1 files changed, 114 insertions, 0 deletions
diff --git a/libc/syscall/execve.c b/libc/syscall/execve.c
new file mode 100644
index 0000000..aee7182
--- /dev/null
+++ b/libc/syscall/execve.c
@@ -0,0 +1,114 @@
+
+#include <errno.h>
+
+extern char ** environ;
+
+#ifdef L_execl
+int
+execl(fname, arg0)
+char * fname, *arg0;
+{
+   return execve(fname, &arg0, environ);
+}
+#endif
+
+#ifdef L_execv
+int
+execv(fname, argv)
+char * fname, **argv;
+{
+   return execve(fname, argv, environ);
+}
+#endif
+
+#ifdef L_execle
+int
+execle(fname, arg0)
+char *fname, *arg0;
+{
+   char ** envp = &arg0;
+   while(*envp) envp++;
+   return execve(fname, &arg0, envp+1);
+}
+#endif
+
+#ifdef L_execve
+int
+execve(fname, argv, envp)
+char * fname;
+char ** argv;
+char ** envp;
+{
+	char **p;
+	int argv_len=0, argv_count=0;
+	int envp_len=0, envp_count=0;
+	int stack_bytes;
+	unsigned short * pip;
+	char * pcp, * stk_ptr, *baseoff;
+	int rv;
+
+	/* How much space for argv */
+	for(p=argv; p && *p && argv_len >= 0; p++)
+	{
+	   argv_count++; argv_len += strlen(*p)+1;
+	}
+
+	/* How much space for envp */
+	for(p=envp; p && *p && envp_len >= 0; p++)
+	{
+	   envp_count++; envp_len += strlen(*p)+1;
+	}
+
+	/* tot it all up */
+	stack_bytes = 2				/* argc */
+	            + argv_count * 2 + 2	/* argv */
+		    + argv_len
+		    + envp_count * 2 + 2	/* envp */
+		    + envp_len;
+
+	/* Allocate it */
+	if( argv_len < 0 || envp_len < 0 || stack_bytes <= 0
+	 || (int)(stk_ptr = (char*)sbrk(stack_bytes)) == -1)
+	{
+	   errno = ENOMEM;
+	   return -1;
+	}
+
+/* Sanity check 
+	printf("Argv = (%d,%d), Envp=(%d,%d), stack=%d\n",
+	        argv_count, argv_len, envp_count, envp_len, stack_bytes);
+*/
+
+	/* Now copy in the strings */
+	pip=(unsigned short *) stk_ptr;
+	pcp=stk_ptr+2*(1+argv_count+1+envp_count+1);
+
+	/* baseoff = stk_ptr + stack_bytes; */
+	baseoff = stk_ptr;
+	*pip++ = argv_count;
+	for(p=argv; p && *p; p++)
+	{
+	   int l;
+	   *pip++ = pcp-baseoff;
+	   l = strlen(*p)+1;
+	   memcpy(pcp, *p, l);
+	   pcp += l;
+	}
+	*pip++ = 0;
+
+	for(p=envp; p && *p; p++)
+	{
+	   int l;
+	   *pip++ = pcp-baseoff;
+	   l = strlen(*p)+1;
+	   memcpy(pcp, *p, l);
+	   pcp += l;
+	}
+	*pip++ = 0;
+
+	rv = __exec(fname, stk_ptr, stack_bytes);
+	/* FIXME: This will probably have to interpret '#!' style exe's */
+	sbrk(-stack_bytes);
+	return rv;
+}
+#endif