|
|
examples/ucontext-cp.c: cope with variable SIGSTKSZ
|
|
|
|
|
|
BZ: 1980845
|
|
|
|
|
|
commit 8aac320ae8445c5434ab3be1761414a5247e5d42
|
|
|
Author: Stefan Hajnoczi <stefanha@redhat.com>
|
|
|
Date: Tue Apr 13 16:03:19 2021 +0100
|
|
|
|
|
|
examples/ucontext-cp.c: cope with variable SIGSTKSZ
|
|
|
|
|
|
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>
|
|
|
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
|
|
|
|
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);
|
|
|
|
