Avoid attempting to read 0 bytes from a file in the osinst vtab code.

FossilOrigin-Name: 1fb76c3e7d904cd2754270997d3d0c86237b0a630d6b1417578a8191e6e1687f

diff --git a/manifest b/manifest
index aa80bf6e5b04106134b9b4c0bacc7ec6383c2f62..986f6bb5b9fc594f004683e848a914ec87af054a 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\sin\sMakefile.msc\son\sthis\sbranch.
-D 2019-10-05T19:37:04.210
+C Avoid\sattempting\sto\sread\s0\sbytes\sfrom\sa\sfile\sin\sthe\sosinst\svtab\scode.
+D 2019-10-07T10:29:18.641
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -568,7 +568,7 @@ F src/test_multiplex.c e054459f7633f3ff8ce1245da724f9a8be189e4e
 F src/test_multiplex.h 5436d03f2d0501d04f3ed50a75819e190495b635
 F src/test_mutex.c 7f4337ba23ee6b1d2ec81c189653608cb069926a
 F src/test_onefile.c f31e52e891c5fef6709b9fcef54ce660648a34172423a9cbdf4cbce3ba0049f4
-F src/test_osinst.c 6c94ed7cf950d8af22c0380f91616647bb2a014536042a2e85d5e34fa1a8f52d
+F src/test_osinst.c 446494a025eb5ece24de6a9a1b97b1e390c27d59ccf42d1e5cddd61c16f811c4
 F src/test_pcache.c a5cd24730cb43c5b18629043314548c9169abb00
 F src/test_quota.c 6cb9297115b551f433a9ad1741817a9831abed99
 F src/test_quota.h 2a8ad1952d1d2ca9af0ce0465e56e6c023b5e15d
@@ -1847,7 +1847,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P c9519c0cec3f0eae3ec4abe39fabbcc59a38d3c2eba11e19cfec4b769ed7376e
-R 50521cd2cb2a43a71199778b2b607e03
+P ed3499a1a5c0f860b940af0edc6a6184d834001a68d59b36b0e1b21d2e6579ca
+R 167c91f002f8b3259c9adc1d3ec59b39
 U dan
-Z 3d37686295c95e645e9fd4399b610f64
+Z 798e91aaa2dcc84e3d48ac174ec14d84

diff --git a/manifest.uuid b/manifest.uuid
index 4346968150aa07966ec3af1f3c8ce418637dc06f..4ee4f3bbe9a2b05b742b5cf8b5e8d9d3a2d40959 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ed3499a1a5c0f860b940af0edc6a6184d834001a68d59b36b0e1b21d2e6579ca
\ No newline at end of file
+1fb76c3e7d904cd2754270997d3d0c86237b0a630d6b1417578a8191e6e1687f
\ No newline at end of file

diff --git a/src/test_osinst.c b/src/test_osinst.c
index 5a0692f01a808e0dfff58e12f1ea71d1fcbd6ec8..91e103691600c8b03f16fd909c3d08c13edfc0a5 100644 (file)
--- a/src/test_osinst.c
+++ b/src/test_osinst.c
@@ -994,7 +994,9 @@ static int vlogNext(sqlite3_vtab_cursor *pCursor){
       if( rc==SQLITE_OK ){
         int nStr = get32bits((unsigned char *)buf);
         char *zStr = sqlite3_malloc(nStr+1);
-        rc = p->pFd->pMethods->xRead(p->pFd, zStr, nStr, pCsr->iOffset+nRead);
+        if( nStr>0 ){
+          rc = p->pFd->pMethods->xRead(p->pFd, zStr, nStr, pCsr->iOffset+nRead);
+        }
         zStr[nStr] = '\0';
         nRead += nStr;