Commit Vladimir's simplify_path.

Makefile

@@ -250,7 +250,8 @@ safe_read.c safe_strncpy.c syscalls.c syslog_msg_with_name.c time_string.c \
 trim.c unzip.c vdprintf.c verror_msg.c vperror_msg.c wfopen.c xfuncs.c \
 xgetcwd.c xreadlink.c xregcomp.c interface.c remove_file.c last_char_is.c \
 copyfd.c vherror_msg.c herror_msg.c herror_msg_and_die.c xgethostbyname.c \
-dirname.c make_directory.c create_icmp_socket.c u_signal_names.c arith.c
+dirname.c make_directory.c create_icmp_socket.c u_signal_names.c arith.c \
+simplify_path.c
 LIBBB_OBJS=$(patsubst %.c,$(LIBBB)/%.o, $(LIBBB_CSRC))
 ifeq ($(strip $(BB_SRC_DIR)),)
     LIBBB_CFLAGS += -I$(LIBBB)

include/libbb.h

@@ -264,6 +264,7 @@ char *dirname (const char *path);
 int make_directory (char *path, long mode, int flags);
 
 const char *u_signal_names(const char *str_sig, int *signo, int startnum);
+char *simplify_path(const char *path);
 
 #define CT_AUTO	0
 #define CT_UNIX2DOS	1

libbb/libbb.h

@@ -264,6 +264,7 @@ char *dirname (const char *path);
 int make_directory (char *path, long mode, int flags);
 
 const char *u_signal_names(const char *str_sig, int *signo, int startnum);
+char *simplify_path(const char *path);
 
 #define CT_AUTO	0
 #define CT_UNIX2DOS	1

libbb/simplify_path.c

@@ -0,0 +1,78 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * simplify_path implementation for busybox
+ *
+ *
+ * Copyright (C) 2001  Vladimir N. Oleynik <dzo@simtreas.ru>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <stdlib.h>
+
+#include "libbb.h"
+
+static inline char *strcpy_overlap(char *dst, const char *src)
+{
+	char *ptr = dst;
+
+	do *dst++ = *src; while (*src++);
+	return ptr;
+}
+
+char *simplify_path(const char *path)
+{
+	char *s, *start, *next;
+
+	if (path[0] == '/')
+	       start = xstrdup(path);
+	else {
+	       s = xgetcwd(NULL);
+	       start = concat_path_file(s, path);
+	       free(s);
+	}
+	s = start;
+	/* remove . and .. */
+	while(*s) {
+		if(*s++ == '/' && (*s == '/' || *s == 0)) {
+			/* remove duplicate and trailing slashes */
+			s = strcpy_overlap(s-1, s);
+		}
+		else if(*(s-1) == '.' && *(s-2)=='/') {
+			if(*s == '/' || *s == 0) {
+				/* remove . */
+				s = strcpy_overlap(s-1, s); /* maybe set // */
+				s--;
+			} else if(*s == '.') {
+				next = s+1;     /* set after ".." */
+				if(*next == '/' || *next == 0) {  /* "../" */
+					if((s-=2) > start)
+						/* skip previous dir */
+						do s--; while(*s != '/');
+					/* remove previous dir */
+					strcpy_overlap(s, next);
+				}
+
+			}
+		}
+	}
+	if(start[0]==0) {
+		start[0]='/';
+		start[1]=0;
+	}
+	return start;
+}

mount.c

@@ -395,18 +395,15 @@ extern int mount_main(int argc, char **argv)
 	if (optind < argc) {
 		/* if device is a filename get its real path */
 		if (stat(argv[optind], &statbuf) == 0) {
-			realpath(argv[optind], device);
+			device = simplify_path(argv[optind]);
 		} else {
 			safe_strncpy(device, argv[optind], PATH_MAX);
 		}
 	}
 
-	if (optind + 1 < argc) {
-		if (realpath(argv[optind + 1], directory) == NULL) {
-			perror_msg_and_die("%s", directory);
-		}
-	}
-	
+	if (optind + 1 < argc)
+		directory = simplify_path(argv[optind + 1]);
+
 	if (all == TRUE || optind + 1 == argc) {
 		struct mntent *m = NULL;
 		FILE *f = setmntent("/etc/fstab", "r");

util-linux/mount.c

@@ -395,18 +395,15 @@ extern int mount_main(int argc, char **argv)
 	if (optind < argc) {
 		/* if device is a filename get its real path */
 		if (stat(argv[optind], &statbuf) == 0) {
-			realpath(argv[optind], device);
+			device = simplify_path(argv[optind]);
 		} else {
 			safe_strncpy(device, argv[optind], PATH_MAX);
 		}
 	}
 
-	if (optind + 1 < argc) {
-		if (realpath(argv[optind + 1], directory) == NULL) {
-			perror_msg_and_die("%s", directory);
-		}
-	}
-	
+	if (optind + 1 < argc)
+		directory = simplify_path(argv[optind + 1]);
+
 	if (all == TRUE || optind + 1 == argc) {
 		struct mntent *m = NULL;
 		FILE *f = setmntent("/etc/fstab", "r");