From 8098a178b26dc7a158d129a092a5b78da6d12b72 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Fri, 30 Sep 2005 14:26:57 -0700 Subject: [PATCH] Add git-symbolic-ref This adds the counterpart of git-update-ref that lets you read and create "symbolic refs". By default it uses a symbolic link to represent ".git/HEAD -> refs/heads/master", but it can be compiled to use the textfile symbolic ref. The places that did 'readlink .git/HEAD' and 'ln -s refs/heads/blah .git/HEAD' have been converted to use new git-symbolic-ref command, so that they can deal with either implementation. Signed-off-by: Junio C Hamano --- .gitignore | 1 + Makefile | 2 +- cache.h | 2 ++ fsck-objects.c | 28 +++++++------------ git-bisect.sh | 7 +++-- git-branch.sh | 6 ++-- git-checkout.sh | 3 +- git-commit.sh | 17 ++++++------ git-sh-setup.sh | 7 +++-- git-status.sh | 4 +-- init-db.c | 10 +++---- refs.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++ setup.c | 16 ++++++----- show-branch.c | 13 ++++++--- symbolic-ref.c | 34 +++++++++++++++++++++++ t/t5400-send-pack.sh | 6 ++-- 16 files changed, 176 insertions(+), 57 deletions(-) create mode 100644 symbolic-ref.c diff --git a/.gitignore b/.gitignore index c3eb9543..e90e2c35 100644 --- a/.gitignore +++ b/.gitignore @@ -82,6 +82,7 @@ git-ssh-push git-ssh-upload git-status git-stripspace +git-symbolic-ref git-tag git-tar-tree git-unpack-file diff --git a/Makefile b/Makefile index e943954c..5648296a 100644 --- a/Makefile +++ b/Makefile @@ -116,7 +116,7 @@ PROGRAMS = \ git-ssh-upload git-tar-tree git-unpack-file \ git-unpack-objects git-update-index git-update-server-info \ git-upload-pack git-verify-pack git-write-tree \ - git-update-ref \ + git-update-ref git-symbolic-ref \ $(SIMPLE_PROGRAMS) # Backward compatibility -- to be removed after 1.0 diff --git a/cache.h b/cache.h index 63823c35..ec2a1610 100644 --- a/cache.h +++ b/cache.h @@ -231,6 +231,8 @@ extern int get_sha1_hex(const char *hex, unsigned char *sha1); extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */ extern int read_ref(const char *filename, unsigned char *sha1); extern const char *resolve_ref(const char *path, unsigned char *sha1, int); +extern int create_symref(const char *git_HEAD, const char *refs_heads_master); +extern int validate_symref(const char *git_HEAD); /* General helper functions */ extern void usage(const char *err) NORETURN; diff --git a/fsck-objects.c b/fsck-objects.c index 247edf05..65cec7d1 100644 --- a/fsck-objects.c +++ b/fsck-objects.c @@ -402,25 +402,17 @@ static void fsck_object_dir(const char *path) static int fsck_head_link(void) { - int fd, count; - char hex[40]; unsigned char sha1[20]; - static char path[PATH_MAX], link[PATH_MAX]; - const char *git_dir = get_git_dir(); - - snprintf(path, sizeof(path), "%s/HEAD", git_dir); - if (readlink(path, link, sizeof(link)) < 0) - return error("HEAD is not a symlink"); - if (strncmp("refs/heads/", link, 11)) - return error("HEAD points to something strange (%s)", link); - fd = open(path, O_RDONLY); - if (fd < 0) - return error("HEAD: %s", strerror(errno)); - count = read(fd, hex, sizeof(hex)); - close(fd); - if (count < 0) - return error("HEAD: %s", strerror(errno)); - if (count < 40 || get_sha1_hex(hex, sha1)) + const char *git_HEAD = strdup(git_path("HEAD")); + const char *git_refs_heads_master = resolve_ref(git_HEAD, sha1, 1); + int pfxlen = strlen(git_HEAD) - 4; /* strip .../.git/ part */ + + if (!git_refs_heads_master) + return error("HEAD is not a symbolic ref"); + if (strncmp(git_refs_heads_master + pfxlen, "refs/heads/", 11)) + return error("HEAD points to something strange (%s)", + git_refs_heads_master + pfxlen); + if (!memcmp(null_sha1, sha1, 20)) return error("HEAD: not a valid git pointer"); return 0; } diff --git a/git-bisect.sh b/git-bisect.sh index 8dc77c99..1ab2f187 100755 --- a/git-bisect.sh +++ b/git-bisect.sh @@ -38,7 +38,8 @@ bisect_start() { # Verify HEAD. If we were bisecting before this, reset to the # top-of-line master first! # - head=$(readlink $GIT_DIR/HEAD) || die "Bad HEAD - I need a symlink" + head=$(GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD) || + die "Bad HEAD - I need a symbolic ref" case "$head" in refs/heads/bisect*) git checkout master || exit @@ -46,7 +47,7 @@ bisect_start() { refs/heads/*) ;; *) - die "Bad HEAD - strange symlink" + die "Bad HEAD - strange symbolic ref" ;; esac @@ -135,7 +136,7 @@ bisect_next() { echo "$rev" > "$GIT_DIR/refs/heads/new-bisect" git checkout new-bisect || exit mv "$GIT_DIR/refs/heads/new-bisect" "$GIT_DIR/refs/heads/bisect" && - ln -sf refs/heads/bisect "$GIT_DIR/HEAD" + GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD refs/heads/bisect git-show-branch "$rev" } diff --git a/git-branch.sh b/git-branch.sh index dcec2a9f..074229c2 100755 --- a/git-branch.sh +++ b/git-branch.sh @@ -14,7 +14,8 @@ If two arguments, create a new branch based off of . delete_branch () { option="$1" branch_name="$2" - headref=$(readlink "$GIT_DIR/HEAD" | sed -e 's|^refs/heads/||') + headref=$(GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD | + sed -e 's|^refs/heads/||') case ",$headref," in ",$branch_name,") die "Cannot delete the branch you are on." ;; @@ -67,7 +68,8 @@ done case "$#" in 0) - headref=$(readlink "$GIT_DIR/HEAD" | sed -e 's|^refs/heads/||') + headref=$(GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD | + sed -e 's|^refs/heads/||') git-rev-parse --symbolic --all | sed -ne 's|^refs/heads/||p' | sort | diff --git a/git-checkout.sh b/git-checkout.sh index 37afcdda..c3825904 100755 --- a/git-checkout.sh +++ b/git-checkout.sh @@ -71,7 +71,8 @@ if [ "$?" -eq 0 ]; then echo $new > "$GIT_DIR/refs/heads/$newbranch" branch="$newbranch" fi - [ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD" + [ "$branch" ] && + GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch" rm -f "$GIT_DIR/MERGE_HEAD" else exit 1 diff --git a/git-commit.sh b/git-commit.sh index 18b259c7..1206c20c 100755 --- a/git-commit.sh +++ b/git-commit.sh @@ -153,15 +153,8 @@ if [ -f "$GIT_DIR/MERGE_HEAD" ]; then fi >>.editmsg PARENTS="-p HEAD" -if [ ! -r "$GIT_DIR/HEAD" ]; then - if [ -z "$(git-ls-files)" ]; then - echo Nothing to commit 1>&2 - exit 1 - fi - PARENTS="" - current= -else - current=$(git-rev-parse --verify HEAD) +if GIT_DIR="$GIT_DIR" git-rev-parse --verify HEAD >/dev/null 2>&1 +then if [ -f "$GIT_DIR/MERGE_HEAD" ]; then PARENTS="-p HEAD "`sed -e 's/^/-p /' "$GIT_DIR/MERGE_HEAD"` fi @@ -194,6 +187,12 @@ else export GIT_AUTHOR_EMAIL export GIT_AUTHOR_DATE fi +else + if [ -z "$(git-ls-files)" ]; then + echo Nothing to commit 1>&2 + exit 1 + fi + PARENTS="" fi git-status >>.editmsg if [ "$?" != "0" -a ! -f $GIT_DIR/MERGE_HEAD ] diff --git a/git-sh-setup.sh b/git-sh-setup.sh index 55db7958..a0172686 100755 --- a/git-sh-setup.sh +++ b/git-sh-setup.sh @@ -13,10 +13,13 @@ unset CDPATH die() { - echo "$@" >&2 + echo >&2 "$@" exit 1 } -[ -h "$GIT_DIR/HEAD" ] && +case "$(GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD 2>/dev/null)" in +refs/*) : ;; +*) false ;; +esac && [ -d "$GIT_DIR/refs" ] && [ -d "$GIT_OBJECT_DIRECTORY/00" ] diff --git a/git-status.sh b/git-status.sh index 621fa49d..ca9a1545 100755 --- a/git-status.sh +++ b/git-status.sh @@ -31,7 +31,7 @@ report () { [ "$header" ] } -branch=`readlink "$GIT_DIR/HEAD"` +branch=$(GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD) case "$branch" in refs/heads/master) ;; *) echo "# On branch $branch" ;; @@ -39,7 +39,7 @@ esac git-update-index --refresh >/dev/null 2>&1 -if test -f "$GIT_DIR/HEAD" +if GIT_DIR="$GIT_DIR" git-rev-parse --verify HEAD >/dev/null 2>&1 then git-diff-index -M --cached HEAD | sed 's/^://' | diff --git a/init-db.c b/init-db.c index da2bc8f4..aabc09f4 100644 --- a/init-db.c +++ b/init-db.c @@ -166,6 +166,7 @@ static void create_default_files(const char *git_dir, { unsigned len = strlen(git_dir); static char path[PATH_MAX]; + unsigned char sha1[20]; if (len > sizeof(path)-50) die("insane git directory %s", git_dir); @@ -186,15 +187,14 @@ static void create_default_files(const char *git_dir, /* * Create the default symlink from ".git/HEAD" to the "master" - * branch + * branch, if it does not exist yet. */ strcpy(path + len, "HEAD"); - if (symlink("refs/heads/master", path) < 0) { - if (errno != EEXIST) { - perror(path); + if (read_ref(path, sha1) < 0) { + if (create_symref(path, "refs/heads/master") < 0) exit(1); - } } + path[len] = 0; copy_templates(path, len, template_path); } diff --git a/refs.c b/refs.c index 6aa6aec8..2aac90ca 100644 --- a/refs.c +++ b/refs.c @@ -7,6 +7,50 @@ /* We allow "recursive" symbolic refs. Only within reason, though */ #define MAXDEPTH 5 +#ifndef USE_SYMLINK_HEAD +#define USE_SYMLINK_HEAD 1 +#endif + +int validate_symref(const char *path) +{ + struct stat st; + char *buf, buffer[256]; + int len, fd; + + if (lstat(path, &st) < 0) + return -1; + + /* Make sure it is a "refs/.." symlink */ + if (S_ISLNK(st.st_mode)) { + len = readlink(path, buffer, sizeof(buffer)-1); + if (len >= 5 && !memcmp("refs/", buffer, 5)) + return 0; + return -1; + } + + /* + * Anything else, just open it and try to see if it is a symbolic ref. + */ + fd = open(path, O_RDONLY); + if (fd < 0) + return -1; + len = read(fd, buffer, sizeof(buffer)-1); + close(fd); + + /* + * Is it a symbolic ref? + */ + if (len < 4 || memcmp("ref:", buffer, 4)) + return -1; + buf = buffer + 4; + len -= 4; + while (len && isspace(*buf)) + buf++, len--; + if (len >= 5 && !memcmp("refs/", buffer, 5)) + return 0; + return -1; +} + const char *resolve_ref(const char *path, unsigned char *sha1, int reading) { int depth = MAXDEPTH, len; @@ -71,6 +115,39 @@ const char *resolve_ref(const char *path, unsigned char *sha1, int reading) return path; } +int create_symref(const char *git_HEAD, const char *refs_heads_master) +{ +#if USE_SYMLINK_HEAD + unlink(git_HEAD); + return symlink(refs_heads_master, git_HEAD); +#else + const char *lockpath; + char ref[1000]; + int fd, len, written; + + len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master); + if (sizeof(ref) <= len) { + error("refname too long: %s", refs_heads_master); + return -1; + } + lockpath = mkpath("%s.lock", git_HEAD); + fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); + written = write(fd, ref, len); + close(fd); + if (written != len) { + unlink(lockpath); + error("Unable to write to %s", lockpath); + return -2; + } + if (rename(lockpath, git_HEAD) < 0) { + unlink(lockpath); + error("Unable to create %s", git_HEAD); + return -3; + } + return 0; +#endif +} + int read_ref(const char *filename, unsigned char *sha1) { if (resolve_ref(filename, sha1, 1)) diff --git a/setup.c b/setup.c index 9e20160d..c487d7eb 100644 --- a/setup.c +++ b/setup.c @@ -76,18 +76,20 @@ const char **get_pathspec(const char *prefix, const char **pathspec) * Test it it looks like we're at the top * level git directory. We want to see a * - * - a HEAD symlink and a refs/ directory under ".git" * - either a .git/objects/ directory _or_ the proper * GIT_OBJECT_DIRECTORY environment variable + * - a refs/ directory under ".git" + * - either a HEAD symlink or a HEAD file that is formatted as + * a proper "ref:". */ static int is_toplevel_directory(void) { - struct stat st; - - return !lstat(".git/HEAD", &st) && - S_ISLNK(st.st_mode) && - !access(".git/refs/", X_OK) && - (getenv(DB_ENVIRONMENT) || !access(".git/objects/", X_OK)); + if (access(".git/refs/", X_OK) || + access(getenv(DB_ENVIRONMENT) ? + getenv(DB_ENVIRONMENT) : ".git/objects/", X_OK) || + validate_symref(".git/HEAD")) + return 0; + return 1; } const char *setup_git_directory(void) diff --git a/show-branch.c b/show-branch.c index 5778a594..8429c171 100644 --- a/show-branch.c +++ b/show-branch.c @@ -349,6 +349,7 @@ int main(int ac, char **av) int all_heads = 0, all_tags = 0; int all_mask, all_revs, shown_merge_point; char head_path[128]; + const char *head_path_p; int head_path_len; unsigned char head_sha1[20]; int merge_base = 0; @@ -430,11 +431,15 @@ int main(int ac, char **av) if (0 <= extra) join_revs(&list, &seen, num_rev, extra); - head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1); - if ((head_path_len < 0) || get_sha1("HEAD", head_sha1)) + head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1); + if (head_path_p) { + head_path_len = strlen(head_path_p); + memcpy(head_path, head_path_p, head_path_len + 1); + } + else { + head_path_len = 0; head_path[0] = 0; - else - head_path[head_path_len] = 0; + } if (merge_base) return show_merge_base(seen, num_rev); diff --git a/symbolic-ref.c b/symbolic-ref.c new file mode 100644 index 00000000..af087d21 --- /dev/null +++ b/symbolic-ref.c @@ -0,0 +1,34 @@ +#include "cache.h" + +static const char git_symbolic_ref_usage[] = +"git-symbolic-ref name [ref]"; + +static int check_symref(const char *HEAD) +{ + unsigned char sha1[20]; + const char *git_HEAD = strdup(git_path("%s", HEAD)); + const char *git_refs_heads_master = resolve_ref(git_HEAD, sha1, 0); + if (git_refs_heads_master) { + /* we want to strip the .git/ part */ + int pfxlen = strlen(git_HEAD) - strlen(HEAD); + puts(git_refs_heads_master + pfxlen); + } + else + die("No such ref: %s", HEAD); +} + +int main(int argc, const char **argv) +{ + setup_git_directory(); + switch (argc) { + case 2: + check_symref(argv[1]); + break; + case 3: + create_symref(strdup(git_path("%s", argv[1])), argv[2]); + break; + default: + usage(git_symbolic_ref_usage); + } + return 0; +} diff --git a/t/t5400-send-pack.sh b/t/t5400-send-pack.sh index 59ce77b6..1a4d2f2f 100755 --- a/t/t5400-send-pack.sh +++ b/t/t5400-send-pack.sh @@ -20,12 +20,12 @@ test_expect_success setup ' commit=$(echo "Commit #$i" | git-commit-tree $tree -p $parent) && parent=$commit || return 1 done && - echo "$commit" >.git/HEAD && + git-update-ref HEAD "$commit" && git-clone -l ./. victim && cd victim && git-log && cd .. && - echo $zero >.git/HEAD && + git-update-ref HEAD "$zero" && parent=$zero && for i in $cnt do @@ -33,7 +33,7 @@ test_expect_success setup ' commit=$(echo "Rebase #$i" | git-commit-tree $tree -p $parent) && parent=$commit || return 1 done && - echo "$commit" >.git/HEAD && + git-update-ref HEAD "$commit" && echo Rebase && git-log' -- 2.11.0