Add support for environment variable expansion

This patch teaches cgit to expand environment variables in certain
cgitrc option values (cache_root, scan-path, include) plus when
finding the location of cgitrc itself.

One use case for this feature is virtual hosting - e.g. by setting
$CGIT_CONFIG='/etc/cgitrc/$HTTP_HOST' in httpd.conf, all virtual
hosts automatically gets their own cgitrc.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

3 files changed, 78 insertions, 5 deletions

diff --git a/cgit.c b/cgit.c
index 9305d0a..37154e3 100644
--- a/cgit.c
+++ b/cgit.c
@@ -1,732 +1,732 @@
 /* cgit.c: cgi for the git scm
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cache.h"
 #include "cmd.h"
 #include "configfile.h"
 #include "html.h"
 #include "ui-shared.h"
 #include "ui-stats.h"
 #include "scan-tree.h"
 
 const char *cgit_version = CGIT_VERSION;
 
 void add_mimetype(const char *name, const char *value)
 {
 	struct string_list_item *item;
 
 	item = string_list_insert(xstrdup(name), &ctx.cfg.mimetypes);
 	item->util = xstrdup(value);
 }
 
 struct cgit_filter *new_filter(const char *cmd, int extra_args)
 {
 	struct cgit_filter *f;
 
 	if (!cmd || !cmd[0])
 		return NULL;
 
 	f = xmalloc(sizeof(struct cgit_filter));
 	f->cmd = xstrdup(cmd);
 	f->argv = xmalloc((2 + extra_args) * sizeof(char *));
 	f->argv[0] = f->cmd;
 	f->argv[1] = NULL;
 	return f;
 }
 
 static void process_cached_repolist(const char *path);
 
 void repo_config(struct cgit_repo *repo, const char *name, const char *value)
 {
 	if (!strcmp(name, "name"))
 		repo->name = xstrdup(value);
 	else if (!strcmp(name, "clone-url"))
 		repo->clone_url = xstrdup(value);
 	else if (!strcmp(name, "desc"))
 		repo->desc = xstrdup(value);
 	else if (!strcmp(name, "owner"))
 		repo->owner = xstrdup(value);
 	else if (!strcmp(name, "defbranch"))
 		repo->defbranch = xstrdup(value);
 	else if (!strcmp(name, "snapshots"))
 		repo->snapshots = ctx.cfg.snapshots & cgit_parse_snapshots_mask(value);
 	else if (!strcmp(name, "enable-log-filecount"))
 		repo->enable_log_filecount = ctx.cfg.enable_log_filecount * atoi(value);
 	else if (!strcmp(name, "enable-log-linecount"))
 		repo->enable_log_linecount = ctx.cfg.enable_log_linecount * atoi(value);
 	else if (!strcmp(name, "enable-remote-branches"))
 		repo->enable_remote_branches = atoi(value);
 	else if (!strcmp(name, "max-stats"))
 		repo->max_stats = cgit_find_stats_period(value, NULL);
 	else if (!strcmp(name, "module-link"))
 		repo->module_link= xstrdup(value);
 	else if (!strcmp(name, "section"))
 		repo->section = xstrdup(value);
 	else if (!strcmp(name, "readme") && value != NULL) {
 		if (*value == '/')
 			repo->readme = xstrdup(value);
 		else
 			repo->readme = xstrdup(fmt("%s/%s", repo->path, value));
 	} else if (ctx.cfg.enable_filter_overrides) {
 		if (!strcmp(name, "about-filter"))
 			repo->about_filter = new_filter(value, 0);
 		else if (!strcmp(name, "commit-filter"))
 			repo->commit_filter = new_filter(value, 0);
 		else if (!strcmp(name, "source-filter"))
 			repo->source_filter = new_filter(value, 1);
 	}
 }
 
 void config_cb(const char *name, const char *value)
 {
 	if (!strcmp(name, "section") || !strcmp(name, "repo.group"))
 		ctx.cfg.section = xstrdup(value);
 	else if (!strcmp(name, "repo.url"))
 		ctx.repo = cgit_add_repo(value);
 	else if (ctx.repo && !strcmp(name, "repo.path"))
 		ctx.repo->path = trim_end(value, '/');
 	else if (ctx.repo && !prefixcmp(name, "repo."))
 		repo_config(ctx.repo, name + 5, value);
 	else if (!strcmp(name, "root-title"))
 		ctx.cfg.root_title = xstrdup(value);
 	else if (!strcmp(name, "root-desc"))
 		ctx.cfg.root_desc = xstrdup(value);
 	else if (!strcmp(name, "root-readme"))
 		ctx.cfg.root_readme = xstrdup(value);
 	else if (!strcmp(name, "css"))
 		ctx.cfg.css = xstrdup(value);
 	else if (!strcmp(name, "favicon"))
 		ctx.cfg.favicon = xstrdup(value);
 	else if (!strcmp(name, "footer"))
 		ctx.cfg.footer = xstrdup(value);
 	else if (!strcmp(name, "head-include"))
 		ctx.cfg.head_include = xstrdup(value);
 	else if (!strcmp(name, "header"))
 		ctx.cfg.header = xstrdup(value);
 	else if (!strcmp(name, "logo"))
 		ctx.cfg.logo = xstrdup(value);
 	else if (!strcmp(name, "index-header"))
 		ctx.cfg.index_header = xstrdup(value);
 	else if (!strcmp(name, "index-info"))
 		ctx.cfg.index_info = xstrdup(value);
 	else if (!strcmp(name, "logo-link"))
 		ctx.cfg.logo_link = xstrdup(value);
 	else if (!strcmp(name, "module-link"))
 		ctx.cfg.module_link = xstrdup(value);
 	else if (!strcmp(name, "virtual-root")) {
 		ctx.cfg.virtual_root = trim_end(value, '/');
 		if (!ctx.cfg.virtual_root && (!strcmp(value, "/")))
 			ctx.cfg.virtual_root = "";
 	} else if (!strcmp(name, "nocache"))
 		ctx.cfg.nocache = atoi(value);
 	else if (!strcmp(name, "noplainemail"))
 		ctx.cfg.noplainemail = atoi(value);
 	else if (!strcmp(name, "noheader"))
 		ctx.cfg.noheader = atoi(value);
 	else if (!strcmp(name, "snapshots"))
 		ctx.cfg.snapshots = cgit_parse_snapshots_mask(value);
 	else if (!strcmp(name, "enable-filter-overrides"))
 		ctx.cfg.enable_filter_overrides = atoi(value);
 	else if (!strcmp(name, "enable-index-links"))
 		ctx.cfg.enable_index_links = atoi(value);
 	else if (!strcmp(name, "enable-log-filecount"))
 		ctx.cfg.enable_log_filecount = atoi(value);
 	else if (!strcmp(name, "enable-log-linecount"))
 		ctx.cfg.enable_log_linecount = atoi(value);
 	else if (!strcmp(name, "enable-remote-branches"))
 		ctx.cfg.enable_remote_branches = atoi(value);
 	else if (!strcmp(name, "enable-tree-linenumbers"))
 		ctx.cfg.enable_tree_linenumbers = atoi(value);
 	else if (!strcmp(name, "max-stats"))
 		ctx.cfg.max_stats = cgit_find_stats_period(value, NULL);
 	else if (!strcmp(name, "cache-size"))
 		ctx.cfg.cache_size = atoi(value);
 	else if (!strcmp(name, "cache-root"))
-		ctx.cfg.cache_root = xstrdup(value);
+		ctx.cfg.cache_root = xstrdup(expand_macros(value));
 	else if (!strcmp(name, "cache-root-ttl"))
 		ctx.cfg.cache_root_ttl = atoi(value);
 	else if (!strcmp(name, "cache-repo-ttl"))
 		ctx.cfg.cache_repo_ttl = atoi(value);
 	else if (!strcmp(name, "cache-scanrc-ttl"))
 		ctx.cfg.cache_scanrc_ttl = atoi(value);
 	else if (!strcmp(name, "cache-static-ttl"))
 		ctx.cfg.cache_static_ttl = atoi(value);
 	else if (!strcmp(name, "cache-dynamic-ttl"))
 		ctx.cfg.cache_dynamic_ttl = atoi(value);
 	else if (!strcmp(name, "about-filter"))
 		ctx.cfg.about_filter = new_filter(value, 0);
 	else if (!strcmp(name, "commit-filter"))
 		ctx.cfg.commit_filter = new_filter(value, 0);
 	else if (!strcmp(name, "embedded"))
 		ctx.cfg.embedded = atoi(value);
 	else if (!strcmp(name, "max-message-length"))
 		ctx.cfg.max_msg_len = atoi(value);
 	else if (!strcmp(name, "max-repodesc-length"))
 		ctx.cfg.max_repodesc_len = atoi(value);
 	else if (!strcmp(name, "max-blob-size"))
 		ctx.cfg.max_blob_size = atoi(value);
 	else if (!strcmp(name, "max-repo-count"))
 		ctx.cfg.max_repo_count = atoi(value);
 	else if (!strcmp(name, "max-commit-count"))
 		ctx.cfg.max_commit_count = atoi(value);
 	else if (!strcmp(name, "scan-path"))
 		if (!ctx.cfg.nocache && ctx.cfg.cache_size)
-			process_cached_repolist(value);
+			process_cached_repolist(expand_macros(value));
 		else
-			scan_tree(value, repo_config);
+			scan_tree(expand_macros(value), repo_config);
 	else if (!strcmp(name, "source-filter"))
 		ctx.cfg.source_filter = new_filter(value, 1);
 	else if (!strcmp(name, "summary-log"))
 		ctx.cfg.summary_log = atoi(value);
 	else if (!strcmp(name, "summary-branches"))
 		ctx.cfg.summary_branches = atoi(value);
 	else if (!strcmp(name, "summary-tags"))
 		ctx.cfg.summary_tags = atoi(value);
 	else if (!strcmp(name, "side-by-side-diffs"))
 		ctx.cfg.ssdiff = atoi(value);
 	else if (!strcmp(name, "agefile"))
 		ctx.cfg.agefile = xstrdup(value);
 	else if (!strcmp(name, "renamelimit"))
 		ctx.cfg.renamelimit = atoi(value);
 	else if (!strcmp(name, "robots"))
 		ctx.cfg.robots = xstrdup(value);
 	else if (!strcmp(name, "clone-prefix"))
 		ctx.cfg.clone_prefix = xstrdup(value);
 	else if (!strcmp(name, "local-time"))
 		ctx.cfg.local_time = atoi(value);
 	else if (!prefixcmp(name, "mimetype."))
 		add_mimetype(name + 9, value);
 	else if (!strcmp(name, "include"))
-		parse_configfile(value, config_cb);
+		parse_configfile(expand_macros(value), config_cb);
 }
 
 static void querystring_cb(const char *name, const char *value)
 {
 	if (!value)
 		value = "";
 
 	if (!strcmp(name,"r")) {
 		ctx.qry.repo = xstrdup(value);
 		ctx.repo = cgit_get_repoinfo(value);
 	} else if (!strcmp(name, "p")) {
 		ctx.qry.page = xstrdup(value);
 	} else if (!strcmp(name, "url")) {
 		if (*value == '/')
 			value++;
 		ctx.qry.url = xstrdup(value);
 		cgit_parse_url(value);
 	} else if (!strcmp(name, "qt")) {
 		ctx.qry.grep = xstrdup(value);
 	} else if (!strcmp(name, "q")) {
 		ctx.qry.search = xstrdup(value);
 	} else if (!strcmp(name, "h")) {
 		ctx.qry.head = xstrdup(value);
 		ctx.qry.has_symref = 1;
 	} else if (!strcmp(name, "id")) {
 		ctx.qry.sha1 = xstrdup(value);
 		ctx.qry.has_sha1 = 1;
 	} else if (!strcmp(name, "id2")) {
 		ctx.qry.sha2 = xstrdup(value);
 		ctx.qry.has_sha1 = 1;
 	} else if (!strcmp(name, "ofs")) {
 		ctx.qry.ofs = atoi(value);
 	} else if (!strcmp(name, "path")) {
 		ctx.qry.path = trim_end(value, '/');
 	} else if (!strcmp(name, "name")) {
 		ctx.qry.name = xstrdup(value);
 	} else if (!strcmp(name, "mimetype")) {
 		ctx.qry.mimetype = xstrdup(value);
 	} else if (!strcmp(name, "s")){
 		ctx.qry.sort = xstrdup(value);
 	} else if (!strcmp(name, "showmsg")) {
 		ctx.qry.showmsg = atoi(value);
 	} else if (!strcmp(name, "period")) {
 		ctx.qry.period = xstrdup(value);
 	} else if (!strcmp(name, "ss")) {
 		ctx.qry.ssdiff = atoi(value);
 	}
 }
 
 char *xstrdupn(const char *str)
 {
 	return (str ? xstrdup(str) : NULL);
 }
 
 static void prepare_context(struct cgit_context *ctx)
 {
 	memset(ctx, 0, sizeof(*ctx));
 	ctx->cfg.agefile = "info/web/last-modified";
 	ctx->cfg.nocache = 0;
 	ctx->cfg.cache_size = 0;
 	ctx->cfg.cache_dynamic_ttl = 5;
 	ctx->cfg.cache_max_create_time = 5;
 	ctx->cfg.cache_repo_ttl = 5;
 	ctx->cfg.cache_root = CGIT_CACHE_ROOT;
 	ctx->cfg.cache_root_ttl = 5;
 	ctx->cfg.cache_scanrc_ttl = 15;
 	ctx->cfg.cache_static_ttl = -1;
 	ctx->cfg.css = "/cgit.css";
 	ctx->cfg.logo = "/cgit.png";
 	ctx->cfg.local_time = 0;
 	ctx->cfg.enable_tree_linenumbers = 1;
 	ctx->cfg.max_repo_count = 50;
 	ctx->cfg.max_commit_count = 50;
 	ctx->cfg.max_lock_attempts = 5;
 	ctx->cfg.max_msg_len = 80;
 	ctx->cfg.max_repodesc_len = 80;
 	ctx->cfg.max_blob_size = 0;
 	ctx->cfg.max_stats = 0;
 	ctx->cfg.module_link = "./?repo=%s&page=commit&id=%s";
 	ctx->cfg.renamelimit = -1;
 	ctx->cfg.robots = "index, nofollow";
 	ctx->cfg.root_title = "Git repository browser";
 	ctx->cfg.root_desc = "a fast webinterface for the git dscm";
 	ctx->cfg.script_name = CGIT_SCRIPT_NAME;
 	ctx->cfg.section = "";
 	ctx->cfg.summary_branches = 10;
 	ctx->cfg.summary_log = 10;
 	ctx->cfg.summary_tags = 10;
 	ctx->cfg.ssdiff = 0;
 	ctx->env.cgit_config = xstrdupn(getenv("CGIT_CONFIG"));
 	ctx->env.http_host = xstrdupn(getenv("HTTP_HOST"));
 	ctx->env.https = xstrdupn(getenv("HTTPS"));
 	ctx->env.no_http = xstrdupn(getenv("NO_HTTP"));
 	ctx->env.path_info = xstrdupn(getenv("PATH_INFO"));
 	ctx->env.query_string = xstrdupn(getenv("QUERY_STRING"));
 	ctx->env.request_method = xstrdupn(getenv("REQUEST_METHOD"));
 	ctx->env.script_name = xstrdupn(getenv("SCRIPT_NAME"));
 	ctx->env.server_name = xstrdupn(getenv("SERVER_NAME"));
 	ctx->env.server_port = xstrdupn(getenv("SERVER_PORT"));
 	ctx->page.mimetype = "text/html";
 	ctx->page.charset = PAGE_ENCODING;
 	ctx->page.filename = NULL;
 	ctx->page.size = 0;
 	ctx->page.modified = time(NULL);
 	ctx->page.expires = ctx->page.modified;
 	ctx->page.etag = NULL;
 	memset(&ctx->cfg.mimetypes, 0, sizeof(struct string_list));
 	if (ctx->env.script_name)
 		ctx->cfg.script_name = ctx->env.script_name;
 	if (ctx->env.query_string)
 		ctx->qry.raw = ctx->env.query_string;
 	if (!ctx->env.cgit_config)
 		ctx->env.cgit_config = CGIT_CONFIG;
 }
 
 struct refmatch {
 	char *req_ref;
 	char *first_ref;
 	int match;
 };
 
 int find_current_ref(const char *refname, const unsigned char *sha1,
 		     int flags, void *cb_data)
 {
 	struct refmatch *info;
 
 	info = (struct refmatch *)cb_data;
 	if (!strcmp(refname, info->req_ref))
 		info->match = 1;
 	if (!info->first_ref)
 		info->first_ref = xstrdup(refname);
 	return info->match;
 }
 
 char *find_default_branch(struct cgit_repo *repo)
 {
 	struct refmatch info;
 	char *ref;
 
 	info.req_ref = repo->defbranch;
 	info.first_ref = NULL;
 	info.match = 0;
 	for_each_branch_ref(find_current_ref, &info);
 	if (info.match)
 		ref = info.req_ref;
 	else
 		ref = info.first_ref;
 	if (ref)
 		ref = xstrdup(ref);
 	return ref;
 }
 
 static int prepare_repo_cmd(struct cgit_context *ctx)
 {
 	char *tmp;
 	unsigned char sha1[20];
 	int nongit = 0;
 
 	setenv("GIT_DIR", ctx->repo->path, 1);
 	setup_git_directory_gently(&nongit);
 	if (nongit) {
 		ctx->page.title = fmt("%s - %s", ctx->cfg.root_title,
 				      "config error");
 		tmp = fmt("Not a git repository: '%s'", ctx->repo->path);
 		ctx->repo = NULL;
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(tmp);
 		cgit_print_docend();
 		return 1;
 	}
 	ctx->page.title = fmt("%s - %s", ctx->repo->name, ctx->repo->desc);
 
 	if (!ctx->qry.head) {
 		ctx->qry.nohead = 1;
 		ctx->qry.head = find_default_branch(ctx->repo);
 		ctx->repo->defbranch = ctx->qry.head;
 	}
 
 	if (!ctx->qry.head) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error("Repository seems to be empty");
 		cgit_print_docend();
 		return 1;
 	}
 
 	if (get_sha1(ctx->qry.head, sha1)) {
 		tmp = xstrdup(ctx->qry.head);
 		ctx->qry.head = ctx->repo->defbranch;
 		ctx->page.status = 404;
 		ctx->page.statusmsg = "not found";
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(fmt("Invalid branch: %s", tmp));
 		cgit_print_docend();
 		return 1;
 	}
 	return 0;
 }
 
 static void process_request(void *cbdata)
 {
 	struct cgit_context *ctx = cbdata;
 	struct cgit_cmd *cmd;
 
 	cmd = cgit_get_cmd(ctx);
 	if (!cmd) {
 		ctx->page.title = "cgit error";
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error("Invalid request");
 		cgit_print_docend();
 		return;
 	}
 
 	if (cmd->want_repo && !ctx->repo) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 		cgit_print_error(fmt("No repository selected"));
 		cgit_print_docend();
 		return;
 	}
 
 	if (ctx->repo && prepare_repo_cmd(ctx))
 		return;
 
 	if (cmd->want_layout) {
 		cgit_print_http_headers(ctx);
 		cgit_print_docstart(ctx);
 		cgit_print_pageheader(ctx);
 	}
 
 	cmd->fn(ctx);
 
 	if (cmd->want_layout)
 		cgit_print_docend();
 }
 
 int cmp_repos(const void *a, const void *b)
 {
 	const struct cgit_repo *ra = a, *rb = b;
 	return strcmp(ra->url, rb->url);
 }
 
 char *build_snapshot_setting(int bitmap)
 {
 	const struct cgit_snapshot_format *f;
 	char *result = xstrdup("");
 	char *tmp;
 	int len;
 
 	for (f = cgit_snapshot_formats; f->suffix; f++) {
 		if (f->bit & bitmap) {
 			tmp = result;
 			result = xstrdup(fmt("%s%s ", tmp, f->suffix));
 			free(tmp);
 		}
 	}
 	len = strlen(result);
 	if (len)
 		result[len - 1] = '\0';
 	return result;
 }
 
 char *get_first_line(char *txt)
 {
 	char *t = xstrdup(txt);
 	char *p = strchr(t, '\n');
 	if (p)
 		*p = '\0';
 	return t;
 }
 
 void print_repo(FILE *f, struct cgit_repo *repo)
 {
 	fprintf(f, "repo.url=%s\n", repo->url);
 	fprintf(f, "repo.name=%s\n", repo->name);
 	fprintf(f, "repo.path=%s\n", repo->path);
 	if (repo->owner)
 		fprintf(f, "repo.owner=%s\n", repo->owner);
 	if (repo->desc) {
 		char *tmp = get_first_line(repo->desc);
 		fprintf(f, "repo.desc=%s\n", tmp);
 		free(tmp);
 	}
 	if (repo->readme)
 		fprintf(f, "repo.readme=%s\n", repo->readme);
 	if (repo->defbranch)
 		fprintf(f, "repo.defbranch=%s\n", repo->defbranch);
 	if (repo->module_link)
 		fprintf(f, "repo.module-link=%s\n", repo->module_link);
 	if (repo->section)
 		fprintf(f, "repo.section=%s\n", repo->section);
 	if (repo->clone_url)
 		fprintf(f, "repo.clone-url=%s\n", repo->clone_url);
 	fprintf(f, "repo.enable-log-filecount=%d\n",
 	        repo->enable_log_filecount);
 	fprintf(f, "repo.enable-log-linecount=%d\n",
 	        repo->enable_log_linecount);
 	if (repo->about_filter && repo->about_filter != ctx.cfg.about_filter)
 		fprintf(f, "repo.about-filter=%s\n", repo->about_filter->cmd);
 	if (repo->commit_filter && repo->commit_filter != ctx.cfg.commit_filter)
 		fprintf(f, "repo.commit-filter=%s\n", repo->commit_filter->cmd);
 	if (repo->source_filter && repo->source_filter != ctx.cfg.source_filter)
 		fprintf(f, "repo.source-filter=%s\n", repo->source_filter->cmd);
 	if (repo->snapshots != ctx.cfg.snapshots) {
 		char *tmp = build_snapshot_setting(repo->snapshots);
 		fprintf(f, "repo.snapshots=%s\n", tmp);
 		free(tmp);
 	}
 	if (repo->max_stats != ctx.cfg.max_stats)
 		fprintf(f, "repo.max-stats=%s\n",
 		        cgit_find_stats_periodname(repo->max_stats));
 	fprintf(f, "\n");
 }
 
 void print_repolist(FILE *f, struct cgit_repolist *list, int start)
 {
 	int i;
 
 	for(i = start; i < list->count; i++)
 		print_repo(f, &list->repos[i]);
 }
 
 /* Scan 'path' for git repositories, save the resulting repolist in 'cached_rc'
  * and return 0 on success.
  */
 static int generate_cached_repolist(const char *path, const char *cached_rc)
 {
 	char *locked_rc;
 	int idx;
 	FILE *f;
 
 	locked_rc = xstrdup(fmt("%s.lock", cached_rc));
 	f = fopen(locked_rc, "wx");
 	if (!f) {
 		/* Inform about the error unless the lockfile already existed,
 		 * since that only means we've got concurrent requests.
 		 */
 		if (errno != EEXIST)
 			fprintf(stderr, "[cgit] Error opening %s: %s (%d)\n",
 				locked_rc, strerror(errno), errno);
 		return errno;
 	}
 	idx = cgit_repolist.count;
 	scan_tree(path, repo_config);
 	print_repolist(f, &cgit_repolist, idx);
 	if (rename(locked_rc, cached_rc))
 		fprintf(stderr, "[cgit] Error renaming %s to %s: %s (%d)\n",
 			locked_rc, cached_rc, strerror(errno), errno);
 	fclose(f);
 	return 0;
 }
 
 static void process_cached_repolist(const char *path)
 {
 	struct stat st;
 	char *cached_rc;
 	time_t age;
 
 	cached_rc = xstrdup(fmt("%s/rc-%8x", ctx.cfg.cache_root,
 		hash_str(path)));
 
 	if (stat(cached_rc, &st)) {
 		/* Nothing is cached, we need to scan without forking. And
 		 * if we fail to generate a cached repolist, we need to
 		 * invoke scan_tree manually.
 		 */
 		if (generate_cached_repolist(path, cached_rc))
 			scan_tree(path, repo_config);
 		return;
 	}
 
 	parse_configfile(cached_rc, config_cb);
 
 	/* If the cached configfile hasn't expired, lets exit now */
 	age = time(NULL) - st.st_mtime;
 	if (age <= (ctx.cfg.cache_scanrc_ttl * 60))
 		return;
 
 	/* The cached repolist has been parsed, but it was old. So lets
 	 * rescan the specified path and generate a new cached repolist
 	 * in a child-process to avoid latency for the current request.
 	 */
 	if (fork())
 		return;
 
 	exit(generate_cached_repolist(path, cached_rc));
 }
 
 static void cgit_parse_args(int argc, const char **argv)
 {
 	int i;
 	int scan = 0;
 
 	for (i = 1; i < argc; i++) {
 		if (!strncmp(argv[i], "--cache=", 8)) {
 			ctx.cfg.cache_root = xstrdup(argv[i]+8);
 		}
 		if (!strcmp(argv[i], "--nocache")) {
 			ctx.cfg.nocache = 1;
 		}
 		if (!strcmp(argv[i], "--nohttp")) {
 			ctx.env.no_http = "1";
 		}
 		if (!strncmp(argv[i], "--query=", 8)) {
 			ctx.qry.raw = xstrdup(argv[i]+8);
 		}
 		if (!strncmp(argv[i], "--repo=", 7)) {
 			ctx.qry.repo = xstrdup(argv[i]+7);
 		}
 		if (!strncmp(argv[i], "--page=", 7)) {
 			ctx.qry.page = xstrdup(argv[i]+7);
 		}
 		if (!strncmp(argv[i], "--head=", 7)) {
 			ctx.qry.head = xstrdup(argv[i]+7);
 			ctx.qry.has_symref = 1;
 		}
 		if (!strncmp(argv[i], "--sha1=", 7)) {
 			ctx.qry.sha1 = xstrdup(argv[i]+7);
 			ctx.qry.has_sha1 = 1;
 		}
 		if (!strncmp(argv[i], "--ofs=", 6)) {
 			ctx.qry.ofs = atoi(argv[i]+6);
 		}
 		if (!strncmp(argv[i], "--scan-tree=", 12) ||
 		    !strncmp(argv[i], "--scan-path=", 12)) {
 			/* HACK: the global snapshot bitmask defines the
 			 * set of allowed snapshot formats, but the config
 			 * file hasn't been parsed yet so the mask is
 			 * currently 0. By setting all bits high before
 			 * scanning we make sure that any in-repo cgitrc
 			 * snapshot setting is respected by scan_tree().
 			 * BTW: we assume that there'll never be more than
 			 * 255 different snapshot formats supported by cgit...
 			 */
 			ctx.cfg.snapshots = 0xFF;
 			scan++;
 			scan_tree(argv[i] + 12, repo_config);
 		}
 	}
 	if (scan) {
 		qsort(cgit_repolist.repos, cgit_repolist.count,
 			sizeof(struct cgit_repo), cmp_repos);
 		print_repolist(stdout, &cgit_repolist, 0);
 		exit(0);
 	}
 }
 
 static int calc_ttl()
 {
 	if (!ctx.repo)
 		return ctx.cfg.cache_root_ttl;
 
 	if (!ctx.qry.page)
 		return ctx.cfg.cache_repo_ttl;
 
 	if (ctx.qry.has_symref)
 		return ctx.cfg.cache_dynamic_ttl;
 
 	if (ctx.qry.has_sha1)
 		return ctx.cfg.cache_static_ttl;
 
 	return ctx.cfg.cache_repo_ttl;
 }
 
 int main(int argc, const char **argv)
 {
 	const char *path;
 	char *qry;
 	int err, ttl;
 
 	prepare_context(&ctx);
 	cgit_repolist.length = 0;
 	cgit_repolist.count = 0;
 	cgit_repolist.repos = NULL;
 
 	cgit_parse_args(argc, argv);
-	parse_configfile(ctx.env.cgit_config, config_cb);
+	parse_configfile(expand_macros(ctx.env.cgit_config), config_cb);
 	ctx.repo = NULL;
 	http_parse_querystring(ctx.qry.raw, querystring_cb);
 
 	/* If virtual-root isn't specified in cgitrc, lets pretend
 	 * that virtual-root equals SCRIPT_NAME.
 	 */
 	if (!ctx.cfg.virtual_root)
 		ctx.cfg.virtual_root = ctx.cfg.script_name;
 
 	/* If no url parameter is specified on the querystring, lets
 	 * use PATH_INFO as url. This allows cgit to work with virtual
 	 * urls without the need for rewriterules in the webserver (as
 	 * long as PATH_INFO is included in the cache lookup key).
 	 */
 	path = ctx.env.path_info;
 	if (!ctx.qry.url && path) {
 		if (path[0] == '/')
 			path++;
 		ctx.qry.url = xstrdup(path);
 		if (ctx.qry.raw) {
 			qry = ctx.qry.raw;
 			ctx.qry.raw = xstrdup(fmt("%s?%s", path, qry));
 			free(qry);
 		} else
 			ctx.qry.raw = xstrdup(ctx.qry.url);
 		cgit_parse_url(ctx.qry.url);
 	}
 
 	ttl = calc_ttl();
 	ctx.page.expires += ttl*60;
 	if (ctx.env.request_method && !strcmp(ctx.env.request_method, "HEAD"))
 		ctx.cfg.nocache = 1;
 	if (ctx.cfg.nocache)
 		ctx.cfg.cache_size = 0;
 	err = cache_process(ctx.cfg.cache_size, ctx.cfg.cache_root,
 			    ctx.qry.raw, ttl, process_request, &ctx);
 	if (err)
 		cgit_print_error(fmt("Error processing page: %s (%d)",
 				     strerror(err), err));
 	return err;
 }
diff --git a/cgit.h b/cgit.h
index cd4af72..568e0c0 100644
--- a/cgit.h
+++ b/cgit.h
@@ -1,299 +1,301 @@
 #ifndef CGIT_H
 #define CGIT_H
 
 
 #include <git-compat-util.h>
 #include <cache.h>
 #include <grep.h>
 #include <object.h>
 #include <tree.h>
 #include <commit.h>
 #include <tag.h>
 #include <diff.h>
 #include <diffcore.h>
 #include <refs.h>
 #include <revision.h>
 #include <log-tree.h>
 #include <archive.h>
 #include <string-list.h>
 #include <xdiff-interface.h>
 #include <xdiff/xdiff.h>
 #include <utf8.h>
 
 
 /*
  * Dateformats used on misc. pages
  */
 #define FMT_LONGDATE "%Y-%m-%d %H:%M:%S (%Z)"
 #define FMT_SHORTDATE "%Y-%m-%d"
 #define FMT_ATOMDATE "%Y-%m-%dT%H:%M:%SZ"
 
 
 /*
  * Limits used for relative dates
  */
 #define TM_MIN    60
 #define TM_HOUR  (TM_MIN * 60)
 #define TM_DAY   (TM_HOUR * 24)
 #define TM_WEEK  (TM_DAY * 7)
 #define TM_YEAR  (TM_DAY * 365)
 #define TM_MONTH (TM_YEAR / 12.0)
 
 
 /*
  * Default encoding
  */
 #define PAGE_ENCODING "UTF-8"
 
 typedef void (*configfn)(const char *name, const char *value);
 typedef void (*filepair_fn)(struct diff_filepair *pair);
 typedef void (*linediff_fn)(char *line, int len);
 
 struct cgit_filter {
 	char *cmd;
 	char **argv;
 	int old_stdout;
 	int pipe_fh[2];
 	int pid;
 	int exitstatus;
 };
 
 struct cgit_repo {
 	char *url;
 	char *name;
 	char *path;
 	char *desc;
 	char *owner;
 	char *defbranch;
 	char *module_link;
 	char *readme;
 	char *section;
 	char *clone_url;
 	int snapshots;
 	int enable_log_filecount;
 	int enable_log_linecount;
 	int enable_remote_branches;
 	int max_stats;
 	time_t mtime;
 	struct cgit_filter *about_filter;
 	struct cgit_filter *commit_filter;
 	struct cgit_filter *source_filter;
 };
 
 typedef void (*repo_config_fn)(struct cgit_repo *repo, const char *name,
 	      const char *value);
 
 struct cgit_repolist {
 	int length;
 	int count;
 	struct cgit_repo *repos;
 };
 
 struct commitinfo {
 	struct commit *commit;
 	char *author;
 	char *author_email;
 	unsigned long author_date;
 	char *committer;
 	char *committer_email;
 	unsigned long committer_date;
 	char *subject;
 	char *msg;
 	char *msg_encoding;
 };
 
 struct taginfo {
 	char *tagger;
 	char *tagger_email;
 	unsigned long tagger_date;
 	char *msg;
 };
 
 struct refinfo {
 	const char *refname;
 	struct object *object;
 	union {
 		struct taginfo *tag;
 		struct commitinfo *commit;
 	};
 };
 
 struct reflist {
 	struct refinfo **refs;
 	int alloc;
 	int count;
 };
 
 struct cgit_query {
 	int has_symref;
 	int has_sha1;
 	char *raw;
 	char *repo;
 	char *page;
 	char *search;
 	char *grep;
 	char *head;
 	char *sha1;
 	char *sha2;
 	char *path;
 	char *name;
 	char *mimetype;
 	char *url;
 	char *period;
 	int   ofs;
 	int nohead;
 	char *sort;
 	int showmsg;
 	int ssdiff;
 };
 
 struct cgit_config {
 	char *agefile;
 	char *cache_root;
 	char *clone_prefix;
 	char *css;
 	char *favicon;
 	char *footer;
 	char *head_include;
 	char *header;
 	char *index_header;
 	char *index_info;
 	char *logo;
 	char *logo_link;
 	char *module_link;
 	char *robots;
 	char *root_title;
 	char *root_desc;
 	char *root_readme;
 	char *script_name;
 	char *section;
 	char *virtual_root;
 	int cache_size;
 	int cache_dynamic_ttl;
 	int cache_max_create_time;
 	int cache_repo_ttl;
 	int cache_root_ttl;
 	int cache_scanrc_ttl;
 	int cache_static_ttl;
 	int embedded;
 	int enable_filter_overrides;
 	int enable_index_links;
 	int enable_log_filecount;
 	int enable_log_linecount;
 	int enable_remote_branches;
 	int enable_tree_linenumbers;
 	int local_time;
 	int max_repo_count;
 	int max_commit_count;
 	int max_lock_attempts;
 	int max_msg_len;
 	int max_repodesc_len;
 	int max_blob_size;
 	int max_stats;
 	int nocache;
 	int noplainemail;
 	int noheader;
 	int renamelimit;
 	int snapshots;
 	int summary_branches;
 	int summary_log;
 	int summary_tags;
 	int ssdiff;
 	struct string_list mimetypes;
 	struct cgit_filter *about_filter;
 	struct cgit_filter *commit_filter;
 	struct cgit_filter *source_filter;
 };
 
 struct cgit_page {
 	time_t modified;
 	time_t expires;
 	size_t size;
 	char *mimetype;
 	char *charset;
 	char *filename;
 	char *etag;
 	char *title;
 	int status;
 	char *statusmsg;
 };
 
 struct cgit_environment {
 	char *cgit_config;
 	char *http_host;
 	char *https;
 	char *no_http;
 	char *path_info;
 	char *query_string;
 	char *request_method;
 	char *script_name;
 	char *server_name;
 	char *server_port;
 };
 
 struct cgit_context {
 	struct cgit_environment env;
 	struct cgit_query qry;
 	struct cgit_config cfg;
 	struct cgit_repo *repo;
 	struct cgit_page page;
 };
 
 struct cgit_snapshot_format {
 	const char *suffix;
 	const char *mimetype;
 	write_archive_fn_t write_func;
 	int bit;
 };
 
 extern const char *cgit_version;
 
 extern struct cgit_repolist cgit_repolist;
 extern struct cgit_context ctx;
 extern const struct cgit_snapshot_format cgit_snapshot_formats[];
 
 extern struct cgit_repo *cgit_add_repo(const char *url);
 extern struct cgit_repo *cgit_get_repoinfo(const char *url);
 extern void cgit_repo_config_cb(const char *name, const char *value);
 
 extern int chk_zero(int result, char *msg);
 extern int chk_positive(int result, char *msg);
 extern int chk_non_negative(int result, char *msg);
 
 extern char *trim_end(const char *str, char c);
 extern char *strlpart(char *txt, int maxlen);
 extern char *strrpart(char *txt, int maxlen);
 
 extern void cgit_add_ref(struct reflist *list, struct refinfo *ref);
 extern int cgit_refs_cb(const char *refname, const unsigned char *sha1,
 			int flags, void *cb_data);
 
 extern void *cgit_free_commitinfo(struct commitinfo *info);
 
 extern int cgit_diff_files(const unsigned char *old_sha1,
 			   const unsigned char *new_sha1,
 			   unsigned long *old_size, unsigned long *new_size,
 			   int *binary, linediff_fn fn);
 
 extern void cgit_diff_tree(const unsigned char *old_sha1,
 			   const unsigned char *new_sha1,
 			   filepair_fn fn, const char *prefix);
 
 extern void cgit_diff_commit(struct commit *commit, filepair_fn fn);
 
 extern char *fmt(const char *format,...);
 
 extern struct commitinfo *cgit_parse_commit(struct commit *commit);
 extern struct taginfo *cgit_parse_tag(struct tag *tag);
 extern void cgit_parse_url(const char *url);
 
 extern const char *cgit_repobasename(const char *reponame);
 
 extern int cgit_parse_snapshots_mask(const char *str);
 
 extern int cgit_open_filter(struct cgit_filter *filter);
 extern int cgit_close_filter(struct cgit_filter *filter);
 
 extern int readfile(const char *path, char **buf, size_t *size);
 
+extern char *expand_macros(const char *txt);
+
 #endif /* CGIT_H */
diff --git a/shared.c b/shared.c
index 5f46793..76d26dd 100644
--- a/shared.c
+++ b/shared.c
@@ -1,425 +1,496 @@
 /* shared.c: global vars + some callback functions
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
 struct cgit_repolist cgit_repolist;
 struct cgit_context ctx;
 int cgit_cmd;
 
 int chk_zero(int result, char *msg)
 {
 	if (result != 0)
 		die("%s: %s", msg, strerror(errno));
 	return result;
 }
 
 int chk_positive(int result, char *msg)
 {
 	if (result <= 0)
 		die("%s: %s", msg, strerror(errno));
 	return result;
 }
 
 int chk_non_negative(int result, char *msg)
 {
     	if (result < 0)
 	    	die("%s: %s",msg, strerror(errno));
 	return result;
 }
 
 struct cgit_repo *cgit_add_repo(const char *url)
 {
 	struct cgit_repo *ret;
 
 	if (++cgit_repolist.count > cgit_repolist.length) {
 		if (cgit_repolist.length == 0)
 			cgit_repolist.length = 8;
 		else
 			cgit_repolist.length *= 2;
 		cgit_repolist.repos = xrealloc(cgit_repolist.repos,
 					       cgit_repolist.length *
 					       sizeof(struct cgit_repo));
 	}
 
 	ret = &cgit_repolist.repos[cgit_repolist.count-1];
 	memset(ret, 0, sizeof(struct cgit_repo));
 	ret->url = trim_end(url, '/');
 	ret->name = ret->url;
 	ret->path = NULL;
 	ret->desc = "[no description]";
 	ret->owner = NULL;
 	ret->section = ctx.cfg.section;
 	ret->defbranch = "master";
 	ret->snapshots = ctx.cfg.snapshots;
 	ret->enable_log_filecount = ctx.cfg.enable_log_filecount;
 	ret->enable_log_linecount = ctx.cfg.enable_log_linecount;
 	ret->enable_remote_branches = ctx.cfg.enable_remote_branches;
 	ret->max_stats = ctx.cfg.max_stats;
 	ret->module_link = ctx.cfg.module_link;
 	ret->readme = NULL;
 	ret->mtime = -1;
 	ret->about_filter = ctx.cfg.about_filter;
 	ret->commit_filter = ctx.cfg.commit_filter;
 	ret->source_filter = ctx.cfg.source_filter;
 	return ret;
 }
 
 struct cgit_repo *cgit_get_repoinfo(const char *url)
 {
 	int i;
 	struct cgit_repo *repo;
 
 	for (i=0; i<cgit_repolist.count; i++) {
 		repo = &cgit_repolist.repos[i];
 		if (!strcmp(repo->url, url))
 			return repo;
 	}
 	return NULL;
 }
 
 void *cgit_free_commitinfo(struct commitinfo *info)
 {
 	free(info->author);
 	free(info->author_email);
 	free(info->committer);
 	free(info->committer_email);
 	free(info->subject);
 	free(info->msg);
 	free(info->msg_encoding);
 	free(info);
 	return NULL;
 }
 
 char *trim_end(const char *str, char c)
 {
 	int len;
 	char *s, *t;
 
 	if (str == NULL)
 		return NULL;
 	t = (char *)str;
 	len = strlen(t);
 	while(len > 0 && t[len - 1] == c)
 		len--;
 
 	if (len == 0)
 		return NULL;
 
 	c = t[len];
 	t[len] = '\0';
 	s = xstrdup(t);
 	t[len] = c;
 	return s;
 }
 
 char *strlpart(char *txt, int maxlen)
 {
 	char *result;
 
 	if (!txt)
 		return txt;
 
 	if (strlen(txt) <= maxlen)
 		return txt;
 	result = xmalloc(maxlen + 1);
 	memcpy(result, txt, maxlen - 3);
 	result[maxlen-1] = result[maxlen-2] = result[maxlen-3] = '.';
 	result[maxlen] = '\0';
 	return result;
 }
 
 char *strrpart(char *txt, int maxlen)
 {
 	char *result;
 
 	if (!txt)
 		return txt;
 
 	if (strlen(txt) <= maxlen)
 		return txt;
 	result = xmalloc(maxlen + 1);
 	memcpy(result + 3, txt + strlen(txt) - maxlen + 4, maxlen - 3);
 	result[0] = result[1] = result[2] = '.';
 	return result;
 }
 
 void cgit_add_ref(struct reflist *list, struct refinfo *ref)
 {
 	size_t size;
 
 	if (list->count >= list->alloc) {
 		list->alloc += (list->alloc ? list->alloc : 4);
 		size = list->alloc * sizeof(struct refinfo *);
 		list->refs = xrealloc(list->refs, size);
 	}
 	list->refs[list->count++] = ref;
 }
 
 struct refinfo *cgit_mk_refinfo(const char *refname, const unsigned char *sha1)
 {
 	struct refinfo *ref;
 
 	ref = xmalloc(sizeof (struct refinfo));
 	ref->refname = xstrdup(refname);
 	ref->object = parse_object(sha1);
 	switch (ref->object->type) {
 	case OBJ_TAG:
 		ref->tag = cgit_parse_tag((struct tag *)ref->object);
 		break;
 	case OBJ_COMMIT:
 		ref->commit = cgit_parse_commit((struct commit *)ref->object);
 		break;
 	}
 	return ref;
 }
 
 int cgit_refs_cb(const char *refname, const unsigned char *sha1, int flags,
 		  void *cb_data)
 {
 	struct reflist *list = (struct reflist *)cb_data;
 	struct refinfo *info = cgit_mk_refinfo(refname, sha1);
 
 	if (info)
 		cgit_add_ref(list, info);
 	return 0;
 }
 
 void cgit_diff_tree_cb(struct diff_queue_struct *q,
 		       struct diff_options *options, void *data)
 {
 	int i;
 
 	for (i = 0; i < q->nr; i++) {
 		if (q->queue[i]->status == 'U')
 			continue;
 		((filepair_fn)data)(q->queue[i]);
 	}
 }
 
 static int load_mmfile(mmfile_t *file, const unsigned char *sha1)
 {
 	enum object_type type;
 
 	if (is_null_sha1(sha1)) {
 		file->ptr = (char *)"";
 		file->size = 0;
 	} else {
 		file->ptr = read_sha1_file(sha1, &type, 
 		                           (unsigned long *)&file->size);
 	}
 	return 1;
 }
 
 /*
  * Receive diff-buffers from xdiff and concatenate them as
  * needed across multiple callbacks.
  *
  * This is basically a copy of xdiff-interface.c/xdiff_outf(),
  * ripped from git and modified to use globals instead of
  * a special callback-struct.
  */
 char *diffbuf = NULL;
 int buflen = 0;
 
 int filediff_cb(void *priv, mmbuffer_t *mb, int nbuf)
 {
 	int i;
 
 	for (i = 0; i < nbuf; i++) {
 		if (mb[i].ptr[mb[i].size-1] != '\n') {
 			/* Incomplete line */
 			diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
 			memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
 			buflen += mb[i].size;
 			continue;
 		}
 
 		/* we have a complete line */
 		if (!diffbuf) {
 			((linediff_fn)priv)(mb[i].ptr, mb[i].size);
 			continue;
 		}
 		diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
 		memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
 		((linediff_fn)priv)(diffbuf, buflen + mb[i].size);
 		free(diffbuf);
 		diffbuf = NULL;
 		buflen = 0;
 	}
 	if (diffbuf) {
 		((linediff_fn)priv)(diffbuf, buflen);
 		free(diffbuf);
 		diffbuf = NULL;
 		buflen = 0;
 	}
 	return 0;
 }
 
 int cgit_diff_files(const unsigned char *old_sha1,
 		    const unsigned char *new_sha1, unsigned long *old_size,
 		    unsigned long *new_size, int *binary, linediff_fn fn)
 {
 	mmfile_t file1, file2;
 	xpparam_t diff_params;
 	xdemitconf_t emit_params;
 	xdemitcb_t emit_cb;
 
 	if (!load_mmfile(&file1, old_sha1) || !load_mmfile(&file2, new_sha1))
 		return 1;
 
 	*old_size = file1.size;
 	*new_size = file2.size;
 
 	if ((file1.ptr && buffer_is_binary(file1.ptr, file1.size)) ||
 	    (file2.ptr && buffer_is_binary(file2.ptr, file2.size))) {
 		*binary = 1;
 		return 0;
 	}
 
 	memset(&diff_params, 0, sizeof(diff_params));
 	memset(&emit_params, 0, sizeof(emit_params));
 	memset(&emit_cb, 0, sizeof(emit_cb));
 	diff_params.flags = XDF_NEED_MINIMAL;
 	emit_params.ctxlen = 3;
 	emit_params.flags = XDL_EMIT_FUNCNAMES;
 	emit_cb.outf = filediff_cb;
 	emit_cb.priv = fn;
 	xdl_diff(&file1, &file2, &diff_params, &emit_params, &emit_cb);
 	return 0;
 }
 
 void cgit_diff_tree(const unsigned char *old_sha1,
 		    const unsigned char *new_sha1,
 		    filepair_fn fn, const char *prefix)
 {
 	struct diff_options opt;
 	int ret;
 	int prefixlen;
 
 	diff_setup(&opt);
 	opt.output_format = DIFF_FORMAT_CALLBACK;
 	opt.detect_rename = 1;
 	opt.rename_limit = ctx.cfg.renamelimit;
 	DIFF_OPT_SET(&opt, RECURSIVE);
 	opt.format_callback = cgit_diff_tree_cb;
 	opt.format_callback_data = fn;
 	if (prefix) {
 		opt.nr_paths = 1;
 		opt.paths = &prefix;
 		prefixlen = strlen(prefix);
 		opt.pathlens = &prefixlen;
 	}
 	diff_setup_done(&opt);
 
 	if (old_sha1 && !is_null_sha1(old_sha1))
 		ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
 	else
 		ret = diff_root_tree_sha1(new_sha1, "", &opt);
 	diffcore_std(&opt);
 	diff_flush(&opt);
 }
 
 void cgit_diff_commit(struct commit *commit, filepair_fn fn)
 {
 	unsigned char *old_sha1 = NULL;
 
 	if (commit->parents)
 		old_sha1 = commit->parents->item->object.sha1;
 	cgit_diff_tree(old_sha1, commit->object.sha1, fn, NULL);
 }
 
 int cgit_parse_snapshots_mask(const char *str)
 {
 	const struct cgit_snapshot_format *f;
 	static const char *delim = " \t,:/|;";
 	int tl, sl, rv = 0;
 
 	/* favor legacy setting */
 	if(atoi(str))
 		return 1;
 	for(;;) {
 		str += strspn(str,delim);
 		tl = strcspn(str,delim);
 		if (!tl)
 			break;
 		for (f = cgit_snapshot_formats; f->suffix; f++) {
 			sl = strlen(f->suffix);
 			if((tl == sl && !strncmp(f->suffix, str, tl)) ||
 			   (tl == sl-1 && !strncmp(f->suffix+1, str, tl-1))) {
 				rv |= f->bit;
 				break;
 			}
 		}
 		str += tl;
 	}
 	return rv;
 }
 
 int cgit_open_filter(struct cgit_filter *filter)
 {
 
 	filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
 		"Unable to duplicate STDOUT");
 	chk_zero(pipe(filter->pipe_fh), "Unable to create pipe to subprocess");
 	filter->pid = chk_non_negative(fork(), "Unable to create subprocess");
 	if (filter->pid == 0) {
 		close(filter->pipe_fh[1]);
 		chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO),
 			"Unable to use pipe as STDIN");
 		execvp(filter->cmd, filter->argv);
 		die("Unable to exec subprocess %s: %s (%d)", filter->cmd,
 			strerror(errno), errno);
 	}
 	close(filter->pipe_fh[0]);
 	chk_non_negative(dup2(filter->pipe_fh[1], STDOUT_FILENO),
 		"Unable to use pipe as STDOUT");
 	close(filter->pipe_fh[1]);
 	return 0;
 }
 
 int cgit_close_filter(struct cgit_filter *filter)
 {
 	chk_non_negative(dup2(filter->old_stdout, STDOUT_FILENO),
 		"Unable to restore STDOUT");
 	close(filter->old_stdout);
 	if (filter->pid < 0)
 		return 0;
 	waitpid(filter->pid, &filter->exitstatus, 0);
 	if (WIFEXITED(filter->exitstatus) && !WEXITSTATUS(filter->exitstatus))
 		return 0;
 	die("Subprocess %s exited abnormally", filter->cmd);
 }
 
 /* Read the content of the specified file into a newly allocated buffer,
  * zeroterminate the buffer and return 0 on success, errno otherwise.
  */
 int readfile(const char *path, char **buf, size_t *size)
 {
 	int fd, e;
 	struct stat st;
 
 	fd = open(path, O_RDONLY);
 	if (fd == -1)
 		return errno;
 	if (fstat(fd, &st)) {
 		e = errno;
 		close(fd);
 		return e;
 	}
 	if (!S_ISREG(st.st_mode)) {
 		close(fd);
 		return EISDIR;
 	}
 	*buf = xmalloc(st.st_size + 1);
 	*size = read_in_full(fd, *buf, st.st_size);
 	e = errno;
 	(*buf)[*size] = '\0';
 	close(fd);
 	return (*size == st.st_size ? 0 : e);
 }
+
+int is_token_char(char c)
+{
+	return isalnum(c) || c == '_';
+}
+
+/* Replace name with getenv(name), return pointer to zero-terminating char
+ */
+char *expand_macro(char *name, int maxlength)
+{
+	char *value;
+	int len;
+
+	len = 0;
+	value = getenv(name);
+	if (value) {
+		len = strlen(value);
+		if (len > maxlength)
+			len = maxlength;
+		strncpy(name, value, len);
+	}
+	return name + len;
+}
+
+#define EXPBUFSIZE (1024 * 8)
+
+/* Replace all tokens prefixed by '$' in the specified text with the
+ * value of the named environment variable.
+ * NB: the return value is a static buffer, i.e. it must be strdup'd
+ * by the caller.
+ */
+char *expand_macros(const char *txt)
+{
+	static char result[EXPBUFSIZE];
+	char *p, *start;
+	int len;
+
+	p = result;
+	start = NULL;
+	while (p < result + EXPBUFSIZE - 1 && txt && *txt) {
+		*p = *txt;
+		if (start) {
+			if (!is_token_char(*txt)) {
+				if (p - start > 0) {
+					*p = '\0';
+					len = result + EXPBUFSIZE - start - 1;
+					p = expand_macro(start, len) - 1;
+				}
+				start = NULL;
+				txt--;
+			}
+			p++;
+			txt++;
+			continue;
+		}
+		if (*txt == '$') {
+			start = p;
+			txt++;
+			continue;
+		}
+		p++;
+		txt++;
+	}
+	*p = '\0';
+	if (start && p - start > 0) {
+		len = result + EXPBUFSIZE - start - 1;
+		p = expand_macro(start, len);
+		*p = '\0';
+	}
+	return result;
+}