[hackers] [sbase] [PATCH] ls: allow listing contents of directories with +r-x

From: David Phillips <david_AT_sighup.nz>
Date: Tue, 17 Oct 2017 22:27:44 +1300

chdir()ing into a directory with +r-x fails, so we should manually use the
directory name as a prefix rather than chdir()ing into it.

Also adds new parameters to mkent for the prefix, and for dictating whether
or not a permission denied error when stat()ing shall be fatal or not. This
allows errors stat()ing children of `foo` to be reported and non-fatal, while
a permission denied error on `foo` itself would be fatal.

---
 ls.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/ls.c b/ls.c
index b716aba..c01a277 100644
--- a/ls.c
+++ b/ls.c
_AT_@ -10,6 +10,7 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include "utf.h"
 #include "util.h"
_AT_@ -58,15 +59,29 @@ static int showdirs;
 static void ls(const char *, const struct entry *, int);
 
 static void
-mkent(struct entry *ent, char *path, int dostat, int follow)
+mkent(struct entry *ent, char *prefix, char *name, int dostat, int follow,
+      int fatal)
 {
 	struct stat st;
+	char path[PATH_MAX];
 
-	ent->name = path;
+	ent->name = name;
 	if (!dostat)
 		return;
-	if ((follow ? stat : lstat)(path, &st) < 0)
-		eprintf("%s %s:", follow ? "stat" : "lstat", path);
+
+	if (prefix != NULL)
+		snprintf(path, PATH_MAX, "%s/%s", prefix, name);
+	else
+		strncpy(path, name, PATH_MAX);
+
+	if ((follow ? stat : lstat)(path, &st) < 0) {
+		if (errno == EACCES && !fatal) {
+			weprintf("%s %s:", follow ? "stat" : "lstat", path);
+			return;
+		} else {
+			eprintf("%s %s:", follow ? "stat" : "lstat", path);
+		}
+	}
 	ent->mode  = st.st_mode;
 	ent->nlink = st.st_nlink;
 	ent->uid   = st.st_uid;
_AT_@ -252,8 +267,6 @@ lsdir(const char *path, const struct entry *dir)
 		weprintf("opendir %s%s:", path, dir->name);
 		return;
 	}
-	if (chdir(dir->name) < 0)
-		eprintf("chdir %s:", dir->name);
 
 	while ((d = readdir(dp))) {
 		if (d->d_name[0] == '.' && !aflag && !Aflag)
_AT_@ -264,8 +277,8 @@ lsdir(const char *path, const struct entry *dir)
 				continue;
 
 		ents = ereallocarray(ents, ++n, sizeof(*ents));
-		mkent(&ents[n - 1], estrdup(d->d_name), Fflag || iflag ||
-		    lflag || pflag || Rflag || sort, Lflag);
+		mkent(&ents[n - 1], dir->name, estrdup(d->d_name), Fflag || iflag ||
+		    lflag || pflag || Rflag || sort, Lflag, 0);
 	}
 
 	closedir(dp);
_AT_@ -446,7 +459,7 @@ main(int argc, char *argv[])
 	case 0: /* fallthrough */
 		*--argv = ".", ++argc;
 	case 1:
-		mkent(&ent, argv[0], 1, Hflag || Lflag);
+		mkent(&ent, NULL, argv[0], 1, Hflag || Lflag, 1);
 		ls("", &ent, (!dflag && S_ISDIR(ent.mode)) ||
 		    (S_ISLNK(ent.mode) && S_ISDIR(ent.tmode) &&
 		     !(dflag || Fflag || lflag)));
_AT_@ -454,7 +467,7 @@ main(int argc, char *argv[])
 		break;
 	default:
 		for (i = ds = fs = 0, fents = dents = NULL; i < argc; ++i) {
-			mkent(&ent, argv[i], 1, Hflag || Lflag);
+			mkent(&ent, NULL, argv[i], 1, Hflag || Lflag, 1);
 
 			if ((!dflag && S_ISDIR(ent.mode)) ||
 			    (S_ISLNK(ent.mode) && S_ISDIR(ent.tmode) &&
-- 
2.14.2

Received on Tue Oct 17 2017 - 11:27:44 CEST