From 7cc8a552a3efa25cf38ad81067a47ea5da970dfb Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Wed, 11 Jan 2012 16:47:37 -0600
Subject: [PATCH] db: Allow single-char accesses as long strings

Clients try to use long string support to fetch DBF_STRING
fields use DBF_CTRL_CHAR with a 1-element array, but the IOC
was rejecting that.  This permits it, and also ensures that
the resulting strings are zero-terminated.

Fixes lp:907761
---
 documentation/RELEASE_NOTES.html | 12 ++++++++++++
 src/db/dbAccess.c                | 12 ++++++------
 src/db/dbConvert.c               | 14 ++++++++++++++
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/documentation/RELEASE_NOTES.html b/documentation/RELEASE_NOTES.html
index 91a84f214..93d3045c8 100644
--- a/documentation/RELEASE_NOTES.html
+++ b/documentation/RELEASE_NOTES.html
@@ -13,6 +13,18 @@
 
 <!-- Insert new items immediately below here ... -->
 
+<h4>Launchpad Bugs Resolved</h4>
+
+<p>The following are links to bugs in the Launchpad bug tracker that have been
+fixed in this release:</p>
+
+<ul>
+<li>907761
+  <a href="https://launchpad.net/bugs/907761">
+    reading only 1st char of link in "long string" ($) syntax fails in read
+    error</a></li>
+</ul>
+
 <h4>Comments in iocsh scripts</h4>
 
 <p>The IOC shell was very particular about comments in previous versions of
diff --git a/src/db/dbAccess.c b/src/db/dbAccess.c
index a358270f3..22f4e20e7 100644
--- a/src/db/dbAccess.c
+++ b/src/db/dbAccess.c
@@ -969,7 +969,7 @@ long epicsShareAPI dbGetField(DBADDR *paddr,short dbrType,
 
         case DBR_CHAR:
         case DBR_UCHAR:
-            if (nRequest && *nRequest > 1) {
+            if (nRequest && *nRequest > 0) {
                 maxlen = *nRequest - 1;
                 break;
             }
@@ -984,8 +984,8 @@ long epicsShareAPI dbGetField(DBADDR *paddr,short dbrType,
         if (!status) status = dbFindField(&dbEntry, pfldDes->name);
         if (!status) {
             rtnString = dbGetString(&dbEntry);
-            strncpy(pbuf, rtnString, maxlen - 1);
-            pbuf[maxlen - 1] = 0;
+            strncpy(pbuf, rtnString, maxlen);
+            pbuf[maxlen] = 0;
         }
         dbFinishEntry(&dbEntry);
     } else {
@@ -1028,7 +1028,7 @@ long epicsShareAPI dbGet(DBADDR *paddr, short dbrType,
 
         case DBR_CHAR:
         case DBR_UCHAR:
-            if (nRequest && *nRequest > 1) {
+            if (nRequest && *nRequest > 0) {
                 maxlen = *nRequest - 1;
                 break;
             }
@@ -1037,8 +1037,8 @@ long epicsShareAPI dbGet(DBADDR *paddr, short dbrType,
             return S_db_badDbrtype;
         }
 
-        strncpy(pbuf, (char *)paddr->pfield, maxlen - 1);
-        pbuf[maxlen - 1] = 0;
+        strncpy(pbuf, (char *)paddr->pfield, maxlen);
+        pbuf[maxlen] = 0;
         return 0;
     }
 
diff --git a/src/db/dbConvert.c b/src/db/dbConvert.c
index f370e0aa2..4b7ad7da1 100644
--- a/src/db/dbConvert.c
+++ b/src/db/dbConvert.c
@@ -416,6 +416,13 @@ static long getCharChar(
     char *pbuffer = (char *)pto;
     char *psrc=(char *)(paddr->pfield);
 
+    if (paddr->pfldDes->field_type == DBF_STRING) {
+        /* This is a DBF_STRING field being read as a long string.
+         * The buffer we return must be zero-terminated.
+         */
+        pbuffer[--nRequest] = 0;
+        if (nRequest == 0) return(0);
+    }
     if(nRequest==1 && offset==0) {
 	*pbuffer = *psrc;
 	return(0);
@@ -436,6 +443,13 @@ static long getCharUchar(
     unsigned char *pbuffer = (unsigned char *)pto;
     char *psrc=(char *)(paddr->pfield);
 
+    if (paddr->pfldDes->field_type == DBF_STRING) {
+        /* This is a DBF_STRING field being read as a long string.
+         * The buffer we return must be zero-terminated.
+         */
+        pbuffer[--nRequest] = 0;
+        if (nRequest == 0) return(0);
+    }
     if(nRequest==1 && offset==0) {
 	*pbuffer = *psrc;
 	return(0);