[PATCH v2 21/32] tools/nolibc: implement waitpid() in terms of waitid()

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

The old wait4() syscall used by waitpid() before is not available everywhere.
Switch to the waitid() syscall which is the new replacement.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Willy Tarreau <w@1wt.eu>
---
 tools/include/nolibc/sys.h | 71 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 59 insertions(+), 12 deletions(-)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 5c71a2f65c7bd93f6f516a54f7e63244466fad47..e39eefb2b82cc97eccfc030005fe0321632f12c4 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -1267,6 +1267,7 @@ int unlink(const char *path)
  * pid_t wait(int *status);
  * pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage);
  * pid_t waitpid(pid_t pid, int *status, int options);
+ * int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
  */
 
 static __attribute__((unused))
@@ -1291,18 +1292,6 @@ pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage)
 	return __sysret(sys_wait4(pid, status, options, rusage));
 }
 
-
-static __attribute__((unused))
-pid_t waitpid(pid_t pid, int *status, int options)
-{
-	return __sysret(sys_wait4(pid, status, options, NULL));
-}
-
-
-/*
- * int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
- */
-
 static __attribute__((unused))
 int sys_waitid(int which, pid_t pid, siginfo_t *infop, int options, struct rusage *rusage)
 {
@@ -1316,6 +1305,64 @@ int waitid(int which, pid_t pid, siginfo_t *infop, int options)
 }
 
 
+static __attribute__((unused))
+pid_t waitpid(pid_t pid, int *status, int options)
+{
+	int idtype, ret;
+	siginfo_t info;
+	pid_t id;
+
+	if (pid == INT_MIN) {
+		SET_ERRNO(ESRCH);
+		return -1;
+	} else if (pid < -1) {
+		idtype = P_PGID;
+		id = -pid;
+	} else if (pid == -1) {
+		idtype = P_ALL;
+		id = 0;
+	} else if (pid == 0) {
+		idtype = P_PGID;
+		id = 0;
+	} else {
+		idtype = P_PID;
+		id = pid;
+	}
+
+	options |= WEXITED;
+
+	ret = waitid(idtype, id, &info, options);
+	if (ret)
+		return ret;
+
+	switch (info.si_code) {
+	case 0:
+		*status = 0;
+		break;
+	case CLD_EXITED:
+		*status = (info.si_status & 0xff) << 8;
+		break;
+	case CLD_KILLED:
+		*status = info.si_status & 0x7f;
+		break;
+	case CLD_DUMPED:
+		*status = (info.si_status & 0x7f) | 0x80;
+		break;
+	case CLD_STOPPED:
+	case CLD_TRAPPED:
+		*status = (info.si_status << 8) + 0x7f;
+		break;
+	case CLD_CONTINUED:
+		*status = 0xffff;
+		break;
+	default:
+		return -1;
+	}
+
+	return info.si_pid;
+}
+
+
 /*
  * ssize_t write(int fd, const void *buf, size_t count);
  */

-- 
2.49.0