bce9db6de9
Teach git to read the system and global config files for default Trace2 settings. This allows system-wide Trace2 settings to be installed and inherited to make it easier to manage a collection of systems. The original GIT_TR2* environment variables are loaded afterwards and can be used to override the system settings. Only the system and global config files are used. Repo and worktree local config files are ignored. Likewise, the "-c" command line arguments are also ignored. These limits are for performance reasons. (1) For users not using Trace2, there should be minimal overhead to detect that Trace2 is not enabled. In particular, Trace2 should not allocate lots of otherwise unused data strucutres. (2) For accurate performance measurements, Trace2 should be initialized as early in the git process as possible, and before most of the normal git process initialization (which involves discovering the .git directory and reading a hierarchy of config files). Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
#include "cache.h"
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#include "config.h"
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#include "dir.h"
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#include "tr2_sysenv.h"
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/*
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* Each entry represents a trace2 setting.
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* See Documentation/technical/api-trace2.txt
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*/
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struct tr2_sysenv_entry {
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const char *env_var_name;
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const char *git_config_name;
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char *value;
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unsigned int getenv_called : 1;
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};
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/*
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* This table must match "enum tr2_sysenv_variable" in tr2_sysenv.h.
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*
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* The strings in this table are constant and must match the published
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* config and environment variable names as described in the documentation.
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*
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* We do not define entries for the GIT_TR2_PARENT_* environment
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* variables because they are transient and used to pass information
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* from parent to child git processes, rather than settings.
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*/
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/* clang-format off */
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static struct tr2_sysenv_entry tr2_sysenv_settings[] = {
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[TR2_SYSENV_CFG_PARAM] = { "GIT_TR2_CONFIG_PARAMS",
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"trace2.configparams" },
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[TR2_SYSENV_DST_DEBUG] = { "GIT_TR2_DST_DEBUG",
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"trace2.destinationdebug" },
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[TR2_SYSENV_NORMAL] = { "GIT_TR2",
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"trace2.normaltarget" },
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[TR2_SYSENV_NORMAL_BRIEF] = { "GIT_TR2_BRIEF",
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"trace2.normalbrief" },
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[TR2_SYSENV_EVENT] = { "GIT_TR2_EVENT",
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"trace2.eventtarget" },
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[TR2_SYSENV_EVENT_BRIEF] = { "GIT_TR2_EVENT_BRIEF",
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"trace2.eventbrief" },
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[TR2_SYSENV_EVENT_NESTING] = { "GIT_TR2_EVENT_NESTING",
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"trace2.eventnesting" },
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[TR2_SYSENV_PERF] = { "GIT_TR2_PERF",
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"trace2.perftarget" },
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[TR2_SYSENV_PERF_BRIEF] = { "GIT_TR2_PERF_BRIEF",
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"trace2.perfbrief" },
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};
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/* clang-format on */
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static int tr2_sysenv_cb(const char *key, const char *value, void *d)
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{
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int k;
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if (!starts_with(key, "trace2."))
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return 0;
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for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++) {
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if (!strcmp(key, tr2_sysenv_settings[k].git_config_name)) {
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free(tr2_sysenv_settings[k].value);
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tr2_sysenv_settings[k].value = xstrdup(value);
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return 0;
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}
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}
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return 0;
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}
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/*
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* Load Trace2 settings from the system config (usually "/etc/gitconfig"
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* unless we were built with a runtime-prefix). These are intended to
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* define the default values for Trace2 as requested by the administrator.
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*
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* Then override with the Trace2 settings from the global config.
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*/
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void tr2_sysenv_load(void)
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{
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if (ARRAY_SIZE(tr2_sysenv_settings) != TR2_SYSENV_MUST_BE_LAST)
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BUG("tr2_sysenv_settings size is wrong");
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read_very_early_config(tr2_sysenv_cb, NULL);
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}
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/*
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* Return the value for the requested Trace2 setting from these sources:
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* the system config, the global config, and the environment.
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*/
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const char *tr2_sysenv_get(enum tr2_sysenv_variable var)
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{
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if (var >= TR2_SYSENV_MUST_BE_LAST)
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BUG("tr2_sysenv_get invalid var '%d'", var);
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if (!tr2_sysenv_settings[var].getenv_called) {
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const char *v = getenv(tr2_sysenv_settings[var].env_var_name);
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if (v && *v) {
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free(tr2_sysenv_settings[var].value);
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tr2_sysenv_settings[var].value = xstrdup(v);
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}
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tr2_sysenv_settings[var].getenv_called = 1;
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}
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return tr2_sysenv_settings[var].value;
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}
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/*
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* Return a friendly name for this setting that is suitable for printing
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* in an error messages.
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*/
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const char *tr2_sysenv_display_name(enum tr2_sysenv_variable var)
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{
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if (var >= TR2_SYSENV_MUST_BE_LAST)
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BUG("tr2_sysenv_get invalid var '%d'", var);
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return tr2_sysenv_settings[var].env_var_name;
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}
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void tr2_sysenv_release(void)
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{
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int k;
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for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++)
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free(tr2_sysenv_settings[k].value);
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}
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