[PATCH v3 4/9] bugreport: add config values from whitelist

[Emily Shaffer <emilyshaffer@google.com>]

Teach bugreport to gather the values of config options which are present
in 'git-bugreport-config-whitelist'.

Many config options are sensitive, and many Git add-ons use config
options which git-core does not know about; it is better only to gather
config options which we know to be safe, rather than excluding options
which we know to be unsafe.

Reading the whitelist into memory and sorting it saves us time -
since git_config_bugreport() is called for every option the user has
configured, limiting the file IO to one open/read/close and performing
option lookup in sublinear time is a useful optimization.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
---
 bugreport.c         | 50 +++++++++++++++++++++++++++++++++++++++++++++
 bugreport.h         |  7 +++++++
 builtin/bugreport.c |  4 ++++
 3 files changed, 61 insertions(+)

diff --git a/bugreport.c b/bugreport.c
index ada54fe583..afa4836ab1 100644
--- a/bugreport.c
+++ b/bugreport.c
@@ -1,10 +1,24 @@
 #include "cache.h"
 
 #include "bugreport.h"
+#include "config.h"
+#include "exec-cmd.h"
 #include "help.h"
 #include "run-command.h"
 #include "version.h"
 
+/**
+ * A sorted list of config options which we will add to the bugreport. Managed
+ * by 'gather_whitelist(...)'.
+ */
+struct string_list whitelist = STRING_LIST_INIT_DUP;
+struct strbuf configs_and_values = STRBUF_INIT;
+
+// git version --build-options
+// uname -a
+// curl-config --version
+// ldd --version
+// echo $SHELL
 void get_system_info(struct strbuf *sys_info)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -53,3 +67,39 @@ void get_system_info(struct strbuf *sys_info)
 	argv_array_clear(&cp.args);
 	strbuf_reset(&std_out);
 }
+
+void gather_whitelist(struct strbuf *path)
+{
+	struct strbuf tmp = STRBUF_INIT;
+	strbuf_read_file(&tmp, path->buf, 0);
+	string_list_init(&whitelist, 1);
+	string_list_split(&whitelist, tmp.buf, '\n', -1);
+	string_list_sort(&whitelist);
+}
+
+int git_config_bugreport(const char *var, const char *value, void *cb)
+{
+	if (string_list_has_string(&whitelist, var)) {
+		strbuf_addf(&configs_and_values,
+			    "%s : %s\n",
+			    var, value);
+	}
+
+	return 0;
+}
+
+void get_whitelisted_config(struct strbuf *config_info)
+{
+	struct strbuf path = STRBUF_INIT;
+
+	strbuf_addstr(&path, git_exec_path());
+	strbuf_addstr(&path, "/git-bugreport-config-whitelist");
+
+	gather_whitelist(&path);
+	strbuf_init(&configs_and_values, whitelist.nr);
+
+	git_config(git_config_bugreport, NULL);
+
+	strbuf_reset(config_info);
+	strbuf_addbuf(config_info, &configs_and_values);
+}
diff --git a/bugreport.h b/bugreport.h
index ba216acf3f..7413e7e1be 100644
--- a/bugreport.h
+++ b/bugreport.h
@@ -5,3 +5,10 @@
  * The previous contents of sys_info will be discarded.
  */
 void get_system_info(struct strbuf *sys_info);
+
+/**
+ * Adds the values of the config items listed in
+ * 'git-bugreport-config-whitelist' to config_info. The previous contents of
+ * config_info will be discarded.
+ */
+void get_whitelisted_config(struct strbuf *sys_info);
diff --git a/builtin/bugreport.c b/builtin/bugreport.c
index 7232d31be7..70fe0d2b85 100644
--- a/builtin/bugreport.c
+++ b/builtin/bugreport.c
@@ -56,6 +56,10 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
 	get_system_info(&buffer);
 	strbuf_write(&buffer, report);
 
+	add_header(report, "Whitelisted Config");
+	get_whitelisted_config(&buffer);
+	strbuf_write(&buffer, report);
+
 	fclose(report);
 
 	launch_editor(report_path.buf, NULL, NULL);
-- 
2.24.0.rc0.303.g954a862665-goog