Merge pull request #595 from EricEngle-NOAA/develop

Potential fix for #438.

Author: Hang-Lei-NOAA

.github/workflows/MacOS.yml

@@ -66,14 +66,14 @@ jobs:
       uses: actions/cache@v4
       with:
         path: ~/png
-        key: png-${{ runner.os }}-1.6.37-macOS
+        key: png-${{ runner.os }}-1.6.45-macOS
 
     - name: build-png
       if: steps.cache-png.outputs.cache-hit != 'true'
       run: |
-        wget https://github.com/glennrp/libpng/archive/refs/tags/v1.6.37.tar.gz &> /dev/null
-        tar zxf v1.6.37.tar.gz
-        cd libpng-1.6.37
+        wget https://github.com/glennrp/libpng/archive/refs/tags/v1.6.45.tar.gz &> /dev/null
+        tar zxf v1.6.45.tar.gz
+        cd libpng-1.6.45
         mkdir build
         cd build
         cmake .. -DCMAKE_INSTALL_PREFIX=~/png -DCMAKE_C_FLAGS="-Wno-implicit-function-declaration" -DPNG_ARM_NEON=off

src/g2_addfield.c

@@ -120,7 +120,7 @@ g2_addfield(unsigned char *cgrib, g2int ipdsnum, g2int *ipdstmpl,
 
     /* Check for GRIB header and terminator. Translate the error codes
      * to the legacy G2 error codes. */
-    if ((ret = g2c_check_msg(cgrib, &lencurr, 1)))
+    if ((ret = g2c_check_msg(cgrib, &lencurr, 1, 3)))
     {
         if (ret == G2C_ENOTGRIB)
             return G2_ADD_MSG_INIT;

src/g2_addgrid.c

@@ -74,7 +74,7 @@ g2_addgrid(unsigned char *cgrib, g2int *igds, g2int *igdstmpl, g2int *ideflist,
 
     /* Check for GRIB header and terminator. Translate the error codes
      * to the legacy G2 error codes. */
-    if ((ret = g2c_check_msg(cgrib, &lencurr, 1)))
+    if ((ret = g2c_check_msg(cgrib, &lencurr, 1, 2)))
     {
         if (ret == G2C_ENOTGRIB)
             return G2_ADD_MSG_INIT;

src/g2_addlocal.c

@@ -47,7 +47,7 @@ g2_addlocal(unsigned char *cgrib, unsigned char *csec2, g2int lcsec2)
 
     /* Check for GRIB header and terminator. Translate the error codes
      * to the legacy G2 error codes. */
-    if ((ret = g2c_check_msg(cgrib, &lencurr, 1)))
+    if ((ret = g2c_check_msg(cgrib, &lencurr, 1, 1)))
     {
         if (ret == G2C_ENOTGRIB)
             return G2_ADD_MSG_INIT;

src/g2_gribend.c

@@ -46,7 +46,7 @@ g2_gribend(unsigned char *cgrib)
 
     /* Check for GRIB header and terminator. Translate the error codes
      * to the legacy G2 error codes. */
-    if ((ret = g2c_check_msg(cgrib, &lencurr, 1)))
+    if ((ret = g2c_check_msg(cgrib, &lencurr, 1, 4)))
     {
         if (ret == G2C_ENOTGRIB)
             return G2_ADD_MSG_INIT;

src/grib2_int.h

@@ -384,7 +384,7 @@ int pack_gp(g2int *kfildo, g2int *ic, g2int *nxy,
             g2int *novref, g2int *lbitref, g2int *ier);
 
 /* Check the message header and check for message termination. */
-int g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose);
+int g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose, int from);
 
 /* Basic file I/O. */
 int g2c_file_io(FILE *f, int write, int g2ctype, void *var);

src/util.c

@@ -7,30 +7,48 @@
 #include "grib2_int.h"
 #include <stdarg.h>
 
+/** If pthreads are enabled, use externally-defined mutex for
+ * thread-safety. */
+EXTERN_MUTEX(m);
+
 /**
  * Check for 'GRIB' at the beginning of a GRIB message, and check to
  * see if the message is already terminated with '7777'.
  *
+ * On rare occasions, the last 4 bytes of section 7 (data section)
+ * can be the GRIB terminating string of '7777'. This function
+ * accommodates for this by tracking which function called g2c_check_msg()
+ * via the from argument (see below).
+ *
  * @param cgrib Buffer that contains the GRIB message.
  * @param lencurr Pointer that gets the length of the GRIB message.
  * @param verbose If non-zero, print any error messages to stdout.
+ * @param from Mapping of where this function was called from.
+ * - 1 = From g2_addlocal()
+ * - 2 = From g2_addgrid()
+ * - 3 = From g2_addfield()
+ * - 4 = From g2_gribend()
  *
  * @return
  * - ::G2C_NOERROR No error.
  * - ::G2C_ENOTGRIB GRIB header not found.
  * - ::G2C_EMSGCOMPLETE GRIB message already complete.
  *
  * @author Ed Hartnett @date Nov 11, 2021
+ * @author Eric Engle
  */
 int
-g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose)
+g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose, int from)
 {
     unsigned char G = 0x47;     /* 'G' */
     unsigned char R = 0x52;     /* 'R' */
     unsigned char I = 0x49;     /* 'I' */
     unsigned char B = 0x42;     /* 'B' */
     unsigned char seven = 0x37; /* '7' */
 
+    int iret = 0;
+    static int last_from = 0; /* Keep last value of from arg */
+
     assert(cgrib && lencurr);
 
     /* Check to see if beginning of GRIB message exists. */
@@ -39,6 +57,10 @@ g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose)
         if (verbose)
             printf("GRIB not found in given message. A call to routine g2_create() "
                    "is required to to initialize GRIB messge.\n");
+        /* Update last_from. */
+        MUTEX_LOCK(m);
+        last_from = from;
+        MUTEX_UNLOCK(m);
         return G2C_ENOTGRIB;
     }
 
@@ -49,12 +71,26 @@ g2c_check_msg(unsigned char *cgrib, g2int *lencurr, int verbose)
     if (cgrib[*lencurr - 4] == seven && cgrib[*lencurr - 3] == seven &&
         cgrib[*lencurr - 2] == seven && cgrib[*lencurr - 1] == seven)
     {
-        if (verbose)
-            printf("GRIB message already complete.  Cannot add new section.\n");
-        return G2C_EMSGCOMPLETE;
+        /* Allow this to occur if this is called from g2_gribend (from = 4)
+         * and previous call was from g2_addfield where last_from = 3. */
+        if (from == 4 && last_from == 3)
+        {
+            iret = G2C_NOERROR;
+        }
+        else
+        {
+            if (verbose)
+                printf("GRIB message already complete.  Cannot add new section.\n");
+            iret = G2C_EMSGCOMPLETE;
+        }
     }
 
-    return G2C_NOERROR;
+    /* Update last_from. */
+    MUTEX_LOCK(m);
+    last_from = from;
+    MUTEX_UNLOCK(m);
+
+    return iret;
 }
 
 #ifdef LOGGING

tests/CMakeLists.txt

@@ -179,6 +179,7 @@ endif()
 g2c_test(tst_g2_create)
 g2c_test(tst_g2_addgrid)
 g2c_test(tst_g2_addfield)
+g2c_test(tst_rare_packing_gribend)
 g2c_test(tst_decode)
 g2c_test(tst_gbits)
 g2c_test(tst_gridtemplates)

tests/tst_rare_packing_gribend.c

@@ -0,0 +1,83 @@
+/* This is a test for the NCEPLIBS-g2c project. This test is for a rare scenario where
+ * the last 4 bytes of the packed data section could be all 55 or hex 0x37, which when
+ * converted to ASCII, will resemble the GRIB end message terminator of "7777".
+ *
+ * This test purposely builds a very small GRIB2 message, with data values purposely
+ * set so that when using simple packing with no scaling and nbits = 0, will make
+ * the last 4 bytes of the packed data mimic the GRIB terminator.
+ *
+ * Eric Engle 3/17/25
+ */
+
+#include "grib2_int.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#define SEC0_LEN 16
+#define SEC1_LEN 21
+#define SEC3_LEN 72
+#define SEC4_LEN 58
+#define SEC5_LEN 21
+#define SEC6_LEN 6
+#define SEC7_LEN 11
+#define FULL_MSG_LEN 209
+
+int
+main()
+{
+    printf("Testing rare packing condition and grid end.\n");
+    printf("Testing full message creation (expect and ignore error messages)...\n");
+    {
+        unsigned char cgrib[FULL_MSG_LEN];
+        g2int listsec0[2] = {0, 2};
+        g2int listsec1[13] = {7, 0, 2, 1, 1, 2023, 9, 29, 0, 0, 0, 0, 1};
+        g2int igds[5] = {0, 6, 0, 0, 0};
+        g2int igdstmpl[19] = {6, 0, 0, 0, 0, 0, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 50000, 50000, 64};
+        g2int ipdsnum = 8;
+        g2int ipdstmpl[29] = {1, 8, 2, 0, 250, 0, 0, 1, 0, 1, 0, 0, 255, 0, 0, 2023, 9, 30, 0, 0, 0, 1, 0, 1, 2, 1, 24, 255, 0};
+        float coordlist[1] = {1};
+        g2int numcoord = 0;
+        g2int idrsnum = 0; /* Grid Point Data - Simple Packing (see Template 5.0) */
+        g2int idrstmpl[5] = {0, 0, 0, 0, 0};
+        float fld[6] = {0.0, 176.9375, 54.9, 55.1, 54.7, 55.3};
+        g2int ngrdpts = 6;
+        g2int ibmap = 255; // No bit map
+        g2int bmap[6] = {1, 1, 1, 1, 1, 1};
+        int ret;
+
+        /* Initialize empty message to quiet valgrind errors. */
+        for (int i = 0; i < FULL_MSG_LEN; i++)
+            cgrib[i] = 0;
+
+        /* Create the message, filling in sections 0 and 1. */
+        printf("Calling g2_create()... ");
+        ret = g2_create(cgrib, listsec0, listsec1);
+        printf("ret = %d\n", ret);
+        if (ret != SEC0_LEN + SEC1_LEN)
+            return 1;
+
+        /* Add section 3. */
+        printf("Calling g2_addgrid()... ");
+        ret = g2_addgrid(cgrib, igds, igdstmpl, NULL, 0);
+        printf("ret = %d\n", ret);
+        if (ret != SEC0_LEN + SEC1_LEN + SEC3_LEN)
+            return 1;
+
+        /* Add sections 4, 5, 6, and 7. */
+        printf("Calling g2_addfield()... ");
+        ret = g2_addfield(cgrib, ipdsnum, ipdstmpl, coordlist, numcoord,
+                          idrsnum, idrstmpl, fld, ngrdpts, ibmap, bmap);
+        printf("ret = %d\n", ret);
+        if (ret != SEC0_LEN + SEC1_LEN + SEC3_LEN + SEC4_LEN + SEC5_LEN + SEC6_LEN + SEC7_LEN)
+            return 1;
+
+        /* Add section 8. */
+        printf("Calling g2_gribend()... ");
+        ret = g2_gribend(cgrib);
+        if (ret != FULL_MSG_LEN)
+            return 1;
+    }
+    printf("ok!\n");
+    printf("SUCCESS!\n");
+    return 0;
+}