[PULL 11/46] osdep: build with non-working system() function

[Peter Maydell]

From: Joelle van Dyne <j@getutm.app>

Build without error on hosts without a working system(). If system()
is called, return -1 with ENOSYS.

Signed-off-by: Joelle van Dyne <j@getutm.app>
Message-id: 20210126012457.39046-6-j@getutm.app
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 meson.build          |  1 +
 include/qemu/osdep.h | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/meson.build b/meson.build
index 27c31caa2d1..9ecb09dfe21 100644
--- a/meson.build
+++ b/meson.build
@@ -1127,6 +1127,7 @@ config_host_data.set('HAVE_DRM_H', 
cc.has_header('libdrm/drm.h'))
 config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
 config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
 config_host_data.set('HAVE_SYS_KCOV_H', cc.has_header('sys/kcov.h'))
+config_host_data.set('HAVE_SYSTEM_FUNCTION', cc.has_function('system', prefix: 
'#include <stdlib.h>'))
 
 config_host_data.set('CONFIG_PREADV', cc.has_function('preadv', prefix: 
'#include <sys/uio.h>'))
 
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index b6ffdc15bf3..ba15be9c569 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -710,4 +710,16 @@ static inline void qemu_thread_jit_write(void) {}
 static inline void qemu_thread_jit_execute(void) {}
 #endif
 
+/**
+ * Platforms which do not support system() return ENOSYS
+ */
+#ifndef HAVE_SYSTEM_FUNCTION
+#define system platform_does_not_support_system
+static inline int platform_does_not_support_system(const char *command)
+{
+    errno = ENOSYS;
+    return -1;
+}
+#endif /* !HAVE_SYSTEM_FUNCTION */
+
 #endif
-- 
2.20.1