Work around an infinite loop issue

This commit is contained in:
Přemysl Eric Janouch 2020-04-19 22:40:57 +02:00
parent c0f0328762
commit 623c4914d1
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 23 additions and 2 deletions

25
sdn.cpp
View File

@ -41,6 +41,7 @@
#include <pwd.h> #include <pwd.h>
#include <grp.h> #include <grp.h>
#include <libgen.h> #include <libgen.h>
#include <time.h>
#include <sys/inotify.h> #include <sys/inotify.h>
#include <sys/xattr.h> #include <sys/xattr.h>
@ -1126,6 +1127,9 @@ fun handle_editor (wint_t c) {
} }
fun handle (wint_t c) -> bool { fun handle (wint_t c) -> bool {
if (c == WEOF)
return false;
// If an editor is active, let it handle the key instead and eat it // If an editor is active, let it handle the key instead and eat it
if (g.editor) { if (g.editor) {
handle_editor (c); handle_editor (c);
@ -1369,10 +1373,27 @@ fun load_colors () {
} }
} }
fun monotonic_ts_ms () -> int64_t {
timespec ts{1, 0}; // A very specific fail-safe value
(void) clock_gettime (CLOCK_MONOTONIC, &ts);
return ts.tv_sec * 1e3 + ts.tv_nsec / 1e6;
}
fun read_key (wint_t &c) -> bool { fun read_key (wint_t &c) -> bool {
// XXX: on at least some systems, when run over ssh in a bind handler,
// after closing the terminal emulator we receive no fatal signal but our
// parent shell gets reparented under init and our stdin gets closed,
// so we'd keep getting ERR in an infinite loop, as that is what ncurses
// automatically converts EOF into. The most reasonable way to detect this
// situation appears to be via timing. Checking errno doesn't work and
// resetting signal dispositions or the signal mask has no effect.
auto start = monotonic_ts_ms ();
int res = get_wch (&c); int res = get_wch (&c);
if (res == ERR) if (res == ERR) {
return false; c = WEOF;
if (monotonic_ts_ms () - start >= 50)
return false;
}
wint_t metafied{}; wint_t metafied{};
if (c == 27 && (res = get_wch (&metafied)) != ERR) if (c == 27 && (res = get_wch (&metafied)) != ERR)