1 files changed, 61 insertions, 0 deletions
diff --git a/src/stdlib/system.c b/src/stdlib/system.c
new file mode 100644
index 00000000..ac0d54d5
--- /dev/null
+++ b/src/stdlib/system.c
@@ -0,0 +1,61 @@
+#include <stdlib.h>
+
+#if defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || defined _XOPEN_SOURCE
+# include "errno.h"
+# include "sys/types.h"
+# include "unistd.h"
+# include "sys/wait.h"
+# define USE_FORK
+#endif
+
+/** execute a command **/
+
+int system(const char * string)
+{
+	#if defined USE_FORK
+	pid_t pid;
+	int status;
+
+	if (string == NULL) {
+		return 0;
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		/* errno comes from fork() */
+		return -1;
+	}
+
+	if (pid == 0) {
+		execl("/bin/sh", "sh", "-c", string, (char *)0);
+		_exit(1);
+	}
+	
+	if (waitpid(pid, &status, 0) == -1) {
+		errno = ECHILD;
+		return -1;
+	}
+
+	return status;
+
+	#else
+	(void)string;
+	return 1;
+	#endif
+}
+
+/***
+runs the command ARGUMENT(string) using the host environment's command
+processor.
+
+Specifying CONSTANT(NULL) for ARGUMENT(string) tests whether a command
+processor is available.
+***/
+
+/*
+IMPLEMENTATION(How the command processor is invoked)
+IMPLEMENTATION(The return value when ARGUMENT(string) is not CONSTANT(NULL))
+RETURN(NONZERO, If ARGUMENT(string) is CONSTANT(NULL), a command processor is available)
+RETURN(0, If ARGUMENT(string) is CONSTANT(NULL), a command processor is not available)
+STDC(1)
+*/