From 48d91cf4cc53e820dafa3c6d5efdf4e5a06c2c29 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Wed, 17 Jul 2019 12:36:11 +0200
Subject: [PATCH] Rio: remember read/write error conditions.

---
 src/rdb.c |  1 -
 src/rio.c |  4 ++++
 src/rio.h | 33 ++++++++++++++++++++++++++++-----
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/rdb.c b/src/rdb.c
index 5111b6b88..e94f2934a 100644
--- a/src/rdb.c
+++ b/src/rdb.c
@@ -2168,7 +2168,6 @@ int rdbLoadRio(rio *rdb, rdbSaveInfo *rsi, int loading_aof) {
 eoferr: /* unexpected end of file is handled here with a fatal exit */
     serverLog(LL_WARNING,"Short read or OOM loading DB. Unrecoverable error, aborting now.");
     rdbReportReadError("Unexpected EOF reading RDB file");
-err:
     return C_ERR;
 }
 
diff --git a/src/rio.c b/src/rio.c
index 5359bc3d6..bdbc5d0e9 100644
--- a/src/rio.c
+++ b/src/rio.c
@@ -92,6 +92,7 @@ static const rio rioBufferIO = {
     rioBufferFlush,
     NULL,           /* update_checksum */
     0,              /* current checksum */
+    0,              /* flags */
     0,              /* bytes read or written */
     0,              /* read/write chunk size */
     { { NULL, 0 } } /* union for io-specific vars */
@@ -145,6 +146,7 @@ static const rio rioFileIO = {
     rioFileFlush,
     NULL,           /* update_checksum */
     0,              /* current checksum */
+    0,              /* flags */
     0,              /* bytes read or written */
     0,              /* read/write chunk size */
     { { NULL, 0 } } /* union for io-specific vars */
@@ -239,6 +241,7 @@ static const rio rioFdIO = {
     rioFdFlush,
     NULL,           /* update_checksum */
     0,              /* current checksum */
+    0,              /* flags */
     0,              /* bytes read or written */
     0,              /* read/write chunk size */
     { { NULL, 0 } } /* union for io-specific vars */
@@ -374,6 +377,7 @@ static const rio rioFdsetIO = {
     rioFdsetFlush,
     NULL,           /* update_checksum */
     0,              /* current checksum */
+    0,              /* flags */
     0,              /* bytes read or written */
     0,              /* read/write chunk size */
     { { NULL, 0 } } /* union for io-specific vars */
diff --git a/src/rio.h b/src/rio.h
index beea06888..66036b5bd 100644
--- a/src/rio.h
+++ b/src/rio.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2009-2012, Pieter Noordhuis <pcnoordhuis at gmail dot com>
- * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2009-2019, Salvatore Sanfilippo <antirez at gmail dot com>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -36,6 +36,9 @@
 #include <stdint.h>
 #include "sds.h"
 
+#define RIO_FLAG_READ_ERROR (1<<0)
+#define RIO_FLAG_WRITE_ERROR (1<<1)
+
 struct _rio {
     /* Backend functions.
      * Since this functions do not tolerate short writes or reads the return
@@ -51,8 +54,8 @@ struct _rio {
      * computation. */
     void (*update_cksum)(struct _rio *, const void *buf, size_t len);
 
-    /* The current checksum */
-    uint64_t cksum;
+    /* The current checksum and flags (see RIO_FLAG_*) */
+    uint64_t cksum, flags;
 
     /* number of bytes read or written */
     size_t processed_bytes;
@@ -102,8 +105,10 @@ static inline size_t rioWrite(rio *r, const void *buf, size_t len) {
     while (len) {
         size_t bytes_to_write = (r->max_processing_chunk && r->max_processing_chunk < len) ? r->max_processing_chunk : len;
         if (r->update_cksum) r->update_cksum(r,buf,bytes_to_write);
-        if (r->write(r,buf,bytes_to_write) == 0)
+        if (r->write(r,buf,bytes_to_write) == 0) {
+            r->flags |= RIO_FLAG_WRITE_ERROR;
             return 0;
+        }
         buf = (char*)buf + bytes_to_write;
         len -= bytes_to_write;
         r->processed_bytes += bytes_to_write;
@@ -114,8 +119,10 @@ static inline size_t rioWrite(rio *r, const void *buf, size_t len) {
 static inline size_t rioRead(rio *r, void *buf, size_t len) {
     while (len) {
         size_t bytes_to_read = (r->max_processing_chunk && r->max_processing_chunk < len) ? r->max_processing_chunk : len;
-        if (r->read(r,buf,bytes_to_read) == 0)
+        if (r->read(r,buf,bytes_to_read) == 0) {
+            r->flags |= RIO_FLAG_READ_ERROR;
             return 0;
+        }
         if (r->update_cksum) r->update_cksum(r,buf,bytes_to_read);
         buf = (char*)buf + bytes_to_read;
         len -= bytes_to_read;
@@ -132,6 +139,22 @@ static inline int rioFlush(rio *r) {
     return r->flush(r);
 }
 
+/* This function allows to know if there was a read error in any past
+ * operation, since the rio stream was created or since the last call
+ * to rioClearError(). */
+static inline int rioGetReadError(rio *r) {
+    return (r->flags & RIO_FLAG_READ_ERROR) != 0;
+}
+
+/* Like rioGetReadError() but for write errors. */
+static inline int rioGetWriteError(rio *r) {
+    return (r->flags & RIO_FLAG_READ_ERROR) != 0;
+}
+
+static inline void rioClearErrors(rio *r) {
+    r->flags &= ~(RIO_FLAG_READ_ERROR|RIO_FLAG_WRITE_ERROR);
+}
+
 void rioInitWithFile(rio *r, FILE *fp);
 void rioInitWithBuffer(rio *r, sds s);
 void rioInitWithFd(rio *r, int fd, size_t read_limit);