out of memory checks: add missing sh_getcwd() wrapper (re: 7ad274f8)

getcwd() with 0/NULL arguments also mallocs, so needs a check.

src/cmd/ksh93/include/defs.h

@@ -400,6 +400,7 @@ extern void		*sh_realloc(void *ptr, size_t size);
 extern void		*sh_calloc(size_t nmemb, size_t size);
 extern char		*sh_strdup(const char *s);
 extern void		*sh_memdup(const void *s, size_t n);
+extern char		*sh_getcwd(void);
 #define new_of(type,x)	((type*)sh_malloc((unsigned)sizeof(type)+(x)))
 #define sh_newof(p,t,n,x)	((p)?(t*)sh_realloc((char*)(p),sizeof(t)*(n)+(x)):(t*)sh_calloc(1,sizeof(t)*(n)+(x)))
 

src/cmd/ksh93/sh/init.c

@@ -271,6 +271,14 @@ void *sh_memdup(const void *s, size_t n)
 	return(dup);
 }
 
+char *sh_getcwd(void)
+{
+	char *cwd = getcwd(NIL(char*), 0);
+	if(!cwd && errno==ENOMEM)
+		nomemory(0);
+	return(cwd);
+}
+
 #if SHOPT_VSH || SHOPT_ESH
 /* Trap for VISUAL and EDITOR variables */
 static void put_ed(register Namval_t* np,const char *val,int flags,Namfun_t *fp)

src/cmd/ksh93/sh/path.c

@@ -262,7 +262,7 @@ char *path_pwd(Shell_t *shp,int flag)
 		if(!(cp && *cp=='/' && test_inode(cp,e_dot)))
 		{
 			/* Get physical PWD (no symlinks) using getcwd(3), fall back to "." */
-			cp = getcwd(NIL(char*),0);
+			cp = sh_getcwd();
 			if(!cp)
 				return((char*)e_dot);
 			tofree++;