xbps-pkgdb: rework symlinks checks to avoid false positives with -r.

bin/xbps-pkgdb/check_pkg_symlinks.c

@@ -45,30 +45,52 @@
  *
  * returns 0 if test ran successfully, 1 otherwise and -1 on error.
  */
+
 static char *
-symlink_target(const char *pkgname, const char *path)
+symlink_target(struct xbps_handle *xhp, const char *path)
 {
 	struct stat sb;
-	char *lnk;
+	char *lnk, *res;
 	ssize_t r;
 
-	if (lstat(path, &sb) == -1) {
+	if (lstat(path, &sb) == -1)
-		xbps_error_printf("%s: lstat failed for %s\n", pkgname, path);
 		return NULL;
-	}
 
 	lnk = malloc(sb.st_size + 1);
 	assert(lnk);
 
 	r = readlink(path, lnk, sb.st_size + 1);
 	if (r < 0 || r > sb.st_size) {
-		xbps_error_printf("%s: readlink failed for %s\n", pkgname, path);
 		free(lnk);
 		return NULL;
 	}
 	lnk[sb.st_size] = '\0';
+	if (lnk[0] != '/') {
+		char tpath[PATH_MAX], *p, *dname;
 
-	return lnk;
+		/* relative */
+		p = strdup(path);
+		assert(p);
+		dname = dirname(p);
+		assert(dname);
+		snprintf(tpath, sizeof(tpath), "%s/%s", dname, lnk);
+		free(p);
+		if ((res = realpath(tpath, NULL)) == NULL) {
+			free(lnk);
+			return NULL;
+		}
+		if (strcmp(xhp->rootdir, "/") == 0)
+			p = strdup(res);
+		else
+			p = strdup(res + strlen(xhp->rootdir));
+		free(res);
+		res = p;
+		free(lnk);
+	} else {
+		/* absolute */
+		res = lnk;
+	}
+	return res;
 }
 
 int
@@ -77,9 +99,6 @@ check_pkg_symlinks(struct xbps_handle *xhp, const char *pkgname, void *arg)
 	xbps_array_t array;
 	xbps_object_t obj;
 	xbps_dictionary_t filesd = arg;
-	const char *file, *tgt = NULL;
-	char path[PATH_MAX], tgt_path[PATH_MAX], *p, *buf, *buf2, *lnk, *dname;
-	int rv;
 	bool broken = false;
 
 	array = xbps_dictionary_get(filesd, "links");
@@ -87,6 +106,9 @@ check_pkg_symlinks(struct xbps_handle *xhp, const char *pkgname, void *arg)
 		return false;
 
 	for (unsigned int i = 0; i < xbps_array_count(array); i++) {
+		const char *file = NULL, *tgt = NULL;
+		char path[PATH_MAX], *lnk = NULL, *tlnk = NULL;
+
 		obj = xbps_array_get(array, i);
 		if (!xbps_dictionary_get_cstring_nocopy(obj, "file", &file))
 			continue;
@@ -96,62 +118,61 @@ check_pkg_symlinks(struct xbps_handle *xhp, const char *pkgname, void *arg)
 			    "empty target object!\n", pkgname, file);
 			continue;
 		}
-		if (strcmp(tgt, "") == 0) {
+		if (tgt[0] == '\0') {
 			xbps_warn_printf("%s: `%s' symlink with "
 			    "empty target object!\n", pkgname, file);
 			continue;
 		}
-
+		snprintf(path, sizeof(path), "%s/%s", xhp->rootdir, file);
-		if (strcmp(xhp->rootdir, "/")) {
+		if ((lnk = symlink_target(xhp, path)) == NULL) {
-			snprintf(path, sizeof(path), "%s%s", xhp->rootdir, file);
+			xbps_error_printf("%s: broken symlink %s (target: %s)\n", pkgname, file, tgt);
-			snprintf(tgt_path, sizeof(tgt_path), "%s%s", xhp->rootdir, tgt);
+			broken = true;
-
-			strncpy(tgt_path, tgt, sizeof(tgt_path)-1);
-		} else  {
-			strncpy(path, file, sizeof(path)-1);
-			strncpy(tgt_path, tgt, sizeof(tgt_path)-1);
-		}
-
-		if ((lnk = symlink_target(pkgname, path)) == NULL)
-			continue;
-
-		p = strdup(path);
-		assert(p);
-		dname = dirname(p);
-		buf = xbps_xasprintf("%s/%s", dname, lnk);
-		free(p);
-
-		buf2 = realpath(path, NULL);
-		if (buf2 == NULL) {
-			xbps_warn_printf("%s: broken symlink %s (target: %s)\n",
-			     pkgname, file, tgt);
-			free(buf);
-			free(lnk);
 			continue;
 		}
+		if (tgt[0] != '/') {
+			char *p, *p1, *dname;
 
-		rv = 1;
+			p = strdup(file);
-		if (lnk[0] != '/') {
+			assert(p);
-			/* relative symlink */
+			dname = dirname(p);
-			if ((strcmp(lnk, tgt) == 0) ||
+			assert(dname);
-			    (strcmp(buf, tgt_path) == 0) ||
+			snprintf(path, sizeof(path), "%s/%s", dname, tgt);
-			    (strcmp(buf2, tgt_path) == 0))
+			p1 = realpath(path, NULL);
-				rv = 0;
+			free(p);
+			if (p1 == NULL) {
+				xbps_error_printf("%s: failed to realpath %s: %s\n",
+				    pkgname, file, strerror(errno));
+				free(lnk);
+				continue;
+			}
+			if (strcmp(xhp->rootdir, "/") == 0)
+				tlnk = strdup(p1);
+			else
+				tlnk = strdup(p1 + strlen(xhp->rootdir));
+			free(p1);
 		} else {
-			/* absolute symlink */
+			char *p;
-			if (strcmp(lnk, tgt) == 0)
-				rv = 0;
-		}
 
-		if (rv) {
+			snprintf(path, sizeof(path), "%s/%s", xhp->rootdir, tgt);
+			if ((p = realpath(path, NULL))) {
+				if (strcmp(xhp->rootdir, "/") == 0)
+					tlnk = strdup(p);
+				else
+					tlnk = strdup(p + strlen(xhp->rootdir));
+				free(p);
+			} else {
+				tlnk = strdup(tgt);
+			}
+		}
+		/* absolute */
+		if (strcmp(lnk, tlnk)) {
 			xbps_warn_printf("%s: modified symlink %s "
 			    "points to %s (shall be %s)\n",
-			    pkgname, file, lnk, tgt);
+			    pkgname, file, lnk, tlnk);
 			broken = true;
 		}
-		free(buf);
-		free(buf2);
 		free(lnk);
+		free(tlnk);
 	}
 	return broken;
 }