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authorStephan Mueller <smueller@chronox.de>2015-05-25 15:08:47 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2015-05-27 17:51:53 +0800
commit16b369a91d0dd80be214b7f7801fbc51875454cc (patch)
tree651637281b51655197049065eeba784d3404ac6b
parent1d9de44e268d880cbe2d0bd3be1ef0661f93fd34 (diff)
random: Blocking API for accessing nonblocking_pool
The added API calls provide a synchronous function call get_blocking_random_bytes where the caller is blocked until the nonblocking_pool is initialized. CC: Andreas Steffen <andreas.steffen@strongswan.org> CC: Theodore Ts'o <tytso@mit.edu> CC: Sandy Harris <sandyinchina@gmail.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--drivers/char/random.c12
-rw-r--r--include/linux/random.h1
2 files changed, 13 insertions, 0 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 8b8c46b5fd5c..159d0700f7d8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1245,6 +1245,18 @@ void get_random_bytes(void *buf, int nbytes)
EXPORT_SYMBOL(get_random_bytes);
/*
+ * Equivalent function to get_random_bytes with the difference that this
+ * function blocks the request until the nonblocking_pool is initialized.
+ */
+void get_blocking_random_bytes(void *buf, int nbytes)
+{
+ if (unlikely(nonblocking_pool.initialized == 0))
+ wait_event(urandom_init_wait, nonblocking_pool.initialized);
+ extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
+}
+EXPORT_SYMBOL(get_blocking_random_bytes);
+
+/*
* This function will use the architecture-specific hardware random
* number generator if it is available. The arch-specific hw RNG will
* almost certainly be faster than what we can do in software, but it
diff --git a/include/linux/random.h b/include/linux/random.h
index b05856e16b75..796267d56901 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -14,6 +14,7 @@ extern void add_input_randomness(unsigned int type, unsigned int code,
extern void add_interrupt_randomness(int irq, int irq_flags);
extern void get_random_bytes(void *buf, int nbytes);
+extern void get_blocking_random_bytes(void *buf, int nbytes);
extern void get_random_bytes_arch(void *buf, int nbytes);
void generate_random_uuid(unsigned char uuid_out[16]);
extern int random_int_secret_init(void);