[PATCHv3 05/13] run-command: factor out return value computation

[Stefan Beller <sbeller@google.com>]

We will need computing the return value in a later patch without the
wait.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 run-command.c | 54 ++++++++++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/run-command.c b/run-command.c
index 28e1d55..674e348 100644
--- a/run-command.c
+++ b/run-command.c
@@ -232,6 +232,35 @@ static inline void set_cloexec(int fd)
 		fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 }
 
+static int determine_return_value(int wait_status,
+				  int *result,
+				  int *error_code,
+				  const char *argv0)
+{
+	if (WIFSIGNALED(wait_status)) {
+		*result = WTERMSIG(wait_status);
+		if (*result != SIGINT && *result != SIGQUIT)
+			error("%s died of signal %d", argv0, *result);
+		/*
+		 * This return value is chosen so that code & 0xff
+		 * mimics the exit code that a POSIX shell would report for
+		 * a program that died from this signal.
+		 */
+		*result += 128;
+	} else if (WIFEXITED(wait_status)) {
+		*result = WEXITSTATUS(wait_status);
+		/*
+		 * Convert special exit code when execvp failed.
+		 */
+		if (*result == 127) {
+			*result = -1;
+			*error_code = ENOENT;
+		}
+	} else
+		return -1;
+	return 0;
+}
+
 static int wait_or_whine(pid_t pid, const char *argv0)
 {
 	int status, code = -1;
@@ -244,29 +273,10 @@ static int wait_or_whine(pid_t pid, const char *argv0)
 	if (waiting < 0) {
 		failed_errno = errno;
 		error("waitpid for %s failed: %s", argv0, strerror(errno));
-	} else if (waiting != pid) {
-		error("waitpid is confused (%s)", argv0);
-	} else if (WIFSIGNALED(status)) {
-		code = WTERMSIG(status);
-		if (code != SIGINT && code != SIGQUIT)
-			error("%s died of signal %d", argv0, code);
-		/*
-		 * This return value is chosen so that code & 0xff
-		 * mimics the exit code that a POSIX shell would report for
-		 * a program that died from this signal.
-		 */
-		code += 128;
-	} else if (WIFEXITED(status)) {
-		code = WEXITSTATUS(status);
-		/*
-		 * Convert special exit code when execvp failed.
-		 */
-		if (code == 127) {
-			code = -1;
-			failed_errno = ENOENT;
-		}
 	} else {
-		error("waitpid is confused (%s)", argv0);
+		if (waiting != pid
+		   || (determine_return_value(status, &code, &failed_errno, argv0) < 0))
+			error("waitpid is confused (%s)", argv0);
 	}
 
 	clear_child_for_cleanup(pid);
-- 
2.5.0.275.ge015d2a