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Clean-up my modification of popen.c for vfork. Bruce's (this) is better.

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Submitted by:	Bruce Evans <bde@freebsd.org>
This commit is contained in:
John Dyson 1997-04-20 20:17:04 +00:00
parent fd48862f47
commit 5ae9116a7d
1 changed files with 12 additions and 10 deletions
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22
lib/libc/gen/popen.c
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@ -94,18 +94,20 @@ popen(command, type)
case 0: /* Child. */
if (*type == 'r') {
/*
* We must NOT modify pdes, due to the
* semantics of vfork.
* The dup2() to STDIN_FILENO is repeated to avoid
* writing to pdes[1], which might corrupt the
* parent's copy. This isn't good enough in
* general, since the _exit() is no return, so
* the compiler is free to corrupt all the local
* variables.
*/
int tpdes1 = pdes[1];
if (tpdes1 != STDOUT_FILENO) {
(void)dup2(tpdes1, STDOUT_FILENO);
(void)close(tpdes1);
tpdes1 = STDOUT_FILENO;
}
(void) close(pdes[0]);
if (twoway && (tpdes1 != STDIN_FILENO))
(void)dup2(tpdes1, STDIN_FILENO);
if (pdes[1] != STDOUT_FILENO) {
(void)dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
(void)dup2(STDOUT_FILENO, STDIN_FILENO);
} else if (twoway && (pdes[1] != STDIN_FILENO))
(void)dup2(pdes[1], STDIN_FILENO);
} else {
if (pdes[0] != STDIN_FILENO) {
(void)dup2(pdes[0], STDIN_FILENO);