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[Qemu-devel] [PATCH v5 04/24] crypto: Do not fail for EINTR during qcryp
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH v5 04/24] crypto: Do not fail for EINTR during qcrypto_random_bytes |
Date: |
Thu, 9 May 2019 18:24:38 -0700 |
We can always get EINTR for read; /dev/urandom is no exception.
Rearrange the order of tests for likelihood; allow degenerate buflen==0
case to perform a no-op zero-length read. This means that the normal
success path is a straight line with a single test for success.
Reviewed-by: Laurent Vivier <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
v3: Rearrage the read loop again.
---
crypto/random-platform.c | 36 +++++++++++++++---------------------
1 file changed, 15 insertions(+), 21 deletions(-)
diff --git a/crypto/random-platform.c b/crypto/random-platform.c
index f995fc0ef1..260b64564d 100644
--- a/crypto/random-platform.c
+++ b/crypto/random-platform.c
@@ -65,29 +65,23 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
"Unable to read random bytes");
return -1;
}
-
- return 0;
#else
- int ret = -1;
- int got;
-
- while (buflen > 0) {
- got = read(fd, buf, buflen);
- if (got < 0) {
- error_setg_errno(errp, errno,
- "Unable to read random bytes");
- goto cleanup;
- } else if (!got) {
- error_setg(errp,
- "Unexpected EOF reading random bytes");
- goto cleanup;
+ while (1) {
+ ssize_t got = read(fd, buf, buflen);
+ if (likely(got == buflen)) {
+ return 0;
+ }
+ if (got > 0) {
+ buflen -= got;
+ buf += got;
+ } else if (got == 0) {
+ error_setg(errp, "Unexpected EOF reading random bytes");
+ return -1;
+ } else if (errno != EINTR) {
+ error_setg_errno(errp, errno, "Unable to read random bytes");
+ return -1;
}
- buflen -= got;
- buf += got;
}
-
- ret = 0;
- cleanup:
- return ret;
#endif
+ return 0;
}
--
2.17.1
- [Qemu-devel] [PATCH v5 00/24] Add qemu_getrandom and ARMv8.5-RNG etc, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 06/24] crypto: Use getrandom for qcrypto_random_bytes, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 01/24] configure: Link test before auto-enabling crypto libraries, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 04/24] crypto: Do not fail for EINTR during qcrypto_random_bytes,
Richard Henderson <=
- [Qemu-devel] [PATCH v5 12/24] linux-user: Initialize pseudo-random seeds for all guest cpus, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 03/24] crypto: Reverse code blocks in random-platform.c, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 11/24] cpus: Initialize pseudo-random seeds for all guest cpus, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 18/24] hw/misc/nrf51_rng: Use qemu_guest_getrandom_nofail, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 05/24] crypto: Use O_CLOEXEC in qcrypto_random_init, Richard Henderson, 2019/05/09
- [Qemu-devel] [PATCH v5 02/24] crypto: Merge crypto-obj-y into libqemuutil.a, Richard Henderson, 2019/05/09