echo: do not assume that free() leaves errno unmodified
musl libc's mallocng free() may modify errno if kernel does not support
MADV_FREE which causes echo to echo with error when it shouldn't.
Future versions of POSIX[1] will require that free() leaves errno
unmodified but til then, do not rely free() implementation.
Should fix downstream issues:
https://github.com/alpinelinux/docker-alpine/issues/134
https://gitlab.alpinelinux.org/alpine/aports/-/issues/12311
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/echo.c b/coreutils/echo.c
index b382889..61ba060 100644
--- a/coreutils/echo.c
+++ b/coreutils/echo.c
@@ -97,6 +97,7 @@
#else
char nflag = 1;
char eflag = 0;
+ int err;
while ((arg = *++argv) != NULL) {
char n, e;
@@ -185,13 +186,12 @@
do_write:
/* Careful to error out on partial writes too (think ENOSPC!) */
errno = 0;
- /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
- free(buffer);
- if (/*WRONG:r < 0*/ errno) {
+ err = full_write(STDOUT_FILENO, buffer, out - buffer) != out - buffer;
+ if (err) {
bb_simple_perror_msg(bb_msg_write_error);
- return 1;
}
- return 0;
+ free(buffer);
+ return err;
}
/*