Merge #18359: build: fix sysctl() detection on macOS

e90e3e684ffa7b25f0dfb5b45e70bb0c358261fb build: fix sysctl() detection on macOS (fanquake)

Pull request description:

  [`sysctl()` on *BSD](https://www.unix.com/man-page/FreeBSD/3/sysctl/) takes a "const int *name", whereas [`sysctl()` on macOS](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/sysctl.3.html)
  it takes an "int *name". So our configure check and `sysctl()` detection on
  macOS currently fails:

  ```bash
  /usr/include/sys/sysctl.h:759:9: note: candidate function not viable:
  	no known conversion from 'const int [2]' to 'int *' for 1st argument
  int     sysctl(int *, u_int, void *, size_t *, void *, size_t);
  ```

  The simplest change seems to be to change the param to a "int *name", which
  will work during configure on macOS and *BSD systems.

  For consistency I've changed both calls, but note that macOS doesn't
  have `KERN_ARND`, so that check will always fail regardless. We can revert/add
  documentation if preferred.

ACKs for top commit:
  laanwj:
    Re-ACK e90e3e684ffa7b25f0dfb5b45e70bb0c358261fb

Tree-SHA512: 29e9348136fc72882f63079bf10d2490e845d7656aae2c003e282bea49dd2778204a7776a67086bd88c2852af9a07dd04ba358eede7e37029e1c10f73c85d6a5
This commit is contained in:
Wladimir J. van der Laan 2020-03-19 15:23:12 +01:00 committed by pasta
parent 0c3a7469fb
commit b582fbb9a6
2 changed files with 8 additions and 6 deletions

View File

@ -1090,11 +1090,10 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <unistd.h>
AC_MSG_CHECKING(for sysctl)
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
#include <sys/sysctl.h>]],
[[ static const int name[2] = {CTL_KERN, KERN_VERSION};
#ifdef __linux__
[[ #ifdef __linux__
#error "Don't use sysctl on Linux, it's deprecated even when it works"
#endif
sysctl(name, 2, nullptr, nullptr, nullptr, 0); ]])],
sysctl(nullptr, 2, nullptr, nullptr, nullptr, 0); ]])],
[ AC_MSG_RESULT(yes); AC_DEFINE(HAVE_SYSCTL, 1,[Define this symbol if the BSD sysctl() is available]) ],
[ AC_MSG_RESULT(no)]
)
@ -1102,7 +1101,10 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
AC_MSG_CHECKING(for sysctl KERN_ARND)
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
#include <sys/sysctl.h>]],
[[ static const int name[2] = {CTL_KERN, KERN_ARND};
[[ #ifdef __linux__
#error "Don't use sysctl on Linux, it's deprecated even when it works"
#endif
static int name[2] = {CTL_KERN, KERN_ARND};
sysctl(name, 2, nullptr, nullptr, nullptr, 0); ]])],
[ AC_MSG_RESULT(yes); AC_DEFINE(HAVE_SYSCTL_ARND, 1,[Define this symbol if the BSD sysctl(KERN_ARND) is available]) ],
[ AC_MSG_RESULT(no)]

View File

@ -326,10 +326,10 @@ void GetOSRand(unsigned char *ent32)
// Silence a compiler warning about unused function.
(void)GetDevURandom;
#elif defined(HAVE_SYSCTL_ARND)
/* FreeBSD and similar. It is possible for the call to return less
/* FreeBSD, NetBSD and similar. It is possible for the call to return less
* bytes than requested, so need to read in a loop.
*/
static const int name[2] = {CTL_KERN, KERN_ARND};
static int name[2] = {CTL_KERN, KERN_ARND};
int have = 0;
do {
size_t len = NUM_OS_RANDOM_BYTES - have;