[2/2] Add a test for setjmp/longjmp within user context
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Commit Message
Verify that setjmp/longjmp works correctly within a user context.
---
stdlib/Makefile | 1 +
stdlib/tst-setcontext11.c | 178 ++++++++++++++++++++++++++++++++++++++
2 files changed, 179 insertions(+)
create mode 100644 stdlib/tst-setcontext11.c
Comments
On Thu, Dec 14, 2023 at 1:37 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Verify that setjmp/longjmp works correctly within a user context.
> ---
> stdlib/Makefile | 1 +
> stdlib/tst-setcontext11.c | 178 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 179 insertions(+)
> create mode 100644 stdlib/tst-setcontext11.c
>
> diff --git a/stdlib/Makefile b/stdlib/Makefile
> index 8c6249aab4..0b5ef699a2 100644
> --- a/stdlib/Makefile
> +++ b/stdlib/Makefile
> @@ -235,6 +235,7 @@ tests := \
> tst-setcontext8 \
> tst-setcontext9 \
> tst-setcontext10 \
> + tst-setcontext11 \
> tst-strfmon_l \
> tst-strfrom \
> tst-strfrom-locale \
> diff --git a/stdlib/tst-setcontext11.c b/stdlib/tst-setcontext11.c
> new file mode 100644
> index 0000000000..5f5df5b81b
> --- /dev/null
> +++ b/stdlib/tst-setcontext11.c
> @@ -0,0 +1,178 @@
> +/* Check setjmp/longjmp within user context.
> + Copyright (C) 2023 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <errno.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <setjmp.h>
> +#include <ucontext.h>
> +#include <unistd.h>
> +
> +static ucontext_t ctx[3];
> +static jmp_buf jmpbuf;
> +
> +static int was_in_f1;
> +static int was_in_f2;
> +static int longjmp_called;
> +
> +static char st2[32768];
> +
> +static void
> +f1 (int a0, int a1, int a2, int a3)
> +{
> + printf ("start f1(a0=%x,a1=%x,a2=%x,a3=%x)\n", a0, a1, a2, a3);
> +
> + if (a0 != 1 || a1 != 2 || a2 != 3 || a3 != -4)
> + {
> + puts ("arg mismatch");
> + exit (EXIT_FAILURE);
> + }
> +
> + if (swapcontext (&ctx[1], &ctx[2]) != 0)
> + {
> + printf ("%s: swapcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> + puts ("finish f1");
> + was_in_f1 = 1;
> +}
> +
> +static void
> +__attribute__ ((noinline, noclone))
> +call_longjmp (void)
> +{
> + longjmp_called = 1;
> + longjmp (jmpbuf, 1);
> +}
> +
> +static void
> +f2 (void)
> +{
> + if (!longjmp_called)
> + {
> + if (setjmp (jmpbuf) == 0)
> + call_longjmp ();
> + }
> +
> + puts ("start f2");
> + if (swapcontext (&ctx[2], &ctx[1]) != 0)
> + {
> + printf ("%s: swapcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> + puts ("finish f2");
> + was_in_f2 = 1;
> +}
> +
> +volatile int global;
> +static int back_in_main;
> +
> +static void
> +check_called (void)
> +{
> + if (back_in_main == 0)
> + {
> + puts ("program did not reach main again");
> + _exit (EXIT_FAILURE);
> + }
> +}
> +
> +static int
> +do_test (void)
> +{
> + atexit (check_called);
> +
> + char st1[32768];
> +
> + puts ("making contexts");
> + if (getcontext (&ctx[1]) != 0)
> + {
> + if (errno == ENOSYS)
> + {
> + back_in_main = 1;
> + exit (EXIT_SUCCESS);
> + }
> +
> + printf ("%s: getcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> +
> + /* Play some tricks with this context. */
> + if (++global == 1)
> + if (setcontext (&ctx[1]) != 0)
> + {
> + printf ("%s: setcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> + if (global != 2)
> + {
> + printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> +
> + ctx[1].uc_stack.ss_sp = st1;
> + ctx[1].uc_stack.ss_size = sizeof st1;
> + ctx[1].uc_link = &ctx[0];
> + {
> + ucontext_t tempctx = ctx[1];
> + makecontext (&ctx[1], (void (*) (void)) f1, 4, 1, 2, 3, -4);
> +
> + /* Without this check, a stub makecontext can make us spin forever. */
> + if (memcmp (&tempctx, &ctx[1], sizeof ctx[1]) == 0)
> + {
> + puts ("makecontext was a no-op, presuming not implemented");
> + return 0;
> + }
> + }
> +
> + if (getcontext (&ctx[2]) != 0)
> + {
> + printf ("%s: second getcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> + ctx[2].uc_stack.ss_sp = st2;
> + ctx[2].uc_stack.ss_size = sizeof st2;
> + ctx[2].uc_link = &ctx[1];
> + makecontext (&ctx[2], f2, 0);
> +
> + puts ("swapping contexts");
> + if (swapcontext (&ctx[0], &ctx[2]) != 0)
> + {
> + printf ("%s: swapcontext: %m\n", __FUNCTION__);
> + exit (EXIT_FAILURE);
> + }
> + puts ("back at main program");
> + back_in_main = 1;
> +
> + if (was_in_f1 == 0)
> + {
> + puts ("didn't reach f1");
> + exit (EXIT_FAILURE);
> + }
> + if (was_in_f2 == 0)
> + {
> + puts ("didn't reach f2");
> + exit (EXIT_FAILURE);
> + }
> +
> + puts ("test succeeded");
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.43.0
>
LGTM.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
@@ -235,6 +235,7 @@ tests := \
tst-setcontext8 \
tst-setcontext9 \
tst-setcontext10 \
+ tst-setcontext11 \
tst-strfmon_l \
tst-strfrom \
tst-strfrom-locale \
new file mode 100644
@@ -0,0 +1,178 @@
+/* Check setjmp/longjmp within user context.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+static ucontext_t ctx[3];
+static jmp_buf jmpbuf;
+
+static int was_in_f1;
+static int was_in_f2;
+static int longjmp_called;
+
+static char st2[32768];
+
+static void
+f1 (int a0, int a1, int a2, int a3)
+{
+ printf ("start f1(a0=%x,a1=%x,a2=%x,a3=%x)\n", a0, a1, a2, a3);
+
+ if (a0 != 1 || a1 != 2 || a2 != 3 || a3 != -4)
+ {
+ puts ("arg mismatch");
+ exit (EXIT_FAILURE);
+ }
+
+ if (swapcontext (&ctx[1], &ctx[2]) != 0)
+ {
+ printf ("%s: swapcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ puts ("finish f1");
+ was_in_f1 = 1;
+}
+
+static void
+__attribute__ ((noinline, noclone))
+call_longjmp (void)
+{
+ longjmp_called = 1;
+ longjmp (jmpbuf, 1);
+}
+
+static void
+f2 (void)
+{
+ if (!longjmp_called)
+ {
+ if (setjmp (jmpbuf) == 0)
+ call_longjmp ();
+ }
+
+ puts ("start f2");
+ if (swapcontext (&ctx[2], &ctx[1]) != 0)
+ {
+ printf ("%s: swapcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ puts ("finish f2");
+ was_in_f2 = 1;
+}
+
+volatile int global;
+static int back_in_main;
+
+static void
+check_called (void)
+{
+ if (back_in_main == 0)
+ {
+ puts ("program did not reach main again");
+ _exit (EXIT_FAILURE);
+ }
+}
+
+static int
+do_test (void)
+{
+ atexit (check_called);
+
+ char st1[32768];
+
+ puts ("making contexts");
+ if (getcontext (&ctx[1]) != 0)
+ {
+ if (errno == ENOSYS)
+ {
+ back_in_main = 1;
+ exit (EXIT_SUCCESS);
+ }
+
+ printf ("%s: getcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+
+ /* Play some tricks with this context. */
+ if (++global == 1)
+ if (setcontext (&ctx[1]) != 0)
+ {
+ printf ("%s: setcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ if (global != 2)
+ {
+ printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+
+ ctx[1].uc_stack.ss_sp = st1;
+ ctx[1].uc_stack.ss_size = sizeof st1;
+ ctx[1].uc_link = &ctx[0];
+ {
+ ucontext_t tempctx = ctx[1];
+ makecontext (&ctx[1], (void (*) (void)) f1, 4, 1, 2, 3, -4);
+
+ /* Without this check, a stub makecontext can make us spin forever. */
+ if (memcmp (&tempctx, &ctx[1], sizeof ctx[1]) == 0)
+ {
+ puts ("makecontext was a no-op, presuming not implemented");
+ return 0;
+ }
+ }
+
+ if (getcontext (&ctx[2]) != 0)
+ {
+ printf ("%s: second getcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ ctx[2].uc_stack.ss_sp = st2;
+ ctx[2].uc_stack.ss_size = sizeof st2;
+ ctx[2].uc_link = &ctx[1];
+ makecontext (&ctx[2], f2, 0);
+
+ puts ("swapping contexts");
+ if (swapcontext (&ctx[0], &ctx[2]) != 0)
+ {
+ printf ("%s: swapcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ puts ("back at main program");
+ back_in_main = 1;
+
+ if (was_in_f1 == 0)
+ {
+ puts ("didn't reach f1");
+ exit (EXIT_FAILURE);
+ }
+ if (was_in_f2 == 0)
+ {
+ puts ("didn't reach f2");
+ exit (EXIT_FAILURE);
+ }
+
+ puts ("test succeeded");
+ return 0;
+}
+
+#include <support/test-driver.c>