From 3828942550fba1f88136ffbc018a72bdeb930902 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Mon, 13 Jul 2015 09:46:17 -0700 Subject: [PATCH] tar: port -d to longer symlinks * src/compare.c (diff_symlink): Don't use alloca on symlink length; it might be too big for the stack. Don't assume that readlinkat's return value fits in 'int'. Prefer memcmp to strncmp where either will do. --- src/compare.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/compare.c b/src/compare.c index d29cfdd..7ed4558 100644 --- a/src/compare.c +++ b/src/compare.c @@ -270,11 +270,12 @@ diff_link (void) static void diff_symlink (void) { + char buf[1024]; size_t len = strlen (current_stat_info.link_name); - char *linkbuf = alloca (len + 1); + char *linkbuf = len < sizeof buf ? buf : xmalloc (len + 1); - int status = readlinkat (chdir_fd, current_stat_info.file_name, - linkbuf, len + 1); + ssize_t status = readlinkat (chdir_fd, current_stat_info.file_name, + linkbuf, len + 1); if (status < 0) { @@ -285,8 +286,11 @@ diff_symlink (void) report_difference (¤t_stat_info, NULL); } else if (status != len - || strncmp (current_stat_info.link_name, linkbuf, len) != 0) + || memcmp (current_stat_info.link_name, linkbuf, len) != 0) report_difference (¤t_stat_info, _("Symlink differs")); + + if (linkbuf != buf) + free (linkbuf); } #endif -- 2.45.2