From 9a460514997d9731923225483a90e7ea45a9955c Mon Sep 17 00:00:00 2001
From: Duncan Overbruck <mail@duncano.de>
Date: Thu, 22 Dec 2022 21:42:32 +0100
Subject: [PATCH] bin/xbps-create: cleanup readlink related code

---
 bin/xbps-create/main.c | 45 ++++++++++++++++++++----------------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/bin/xbps-create/main.c b/bin/xbps-create/main.c
index 985a18d6..d61f0aa0 100644
--- a/bin/xbps-create/main.c
+++ b/bin/xbps-create/main.c
@@ -311,9 +311,8 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 	struct xentry *xe = NULL;
 	xbps_dictionary_t fileinfo = NULL;
 	const char *filep = NULL;
-	char *buf, *p, *p2, *dname;
+	char *p, *p2, *dname;
 	char sha256[XBPS_SHA256_SIZE];
-	ssize_t r;
 
 	/* Ignore metadata files generated by xbps-src and destdir */
 	if ((strcmp(fpath, ".") == 0) ||
@@ -353,6 +352,9 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 	}
 
 	if (S_ISLNK(sb->st_mode)) {
+		char buf[PATH_MAX];
+		ssize_t len;
+
 		/*
 		 * Symlinks.
 		 *
@@ -362,13 +364,12 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 		xe->type = strdup("links");
 		assert(xe->type);
 		xbps_dictionary_set_cstring_nocopy(fileinfo, "type", "links");
-		buf = malloc(sb->st_size+1);
-		assert(buf);
-		r = readlink(fpath, buf, sb->st_size+1);
-		if (r < 0 || r > sb->st_size)
-			die("failed to process symlink %s:", fpath);
 
-		buf[sb->st_size] = '\0';
+		len = readlink(fpath, buf, sizeof(buf));
+		if (len < 0 || len >= (int)sizeof(buf))
+			die("readlink: %s:", fpath);
+		buf[len] = '\0';
+
 		/*
 		 * Check if symlink is absolute or relative; on the former
 		 * make it absolute for the target object.
@@ -422,7 +423,6 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 		}
 		assert(xe->target);
 		assert(xbps_dictionary_get(fileinfo, "target"));
-		free(buf);
 	} else if (S_ISREG(sb->st_mode)) {
 		struct xentry *xep;
 		bool hlink = false;
@@ -671,8 +671,7 @@ process_entry_file(struct archive *ar,
 {
 	struct archive_entry *entry, *sparse_entry;
 	struct stat st;
-	char *buf = NULL, *p;
-	ssize_t len;
+	char path[PATH_MAX];
 
 	assert(ar);
 	assert(xe);
@@ -680,8 +679,9 @@ process_entry_file(struct archive *ar,
 	if (filematch && strcmp(xe->file, filematch))
 		return;
 
-	p = xbps_xasprintf("%s/%s", destdir, xe->file);
-	if (lstat(p, &st) == -1)
+	if (xbps_path_join(path, sizeof(path), destdir, xe->file, (char *)NULL) == -1)
+		die("path too long %s:", xe->file);
+	if (lstat(path, &st) == -1)
 		die("failed to add entry (fstat) %s to archive:", xe->file);
 
 	entry = archive_entry_new();
@@ -695,24 +695,23 @@ process_entry_file(struct archive *ar,
 		st.st_gid = 0;
 
 	archive_entry_copy_stat(entry, &st);
-	archive_entry_copy_sourcepath(entry, p);
+	archive_entry_copy_sourcepath(entry, path);
 	if (st.st_uid == geteuid())
 		archive_entry_set_uname(entry, "root");
 	if (st.st_gid == getegid())
 		archive_entry_set_gname(entry, "root");
 
 	if (S_ISLNK(st.st_mode)) {
-		buf = malloc(st.st_size+1);
-		if (buf == NULL)
-			die("failed to allocate readlink buffer", xe->file);
-		len = readlink(p, buf, st.st_size+1);
-		if (len < 0 || len > st.st_size)
-			die("failed to add entry %s (readlink) to archive:",
-			    xe->file);
+		char buf[PATH_MAX];
+		ssize_t len;
+
+		len = readlink(path, buf, sizeof(buf));
+		if (len < 0 || len >= (int)sizeof(buf))
+			die("readlink: %s:", xe->file);
 		buf[len] = '\0';
+
 		archive_entry_set_symlink(entry, buf);
 	}
-	free(p);
 
 	archive_entry_linkify(resolver, &entry, &sparse_entry);
 
@@ -720,8 +719,6 @@ process_entry_file(struct archive *ar,
 		write_entry(ar, entry);
 	if (sparse_entry != NULL)
 		write_entry(ar, sparse_entry);
-	if (buf)
-		free(buf);
 }
 
 static void