diff options
Diffstat (limited to 'libc/sysdeps')
-rw-r--r-- | libc/sysdeps/linux/common/getentropy.c | 43 | ||||
-rw-r--r-- | libc/sysdeps/linux/common/getrandom.c | 3 | ||||
-rw-r--r-- | libc/sysdeps/linux/common/sys/random.h | 18 |
3 files changed, 61 insertions, 3 deletions
diff --git a/libc/sysdeps/linux/common/getentropy.c b/libc/sysdeps/linux/common/getentropy.c new file mode 100644 index 000000000..971674c4f --- /dev/null +++ b/libc/sysdeps/linux/common/getentropy.c @@ -0,0 +1,43 @@ +/* + * getentropy() by wrapping getrandom(), for µClibc-ng + * + * © 2025 mirabilos Ⓕ CC0 or MirBSD or GNU LGPLv2 + * + * Note: may be a thread cancellation point, unlike the + * implementations in glibc and musl libc. Should this + * ever become a concern, it will need patching. + */ + +#define _DEFAULT_SOURCE +#include <errno.h> +#include <unistd.h> +#include <sys/random.h> + +int +getentropy(void *__buf, size_t __len) +{ + ssize_t n; + + if (__len > 256U) { + errno = EIO; + return (-1); + } + + again: + if ((n = getrandom(__buf, __len, 0)) == -1) + switch (errno) { + case EAGAIN: /* should not happen but better safe than sorry */ + case EINTR: + goto again; + default: + errno = EIO; + /* FALLTHROUGH */ + case EFAULT: + case ENOSYS: + return (-1); + } + if ((size_t)n != __len) + /* also shouldn’t happen (safety net) */ + goto again; + return (0); +} diff --git a/libc/sysdeps/linux/common/getrandom.c b/libc/sysdeps/linux/common/getrandom.c index bb9841463..1db1663b9 100644 --- a/libc/sysdeps/linux/common/getrandom.c +++ b/libc/sysdeps/linux/common/getrandom.c @@ -8,6 +8,7 @@ #include <sys/syscall.h> #include <sys/random.h> + #ifdef __NR_getrandom -_syscall3(int, getrandom, void *, buf, size_t, buflen, unsigned int, flags) +_syscall3(ssize_t, getrandom, void *, buf, size_t, buflen, unsigned int, flags) #endif diff --git a/libc/sysdeps/linux/common/sys/random.h b/libc/sysdeps/linux/common/sys/random.h index 3d24e439b..c3d9cf575 100644 --- a/libc/sysdeps/linux/common/sys/random.h +++ b/libc/sysdeps/linux/common/sys/random.h @@ -4,11 +4,19 @@ #ifndef _SYS_RANDOM_H #define _SYS_RANDOM_H 1 + #include <features.h> #include <stddef.h> __BEGIN_DECLS +#include <bits/types.h> + +#ifndef __ssize_t_defined +typedef __ssize_t ssize_t; +# define __ssize_t_defined +#endif + #if defined __UCLIBC_LINUX_SPECIFIC__ # if 0 /*def __ASSUME_GETRANDOM_SYSCALL */ # include <linux/random.h> @@ -26,9 +34,15 @@ __BEGIN_DECLS # define GRND_RANDOM 0x0002 # define GRND_INSECURE 0x0004 # endif -/* FIXME: aren't there a couple of __restrict and const missing ? */ -extern int getrandom(void *__buf, size_t count, unsigned int flags) +extern ssize_t getrandom(void *__buf, size_t count, unsigned int flags) __nonnull ((1)) __wur; + +/* OpenBSD-compatible access to random bytes. + May be a cancellation point here, unlike in glibc/musl. */ +# ifndef __getentropy_defined +extern int getentropy(void *__buf, size_t __len) __nonnull ((1)) __wur; +# define __getentropy_defined +# endif #endif __END_DECLS |