| Andrew Geissler | c926e17 | 2021-05-07 16:11:35 -0500 | [diff] [blame^] | 1 | From 69238f15129f35eb4756ad8e2004e0d7907cb175 Mon Sep 17 00:00:00 2001 |
| 2 | From: Khem Raj <raj.khem@gmail.com> |
| 3 | Date: Fri, 30 Apr 2021 17:40:36 -0700 |
| 4 | Subject: [PATCH] c-stack: stop using SIGSTKSZ |
| 5 | |
| 6 | This patch is required with glibc 2.34+ |
| 7 | based on gnulib [1] |
| 8 | |
| 9 | [1] https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=f9e2b20a12a230efa30f1d479563ae07d276a94b |
| 10 | |
| 11 | Upstream-Status: Pending |
| 12 | Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| 13 | --- |
| 14 | lib/c-stack.c | 22 +++++++++++++--------- |
| 15 | 1 file changed, 13 insertions(+), 9 deletions(-) |
| 16 | |
| 17 | diff --git a/lib/c-stack.c b/lib/c-stack.c |
| 18 | index 5353c08..863f764 100644 |
| 19 | --- a/lib/c-stack.c |
| 20 | +++ b/lib/c-stack.c |
| 21 | @@ -51,13 +51,14 @@ |
| 22 | typedef struct sigaltstack stack_t; |
| 23 | #endif |
| 24 | #ifndef SIGSTKSZ |
| 25 | -# define SIGSTKSZ 16384 |
| 26 | -#elif HAVE_LIBSIGSEGV && SIGSTKSZ < 16384 |
| 27 | +#define get_sigstksz() (16384) |
| 28 | +#elif HAVE_LIBSIGSEGV |
| 29 | /* libsigsegv 2.6 through 2.8 have a bug where some architectures use |
| 30 | more than the Linux default of an 8k alternate stack when deciding |
| 31 | if a fault was caused by stack overflow. */ |
| 32 | -# undef SIGSTKSZ |
| 33 | -# define SIGSTKSZ 16384 |
| 34 | +#define get_sigstksz() ((SIGSTKSZ) < 16384 ? 16384 : (SIGSTKSZ)) |
| 35 | +#else |
| 36 | +#define get_sigstksz() ((SIGSTKSZ)) |
| 37 | #endif |
| 38 | |
| 39 | #include <stdlib.h> |
| 40 | @@ -131,7 +132,8 @@ die (int signo) |
| 41 | /* Storage for the alternate signal stack. */ |
| 42 | static union |
| 43 | { |
| 44 | - char buffer[SIGSTKSZ]; |
| 45 | + /* allocate buffer with size from get_sigstksz() */ |
| 46 | + char *buffer; |
| 47 | |
| 48 | /* These other members are for proper alignment. There's no |
| 49 | standard way to guarantee stack alignment, but this seems enough |
| 50 | @@ -203,10 +205,11 @@ c_stack_action (void (*action) (int)) |
| 51 | program_error_message = _("program error"); |
| 52 | stack_overflow_message = _("stack overflow"); |
| 53 | |
| 54 | + alternate_signal_stack.buffer = malloc(get_sigstksz()); |
| 55 | /* Always install the overflow handler. */ |
| 56 | if (stackoverflow_install_handler (overflow_handler, |
| 57 | alternate_signal_stack.buffer, |
| 58 | - sizeof alternate_signal_stack.buffer)) |
| 59 | + get_sigstksz())) |
| 60 | { |
| 61 | errno = ENOTSUP; |
| 62 | return -1; |
| 63 | @@ -279,14 +282,15 @@ c_stack_action (void (*action) (int)) |
| 64 | stack_t st; |
| 65 | struct sigaction act; |
| 66 | st.ss_flags = 0; |
| 67 | + alternate_signal_stack.buffer = malloc(get_sigstksz()); |
| 68 | # if SIGALTSTACK_SS_REVERSED |
| 69 | /* Irix mistakenly treats ss_sp as the upper bound, rather than |
| 70 | lower bound, of the alternate stack. */ |
| 71 | - st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ - sizeof (void *); |
| 72 | - st.ss_size = sizeof alternate_signal_stack.buffer - sizeof (void *); |
| 73 | + st.ss_sp = alternate_signal_stack.buffer + get_sigstksz() - sizeof (void *); |
| 74 | + st.ss_size = get_sigstksz() - sizeof (void *); |
| 75 | # else |
| 76 | st.ss_sp = alternate_signal_stack.buffer; |
| 77 | - st.ss_size = sizeof alternate_signal_stack.buffer; |
| 78 | + st.ss_size = get_sigstksz(); |
| 79 | # endif |
| 80 | r = sigaltstack (&st, NULL); |
| 81 | if (r != 0) |
| 82 | -- |
| 83 | 2.31.1 |
| 84 | |