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git / setup.c

Linus Torvalds d288a70 
Johannes Schinde… e90fdc3 



Linus Torvalds d288a70 
Nguyễn Thái Ngọc… edc54fb 
Junio C Hamano d089eba 

Carlo Marcelo Ar… 18e051a 

Carlos Martín Ni… e2a57aa 
Carlo Marcelo Ar… 18e051a 



Junio C Hamano d089eba 


Linus Torvalds f332726 
Johannes Sixt f3cad0a 
Junio C Hamano d089eba 
Johannes Sixt 9a13ba1 
Nguyễn Thái Ngọc… 72ec8ba 
Junio C Hamano d089eba 
Junio C Hamano b3100fd 


Nguyễn Thái Ngọc… 72ec8ba 
Junio C Hamano b3100fd 
Junio C Hamano d089eba 
Nguyễn Thái Ngọc… 72ec8ba 
Junio C Hamano d089eba 
Dmitry Potapov 62525ef 
Junio C Hamano d089eba 





Linus Torvalds f332726 

Junio C Hamano c6e8c80 












Matthieu Moy 009fee4 



Junio C Hamano 0e539dc 










Matthieu Moy 009fee4 





Linus Torvalds e23d0b4 










Junio C Hamano c6e8c80 
Linus Torvalds e23d0b4 
Matthieu Moy 009fee4 
Linus Torvalds e23d0b4 

Junio C Hamano ea92f41 






Matthias Lederho… 7ae3df8 
Johannes Schinde… 6802563 
Junio C Hamano ea92f41 

Junio C Hamano c6e8c80 



Junio C Hamano ea92f41 

Junio C Hamano 8a42c98 









Junio C Hamano 6d94292 
Junio C Hamano 8a42c98 





Ramsay Jones 488201c 
Junio C Hamano 8a42c98 



















Ramsay Jones 488201c 
Junio C Hamano 8a42c98 


Junio C Hamano 6d94292 
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Junio C Hamano 2f6c976 


Junio C Hamano 8a42c98 





Junio C Hamano 2f6c976 

Junio C Hamano 8a42c98 





Junio C Hamano 6d94292 
Junio C Hamano 8a42c98 
Junio C Hamano 6d94292 
Junio C Hamano 8a42c98 

Junio C Hamano 6b5ee13 
Linus Torvalds d288a70 
Junio C Hamano 6b5ee13 
Junio C Hamano d089eba 
Linus Torvalds d288a70 

Linus Torvalds f332726 

Linus Torvalds d288a70 








Junio C Hamano d089eba 

Linus Torvalds f332726 
Junio C Hamano d089eba 
Junio C Hamano 8a42c98 
Junio C Hamano d089eba 





Linus Torvalds d288a70 

Linus Torvalds 5f5608b 
Shawn O. Pearce ad1a382 
Junio C Hamano 5e7bfe2 
Linus Torvalds 5f5608b 
Jim Meyering 790296f 
Linus Torvalds 5f5608b 
Shawn O. Pearce ad1a382 
Junio C Hamano 8098a17 
Junio C Hamano c847f53 

Linus Torvalds 5f5608b 
Shawn O. Pearce ad1a382 
Linus Torvalds 5f5608b 
Shawn O. Pearce ad1a382 


Greg Brockman 3c9d041 

Shawn O. Pearce ad1a382 












Junio C Hamano 8098a17 
Shawn O. Pearce ad1a382 

Junio C Hamano c847f53 
Shawn O. Pearce ad1a382 

Junio C Hamano 8098a17 
Linus Torvalds 5f5608b 

Johannes Schinde… 6802563 

Johannes Schinde… e90fdc3 


Matthias Lederho… 892c41b 



Johannes Schinde… e90fdc3 


Matthias Lederho… 892c41b 

Junio C Hamano f3fa183 

Johannes Schinde… 354e653 






Mike Hommey 59f0f2f 
Carlos Martín Ni… e2a57aa 
Mike Hommey 59f0f2f 

Nguyễn Thái Ngọc… 0ed7481 







Carlos Martín Ni… e2a57aa 
Johannes Schinde… 354e653 
Mike Hommey 59f0f2f 

Nguyễn Thái Ngọc… 337e51c 
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Nguyễn Thái Ngọc… 9459aa7 












Johannes Schinde… e90fdc3 
Lars Hjemli b44ebb1 


Junio C Hamano 13d6ec9 
Lars Hjemli b44ebb1 

Brad King 40c813e 

Lars Hjemli b44ebb1 

Jeff King b1905ae 
Lars Hjemli b44ebb1 






Thomas Rast d824cbb 
Lars Hjemli b44ebb1 












Brad King 40c813e 














Carlos Martín Ni… e2a57aa 
Brad King 40c813e 
Lars Hjemli b44ebb1 



Jonathan Nieder e4e3034 
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Jonathan Nieder e4e3034 
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Nguyễn Thái Ngọc… 9b125da 
Jonathan Nieder e4e3034 


Nguyễn Thái Ngọc… b3f66fd 
Junio C Hamano 13d6ec9 
Nguyễn Thái Ngọc… b3f66fd 




Jonathan Nieder e4e3034 


Nguyễn Thái Ngọc… b3f66fd 
Jonathan Nieder e4e3034 



Nguyễn Thái Ngọc… b3f66fd 



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Jonathan Nieder e4e3034 
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Jonathan Nieder e4e3034 
Nguyễn Thái Ngọc… 9b125da 

Carlos Martín Ni… e2a57aa 
Nguyễn Thái Ngọc… b3f66fd 




Nguyễn Thái Ngọc… 9b125da 
Jonathan Nieder 93a0054 
Nguyễn Thái Ngọc… b3f66fd 




Jonathan Nieder 93a0054 

Nguyễn Thái Ngọc… 9951d3b 


Nguyễn Thái Ngọc… 98937be 
Nguyễn Thái Ngọc… 9951d3b 

Nguyễn Thái Ngọc… 98937be 
Jonathan Nieder 4868b2e 


Carlos Martín Ni… e2a57aa 
Jonathan Nieder 4868b2e 




Nguyễn Thái Ngọc… 9951d3b 

Carlos Martín Ni… e2a57aa 
Nguyễn Thái Ngọc… 9951d3b 

Nguyễn Thái Ngọc… 98937be 
Nguyễn Thái Ngọc… 9951d3b 
Nguyễn Thái Ngọc… 98937be 
Nguyễn Thái Ngọc… 9951d3b 



Nguyễn Thái Ngọc… 98937be 
Nguyễn Thái Ngọc… 9951d3b 
Nguyễn Thái Ngọc… 98937be 









Nguyễn Thái Ngọc… 1cd8031 

Jonathan Nieder 68698da 


Nguyễn Thái Ngọc… 1cd8031 


Jonathan Nieder 4868b2e 









Jonathan Nieder 68698da 
Nguyễn Thái Ngọc… 1cd8031 
Jonathan Nieder 68698da 
Nguyễn Thái Ngọc… 8fc0ae8 

Jonathan Nieder 68698da 


Nguyễn Thái Ngọc… 337e51c 
Nguyễn Thái Ngọc… 1cd8031 
Jonathan Nieder 68698da 



Jonathan Nieder f161ede 









Jonathan Nieder 60c98d1 









Lars Hjemli b44ebb1 
Johannes Schinde… e90fdc3 


Nguyễn Thái Ngọc… a60645f 
Linus Torvalds d288a70 
David Reiss 0454dd9 
Linus Torvalds d288a70 
Nguyễn Thái Ngọc… 9951d3b 

Nguyễn Thái Ngọc… 98937be 
Raja R Harinath c7d1d1b 

Linus Torvalds d288a70 
Johannes Schinde… e90fdc3 
SZEDER Gábor af05d67 






Nguyễn Thái Ngọc… b3f66fd 



SZEDER Gábor af05d67 
Johannes Schinde… e90fdc3 



Shawn O. Pearce ad1a382 
Jonathan Nieder e4e3034 
Nguyễn Thái Ngọc… b3f66fd 
Linus Torvalds d288a70 
David Reiss 0454dd9 
Junio C Hamano 17d778e 

Linus Torvalds d288a70 
Matthias Lederho… 892c41b 
Johannes Schinde… e90fdc3 
Lars Hjemli b44ebb1 
Johannes Schinde… e90fdc3 

Lars Hjemli b44ebb1 
Johannes Schinde… e90fdc3 



Matthias Lederho… 892c41b 
Junio C Hamano cf87463 
Jonathan Nieder 60c98d1 

Johannes Schinde… e90fdc3 
Junio C Hamano 13d6ec9 
Nguyễn Thái Ngọc… 9951d3b 















Jonathan Nieder 68698da 
Nguyễn Thái Ngọc… 1cd8031 

David Reiss 0454dd9 
Jonathan Nieder f161ede 

Lars Damerow 8030e44 
Jonathan Nieder 60c98d1 

Lars Damerow 8030e44 







Junio C Hamano cf87463 
Lars Damerow 8030e44 

Lars Damerow 502ffe3 

Thomas Rast d824cbb 
Lars Damerow 502ffe3 
Matthias Lederho… 892c41b 
Linus Torvalds d288a70 
Junio C Hamano 5e7bfe2 
Nguyễn Thái Ngọc… a60645f 




David Aguilar 1f5d271 




Nguyễn Thái Ngọc… f07d6a1 
Nguyễn Thái Ngọc… a60645f 
Nguyễn Thái Ngọc… f07d6a1 

Nguyễn Thái Ngọc… a60645f 


Junio C Hamano 94df250 

Heikki Orsila 06cbe85 























Junio C Hamano 5a688fe 
Heikki Orsila 06cbe85 







Junio C Hamano 94df250 
Heikki Orsila 06cbe85 











Junio C Hamano 5a688fe 
Junio C Hamano 94df250 

Johannes Schinde… ef90d6d 
Junio C Hamano ab9cb76 
Johannes Schinde… 299726d 

Johannes Schinde… 457f06d 
Junio C Hamano 94df250 
Johannes Schinde… e90fdc3 




Junio C Hamano 180483c 

Jim Meyering 8e0f700 
Johannes Schinde… e90fdc3 


Johannes Schinde… 299726d 
Junio C Hamano ab9cb76 



Nguyễn Thái Ngọc… 337e51c 
Junio C Hamano ab9cb76 

Clemens Buchache… e1e5ec8 





Junio C Hamano 5e7bfe2 

Nguyễn Thái Ngọc… b3f66fd 
Junio C Hamano 5e7bfe2 
Fredrik Gustafss… abc0682 




Junio C Hamano efc5fb6 
Fredrik Gustafss… abc0682 
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#include "cache.h"
#include "dir.h"

static int inside_git_dir = -1;
static int inside_work_tree = -1;

char *prefix_path(const char *prefix, int len, const char *path)
{
	const char *orig = path;
	char *sanitized;
	if (is_absolute_path(orig)) {
		const char *temp = real_path(path);
		sanitized = xmalloc(len + strlen(temp) + 1);
		strcpy(sanitized, temp);
	} else {
		sanitized = xmalloc(len + strlen(path) + 1);
		if (len)
			memcpy(sanitized, prefix, len);
		strcpy(sanitized + len, path);
	}
	if (normalize_path_copy(sanitized, sanitized))
		goto error_out;
	if (is_absolute_path(orig)) {
		size_t root_len, len, total;
		const char *work_tree = get_git_work_tree();
		if (!work_tree)
			goto error_out;
		len = strlen(work_tree);
		root_len = offset_1st_component(work_tree);
		total = strlen(sanitized) + 1;
		if (strncmp(sanitized, work_tree, len) ||
		    (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
		error_out:
			die("'%s' is outside repository", orig);
		}
		if (sanitized[len] == '/')
			len++;
		memmove(sanitized, sanitized + len, total - len);
	}
	return sanitized;
}

int check_filename(const char *prefix, const char *arg)
{
	const char *name;
	struct stat st;

	name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
	if (!lstat(name, &st))
		return 1; /* file exists */
	if (errno == ENOENT || errno == ENOTDIR)
		return 0; /* file does not exist */
	die_errno("failed to stat '%s'", arg);
}

static void NORETURN die_verify_filename(const char *prefix, const char *arg)
{
	unsigned char sha1[20];
	unsigned mode;

	/*
	 * Saying "'(icase)foo' does not exist in the index" when the
	 * user gave us ":(icase)foo" is just stupid.  A magic pathspec
	 * begins with a colon and is followed by a non-alnum; do not
	 * let get_sha1_with_mode_1(only_to_die=1) to even trigger.
	 */
	if (!(arg[0] == ':' && !isalnum(arg[1])))
		/* try a detailed diagnostic ... */
		get_sha1_with_mode_1(arg, sha1, &mode, 1, prefix);

	/* ... or fall back the most general message. */
	die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
	    "Use '--' to separate paths from revisions", arg);

}

/*
 * Verify a filename that we got as an argument for a pathspec
 * entry. Note that a filename that begins with "-" never verifies
 * as true, because even if such a filename were to exist, we want
 * it to be preceded by the "--" marker (or we want the user to
 * use a format like "./-filename")
 */
void verify_filename(const char *prefix, const char *arg)
{
	if (*arg == '-')
		die("bad flag '%s' used after filename", arg);
	if (check_filename(prefix, arg))
		return;
	die_verify_filename(prefix, arg);
}

/*
 * Opposite of the above: the command line did not have -- marker
 * and we parsed the arg as a refname.  It should not be interpretable
 * as a filename.
 */
void verify_non_filename(const char *prefix, const char *arg)
{
	if (!is_inside_work_tree() || is_inside_git_dir())
		return;
	if (*arg == '-')
		return; /* flag */
	if (!check_filename(prefix, arg))
		return;
	die("ambiguous argument '%s': both revision and filename\n"
	    "Use '--' to separate filenames from revisions", arg);
}

/*
 * Magic pathspec
 *
 * NEEDSWORK: These need to be moved to dir.h or even to a new
 * pathspec.h when we restructure get_pathspec() users to use the
 * "struct pathspec" interface.
 *
 * Possible future magic semantics include stuff like:
 *
 *	{ PATHSPEC_NOGLOB, '!', "noglob" },
 *	{ PATHSPEC_ICASE, '\0', "icase" },
 *	{ PATHSPEC_RECURSIVE, '*', "recursive" },
 *	{ PATHSPEC_REGEXP, '\0', "regexp" },
 *
 */
#define PATHSPEC_FROMTOP    (1<<0)

static struct pathspec_magic {
	unsigned bit;
	char mnemonic; /* this cannot be ':'! */
	const char *name;
} pathspec_magic[] = {
	{ PATHSPEC_FROMTOP, '/', "top" },
};

/*
 * Take an element of a pathspec and check for magic signatures.
 * Append the result to the prefix.
 *
 * For now, we only parse the syntax and throw out anything other than
 * "top" magic.
 *
 * NEEDSWORK: This needs to be rewritten when we start migrating
 * get_pathspec() users to use the "struct pathspec" interface.  For
 * example, a pathspec element may be marked as case-insensitive, but
 * the prefix part must always match literally, and a single stupid
 * string cannot express such a case.
 */
static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
{
	unsigned magic = 0;
	const char *copyfrom = elt;
	int i;

	if (elt[0] != ':') {
		; /* nothing to do */
	} else if (elt[1] == '(') {
		/* longhand */
		const char *nextat;
		for (copyfrom = elt + 2;
		     *copyfrom && *copyfrom != ')';
		     copyfrom = nextat) {
			size_t len = strcspn(copyfrom, ",)");
			if (copyfrom[len] == ')')
				nextat = copyfrom + len;
			else
				nextat = copyfrom + len + 1;
			if (!len)
				continue;
			for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
				if (strlen(pathspec_magic[i].name) == len &&
				    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
					magic |= pathspec_magic[i].bit;
					break;
				}
			if (ARRAY_SIZE(pathspec_magic) <= i)
				die("Invalid pathspec magic '%.*s' in '%s'",
				    (int) len, copyfrom, elt);
		}
		if (*copyfrom == ')')
			copyfrom++;
	} else {
		/* shorthand */
		for (copyfrom = elt + 1;
		     *copyfrom && *copyfrom != ':';
		     copyfrom++) {
			char ch = *copyfrom;

			if (!is_pathspec_magic(ch))
				break;
			for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
				if (pathspec_magic[i].mnemonic == ch) {
					magic |= pathspec_magic[i].bit;
					break;
				}
			if (ARRAY_SIZE(pathspec_magic) <= i)
				die("Unimplemented pathspec magic '%c' in '%s'",
				    ch, elt);
		}
		if (*copyfrom == ':')
			copyfrom++;
	}

	if (magic & PATHSPEC_FROMTOP)
		return xstrdup(copyfrom);
	else
		return prefix_path(prefix, prefixlen, copyfrom);
}

const char **get_pathspec(const char *prefix, const char **pathspec)
{
	const char *entry = *pathspec;
	const char **src, **dst;
	int prefixlen;

	if (!prefix && !entry)
		return NULL;

	if (!entry) {
		static const char *spec[2];
		spec[0] = prefix;
		spec[1] = NULL;
		return spec;
	}

	/* Otherwise we have to re-write the entries.. */
	src = pathspec;
	dst = pathspec;
	prefixlen = prefix ? strlen(prefix) : 0;
	while (*src) {
		*(dst++) = prefix_pathspec(prefix, prefixlen, *src);
		src++;
	}
	*dst = NULL;
	if (!*pathspec)
		return NULL;
	return pathspec;
}

/*
 * Test if it looks like we're at a git directory.
 * We want to see:
 *
 *  - either an objects/ directory _or_ the proper
 *    GIT_OBJECT_DIRECTORY environment variable
 *  - a refs/ directory
 *  - either a HEAD symlink or a HEAD file that is formatted as
 *    a proper "ref:", or a regular file HEAD that has a properly
 *    formatted sha1 object name.
 */
static int is_git_directory(const char *suspect)
{
	char path[PATH_MAX];
	size_t len = strlen(suspect);

	if (PATH_MAX <= len + strlen("/objects"))
		die("Too long path: %.*s", 60, suspect);
	strcpy(path, suspect);
	if (getenv(DB_ENVIRONMENT)) {
		if (access(getenv(DB_ENVIRONMENT), X_OK))
			return 0;
	}
	else {
		strcpy(path + len, "/objects");
		if (access(path, X_OK))
			return 0;
	}

	strcpy(path + len, "/refs");
	if (access(path, X_OK))
		return 0;

	strcpy(path + len, "/HEAD");
	if (validate_headref(path))
		return 0;

	return 1;
}

int is_inside_git_dir(void)
{
	if (inside_git_dir < 0)
		inside_git_dir = is_inside_dir(get_git_dir());
	return inside_git_dir;
}

int is_inside_work_tree(void)
{
	if (inside_work_tree < 0)
		inside_work_tree = is_inside_dir(get_git_work_tree());
	return inside_work_tree;
}

void setup_work_tree(void)
{
	const char *work_tree, *git_dir;
	static int initialized = 0;

	if (initialized)
		return;
	work_tree = get_git_work_tree();
	git_dir = get_git_dir();
	if (!is_absolute_path(git_dir))
		git_dir = real_path(get_git_dir());
	if (!work_tree || chdir(work_tree))
		die("This operation must be run in a work tree");

	/*
	 * Make sure subsequent git processes find correct worktree
	 * if $GIT_WORK_TREE is set relative
	 */
	if (getenv(GIT_WORK_TREE_ENVIRONMENT))
		setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);

	set_git_dir(relative_path(git_dir, work_tree));
	initialized = 1;
}

static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
{
	char repo_config[PATH_MAX+1];

	/*
	 * git_config() can't be used here because it calls git_pathdup()
	 * to get $GIT_CONFIG/config. That call will make setup_git_env()
	 * set git_dir to ".git".
	 *
	 * We are in gitdir setup, no git dir has been found useable yet.
	 * Use a gentler version of git_config() to check if this repo
	 * is a good one.
	 */
	snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
	git_config_early(check_repository_format_version, NULL, repo_config);
	if (GIT_REPO_VERSION < repository_format_version) {
		if (!nongit_ok)
			die ("Expected git repo version <= %d, found %d",
			     GIT_REPO_VERSION, repository_format_version);
		warning("Expected git repo version <= %d, found %d",
			GIT_REPO_VERSION, repository_format_version);
		warning("Please upgrade Git");
		*nongit_ok = -1;
		return -1;
	}
	return 0;
}

/*
 * Try to read the location of the git directory from the .git file,
 * return path to git directory if found.
 */
const char *read_gitfile(const char *path)
{
	char *buf;
	char *dir;
	const char *slash;
	struct stat st;
	int fd;
	ssize_t len;

	if (stat(path, &st))
		return NULL;
	if (!S_ISREG(st.st_mode))
		return NULL;
	fd = open(path, O_RDONLY);
	if (fd < 0)
		die_errno("Error opening '%s'", path);
	buf = xmalloc(st.st_size + 1);
	len = read_in_full(fd, buf, st.st_size);
	close(fd);
	if (len != st.st_size)
		die("Error reading %s", path);
	buf[len] = '\0';
	if (prefixcmp(buf, "gitdir: "))
		die("Invalid gitfile format: %s", path);
	while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
		len--;
	if (len < 9)
		die("No path in gitfile: %s", path);
	buf[len] = '\0';
	dir = buf + 8;

	if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
		size_t pathlen = slash+1 - path;
		size_t dirlen = pathlen + len - 8;
		dir = xmalloc(dirlen + 1);
		strncpy(dir, path, pathlen);
		strncpy(dir + pathlen, buf + 8, len - 8);
		dir[dirlen] = '\0';
		free(buf);
		buf = dir;
	}

	if (!is_git_directory(dir))
		die("Not a git repository: %s", dir);
	path = real_path(dir);

	free(buf);
	return path;
}

static const char *setup_explicit_git_dir(const char *gitdirenv,
					  char *cwd, int len,
					  int *nongit_ok)
{
	const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
	const char *worktree;
	char *gitfile;
	int offset;

	if (PATH_MAX - 40 < strlen(gitdirenv))
		die("'$%s' too big", GIT_DIR_ENVIRONMENT);

	gitfile = (char*)read_gitfile(gitdirenv);
	if (gitfile) {
		gitfile = xstrdup(gitfile);
		gitdirenv = gitfile;
	}

	if (!is_git_directory(gitdirenv)) {
		if (nongit_ok) {
			*nongit_ok = 1;
			free(gitfile);
			return NULL;
		}
		die("Not a git repository: '%s'", gitdirenv);
	}

	if (check_repository_format_gently(gitdirenv, nongit_ok)) {
		free(gitfile);
		return NULL;
	}

	/* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
	if (work_tree_env)
		set_git_work_tree(work_tree_env);
	else if (is_bare_repository_cfg > 0) {
		if (git_work_tree_cfg) /* #22.2, #30 */
			die("core.bare and core.worktree do not make sense");

		/* #18, #26 */
		set_git_dir(gitdirenv);
		free(gitfile);
		return NULL;
	}
	else if (git_work_tree_cfg) { /* #6, #14 */
		if (is_absolute_path(git_work_tree_cfg))
			set_git_work_tree(git_work_tree_cfg);
		else {
			char core_worktree[PATH_MAX];
			if (chdir(gitdirenv))
				die_errno("Could not chdir to '%s'", gitdirenv);
			if (chdir(git_work_tree_cfg))
				die_errno("Could not chdir to '%s'", git_work_tree_cfg);
			if (!getcwd(core_worktree, PATH_MAX))
				die_errno("Could not get directory '%s'", git_work_tree_cfg);
			if (chdir(cwd))
				die_errno("Could not come back to cwd");
			set_git_work_tree(core_worktree);
		}
	}
	else /* #2, #10 */
		set_git_work_tree(".");

	/* set_git_work_tree() must have been called by now */
	worktree = get_git_work_tree();

	/* both get_git_work_tree() and cwd are already normalized */
	if (!strcmp(cwd, worktree)) { /* cwd == worktree */
		set_git_dir(gitdirenv);
		free(gitfile);
		return NULL;
	}

	offset = dir_inside_of(cwd, worktree);
	if (offset >= 0) {	/* cwd inside worktree? */
		set_git_dir(real_path(gitdirenv));
		if (chdir(worktree))
			die_errno("Could not chdir to '%s'", worktree);
		cwd[len++] = '/';
		cwd[len] = '\0';
		free(gitfile);
		return cwd + offset;
	}

	/* cwd outside worktree */
	set_git_dir(gitdirenv);
	free(gitfile);
	return NULL;
}

static const char *setup_discovered_git_dir(const char *gitdir,
					    char *cwd, int offset, int len,
					    int *nongit_ok)
{
	if (check_repository_format_gently(gitdir, nongit_ok))
		return NULL;

	/* --work-tree is set without --git-dir; use discovered one */
	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
		if (offset != len && !is_absolute_path(gitdir))
			gitdir = xstrdup(real_path(gitdir));
		if (chdir(cwd))
			die_errno("Could not come back to cwd");
		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
	}

	/* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
	if (is_bare_repository_cfg > 0) {
		set_git_dir(offset == len ? gitdir : real_path(gitdir));
		if (chdir(cwd))
			die_errno("Could not come back to cwd");
		return NULL;
	}

	/* #0, #1, #5, #8, #9, #12, #13 */
	set_git_work_tree(".");
	if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
		set_git_dir(gitdir);
	inside_git_dir = 0;
	inside_work_tree = 1;
	if (offset == len)
		return NULL;

	/* Make "offset" point to past the '/', and add a '/' at the end */
	offset++;
	cwd[len++] = '/';
	cwd[len] = 0;
	return cwd + offset;
}

/* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
{
	int root_len;

	if (check_repository_format_gently(".", nongit_ok))
		return NULL;

	/* --work-tree is set without --git-dir; use discovered one */
	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
		const char *gitdir;

		gitdir = offset == len ? "." : xmemdupz(cwd, offset);
		if (chdir(cwd))
			die_errno("Could not come back to cwd");
		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
	}

	inside_git_dir = 1;
	inside_work_tree = 0;
	if (offset != len) {
		if (chdir(cwd))
			die_errno("Cannot come back to cwd");
		root_len = offset_1st_component(cwd);
		cwd[offset > root_len ? offset : root_len] = '\0';
		set_git_dir(cwd);
	}
	else
		set_git_dir(".");
	return NULL;
}

static const char *setup_nongit(const char *cwd, int *nongit_ok)
{
	if (!nongit_ok)
		die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
	if (chdir(cwd))
		die_errno("Cannot come back to cwd");
	*nongit_ok = 1;
	return NULL;
}

static dev_t get_device_or_die(const char *path, const char *prefix)
{
	struct stat buf;
	if (stat(path, &buf))
		die_errno("failed to stat '%s%s%s'",
				prefix ? prefix : "",
				prefix ? "/" : "", path);
	return buf.st_dev;
}

/*
 * We cannot decide in this function whether we are in the work tree or
 * not, since the config can only be read _after_ this function was called.
 */
static const char *setup_git_directory_gently_1(int *nongit_ok)
{
	const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
	static char cwd[PATH_MAX+1];
	const char *gitdirenv, *ret;
	char *gitfile;
	int len, offset, ceil_offset;
	dev_t current_device = 0;
	int one_filesystem = 1;

	/*
	 * Let's assume that we are in a git repository.
	 * If it turns out later that we are somewhere else, the value will be
	 * updated accordingly.
	 */
	if (nongit_ok)
		*nongit_ok = 0;

	if (!getcwd(cwd, sizeof(cwd)-1))
		die_errno("Unable to read current working directory");
	offset = len = strlen(cwd);

	/*
	 * If GIT_DIR is set explicitly, we're not going
	 * to do any discovery, but we still do repository
	 * validation.
	 */
	gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
	if (gitdirenv)
		return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);

	ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
	if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
		ceil_offset = 1;

	/*
	 * Test in the following order (relative to the cwd):
	 * - .git (file containing "gitdir: <path>")
	 * - .git/
	 * - ./ (bare)
	 * - ../.git
	 * - ../.git/
	 * - ../ (bare)
	 * - ../../.git/
	 *   etc.
	 */
	one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
	if (one_filesystem)
		current_device = get_device_or_die(".", NULL);
	for (;;) {
		gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
		if (gitfile)
			gitdirenv = gitfile = xstrdup(gitfile);
		else {
			if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
				gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
		}

		if (gitdirenv) {
			ret = setup_discovered_git_dir(gitdirenv,
						       cwd, offset, len,
						       nongit_ok);
			free(gitfile);
			return ret;
		}
		free(gitfile);

		if (is_git_directory("."))
			return setup_bare_git_dir(cwd, offset, len, nongit_ok);

		while (--offset > ceil_offset && cwd[offset] != '/');
		if (offset <= ceil_offset)
			return setup_nongit(cwd, nongit_ok);
		if (one_filesystem) {
			dev_t parent_device = get_device_or_die("..", cwd);
			if (parent_device != current_device) {
				if (nongit_ok) {
					if (chdir(cwd))
						die_errno("Cannot come back to cwd");
					*nongit_ok = 1;
					return NULL;
				}
				cwd[offset] = '\0';
				die("Not a git repository (or any parent up to mount parent %s)\n"
				"Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
			}
		}
		if (chdir("..")) {
			cwd[offset] = '\0';
			die_errno("Cannot change to '%s/..'", cwd);
		}
	}
}

const char *setup_git_directory_gently(int *nongit_ok)
{
	const char *prefix;

	prefix = setup_git_directory_gently_1(nongit_ok);
	if (prefix)
		setenv("GIT_PREFIX", prefix, 1);
	else
		setenv("GIT_PREFIX", "", 1);

	if (startup_info) {
		startup_info->have_repository = !nongit_ok || !*nongit_ok;
		startup_info->prefix = prefix;
	}
	return prefix;
}

int git_config_perm(const char *var, const char *value)
{
	int i;
	char *endptr;

	if (value == NULL)
		return PERM_GROUP;

	if (!strcmp(value, "umask"))
		return PERM_UMASK;
	if (!strcmp(value, "group"))
		return PERM_GROUP;
	if (!strcmp(value, "all") ||
	    !strcmp(value, "world") ||
	    !strcmp(value, "everybody"))
		return PERM_EVERYBODY;

	/* Parse octal numbers */
	i = strtol(value, &endptr, 8);

	/* If not an octal number, maybe true/false? */
	if (*endptr != 0)
		return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;

	/*
	 * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
	 * a chmod value to restrict to.
	 */
	switch (i) {
	case PERM_UMASK:               /* 0 */
		return PERM_UMASK;
	case OLD_PERM_GROUP:           /* 1 */
		return PERM_GROUP;
	case OLD_PERM_EVERYBODY:       /* 2 */
		return PERM_EVERYBODY;
	}

	/* A filemode value was given: 0xxx */

	if ((i & 0600) != 0600)
		die("Problem with core.sharedRepository filemode value "
		    "(0%.3o).\nThe owner of files must always have "
		    "read and write permissions.", i);

	/*
	 * Mask filemode value. Others can not get write permission.
	 * x flags for directories are handled separately.
	 */
	return -(i & 0666);
}

int check_repository_format_version(const char *var, const char *value, void *cb)
{
	if (strcmp(var, "core.repositoryformatversion") == 0)
		repository_format_version = git_config_int(var, value);
	else if (strcmp(var, "core.sharedrepository") == 0)
		shared_repository = git_config_perm(var, value);
	else if (strcmp(var, "core.bare") == 0) {
		is_bare_repository_cfg = git_config_bool(var, value);
		if (is_bare_repository_cfg == 1)
			inside_work_tree = -1;
	} else if (strcmp(var, "core.worktree") == 0) {
		if (!value)
			return config_error_nonbool(var);
		free(git_work_tree_cfg);
		git_work_tree_cfg = xstrdup(value);
		inside_work_tree = -1;
	}
	return 0;
}

int check_repository_format(void)
{
	return check_repository_format_gently(get_git_dir(), NULL);
}

/*
 * Returns the "prefix", a path to the current working directory
 * relative to the work tree root, or NULL, if the current working
 * directory is not a strict subdirectory of the work tree root. The
 * prefix always ends with a '/' character.
 */
const char *setup_git_directory(void)
{
	return setup_git_directory_gently(NULL);
}

const char *resolve_gitdir(const char *suspect)
{
	if (is_git_directory(suspect))
		return suspect;
	return read_gitfile(suspect);
}