From c1d2a070f282a95316e8f045e8959856518ab2f0 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 21 Sep 2023 14:49:39 +1000 Subject: util: Consolidate and improve workarounds for clang-tidy issue 58992 We have several workarounds for a clang-tidy bug where the checker doesn't recognize that a number of system calls write to - and therefore initialise - a socket address. We can't neatly use a suppression, because the bogus warning shows up some time after the actual system call, when we access a field of the socket address which clang-tidy erroneously thinks is uninitialised. Consolidate these workarounds into one place by using macros to implement wrappers around affected system calls which add a memset() of the sockaddr to silence clang-tidy. This removes the need for the individual memset() workarounds at the callers - and the somewhat longwinded explanatory comments. We can then use a #define to not include the hack in "real" builds, but only consider it for clang-tidy. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- util.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'util.h') diff --git a/util.h b/util.h index 41cf123..57a05fb 100644 --- a/util.h +++ b/util.h @@ -9,6 +9,7 @@ #include #include #include +#include #include "log.h" @@ -225,4 +226,44 @@ int __daemon(int pidfile_fd, int devnull_fd); int fls(unsigned long x); int write_file(const char *path, const char *buf); +/* + * Workarounds for https://github.com/llvm/llvm-project/issues/58992 + * + * For a number (maybe all) system calls that _write_ a socket address, + * clang-tidy doesn't register that the memory of the socket address will be + * initialised after the call. This can't easily be worked around with + * clang-tidy suppressions, because the warning doesn't show on the syscall + * itself but later when we access the supposedly uninitialised field. + */ +static inline void sa_init(struct sockaddr *sa, socklen_t *sl) +{ +#ifdef CLANG_TIDY_58992 + if (sa) + memset(sa, 0, *sl); +#else + (void)sa; + (void)sl; +#endif /* CLANG_TIDY_58992 */ +} + +static inline ssize_t wrap_recvfrom(int sockfd, void *buf, size_t len, + int flags, + struct sockaddr *src_addr, + socklen_t *addrlen) +{ + sa_init(src_addr, addrlen); + return recvfrom(sockfd, buf, len, flags, src_addr, addrlen); +} +#define recvfrom(s, buf, len, flags, src, addrlen) \ + wrap_recvfrom((s), (buf), (len), (flags), (src), (addrlen)) + +static inline int wrap_accept4(int sockfd, struct sockaddr *addr, + socklen_t *addrlen, int flags) +{ + sa_init(addr, addrlen); + return accept4(sockfd, addr, addrlen, flags); +} +#define accept4(s, addr, addrlen, flags) \ + wrap_accept4((s), (addr), (addrlen), (flags)) + #endif /* UTIL_H */ -- cgit v1.2.3