Cleanup the getcwd implementation (again) since I broke it

last night.  Restore malloc-ing when buf=NULL for the syscall
version...  Move getcwd to libc/sysdeps/linux/common and out
of syscalls.c so there is just one getcwd.o object present.
 -Erik

libc/sysdeps/linux/common/Makefile

@@ -29,7 +29,7 @@ ifeq ($(strip $(DOPIC)),true)
 SAFECFLAGS+=-fPIC
 endif
 
-CSRC=	waitpid.c statfix.c getdnnm.c gethstnm.c \
+CSRC=	waitpid.c statfix.c getdnnm.c gethstnm.c getcwd.c \
 	mkfifo.c setegid.c wait.c getpagesize.c seteuid.c \
 	wait3.c setpgrp.c getdtablesize.c create_module.c ptrace.c \
 	cmsg_nxthdr.c statfix64.c longjmp.c open64.c ftruncate64.c \

libc/unistd/getcwd.c → libc/sysdeps/linux/common/getcwd.c

@@ -7,11 +7,52 @@
 #include <string.h>
 #include <sys/syscall.h>
 
-/* if the syscall is not present, we have to recurse up */
-#ifndef __NR_getcwd
+#ifdef __NR_getcwd
+#define __NR___getcwd __NR_getcwd
+static inline _syscall2(int, __getcwd, char *, buf, unsigned long, size);
 
+char *getcwd(char *buf, int size)
+{
+	int olderrno, ret;
+	char *allocbuf;
+	
+	if (size == 0) {
+		__set_errno(EINVAL);
+		return NULL;
+	}
+	if (size < 3) {
+		__set_errno(ERANGE);
+		return NULL;
+	}
+	allocbuf=NULL;
+	olderrno = errno;
+	if (buf == NULL) {
+		buf = allocbuf = malloc (size);
+		if (buf == NULL)
+			return NULL;
+	}
+	ret = __getcwd(buf, size);
+	if (ret < 0) {
+	    if (allocbuf) {
+		free(allocbuf);
+	    }
+	    return NULL;
+	} 
+	__set_errno(olderrno);
+	return buf;
+}
+#else
+
+/* If the syscall is not present, we have to walk up the
+ * directory tree till we hit the root.  Now we _could_
+ * use /proc/self/cwd if /proc is mounted... That approach
+ * is left an an exercise for the reader... */
+
+
+/* Seems a few broken filesystems (like coda) don't like this */
 /* #undef FAST_DIR_SEARCH_POSSIBLE on Linux */
 
+
 /* Routine to find the step back down */
 static char *search_dir(dev_t this_dev, ino_t this_ino, char *path_buf, int path_size)
 {

libc/sysdeps/linux/common/syscalls.c

@@ -1613,13 +1613,7 @@ _syscall3(int, chown, const char *, path, uid_t, owner, gid_t, group);
 #endif
 
 //#define __NR_getcwd                   183
-#ifdef L_getcwd
-#	ifdef __NR_getcwd
-		_syscall2(int, getcwd, char *, buf, unsigned long, size);
-#	else
-// See unistd/getcwd.c if this syscall is not available...
-#	endif
-#endif
+// See getcwd.c in this directory
 
 //#define __NR_capget                   184
 #ifdef L_capget

libc/unistd/Makefile

@@ -25,7 +25,7 @@ TOPDIR=../../
 include $(TOPDIR)Rules.mak
 DIRS:=
 
-CSRC=execl.c execlp.c execv.c execvep.c execvp.c execle.c getcwd.c \
+CSRC=execl.c execlp.c execv.c execvep.c execvp.c execle.c \
 	sleep.c usleep.c getpass.c sysconf_src.c getlogin.c \
 	fpathconf.c confstr.c pathconf.c swab.c usershell.c
 ifeq ($(strip $(HAS_MMU)),true)