohl(hdr.hdr_entries))
-               die("packfile %s claims to have %u objects"
+               return error("packfile %s claims to have %u objects"
                        " while index size indicates %u objects",
                        p->pack_name, ntohl(hdr.hdr_entries),
                        num_packed_objects(p));
        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
-               die("end of packfile %s is unavailable", p->pack_name);
-       read_or_die(p->pack_fd, sha1, sizeof(sha1));
+               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_base) + p->index_size - 40;
        if (hashcmp(sha1, idx_sha1))
-               die("packfile %s does not match index", p->pack_name);
+               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, unsigned long offset)
@@ -557,8 +643,8 @@ unsigned char* use_pack(struct packed_git *p,
 {
        struct pack_window *win = *w_cursor;
 
-       if (p->pack_fd == -1)
-               open_packed_git(p);
+       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
@@ -584,15 +670,22 @@ unsigned char* use_pack(struct packed_git *p,
                        if (win->len > packed_git_window_size)
                                win->len = packed_git_window_size;
                        pack_mapped += win->len;
-                       while (packed_git_limit < pack_mapped && unuse_one_window())
+                       while (packed_git_limit < pack_mapped
+                               && unuse_one_window(p))
                                ; /* nothing */
-                       win->base = mmap(NULL, win->len,
+                       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;
                }
@@ -702,7 +795,7 @@ static void prepare_packed_git_one(char *objdir, int local)
                if (!has_extension(de->d_name, ".idx"))
                        continue;
 
-               /* we have .idx.  Is it a file we can map? */
+               /* 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))
@@ -710,11 +803,13 @@ static void prepare_packed_git_one(char *objdir, int local)
                }
                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;
-               p->next = packed_git;
-               packed_git = p;
+               install_packed_git(p);
        }
        closedir(dir);
 }
@@ -778,10 +873,8 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
                 */
                sha1_file_open_flag = 0;
        }
-       map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       if (map == MAP_FAILED)
-               return NULL;
        *size = st.st_size;
        return map;
 }
@@ -1070,7 +1163,7 @@ static unsigned long unpack_object_header(struct packed_git *p,
 
        /* 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 assurred.)  With our object header encoding
+        * 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.
         */
@@ -1276,7 +1369,7 @@ int nth_packed_object_sha1(const struct packed_git *p, int n,
 unsigned long find_pack_entry_one(const unsigned char *sha1,
                                  struct packed_git *p)
 {
-       unsigned int *level1_ofs = p->index_base;
+       uint32_t *level1_ofs = p->index_base;
        int hi = ntohl(level1_ofs[*sha1]);
        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
        void *index = p->index_base + 256;
@@ -1285,7 +1378,7 @@ unsigned long find_pack_entry_one(const unsigned char *sha1,
                int mi = (lo + hi) / 2;
                int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
                if (!cmp)
-                       return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
+                       return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
                if (cmp > 0)
                        hi = mi;
                else
@@ -1330,6 +1423,18 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
                }
                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);
+                               continue;
+                       }
                        e->offset = offset;
                        e->p = p;
                        hashcpy(e->sha1, sha1);
@@ -1394,21 +1499,77 @@ static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned lo
 {
        struct pack_entry e;
 
-       if (!find_pack_entry(sha1, &e, NULL)) {
-               error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+       if (!find_pack_entry(sha1, &e, NULL))
                return NULL;
+       else
+               return unpack_entry(e.p, e.offset, type, size);
+}
+
+/*
+ * 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];
+       const char *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, const char *type, unsigned char *sha1)
+{
+       struct cached_object *co;
+
+       hash_sha1_file(buf, len, 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);
        }
-       return unpack_entry(e.p, e.offset, type, size);
+       co = &cached_objects[cached_object_nr++];
+       co->size = len;
+       co->type = strdup(type);
+       hashcpy(co->sha1, sha1);
+       return 0;
 }
 
 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 {
        unsigned long mapsize;
        void *map, *buf;
-       struct pack_entry e;
+       struct cached_object *co;
+
+       co = find_cached_object(sha1);
+       if (co) {
+               buf = xmalloc(co->size + 1);
+               memcpy(buf, co->buf, co->size);
+               ((char*)buf)[co->size] = 0;
+               strcpy(type, co->type);
+               *size = co->size;
+               return buf;
+       }
 
-       if (find_pack_entry(sha1, &e, NULL))
-               return read_packed_sha1(sha1, type, 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);
@@ -1416,9 +1577,7 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
                return buf;
        }
        reprepare_packed_git();
-       if (find_pack_entry(sha1, &e, NULL))
-               return read_packed_sha1(sha1, type, size);
-       return NULL;
+       return read_packed_sha1(sha1, type, size);
 }
 
 void *read_object_with_reference(const unsigned char *sha1,
@@ -1556,20 +1715,8 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
 
 static int write_buffer(int fd, const void *buf, size_t len)
 {
-       while (len) {
-               ssize_t size;
-
-               size = write(fd, buf, len);
-               if (!size)
-                       return error("file write: disk full");
-               if (size < 0) {
-                       if (errno == EINTR || errno == EAGAIN)
-                               continue;
-                       return error("file write error (%s)", strerror(errno));
-               }
-               len -= size;
-               buf = (char *) buf + size;
-       }
+       if (write_in_full(fd, buf, len) < 0)
+               return error("file write error (%s)", strerror(errno));
        return 0;
 }
 
@@ -1718,6 +1865,8 @@ static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
 
        /* 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", type, len) + 1;
 
@@ -1814,7 +1963,7 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
                        if (ret != Z_OK)
                                break;
                }
-               size = read(fd, buffer + *bufposn, bufsize - *bufposn);
+               size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
                if (size <= 0) {
                        close(local);
                        unlink(tmpfile);
@@ -1937,10 +2086,8 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
 
        buf = "";
        if (size)
-               buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+               buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       if (buf == MAP_FAILED)
-               return -1;
 
        if (!type)
                type = blob_type;
@@ -1988,3 +2135,24 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
        }
        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;
+}