diff options
Diffstat (limited to 'Src/hist.c')
| -rw-r--r-- | Src/hist.c | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/Src/hist.c b/Src/hist.c index 11d9722d5..303c1dd4a 100644 --- a/Src/hist.c +++ b/Src/hist.c @@ -2610,7 +2610,8 @@ static int flockhistfile(char *fn, int keep_trying) { struct flock lck; - int ctr = keep_trying ? 9 : 0; + long sleep_us = 0x10000; /* about 67 ms */ + time_t end_time; if (flock_fd >= 0) return 0; /* already locked */ @@ -2623,13 +2624,22 @@ flockhistfile(char *fn, int keep_trying) lck.l_start = 0; lck.l_len = 0; /* lock the whole file */ + /* + * Timeout is ten seconds. + */ + end_time = time(NULL) + (time_t)10; while (fcntl(flock_fd, F_SETLKW, &lck) == -1) { - if (--ctr < 0) { + if (!keep_trying || time(NULL) >= end_time || + /* + * Randomise wait to minimise clashes with shells exiting at + * the same time. + */ + !zsleep_random(sleep_us, end_time)) { close(flock_fd); flock_fd = -1; return 1; } - sleep(1); + sleep_us <<= 1; } return 0; @@ -2865,7 +2875,7 @@ savehistfile(char *fn, int err, int writeflags) static int lockhistct; static int -checklocktime(char *lockfile, time_t then) +checklocktime(char *lockfile, long *sleep_usp, time_t then) { time_t now = time(NULL); @@ -2875,9 +2885,19 @@ checklocktime(char *lockfile, time_t then) return -1; } - if (now - then < 10) - sleep(1); - else + if (now - then < 10) { + /* + * To give the effect of a gradually increasing backoff, + * we'll sleep a period based on the time we've spent so far. + */ + DPUTS(now < then, "time flowing backwards through history"); + /* + * Randomise to minimise clashes with shells exiting at the same + * time. + */ + (void)zsleep_random(*sleep_usp, then + 10); + *sleep_usp <<= 1; + } else unlink(lockfile); return 0; @@ -2894,6 +2914,7 @@ lockhistfile(char *fn, int keep_trying) { int ct = lockhistct; int ret = 0; + long sleep_us = 0x10000; /* about 67 ms */ if (!fn && !(fn = getsparam("HISTFILE"))) return 1; @@ -2937,7 +2958,7 @@ lockhistfile(char *fn, int keep_trying) continue; break; } - if (checklocktime(lockfile, sb.st_mtime) < 0) { + if (checklocktime(lockfile, &sleep_us, sb.st_mtime) < 0) { ret = 1; break; } @@ -2965,7 +2986,7 @@ lockhistfile(char *fn, int keep_trying) continue; ret = 2; } else { - if (checklocktime(lockfile, sb.st_mtime) < 0) { + if (checklocktime(lockfile, &sleep_us, sb.st_mtime) < 0) { ret = 1; break; } @@ -2993,7 +3014,7 @@ lockhistfile(char *fn, int keep_trying) ret = 2; break; } - if (checklocktime(lockfile, sb.st_mtime) < 0) { + if (checklocktime(lockfile, &sleep_us, sb.st_mtime) < 0) { ret = 1; break; } |