17c5472c5
Denys Vlasenko
2018-12-05
Subject
bc: switch to SA_RESTART signal handling
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miscutils/bc.c+17 -1
| @@ -7121,7 +7121,23 @@ static BcStatus bc_vm_run(int argc, char *argv[], | |
| if (G.ttyin) { | |
| #if ENABLE_FEATURE_BC_SIGNALS | |
| - | signal_no_SA_RESTART_empty_mask(SIGINT, record_signo); |
| + | // With SA_RESTART, most system calls will restart |
| + | // (IOW: they won't fail with EINTR). |
| + | // In particular, this means ^C won't cause |
| + | // stdout to get into "error state" if SIGINT hits |
| + | // within write() syscall. |
| + | // The downside is that ^C while line input is taken |
| + | // will only be handled after [Enter] since read() |
| + | // from stdin is not interrupted by ^C either, |
| + | // it restarts, thus fgetc() does not return on ^C. |
| + | signal_SA_RESTART_empty_mask(SIGINT, record_signo); |
| + | |
| + | // Without SA_RESTART, this exhibits a bug: |
| + | // "while (1) print 1" and try ^C-ing it. |
| + | // Intermittently, instead of returning to input line, |
| + | // you'll get "output error: Interrupted system call" |
| + | // and exit. |
| + | //signal_no_SA_RESTART_empty_mask(SIGINT, record_signo); |
| #endif | |
| if (!(option_mask32 & BC_FLAG_Q)) | |
| bc_vm_info(); | |