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authorStefan Hajnoczi <stefanha@redhat.com>2021-04-13 16:03:19 +0100
committerJens Axboe <axboe@kernel.dk>2021-04-13 09:11:40 -0600
commit8aac320ae8445c5434ab3be1761414a5247e5d42 (patch)
tree696f5991dbee724e65648c0c467e9c772abf2f44 /examples
parentd3eb6af47886656e811e8f4e274ac361d0efa5bf (diff)
downloadliburing-8aac320ae8445c5434ab3be1761414a5247e5d42.tar.gz
liburing-8aac320ae8445c5434ab3be1761414a5247e5d42.tar.bz2
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>
Diffstat (limited to 'examples')
-rw-r--r--examples/ucontext-cp.c12
1 files 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);