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#include "cache.h"
#include "unix-socket.h"
 
static int unix_stream_socket(void)
{
	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
	if (fd < 0)
		die_errno("unable to create socket");
	return fd;
}
 
static int chdir_len(const char *orig, int len)
{
	char *path = xmemdupz(orig, len);
	int r = chdir(path);
	free(path);
	return r;
}
 
struct unix_sockaddr_context {
	char *orig_dir;
};
 
static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
{
	if (!ctx->orig_dir)
		return;
	/*
	 * If we fail, we can't just return an error, since we have
	 * moved the cwd of the whole process, which could confuse calling
	 * code.  We are better off to just die.
	 */
	if (chdir(ctx->orig_dir) < 0)
		die("unable to restore original working directory");
	free(ctx->orig_dir);
}
 
static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
			      struct unix_sockaddr_context *ctx)
{
	int size = strlen(path) + 1;
 
	ctx->orig_dir = NULL;
	if (size > sizeof(sa->sun_path)) {
		const char *slash = find_last_dir_sep(path);
		const char *dir;
		struct strbuf cwd = STRBUF_INIT;
 
		if (!slash) {
			errno = ENAMETOOLONG;
			return -1;
		}
 
		dir = path;
		path = slash + 1;
		size = strlen(path) + 1;
		if (size > sizeof(sa->sun_path)) {
			errno = ENAMETOOLONG;
			return -1;
		}
		if (strbuf_getcwd(&cwd))
			return -1;
		ctx->orig_dir = strbuf_detach(&cwd, NULL);
		if (chdir_len(dir, slash - dir) < 0)
			return -1;
	}
 
	memset(sa, 0, sizeof(*sa));
	sa->sun_family = AF_UNIX;
	memcpy(sa->sun_path, path, size);
	return 0;
}
 
int unix_stream_connect(const char *path)
{
	int fd, saved_errno;
	struct sockaddr_un sa;
	struct unix_sockaddr_context ctx;
 
	if (unix_sockaddr_init(&sa, path, &ctx) < 0)
		return -1;
	fd = unix_stream_socket();
	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
		goto fail;
	unix_sockaddr_cleanup(&ctx);
	return fd;
 
fail:
	saved_errno = errno;
	unix_sockaddr_cleanup(&ctx);
	close(fd);
	errno = saved_errno;
	return -1;
}
 
int unix_stream_listen(const char *path)
{
	int fd, saved_errno;
	struct sockaddr_un sa;
	struct unix_sockaddr_context ctx;
 
	unlink(path);
 
	if (unix_sockaddr_init(&sa, path, &ctx) < 0)
		return -1;
	fd = unix_stream_socket();
 
	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
		goto fail;
 
	if (listen(fd, 5) < 0)
		goto fail;
 
	unix_sockaddr_cleanup(&ctx);
	return fd;
 
fail:
	saved_errno = errno;
	unix_sockaddr_cleanup(&ctx);
	close(fd);
	errno = saved_errno;
	return -1;
}