From c2f493a4ae159ef99b20be490ae603cd13bab4eb Mon Sep 17 00:00:00 2001 From: Martin Waitz Date: Sun, 7 May 2006 20:19:21 +0200 Subject: [PATCH 1/3] Transitively read alternatives When adding an alternate object store then add entries from its info/alternates files, too. Relative entries are only allowed in the current repository. Loops and duplicate alternates through multiple repositories are ignored. Just to be sure that nothing breaks it is not allow to build deep nesting levels using info/alternates. Signed-off-by: Martin Waitz Signed-off-by: Junio C Hamano --- sha1_file.c | 178 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 106 insertions(+), 72 deletions(-) diff --git a/sha1_file.c b/sha1_file.c index 5464828259..b62d0e3dcd 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -217,6 +217,8 @@ char *sha1_pack_index_name(const unsigned char *sha1) 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. * @@ -232,14 +234,85 @@ static struct alternate_object_database **alt_odb_tail; * SHA1, an extra slash for the first level indirection, and the * terminating NUL. */ -static void link_alt_odb_entries(const char *alt, const char *ep, int sep, - const char *relative_base) +static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth) { - const char *cp, *last; - struct alternate_object_database *ent; + 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 (*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 (*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; @@ -249,60 +322,15 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep, last = cp + 1; continue; } - for ( ; cp < ep && *cp != sep; cp++) - ; + while (cp < ep && *cp != sep) + cp++; if (last != cp) { - struct stat st; - struct alternate_object_database *alt; - /* 43 = 40-byte + 2 '/' + terminating NUL */ - int pfxlen = cp - last; - int entlen = pfxlen + 43; - - if (*last != '/' && 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 (*last != '/' && relative_base) { - memcpy(ent->base, relative_base, base_len - 1); - ent->base[base_len - 1] = '/'; - memcpy(ent->base + base_len, - last, cp - last); - } - else - memcpy(ent->base, last, 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); - goto bad; - } - ent->base[pfxlen] = '/'; - - /* 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)) - goto bad; - if (!memcmp(ent->base, objdir, pfxlen)) { - bad: - free(ent); - } - else { - *alt_odb_tail = ent; - alt_odb_tail = &(ent->next); - ent->next = NULL; + if ((*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) @@ -311,23 +339,14 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep, } } -void prepare_alt_odb(void) +static void read_info_alternates(const char * relative_base, int depth) { - char path[PATH_MAX]; char *map; - int fd; struct stat st; - char *alt; - - alt = getenv(ALTERNATE_DB_ENVIRONMENT); - if (!alt) alt = ""; - - if (alt_odb_tail) - return; - alt_odb_tail = &alt_odb_list; - link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL); + char path[PATH_MAX]; + int fd; - sprintf(path, "%s/info/alternates", get_object_directory()); + sprintf(path, "%s/info/alternates", relative_base); fd = open(path, O_RDONLY); if (fd < 0) return; @@ -340,11 +359,26 @@ void prepare_alt_odb(void) if (map == MAP_FAILED) return; - link_alt_odb_entries(map, map + st.st_size, '\n', - get_object_directory()); + link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth); + munmap(map, st.st_size); } +void prepare_alt_odb(void) +{ + char *alt; + + alt = getenv(ALTERNATE_DB_ENVIRONMENT); + if (!alt) alt = ""; + + if (alt_odb_tail) + return; + 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); From dd05ea1799656024a45017238bbd4857b5256370 Mon Sep 17 00:00:00 2001 From: Martin Waitz Date: Sun, 7 May 2006 20:19:47 +0200 Subject: [PATCH 2/3] test case for transitive info/alternates Signed-off-by: Martin Waitz Signed-off-by: Junio C Hamano --- t/t5710-info-alternate.sh | 105 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100755 t/t5710-info-alternate.sh diff --git a/t/t5710-info-alternate.sh b/t/t5710-info-alternate.sh new file mode 100755 index 0000000000..097d037f5d --- /dev/null +++ b/t/t5710-info-alternate.sh @@ -0,0 +1,105 @@ +#!/bin/sh +# +# Copyright (C) 2006 Martin Waitz +# + +test_description='test transitive info/alternate entries' +. ./test-lib.sh + +# test that a file is not reachable in the current repository +# but that it is after creating a info/alternate entry +reachable_via() { + alternate="$1" + file="$2" + if git cat-file -e "HEAD:$file"; then return 1; fi + echo "$alternate" >> .git/objects/info/alternate + git cat-file -e "HEAD:$file" +} + +test_valid_repo() { + git fsck-objects --full > fsck.log && + test `wc -l < fsck.log` = 0 +} + +base_dir=`pwd` + +test_expect_success 'preparing first repository' \ +'test_create_repo A && cd A && +echo "Hello World" > file1 && +git add file1 && +git commit -m "Initial commit" file1 && +git repack -a -d && +git prune' + +cd "$base_dir" + +test_expect_success 'preparing second repository' \ +'git clone -l -s A B && cd B && +echo "foo bar" > file2 && +git add file2 && +git commit -m "next commit" file2 && +git repack -a -d -l && +git prune' + +cd "$base_dir" + +test_expect_success 'preparing third repository' \ +'git clone -l -s B C && cd C && +echo "Goodbye, cruel world" > file3 && +git add file3 && +git commit -m "one more" file3 && +git repack -a -d -l && +git prune' + +cd "$base_dir" + +test_expect_failure 'creating too deep nesting' \ +'git clone -l -s C D && +git clone -l -s D E && +git clone -l -s E F && +git clone -l -s F G && +test_valid_repo' + +cd "$base_dir" + +test_expect_success 'validity of third repository' \ +'cd C && +test_valid_repo' + +cd "$base_dir" + +test_expect_success 'validity of fourth repository' \ +'cd D && +test_valid_repo' + +cd "$base_dir" + +test_expect_success 'breaking of loops' \ +"echo '$base_dir/B/.git/objects' >> '$base_dir'/A/.git/objects/info/alternates&& +cd C && +test_valid_repo" + +cd "$base_dir" + +test_expect_failure 'that info/alternates is neccessary' \ +'cd C && +rm .git/objects/info/alternates && +test_valid_repo' + +cd "$base_dir" + +test_expect_success 'that relative alternate is possible for current dir' \ +'cd C && +echo "../../../B/.git/objects" > .git/objects/info/alternates && +test_valid_repo' + +cd "$base_dir" + +test_expect_failure 'that relative alternate is only possible for current dir' \ +'cd D && +test_valid_repo' + +cd "$base_dir" + +test_done + From 0438402271cccc1711c603b0a7ba3134f1ce30f1 Mon Sep 17 00:00:00 2001 From: Martin Waitz Date: Sun, 7 May 2006 20:19:33 +0200 Subject: [PATCH 3/3] clone: don't clone the info/alternates file Now that the cloned alternates file is parsed, too we don't need to copy it into our new repository, we just reference it. Signed-off-by: Martin Waitz Signed-off-by: Junio C Hamano --- git-clone.sh | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/git-clone.sh b/git-clone.sh index b78524767c..227245c865 100755 --- a/git-clone.sh +++ b/git-clone.sh @@ -261,11 +261,7 @@ yes,yes) ;; yes) mkdir -p "$GIT_DIR/objects/info" - { - test -f "$repo/objects/info/alternates" && - cat "$repo/objects/info/alternates"; - echo "$repo/objects" - } >>"$GIT_DIR/objects/info/alternates" + echo "$repo/objects" >> "$GIT_DIR/objects/info/alternates" ;; esac git-ls-remote "$repo" >"$GIT_DIR/CLONE_HEAD"