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Bug fix: deal with race-like (select(2) vs wait4(2)) error flow bogon.

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ross 1999-03-22 09:02:47 +00:00
parent 5d25794ed2
commit ac722a849a
1 changed files with 15 additions and 8 deletions
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23
distrib/utils/sysinst/run.c
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@ -1,4 +1,4 @@
/* $NetBSD: run.c,v 1.10 1999/03/11 16:48:27 marc Exp $ */ /* $NetBSD: run.c,v 1.11 1999/03/22 09:02:47 ross Exp $ */
/* /*
* Copyright 1997 Piermont Information Systems Inc. * Copyright 1997 Piermont Information Systems Inc.
@ -260,6 +260,7 @@ launch_subwin(actionwin, args, win, display)
{ {
int xcor,ycor; int xcor,ycor;
int n, i, j; int n, i, j;
int selectfailed;
int status, master, slave; int status, master, slave;
fd_set active_fd_set, read_fd_set; fd_set active_fd_set, read_fd_set;
int dataflow[2]; int dataflow[2];
@ -290,7 +291,7 @@ launch_subwin(actionwin, args, win, display)
case -1: case -1:
return -1; return -1;
break; break;
case 0: { case 0:
(void)close(STDIN_FILENO); (void)close(STDIN_FILENO);
subchild = fork(); subchild = fork();
if (subchild == 0) { if (subchild == 0) {
@ -321,9 +322,9 @@ launch_subwin(actionwin, args, win, display)
execvp(argzero, origargs); execvp(argzero, origargs);
/* the parent will see this as the output from the /* the parent will see this as the output from the
child */ child */
perror("execvp"); warn("execvp %s", argzero);
_exit(EXIT_FAILURE); _exit(EXIT_FAILURE);
} break; /* end of child */ break; /* end of child */
default: break; default: break;
} }
close(dataflow[1]); close(dataflow[1]);
@ -332,15 +333,20 @@ launch_subwin(actionwin, args, win, display)
FD_SET(STDIN_FILENO, &active_fd_set); FD_SET(STDIN_FILENO, &active_fd_set);
pid = wait4(child, &status, WNOHANG, 0); pid = wait4(child, &status, WNOHANG, 0);
for (;;) { for (selectfailed = 0;;) {
if (selectfailed) {
char *msg = "select(2) failed but no child died?";
if(logging)
(void)fprintf(log, msg);
errx(1, msg);
}
read_fd_set = active_fd_set; read_fd_set = active_fd_set;
if (select(FD_SETSIZE, &read_fd_set, NULL, NULL, NULL) < 0) { if (select(FD_SETSIZE, &read_fd_set, NULL, NULL, NULL) < 0) {
perror("select"); perror("select");
if (logging) if (logging)
(void)fprintf(log, "select failure: %s\n", strerror(errno)); (void)fprintf(log, "select failure: %s\n", strerror(errno));
exit(EXIT_FAILURE); ++selectfailed;
} } else for (i = 0; i < FD_SETSIZE; ++i) {
for (i = 0; i < FD_SETSIZE; ++i)
if (FD_ISSET (i, &read_fd_set)) { if (FD_ISSET (i, &read_fd_set)) {
n = read(i, ibuf, MAXBUF); n = read(i, ibuf, MAXBUF);
if (i == STDIN_FILENO) if (i == STDIN_FILENO)
@ -377,6 +383,7 @@ launch_subwin(actionwin, args, win, display)
} }
} }
} }
}
pid = wait4(child, &status, WNOHANG, 0); pid = wait4(child, &status, WNOHANG, 0);
if (pid == child && (WIFEXITED(status) || WIFSIGNALED(status))) if (pid == child && (WIFEXITED(status) || WIFSIGNALED(status)))
break; break;