b24796c292
See the patch for information on why examples/ucontext-cp.c does not build with rawhide's glibc 2.33.9000. I sent this patch upstream to liburing and notified glibc of a potential incompatible change. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
83 lines
2.5 KiB
Diff
83 lines
2.5 KiB
Diff
From 595b858eb0576d70884337a61ace3d98a411b949 Mon Sep 17 00:00:00 2001
|
||
From: Stefan Hajnoczi <stefanha@redhat.com>
|
||
Date: Tue, 13 Apr 2021 15:45:52 +0100
|
||
Subject: [PATCH] examples/ucontext-cp.c: cope with variable SIGSTKSZ
|
||
MIME-Version: 1.0
|
||
Content-Type: text/plain; charset=UTF-8
|
||
Content-Transfer-Encoding: 8bit
|
||
|
||
The size of C arrays at file scope must be constant. The following
|
||
compiler error occurs with recent upstream glibc (2.33.9000):
|
||
|
||
CC ucontext-cp
|
||
ucontext-cp.c:31:23: error: variably modified ‘stack_buf’ at file scope
|
||
31 | unsigned char stack_buf[SIGSTKSZ];
|
||
| ^~~~~~~~~
|
||
make[1]: *** [Makefile:26: ucontext-cp] Error 1
|
||
|
||
The following glibc commit changed SIGSTKSZ from a constant value to a
|
||
variable:
|
||
|
||
commit 6c57d320484988e87e446e2e60ce42816bf51d53
|
||
Author: H.J. Lu <hjl.tools@gmail.com>
|
||
Date: Mon Feb 1 11:00:38 2021 -0800
|
||
|
||
sysconf: Add _SC_MINSIGSTKSZ/_SC_SIGSTKSZ [BZ #20305]
|
||
...
|
||
+# define SIGSTKSZ sysconf (_SC_SIGSTKSZ)
|
||
|
||
Allocate the stack buffer explicitly to avoid declaring an array at file
|
||
scope.
|
||
|
||
Cc: H.J. Lu <hjl.tools@gmail.com>
|
||
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
|
||
---
|
||
Perhaps the glibc change needs to be revised before releasing glibc 2.34
|
||
since it might break applications. That's up to the glibc folks. It
|
||
doesn't hurt for liburing to take a safer approach that copes with the
|
||
SIGSTKSZ change in any case.
|
||
---
|
||
examples/ucontext-cp.c | 12 +++++++++---
|
||
1 file changed, 9 insertions(+), 3 deletions(-)
|
||
|
||
diff --git a/examples/ucontext-cp.c b/examples/ucontext-cp.c
|
||
index 0b2a6b5..ea0c934 100644
|
||
--- a/examples/ucontext-cp.c
|
||
+++ b/examples/ucontext-cp.c
|
||
@@ -28,7 +28,7 @@
|
||
|
||
typedef struct {
|
||
struct io_uring *ring;
|
||
- unsigned char stack_buf[SIGSTKSZ];
|
||
+ unsigned char *stack_buf;
|
||
ucontext_t ctx_main, ctx_fnew;
|
||
} async_context;
|
||
|
||
@@ -115,8 +115,13 @@ static int setup_context(async_context *pctx, struct io_uring *ring)
|
||
perror("getcontext");
|
||
return -1;
|
||
}
|
||
- pctx->ctx_fnew.uc_stack.ss_sp = &pctx->stack_buf;
|
||
- pctx->ctx_fnew.uc_stack.ss_size = sizeof(pctx->stack_buf);
|
||
+ pctx->stack_buf = malloc(SIGSTKSZ);
|
||
+ if (!pctx->stack_buf) {
|
||
+ perror("malloc");
|
||
+ return -1;
|
||
+ }
|
||
+ pctx->ctx_fnew.uc_stack.ss_sp = pctx->stack_buf;
|
||
+ pctx->ctx_fnew.uc_stack.ss_size = SIGSTKSZ;
|
||
pctx->ctx_fnew.uc_link = &pctx->ctx_main;
|
||
|
||
return 0;
|
||
@@ -174,6 +179,7 @@ static void copy_file_wrapper(arguments_bundle *pbundle)
|
||
free(iov.iov_base);
|
||
close(pbundle->infd);
|
||
close(pbundle->outfd);
|
||
+ free(pbundle->pctx->stack_buf);
|
||
free(pbundle->pctx);
|
||
free(pbundle);
|
||
|
||
--
|
||
2.30.2
|
||
|