git/fsmonitor-settings.c
Eric DeCosta 25c2cab08f fsmonitor: check for compatability before communicating with fsmonitor
If fsmonitor is not in a compatible state, warn with an appropriate message.

Signed-off-by: Eric DeCosta <edecosta@mathworks.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-05 11:05:23 -07:00

300 lines
7.4 KiB
C

#include "cache.h"
#include "config.h"
#include "repository.h"
#include "fsmonitor-ipc.h"
#include "fsmonitor-settings.h"
#include "fsmonitor-path-utils.h"
/*
* We keep this structure defintion private and have getters
* for all fields so that we can lazy load it as needed.
*/
struct fsmonitor_settings {
enum fsmonitor_mode mode;
enum fsmonitor_reason reason;
char *hook_path;
};
/*
* Remote working directories are problematic for FSMonitor.
*
* The underlying file system on the server machine and/or the remote
* mount type dictates whether notification events are available at
* all to remote client machines.
*
* Kernel differences between the server and client machines also
* dictate the how (buffering, frequency, de-dup) the events are
* delivered to client machine processes.
*
* A client machine (such as a laptop) may choose to suspend/resume
* and it is unclear (without lots of testing) whether the watcher can
* resync after a resume. We might be able to treat this as a normal
* "events were dropped by the kernel" event and do our normal "flush
* and resync" --or-- we might need to close the existing (zombie?)
* notification fd and create a new one.
*
* In theory, the above issues need to be addressed whether we are
* using the Hook or IPC API.
*
* So (for now at least), mark remote working directories as
* incompatible unless 'fsmonitor.allowRemote' is true.
*
*/
#ifdef HAVE_FSMONITOR_OS_SETTINGS
static enum fsmonitor_reason check_remote(struct repository *r)
{
int allow_remote = -1; /* -1 unset, 0 not allowed, 1 allowed */
int is_remote = fsmonitor__is_fs_remote(r->worktree);
switch (is_remote) {
case 0:
return FSMONITOR_REASON_OK;
case 1:
repo_config_get_bool(r, "fsmonitor.allowremote", &allow_remote);
if (allow_remote < 1)
return FSMONITOR_REASON_REMOTE;
else
return FSMONITOR_REASON_OK;
default:
return FSMONITOR_REASON_ERROR;
}
}
#endif
static enum fsmonitor_reason check_for_incompatible(struct repository *r, int ipc)
{
if (!r->worktree) {
/*
* Bare repositories don't have a working directory and
* therefore have nothing to watch.
*/
return FSMONITOR_REASON_BARE;
}
#ifdef HAVE_FSMONITOR_OS_SETTINGS
{
enum fsmonitor_reason reason;
reason = check_remote(r);
if (reason != FSMONITOR_REASON_OK)
return reason;
reason = fsm_os__incompatible(r, ipc);
if (reason != FSMONITOR_REASON_OK)
return reason;
}
#endif
return FSMONITOR_REASON_OK;
}
static struct fsmonitor_settings *alloc_settings(void)
{
struct fsmonitor_settings *s;
CALLOC_ARRAY(s, 1);
s->mode = FSMONITOR_MODE_DISABLED;
s->reason = FSMONITOR_REASON_UNTESTED;
return s;
}
static void lookup_fsmonitor_settings(struct repository *r)
{
const char *const_str;
int bool_value;
if (r->settings.fsmonitor)
return;
/*
* Overload the existing "core.fsmonitor" config setting (which
* has historically been either unset or a hook pathname) to
* now allow a boolean value to enable the builtin FSMonitor
* or to turn everything off. (This does imply that you can't
* use a hook script named "true" or "false", but that's OK.)
*/
switch (repo_config_get_maybe_bool(r, "core.fsmonitor", &bool_value)) {
case 0: /* config value was set to <bool> */
if (bool_value)
fsm_settings__set_ipc(r);
else
fsm_settings__set_disabled(r);
return;
case 1: /* config value was unset */
const_str = getenv("GIT_TEST_FSMONITOR");
break;
case -1: /* config value set to an arbitrary string */
if (repo_config_get_pathname(r, "core.fsmonitor", &const_str))
return; /* should not happen */
break;
default: /* should not happen */
return;
}
if (const_str && *const_str)
fsm_settings__set_hook(r, const_str);
else
fsm_settings__set_disabled(r);
}
enum fsmonitor_mode fsm_settings__get_mode(struct repository *r)
{
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
lookup_fsmonitor_settings(r);
return r->settings.fsmonitor->mode;
}
const char *fsm_settings__get_hook_path(struct repository *r)
{
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
lookup_fsmonitor_settings(r);
return r->settings.fsmonitor->hook_path;
}
void fsm_settings__set_ipc(struct repository *r)
{
enum fsmonitor_reason reason = check_for_incompatible(r, 1);
if (reason != FSMONITOR_REASON_OK) {
fsm_settings__set_incompatible(r, reason);
return;
}
/*
* Caller requested IPC explicitly, so avoid (possibly
* recursive) config lookup.
*/
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
r->settings.fsmonitor = alloc_settings();
r->settings.fsmonitor->mode = FSMONITOR_MODE_IPC;
r->settings.fsmonitor->reason = reason;
FREE_AND_NULL(r->settings.fsmonitor->hook_path);
}
void fsm_settings__set_hook(struct repository *r, const char *path)
{
enum fsmonitor_reason reason = check_for_incompatible(r, 0);
if (reason != FSMONITOR_REASON_OK) {
fsm_settings__set_incompatible(r, reason);
return;
}
/*
* Caller requested hook explicitly, so avoid (possibly
* recursive) config lookup.
*/
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
r->settings.fsmonitor = alloc_settings();
r->settings.fsmonitor->mode = FSMONITOR_MODE_HOOK;
r->settings.fsmonitor->reason = reason;
FREE_AND_NULL(r->settings.fsmonitor->hook_path);
r->settings.fsmonitor->hook_path = strdup(path);
}
void fsm_settings__set_disabled(struct repository *r)
{
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
r->settings.fsmonitor = alloc_settings();
r->settings.fsmonitor->mode = FSMONITOR_MODE_DISABLED;
r->settings.fsmonitor->reason = FSMONITOR_REASON_OK;
FREE_AND_NULL(r->settings.fsmonitor->hook_path);
}
void fsm_settings__set_incompatible(struct repository *r,
enum fsmonitor_reason reason)
{
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
r->settings.fsmonitor = alloc_settings();
r->settings.fsmonitor->mode = FSMONITOR_MODE_INCOMPATIBLE;
r->settings.fsmonitor->reason = reason;
FREE_AND_NULL(r->settings.fsmonitor->hook_path);
}
enum fsmonitor_reason fsm_settings__get_reason(struct repository *r)
{
if (!r)
r = the_repository;
if (!r->settings.fsmonitor)
lookup_fsmonitor_settings(r);
return r->settings.fsmonitor->reason;
}
char *fsm_settings__get_incompatible_msg(struct repository *r,
enum fsmonitor_reason reason)
{
struct strbuf msg = STRBUF_INIT;
const char *socket_dir;
switch (reason) {
case FSMONITOR_REASON_UNTESTED:
case FSMONITOR_REASON_OK:
goto done;
case FSMONITOR_REASON_BARE: {
char *cwd = xgetcwd();
strbuf_addf(&msg,
_("bare repository '%s' is incompatible with fsmonitor"),
cwd);
free(cwd);
goto done;
}
case FSMONITOR_REASON_ERROR:
strbuf_addf(&msg,
_("repository '%s' is incompatible with fsmonitor due to errors"),
r->worktree);
goto done;
case FSMONITOR_REASON_REMOTE:
strbuf_addf(&msg,
_("remote repository '%s' is incompatible with fsmonitor"),
r->worktree);
goto done;
case FSMONITOR_REASON_VFS4GIT:
strbuf_addf(&msg,
_("virtual repository '%s' is incompatible with fsmonitor"),
r->worktree);
goto done;
case FSMONITOR_REASON_NOSOCKETS:
socket_dir = dirname((char *)fsmonitor_ipc__get_path(r));
strbuf_addf(&msg,
_("socket directory '%s' is incompatible with fsmonitor due"
" to lack of Unix sockets support"),
socket_dir);
goto done;
}
BUG("Unhandled case in fsm_settings__get_incompatible_msg: '%d'",
reason);
done:
return strbuf_detach(&msg, NULL);
}