From b6811019e62a7561a4922f90e54b30ac306efe0b Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 3 Mar 2023 09:27:04 -0500 Subject: poll: fix misuse of timespec type on 32-bit archs without poll syscall this function was overlooked during the time64 transition, probably as a result of not having any time-related types in its application-side interface. however, for archs that lack the traditional poll syscall and have only ppoll, it used timespec as part of its interface with the kernel: the millisecond timeout was converted to a timespec to pass to SYS_ppoll. this is a type/ABI mismatch on 32-bit archs with legacy time32 syscalls. only one supported arch, or1k, is affected. all of the others either have SYS_poll, or are 64-bit. rather than using timespec, define a type locally to match what the kernel expects. the condition (SYS_ppoll_time64 == SYS_ppoll), comparable to conditions used elsewhere in timespec-handling code, evaluates true for "natively time64" 32-bit archs including x32, future riscv32, and all future 32-bit archs (via definitions in internal syscall.h). otherwise, the arch is either 64-bit or has syscalls that take the legacy type, and in either case "long" is correct. this fix is based on bug report and proposal by Alexey Izbyshev but with a different approach to the changes to minimize the contextual knowledge needed for a reader to understand the source file. --- src/select/poll.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/src/select/poll.c b/src/select/poll.c index c84c8a99..7883dfab 100644 --- a/src/select/poll.c +++ b/src/select/poll.c @@ -8,8 +8,13 @@ int poll(struct pollfd *fds, nfds_t n, int timeout) #ifdef SYS_poll return syscall_cp(SYS_poll, fds, n, timeout); #else +#if SYS_ppoll_time64 == SYS_ppoll + typedef long long ppoll_ts_t[2]; +#else + typedef long ppoll_ts_t[2]; +#endif return syscall_cp(SYS_ppoll, fds, n, timeout>=0 ? - &((struct timespec){ .tv_sec = timeout/1000, - .tv_nsec = timeout%1000*1000000 }) : 0, 0, _NSIG/8); + ((ppoll_ts_t){ timeout/1000, timeout%1000*1000000 }) : 0, + 0, _NSIG/8); #endif } -- cgit v1.2.1