git/trace2/tr2_sysenv.c
Josh Steadmon 3d3adaad91 trace2: teach Git to log environment variables
Via trace2, Git can already log interesting config parameters (see the
trace2_cmd_list_config() function). However, this can grant an
incomplete picture because many config parameters also allow overrides
via environment variables.

To allow for more complete logs, we add a new trace2_cmd_list_env_vars()
function and supporting implementation, modeled after the pre-existing
config param logging implementation.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-23 13:14:53 -07:00

133 lines
3.6 KiB
C

#include "cache.h"
#include "config.h"
#include "dir.h"
#include "tr2_sysenv.h"
/*
* Each entry represents a trace2 setting.
* See Documentation/technical/api-trace2.txt
*/
struct tr2_sysenv_entry {
const char *env_var_name;
const char *git_config_name;
char *value;
unsigned int getenv_called : 1;
};
/*
* This table must match "enum tr2_sysenv_variable" in tr2_sysenv.h.
*
* The strings in this table are constant and must match the published
* config and environment variable names as described in the documentation.
*
* We do not define entries for the GIT_TRACE2_PARENT_* environment
* variables because they are transient and used to pass information
* from parent to child git processes, rather than settings.
*/
/* clang-format off */
static struct tr2_sysenv_entry tr2_sysenv_settings[] = {
[TR2_SYSENV_CFG_PARAM] = { "GIT_TRACE2_CONFIG_PARAMS",
"trace2.configparams" },
[TR2_SYSENV_ENV_VARS] = { "GIT_TRACE2_ENV_VARS",
"trace2.envvars" },
[TR2_SYSENV_DST_DEBUG] = { "GIT_TRACE2_DST_DEBUG",
"trace2.destinationdebug" },
[TR2_SYSENV_NORMAL] = { "GIT_TRACE2",
"trace2.normaltarget" },
[TR2_SYSENV_NORMAL_BRIEF] = { "GIT_TRACE2_BRIEF",
"trace2.normalbrief" },
[TR2_SYSENV_EVENT] = { "GIT_TRACE2_EVENT",
"trace2.eventtarget" },
[TR2_SYSENV_EVENT_BRIEF] = { "GIT_TRACE2_EVENT_BRIEF",
"trace2.eventbrief" },
[TR2_SYSENV_EVENT_NESTING] = { "GIT_TRACE2_EVENT_NESTING",
"trace2.eventnesting" },
[TR2_SYSENV_PERF] = { "GIT_TRACE2_PERF",
"trace2.perftarget" },
[TR2_SYSENV_PERF_BRIEF] = { "GIT_TRACE2_PERF_BRIEF",
"trace2.perfbrief" },
[TR2_SYSENV_MAX_FILES] = { "GIT_TRACE2_MAX_FILES",
"trace2.maxfiles" },
};
/* clang-format on */
static int tr2_sysenv_cb(const char *key, const char *value, void *d)
{
int k;
if (!starts_with(key, "trace2."))
return 0;
for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++) {
if (!strcmp(key, tr2_sysenv_settings[k].git_config_name)) {
free(tr2_sysenv_settings[k].value);
tr2_sysenv_settings[k].value = xstrdup(value);
return 0;
}
}
return 0;
}
/*
* Load Trace2 settings from the system config (usually "/etc/gitconfig"
* unless we were built with a runtime-prefix). These are intended to
* define the default values for Trace2 as requested by the administrator.
*
* Then override with the Trace2 settings from the global config.
*/
void tr2_sysenv_load(void)
{
if (ARRAY_SIZE(tr2_sysenv_settings) != TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_settings size is wrong");
read_very_early_config(tr2_sysenv_cb, NULL);
}
/*
* Return the value for the requested Trace2 setting from these sources:
* the system config, the global config, and the environment.
*/
const char *tr2_sysenv_get(enum tr2_sysenv_variable var)
{
if (var >= TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_get invalid var '%d'", var);
if (!tr2_sysenv_settings[var].getenv_called) {
const char *v = getenv(tr2_sysenv_settings[var].env_var_name);
if (v && *v) {
free(tr2_sysenv_settings[var].value);
tr2_sysenv_settings[var].value = xstrdup(v);
}
tr2_sysenv_settings[var].getenv_called = 1;
}
return tr2_sysenv_settings[var].value;
}
/*
* Return a friendly name for this setting that is suitable for printing
* in an error messages.
*/
const char *tr2_sysenv_display_name(enum tr2_sysenv_variable var)
{
if (var >= TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_get invalid var '%d'", var);
return tr2_sysenv_settings[var].env_var_name;
}
void tr2_sysenv_release(void)
{
int k;
for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++)
free(tr2_sysenv_settings[k].value);
}