From e880c9c100028e6b0e805d4637139c67aea83748 Mon Sep 17 00:00:00 2001 From: Natanael Copa Date: Fri, 22 Jan 2021 08:35:55 +0100 Subject: [PATCH] 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 Signed-off-by: Denys Vlasenko --- coreutils/echo.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/coreutils/echo.c b/coreutils/echo.c index b3828894c..61ba060ec 100644 --- a/coreutils/echo.c +++ b/coreutils/echo.c @@ -97,6 +97,7 @@ int echo_main(int argc UNUSED_PARAM, char **argv) #else char nflag = 1; char eflag = 0; + int err; while ((arg = *++argv) != NULL) { char n, e; @@ -185,13 +186,12 @@ int echo_main(int argc UNUSED_PARAM, char **argv) 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; } /*