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script: preserve child exit status 

The patch also removes unnecessary detection of child process
existence (by kill()). This code was replaces with SIGCHLD
hold/release around fork().

Based on the patch from therealneworld@gmail.com.

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2010-04-27 12:11:31 +02:00
parent 9f1d967639
commit f1014a4f33
2 changed files with 34 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
misc-utils/script.1
View File

@ -41,6 +41,7 @@
.Nm script
.Op Fl a
.Op Fl c Ar COMMAND
.Op Fl e
.Op Fl f
.Op Fl q
.Op Fl t
@ -74,6 +75,9 @@ retaining the prior contents.
Run the COMMAND rather than an interactive shell.
This makes it easy for a script to capture the output of a program that
behaves differently when its stdout is not a tty.
.It Fl e
Return the exit code of the child process. Uses the same format as bash
termination on signal termination exit code is 128+n.
.It Fl f
Flush output after each write. This is nice for telecooperation:
One person does `mkfifo foo; script -f foo' and another can

48
misc-utils/script.c
View File

@ -81,6 +81,7 @@ int master;
int slave;
int child;
int subchild;
int childstatus;
char *fname;
struct termios tt;
@ -92,6 +93,7 @@ char line[] = "/dev/ptyXX";
#endif
int aflg = 0;
char *cflg = NULL;
int eflg = 0;
int fflg = 0;
int qflg = 0;
int tflg = 0;
@ -127,6 +129,7 @@ die_if_link(char *fn) {
int
main(int argc, char **argv) {
sigset_t block_mask, unblock_mask;
struct sigaction sa;
extern int optind;
char *p;
@ -150,7 +153,7 @@ main(int argc, char **argv) {
}
}
while ((ch = getopt(argc, argv, "ac:fqt")) != -1)
while ((ch = getopt(argc, argv, "ac:efqt")) != -1)
switch((char)ch) {
case 'a':
aflg++;
@ -158,6 +161,9 @@ main(int argc, char **argv) {
case 'c':
cflg = optarg;
break;
case 'e':
eflg++;
break;
case 'f':
fflg++;
break;
@ -170,7 +176,7 @@ main(int argc, char **argv) {
case '?':
default:
fprintf(stderr,
_("usage: script [-a] [-f] [-q] [-t] [file]\n"));
_("usage: script [-a] [-e] [-f] [-q] [-t] [file]\n"));
exit(1);
}
argc -= optind;
@ -196,19 +202,30 @@ main(int argc, char **argv) {
printf(_("Script started, file is %s\n"), fname);
fixtty();
/* setup SIGCHLD handler */
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = finish;
sigaction(SIGCHLD, &sa, NULL);
/* init mask for SIGCHLD */
sigprocmask(SIG_SETMASK, NULL, &block_mask);
sigaddset(&block_mask, SIGCHLD);
sigprocmask(SIG_SETMASK, &block_mask, &unblock_mask);
child = fork();
sigprocmask(SIG_SETMASK, &unblock_mask, NULL);
if (child < 0) {
perror("fork");
fail();
}
if (child == 0) {
sigprocmask(SIG_SETMASK, &block_mask, NULL);
subchild = child = fork();
sigprocmask(SIG_SETMASK, &unblock_mask, NULL);
if (child < 0) {
perror("fork");
fail();
@ -233,9 +250,6 @@ doinput() {
(void) fclose(fscript);
if (die == 0 && child && kill(child, 0) == -1 && errno == ESRCH)
die = 1;
while (die == 0) {
if ((cc = read(0, ibuf, BUFSIZ)) > 0) {
ssize_t wrt = write(master, ibuf, cc);
@ -263,8 +277,10 @@ finish(int dummy) {
register int pid;
while ((pid = wait3(&status, WNOHANG, 0)) > 0)
if (pid == child)
if (pid == child) {
childstatus = status;
die = 1;
}
}
void
@ -303,17 +319,6 @@ dooutput() {
my_strftime(obuf, sizeof obuf, "%c\n", localtime(&tvec));
fprintf(fscript, _("Script started on %s"), obuf);
if (die == 0 && child && kill(child, 0) == -1 && errno == ESRCH)
/*
* the SIGCHLD handler could be executed when the "child"
* variable is not set yet. It means that the "die" is zero
* althought the child process is already done. We have to
* check this thing now. Now we have the "child" variable
* already initialized. For more details see main() and
* finish(). --kzak 07-Aug-2007
*/
die = 1;
do {
if (die && flgs == 0) {
/* ..child is dead, but it doesn't mean that there is
@ -436,6 +441,13 @@ done() {
if (!qflg)
printf(_("Script done, file is %s\n"), fname);
}
if(eflg) {
if (WIFSIGNALED(childstatus))
exit(WTERMSIG(childstatus) + 0x80);
else
exit(WEXITSTATUS(childstatus));
}
exit(0);
}