fix different signedness comparison

../ipmbbridged.cpp:368:12: warning: comparison of integer expressions of different signedness: ‘int’ and ‘const size_t’ {aka ‘const long unsigned int’} [-Wsign-compare]

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I12bff463c9422f050a572f0936ca5488a461c807
diff --git a/ipmbbridged.cpp b/ipmbbridged.cpp
index 678c750..5b22a7a 100644
--- a/ipmbbridged.cpp
+++ b/ipmbbridged.cpp
@@ -354,7 +354,13 @@
     IPMB_HEADER* ipmbFrame = &(ipmbPkt->hdr);
 
     lseek(ipmbi2cSlaveFd, 0, SEEK_SET);
-    int r = read(ipmbi2cSlaveFd, buffer.data(), ipmbMaxFrameLength);
+    ssize_t r = read(ipmbi2cSlaveFd, buffer.data(), ipmbMaxFrameLength);
+
+    // Handle error cases.
+    if (r < 0)
+    {
+        goto end;
+    }
 
     /* Substract first byte len size from total frame length */
     r--;
diff --git a/ipmbbridged.hpp b/ipmbbridged.hpp
index 08c68e8..d7a75a7 100644
--- a/ipmbbridged.hpp
+++ b/ipmbbridged.hpp
@@ -73,8 +73,8 @@
 constexpr size_t ipmbPktLenSize = 1;
 constexpr size_t ipmbChecksumSize = 1;
 constexpr size_t ipmbChecksum2StartOffset = 3;
-constexpr size_t ipmbMinFrameLength = 7;
-constexpr size_t ipmbMaxFrameLength =
+constexpr ssize_t ipmbMinFrameLength = 7;
+constexpr ssize_t ipmbMaxFrameLength =
     ipmbPktLenSize + ipmbConnectionHeaderLength + ipmbResponseDataHeaderLength +
     ipmbChecksumSize + ipmbMaxDataSize;