pipeln

commit 0e7a061a6592b3dae5c7519a73d32579860b3560
parent 8afeed1a607f70606a81ab39cac8d684964fdab1
Author: Louis Burda <quent.burda@gmail.com>
Date:   Mon, 16 Oct 2023 13:59:50 +0200

Only return status code of last command in pipeline

Diffstat:
M
pipeln.c
 | 
30
++++++++++++++++++------------

1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/pipeln.c b/pipeln.c
@@ -68,7 +68,7 @@ findbin(const char *name)
 	die("findbin %s", name);
 }
 
-void
+pid_t
 run(int *in, int *out, const char **argv)
 {
 	pid_t child;
@@ -100,24 +100,29 @@ run(int *in, int *out, const char **argv)
 
 	if (in) close(in[0]);
 	if (out) close(out[1]);
+
+	return child;
 }
 
 void
-waitall(void)
+waitall(pid_t tpid)
 {
-	int rc, status, exitcode;
+	int status, exitcode;
+	pid_t pid;
 
 	errno = 0;
 	exitcode = 0;
 	do {
-		rc = waitpid(-1, &status, 0);
-		if (rc < 0 && errno != EINTR && errno != ECHILD)
+		pid = waitpid(-1, &status, 0);
+		if (pid < 0 && errno != EINTR && errno != ECHILD)
 			die("waitpid:");
-		if (!exitcode && WIFEXITED(status))
-			exitcode = WEXITSTATUS(status);
-		else if (!exitcode && WIFSIGNALED(status))
-			exitcode = 128 + WTERMSIG(status);
-	} while (rc >= 0 && errno != ECHILD);
+		if (pid == tpid) {
+			if (!exitcode && WIFEXITED(status))
+				exitcode = WEXITSTATUS(status);
+			else if (!exitcode && WIFSIGNALED(status))
+				exitcode = 128 + WTERMSIG(status);
+		}
+	} while (pid >= 0 && errno != ECHILD);
 
 	exit(exitcode);
 }
@@ -128,6 +133,7 @@ main(int argc, const char **argv)
 	const char **arg, **cmdargs;
 	int pipe1[2], pipe2[2];
 	int *in, *out;
+	pid_t pid;
 
 	/* first cmd from stdin */
 	in = NULL;
@@ -142,8 +148,8 @@ main(int argc, const char **argv)
 
 			/* run piped cmd */
 			*arg = NULL;
-			run(in, out, cmdargs);
-			if (!out) waitall();
+			pid = run(in, out, cmdargs);
+			if (!out) waitall(pid);
 			cmdargs = arg + 1;
 
 			/* out => in */