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4db4393e69
strlcat provides better protection against buffer overflows. Code is taken from the FreeBSD project source code. Specifically: https://github.com/freebsd/freebsd/blob/master/lib/libc/string/strlcat.c License appears to be acceptable, but needs to be checked by e.g. Debian. Step 1: 1. Add to netcdf-c/include/ncconfigure.h to use our version if not already available as determined by HAVE_STRLCAT in config.h. 2. Add the strlcat code to libdispatch/dstring.c 3. Turns out that strlcat was already defined in several places. So remove it from: ncgen3/genlib.c ncdump/dumplib.c 3. Define strlcat extern definition in ncconfigure.h. 4. Modify following directories to use strlcat: libdap2 libdap4 ncdap_test dap4_test Will do others in subsequent steps.
297 lines
7.1 KiB
C
297 lines
7.1 KiB
C
/*
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Report from Ansely Manke:
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I've attached a file with a short c program that
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demonstrates what I'm seeing. I don't know that we'd call
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this a constraint, so that was a misleading description.
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The thing I'm mimicking is a sequence where I read the 2-D
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coordinate variables, make some decisions about the size of
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a subset region, and then define index ranges and strides
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for reading other variables. Reading the full variable
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happens correctly, but the read with strides winds up
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messing up the data. Here it shows up returning some valid
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data and some zero's, but in other sequences of events it
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seems to be actually mis-ordered.
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I notice that the results are correct if the initial read of
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the variable uses counts that are size-1. So that might be a
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clue. And the read is correct if I either close and reopen
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the dataset after reading the original full variable, or if
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I don't do that step of first reading the whole grid. It's
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also fine with NetCDF 4.2.1.1.
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-Ansley
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Problem was two-fold:
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1. struct Getvara has the dsttype field as OC_Type rather than nc_type
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2. the dap odometer code dapnew_segment was incorrectly
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handling strides > 1: specifically, the stop position was incorrect.
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*/
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/* vars_whoi_test */
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/* acm 4/2013 */
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/* ansley.b.manke@noaa.gov */
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/* test nc_get_vars_float with calls similar to Ferret calls */
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/*linked with:
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cc vars_whoi_test.c -g -o vars_whoi_test_4211 /usr/local/netcdf_4211/lib/libnetcdf.a /usr/local/hdf5_189/lib/libhdf5_hl.a /usr/local/hdf5_189/lib/libhdf5.a /usr/local/lib/libz.a -L/usr/lib64 -lc -lm -lcurl
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cc vars_whoi_test.c -g -o vars_whoi_test /home/users/ansley/local/x86_nc43/lib/libnetcdf.a /usr/local/hdf5_189/lib/libhdf5_hl.a /usr/local/hdf5_189/lib/libhdf5.a /usr/local/lib/libz.a -L/usr/lib64 -lc -lm -lcurl
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Closing and reopening the dataset between the two reads fixes the
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incorrect data return
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Setting the count to one less in the full data read also fixes the
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incorrect data return
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*/
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#include<stdlib.h>
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#include<stdio.h>
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#include<string.h>
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#include "netcdf.h"
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#include "ncdispatch.h"
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#include "nctestserver.h"
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#define VERBOSE 1
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/*
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2014-07-01: (DMH) Changed the URL to use one from remotetest server.
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to remove dependence on an external server.
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*/
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/*
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static char* URL="http://geoport.whoi.edu/thredds/dodsC/coawst_4/use/fmrc/coawst_4_use_best.ncd";
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Float64 lon_rho[eta_rho = 336][xi_rho = 896];
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Float64 lat_rho[eta_rho = 336][xi_rho = 896];
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*/
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#define URL "%s/dodsC/testdods/rtofs.nc"
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#define VAR1 "Latitude"
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#define VAR2 "Longitude"
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#define XSIZE 850
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#define YSIZE 712
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static char url[1024];
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int
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main()
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{
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int ncid;
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int varid;
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int i;
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int ncstatus;
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size_t start[5], count[5];
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ptrdiff_t stride[5];
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int pass = 1;
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int nelems = XSIZE*YSIZE;
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int idim, ndim;
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float *dat = (float*)malloc(sizeof(float)*nelems);
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float sdat[10];
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char* svc;
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/* Find Test Server */
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svc = nc_findtestserver("thredds",0,REMOTETESTSERVERS);
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if(svc == NULL) {
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fprintf(stderr,"Cannot locate test server\n");
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exit(0);
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}
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snprintf(url,sizeof(url),URL,svc);
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for (idim=0; idim<5; idim++) {
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start[idim] = 0;
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count[idim] = 1;
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stride[idim] = 1;
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}
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ndim=2;
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printf(" \n");
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printf("********************\n");
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printf("open URL %s\n",url);
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printf(" \n");
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ncstatus = nc_open(url, NC_NOWRITE, &ncid);
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if(ncstatus != NC_NOERR) {
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fprintf(stderr,"Could not open: %s; server may be down; test ignored\n",url);
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exit(0);
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}
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ncstatus = nc_inq_varid(ncid, VAR1, &varid);
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ndim=2;
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Read %s data w/o strides\n",VAR1);
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printf(" \n");
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#endif
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start[0] = 0;
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start[1] = 0;
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start[2] = 0;
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start[3] = 0;
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count[0] = XSIZE;
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count[1] = YSIZE;
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stride[0] = 1;
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stride[1] = 1;
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#ifdef VERBOSE
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for (idim=0; idim<ndim; idim++)
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printf("start[%1d]=%3lu count[%1d]=%3lu stride[%1d]=%3lu\n",
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idim,start[idim],idim,count[idim],idim,stride[idim]);
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#endif
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ncstatus = nc_get_vars_float (ncid, varid, start, count, stride, (float*) dat);
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Print some of %s\n",VAR1);
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printf(" \n");
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for (i=0; i<10; i++)
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printf("%s[%d] = %f\n",VAR1,i,dat[i]);
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printf(" \n");
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for (i=(nelems-11); i<(nelems-1); i++)
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printf("%s[%d] = %f\n",VAR1,i,dat[i]);
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printf(" \n");
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#endif
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memset((void*)dat,0,sizeof(dat));
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/* Read a second variable */
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ncstatus = nc_inq_varid(ncid, VAR2, &varid);
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ndim=2;
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Read %s data w/o strides\n",VAR2);
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printf(" \n");
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#endif
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start[0] = 0;
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start[1] = 0;
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start[2] = 0;
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start[3] = 0;
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count[0] = XSIZE;
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count[1] = YSIZE;
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stride[0] = 1;
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stride[1] = 1;
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#ifdef VERBOSE
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for (idim=0; idim<ndim; idim++)
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printf("start[%d]=%3lu count[%d]=%3lu stride[%d]=%3lu\n",
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idim, start[idim], idim, count[idim], idim, stride[idim]);
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#endif
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ncstatus = nc_get_vars_float (ncid, varid, start, count, stride, (float*) dat);
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Print some of %s\n",VAR2);
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printf(" \n");
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for (i=0; i<10; i++)
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printf("%s[%d] = %f\n",VAR2,i,dat[i]);
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printf(" \n");
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printf(" \n");
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for (i=(nelems-11); i<(nelems-1); i++)
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printf("%s[%d] = %f\n",VAR2,i,dat[i]);
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printf(" \n");
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#endif
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memset((void*)dat,0,sizeof(dat));
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/* close and reopen the dataset, then the below read is correct */
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Close and reopen the dataset\n");
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#endif
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ncstatus = nc_close (ncid);
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ncstatus = nc_open(url, NC_NOWRITE, &ncid);
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/* ----------------------------------------------------- */
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/* Read a subset of the data with strides */
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ncstatus = nc_inq_varid(ncid, VAR1, &varid);
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Read a subset of %s data with strides\n",VAR1);
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printf(" \n");
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#endif
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start[0] = 250;
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start[1] = 704;
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count[0] = 5;
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count[1] = 2;
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stride[0] = 2;
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stride[1] = 4;
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#ifdef VERBOSE
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for (idim=0; idim<ndim; idim++)
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printf("start[%1d]=%3lu count[%1d]=%3lu stride[%1d]=%3lu\n",
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idim,start[idim],idim,count[idim],idim,stride[idim]);
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#endif
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memset((void*)sdat,0,sizeof(sdat));
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ncstatus = nc_get_vars_float (ncid, varid, start, count, stride, (float*) sdat);
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printf("status = %d\n", ncstatus);
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/* Verify that all read values are 50 <= n < 51 */
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for (i=0; i<10; i++) {
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if(sdat[i] <= 50.0 || sdat[i] > 51.0) {
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printf("Out of range: %s[%d] = %f\n",VAR1, i,sdat[i]);
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pass = 0;
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}
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}
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#ifdef VERBOSE
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printf(" \n");
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printf("********************\n");
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printf("Print values read. They should all be 50.xxxx \n");
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printf(" \n");
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for (i=0; i<10; i++)
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printf("%s[%d] = %f\n",VAR1,i,sdat[i]);
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#endif
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ncstatus = nc_close (ncid);
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if(!pass) {
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printf("*** FAIL: %s value out of range.\n",VAR1);
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exit(1);
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}
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printf("*** PASS\n");
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free(dat);
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exit(0);
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}
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