Glibc 2.24 and older do not provide an interface for the getrandom() system call. Linux kernels have been implementing this sytem call since kernel 3.17.
Let's address the situation where glibc <= 2.24 and Linux >= 3.17 by providing the system call interface ourselves when needed. This allows users to take advantage of getrandom() as long as the kernel supports it, even if glibc doesn't provide access to it. Signed-off-by: Markus Mayer <[email protected]> --- miscutils/getrandom.c | 22 ++++++++++++++++++++++ miscutils/random.h | 19 +++++++++++++++++++ miscutils/seedrng.c | 6 +++++- 3 files changed, 46 insertions(+), 1 deletion(-) create mode 100644 miscutils/getrandom.c create mode 100644 miscutils/random.h diff --git a/miscutils/getrandom.c b/miscutils/getrandom.c new file mode 100644 index 000000000000..ab6a57f8042e --- /dev/null +++ b/miscutils/getrandom.c @@ -0,0 +1,22 @@ +#include <features.h> + +#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ <= 24 + +#ifndef __NR_getrandom +#include <errno.h> +#endif +#include <sys/syscall.h> +#include "random.h" + +ssize_t getrandom(void *buffer, size_t length, unsigned int flags) +{ +#ifdef __NR_getrandom + return syscall(__NR_getrandom, buffer, length, flags); +#else + /* For kernels that don't support getrandom() (< 3.17). */ + errno = ENOSYS; + return -1; +#endif +} + +#endif /* __GLIBC__ ... */ diff --git a/miscutils/random.h b/miscutils/random.h new file mode 100644 index 000000000000..3131df5e8a5d --- /dev/null +++ b/miscutils/random.h @@ -0,0 +1,19 @@ +#ifndef _RANDOM_H +#define _RANDOM_H 1 + +#include <features.h> +#include <sys/types.h> + +#ifndef GRND_NONBLOCK +#define GRND_NONBLOCK 0x01 +#endif +#ifndef GRND_RANDOM +#define GRND_RANDOM 0x02 +#endif +#ifndef GRND_INSECURE +#define GRND_INSECURE 0x04 +#endif + +ssize_t getrandom(void *buffer, size_t length, unsigned int flags); + +#endif /* _RANDOM_H */ diff --git a/miscutils/seedrng.c b/miscutils/seedrng.c index 967741dc72ea..8ce553e460b1 100644 --- a/miscutils/seedrng.c +++ b/miscutils/seedrng.c @@ -29,7 +29,7 @@ //applet:IF_SEEDRNG(APPLET(seedrng, BB_DIR_USR_SBIN, BB_SUID_DROP)) -//kbuild:lib-$(CONFIG_SEEDRNG) += seedrng.o +//kbuild:lib-$(CONFIG_SEEDRNG) += getrandom.o seedrng.o //usage:#define seedrng_trivial_usage //usage: "[-d DIR] [-n]" @@ -42,7 +42,11 @@ #include "libbb.h" #include <linux/random.h> +#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ <= 24 +#include "random.h" +#else #include <sys/random.h> +#endif #include <sys/file.h> #ifndef GRND_INSECURE -- 2.34.1 _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
