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-rw-r--r--coreutils/tac.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/coreutils/tac.c b/coreutils/tac.c
new file mode 100644
index 000000000..6aa0528e0
--- /dev/null
+++ b/coreutils/tac.c
@@ -0,0 +1,68 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * tac implementation for busybox
+ *
+ * Copyright (C) 2003 Yang Xiaopeng <yxp at hanwang.com.cn>
+ * Copyright (C) 2007 Natanael Copa <natanael.copa@gmail.com>
+ * Copyright (C) 2007 Tito Ragusa <farmatito@tiscali.it>
+ *
+ * Licensed under GPLv2, see file License in this tarball for details.
+ *
+ */
+
+/* tac - concatenate and print files in reverse */
+
+/* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch
+ * http://www.uclibc.org/lists/busybox/2003-July/008813.html
+ */
+
+#include "libbb.h"
+
+/* This is a NOEXEC applet. Be very careful! */
+
+int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int tac_main(int argc, char **argv)
+{
+ char **name;
+ FILE *f;
+ char *line;
+ llist_t *list = NULL;
+ int retval = EXIT_SUCCESS;
+
+ argv++;
+ if (!*argv)
+ *--argv = (char *)"-";
+ /* We will read from last file to first */
+ name = argv;
+ while (*name)
+ name++;
+
+ do {
+ name--;
+ f = fopen_or_warn_stdin(*name);
+ if (f == NULL) {
+ retval = EXIT_FAILURE;
+ continue;
+ }
+
+ errno = 0;
+ /* FIXME: NUL bytes are mishandled. */
+ while ((line = xmalloc_fgets(f)) != NULL)
+ llist_add_to(&list, line);
+
+ /* xmalloc_fgets uses getc and returns NULL on error or EOF. */
+ /* It sets errno to ENOENT on EOF, but fopen_or_warn_stdin would */
+ /* catch this error so we can filter it out here. */
+ if (errno && errno != ENOENT) {
+ bb_simple_perror_msg(*name);
+ retval = EXIT_FAILURE;
+ }
+ } while (name != argv);
+
+ while (list) {
+ printf("%s", list->data);
+ list = list->link;
+ }
+
+ return retval;
+}