Commit Graph

32 Commits

Author SHA1 Message Date
Dennis Heimbigner
126b3f9423 Support installation of filters into user-specified location
re: https://github.com/Unidata/netcdf-c/issues/2294

Ed Hartnett suggested that the netcdf library installation process
be extended to install the standard filters into a user specified
location. The user can then set HDF5_PLUGIN_PATH to that location.

This PR provides that capability using:
````
configure option: --with-plugin-dir=<absolute directory path>
cmake option: -DPLUGIN_INSTALL_DIR=<absolute directory path>
````

Currently, the following plugins are always installed, if
available: bzip2, zstd, blosc.
If NCZarr is enabled, then additional plugins are installed:
fletcher32, shuffle, deflate, szip.

Additionally, the necessary codec support is installed
for each of the above filters that is installed.

## Changes:
1. Cleanup handling of built-in bzip2.
2. Add documentation to docs/filters.md
3. Re-factor the NCZarr codec libraries
4. Add a test, although it can only be exercised after
   the library is installed, so it cannot be used during
   normal testing.
5. Cleanup use of HDF5_PLUGIN_PATH in the filter test cases.
2022-04-29 14:31:55 -06:00
Dennis Heimbigner
2856ee751d restore 2022-04-29 12:36:33 -06:00
Dennis Heimbigner
ad62ed2d41 ckp 2022-04-26 17:58:20 -06:00
Ward Fisher
3446aa0c13 Merge branch 'winutf8.dmh' of https://github.com/DennisHeimbigner/netcdf-c into gh2222.wif 2022-04-05 10:46:22 -06:00
Dennis Heimbigner
36102e3c32 Improve UTF8 Support On Windows
re: Issue https://github.com/Unidata/netcdf-c/issues/2190

The primary purpose of this PR is to improve the utf8 support
for windows. This is persuant to a change in Windows that
supports utf8 natively (almost). The almost means that it is
still utf16 internally and the set of characters representable
by utf8 is larger than those representable by utf16.

This leaves open the question in the Issue about handling
the Windows 1252 character set.

This required the following changes:

1. Test the Windows build and major version in order to see if
   native utf8 is supported.
2. If native utf8 is supported, Modify dpathmgr.c to call the 8-bit
   version of the windows fopen() and open() functions.
3. In support of this, programs that use XGetOpt (Windows versions)
   need to get the command line as utf8 and then parse to
   arc+argv as utf8. This requires using a homegrown command line parser
   named XCommandLineToArgvA.
4. Add a utility program called "acpget" that prints out the
   current Windows code page and locale.

Additionally, some technical debt was cleaned up as follows:

1. Unify all the places which attempt to read all or a part
   of a file into the dutil.c#NC_readfile code.
2. Similary unify all the code that creates temp files into
   dutil.c#NC_mktmp code.
3. Convert almost all remaining calls to fopen() and open()
   to NCfopen() and NCopen3(). This is to ensure that path management
   is used consistently. This touches a number of files.
4. extern->EXTERNL as needed to get it to work under Windows.
2022-02-08 20:53:30 -07:00
Dennis Heimbigner
f3e711e2b8 Add support for setting HDF5 alignment property when creating a file
re: https://github.com/Unidata/netcdf-c/issues/2177
re: https://github.com/Unidata/netcdf-c/pull/2178

Provide get/set functions to store global data alignment
information and apply it when a file is created.

The api is as follows:
````
int nc_set_alignment(int threshold, int alignment);
int nc_get_alignment(int* thresholdp, int* alignmentp);
````

If defined, then for every file created opened after the call to
nc_set_alignment, for every new variable added to the file, the
most recently set threshold and alignment values will be applied
to that variable.

The nc_get_alignment function return the last values set by
nc_set_alignment.  If nc_set_alignment has not been called, then
it returns the value 0 for both threshold and alignment.

The alignment parameters are stored in the NCglobalstate object
(see below) for use as needed. Repeated calls to nc_set_alignment
will overwrite any existing values in NCglobalstate.

The alignment parameters are applied in libhdf5/hdf5create.c
and libhdf5/hdf5open.c

The set/get alignment functions are defined in libsrc4/nc4internal.c.

A test program was added as nc_test4/tst_alignment.c.

## Misc. Changes Unrelated to Alignment

* The NCRCglobalstate type was renamed to NCglobalstate to
  indicate that it represented more general global state than
  just .rc data.  It was also moved to nc4internal.h.  This led
  to a large number of small changes: mostly renaming. The
  global state management functions were moved to nc4internal.c.

* The global chunk cache variables have been moved into
  NCglobalstate.  As warranted, other global state will be moved
  as well.

* Some misc. problems with the nczarr performance tests were corrected.
2022-01-29 15:27:52 -07:00
Ward Fisher
34b096515c Dangling undefined references to nulldup. These should be unified in a header, but that is a separate issue to open/resolve. For now, resolving these as part of getting mingw/msys2-based github actions working. 2022-01-24 13:48:41 -07:00
Dennis Heimbigner
9380790ea8 Support MSYS2/Mingw platform
re:

The current netcdf-c release has some problems with the mingw platform
on windows. Mostly they are path issues.

Changes to support mingw+msys2:
-------------------------------
* Enable option of looking into the windows registry to find
  the mingw root path. In aid of proper path handling.
* Add mingw+msys as a specific platform in configure.ac and move testing
  of the platform to the front so it is available early.
* Handle mingw X libncpoco (dynamic loader) properly even though
  mingw does not yet support it.
* Handle mingw X plugins properly even though mingw does not yet support it.
* Alias pwd='pwd -W' to better handle paths in shell scripts.
* Plus a number of other minor compile irritations.
* Disallow the use of multiple nc_open's on the same file for windows
  (and mingw) because windows does not seem to handle these properly.
  Not sure why we did not catch this earlier.
* Add mountpoint info to dpathmgr.c to help support mingw.
* Cleanup dpathmgr conversions.

Known problems:
---------------
* I have not been able to get shared libraries to work, so
  plugins/filters must be disabled.
* There is some kind of problem with libcurl that I have not solved,
  so all uses of libcurl (currently DAP+Byterange) must be disabled.

Misc. other fixes:
------------------
* Cleanup the relationship between ENABLE_PLUGINS and various other flags
  in CMakeLists.txt and configure.ac.
* Re-arrange the TESTDIRS order in Makefile.am.
* Add pseudo-breakpoint to nclog.[ch] for debugging.
* Improve the documentation of the path manager code in ncpathmgr.h
* Add better support for relative paths in dpathmgr.c
* Default the mode args to NCfopen to include "b" (binary) for windows.
* Add optional debugging output in various places.
* Make sure that everything builds with plugins disabled.
* Fix numerous (s)printf inconsistencies betweenb the format spec
  and the arguments.
2021-12-23 22:18:56 -07:00
Dennis Heimbigner
55a2643cac Fix a number of OS specific bugs
1. Issue https://github.com/Unidata/netcdf-c/issues/2043
   * FreeBSD build fails because of conflicts in defining the fileno() function. So removed all extern declarations of fileno.

2. Issue https://github.com/Unidata/netcdf-c/issues/2124
   * There were a couple of problems here.
     * I was conflating msys with mingw and they need separate handling of paths. So treat mingw like windows.
     * memio.c was not always writing the full content of the memory to file. Untested fix by properly accounting for zero size writes.
     * Fix bug when skipping white space in tst_xcache.c

3. Issue https://github.com/Unidata/netcdf-c/pull/2105
   * On MINGW, bash and other POSIX utilities use a mounted root directory,
     but executables compiled for Windows do not recognise the mount point.
     Ensure that Windows paths are used in tests of Windows executables.

4. Issue https://github.com/Unidata/netcdf-c/issues/2132
   * Apparently the Intel C compiler on OSX defines isnan etc.
     So disable declaration in dutil.c under that condition.

5. Fix and re-enable test_rcmerge.sh by allowing override of where to
   look for .rc files

6. CMakeLists.txt suppresses certain ncdump directory tests because of differences in printing floats/doubles.
   * Extend the list to include those that also fail under mingw.
   * Suppress the mingw tests in ncdump/Makefile.am
2021-11-03 12:49:54 -06:00
Dennis Heimbigner
f6e25b695e Fix additional S3 support issues
re: https://github.com/Unidata/netcdf-c/issues/2117
re: https://github.com/Unidata/netcdf-c/issues/2119

* Modify libsrc to allow byte-range reading of netcdf-3 files in private S3 buckets; this required using the aws sdk. Also add a test case.
* The aws sdk can sometimes cause problems if the Awd::ShutdownAPI function is not called. So at optional atexit() support to ensure it is called. This is disabled for Windows.
* Add documentation to nczarr.md on how to build and use the aws sdk under windows. Currently it builds, but testing fails.
* Switch testing from stratus to the Unidata bucket on S3.
* Improve support for the s3: url protocol.
* Add a s3 specific utility code file: ds3util.c
* Modify NC_infermodel to attempt to read the magic number of byte-ranged files in S3.

## Misc.

* Move and rename the core S3 SDK wrapper code (libnczarr/zs3sdk.cpp) to libdispatch since it now used in libsrc as well as libnczarr.
* Add calls to nc_finalize in the utilities in case atexit is disabled.
* Add header only json parser to the distribution rather than as a built source.
2021-10-29 20:06:37 -06:00
Dennis Heimbigner
6b69b9c52c Significantly Improve Amazon S3 Cloud Storage Support
## S3 Related Fixes

* Add comprehensive support for specifying AWS profiles to provide access credentials.
* Parse the files "~/.aws/config" and "~/.aws/credentials to provide credentials for the HDF5 ROS3 driver and to locate default region.
* Add a function to obtain the currently active S3 credentials. The search rules are defined in docs/nczarr.md.
* Provide documentation for the new features.
* Modify the struct NCauth (in include/ncauth.h) to replace specific S3 credentials with a profile name.
* Add a unit test to test the operation of profile and credentials management.
* Add support for URLS of the form "s3://<bucket>/<key>"; this requires obtaining a default region.
* Allows the specification of profile and/or region in a URL of the form "#mode=nczarr,...&aws.region=...&aws.profile=..."

## Misc. Fixes

* Move the ezxml code to libdispatch so that it can be used both by DAP4 and nczarr.
* Modify nclist to provide a deep clone operation.
* Modify ncuri to provide a deep clone operation.
* Modify the .rc file format to allow the specification of a path to be tested when looking for an entry in the .rc file.
* Ensure that the NC_rcload function is called.
* Modify nchttp to support setting request headers.
2021-09-27 18:36:33 -06:00
Dennis Heimbigner
6901206927 Regularize the semantics of mkstemp.
re: https://github.com/Unidata/netcdf-c/issues/1827

The issue is partly resolved by this PR. The proximate problem appears to be that the semantics of mkstemp in **nix is different than the semantics of _mktemp_s in Windows. I had thought they were the same but that is incorrect. The _mktemp_s function will only produce 26 different files and so the netcdf temp file code will fail after about that many iterations.

So, to solve this, I created my own version of mkstemp for windows that uses a random number generator. This appears to solve the reported issue.  I also added the testcase ncdap_test/test_manyurls but made it conditional on --enable-dap-long-tests because it is very slow.

I did note that the provided test program now fails after some 800 iterations with a libcurl error claiming it cannot resolve the host name. My belief is that the library is just running out of resources at this point: too many open curl handles or some such. I doubt if this failure is fixable.

So bottom line is that it is really important to do nc_close when you are finished with a file.

Misc. Other Changes:

1. I took the opportunity to clean up some bad string hacks in the code. Specifically
    * change all uses of strncat to strlcat
    * remove old string hacks: occoncat and occopycat
2. Add heck to see if test.opendap.org is running and if not, then skip test
3. Make CYGWIN use TEMP environment variable
2021-05-14 11:33:03 -06:00
Dennis Heimbigner
efd1be5d62 Fix shell handling of escapes
re: https://github.com/Unidata/netcdf-c/issues/1988

There was an issue with certain shell programs (bash notably).
For certain platforms and when given a url that had an escaped
'#' character (e.g. \\#) bash would not remove the backslash. So I
had to add a hack for this. Unfortunately I overdid it and it
removed all '' characters. This is ok for non-windows platforms,
but obviously fails for windows.

The fix is this.

1. In a utility program (ncgen, ncdump, nccopy, etc) there is probably a call (or calls) to NC_backslashUnescape(xxx) where xxx is a path argument from the command line.
2. Replace each such call with NC_shellUnescape(xxx).

The NC_shellUnescape function was added and searched only for occurrences of "\#" and replaces them with "#".
2021-04-21 14:59:15 -06:00
Dennis Heimbigner
0b7a5382e7 Codify cross-platform file paths
The netcdf-c code has to deal with a variety of platforms:
Windows, OSX, Linux, Cygwin, MSYS, etc.  These platforms differ
significantly in the kind of file paths that they accept.  So in
order to handle this, I have created a set of replacements for
the most common file system operations such as _open_ or _fopen_
or _access_ to manage the file path differences correctly.

A more limited version of this idea was already implemented via
the ncwinpath.h and dwinpath.c code. So this can be viewed as a
replacement for that code. And in path in many cases, the only
change that was required was to replace '#include <ncwinpath.h>'
with '#include <ncpathmgt.h>' and then replace file operation
calls with the NCxxx equivalent from ncpathmgr.h Note that
recently, the ncwinpath.h was renamed ncpathmgmt.h, so this pull
request should not require dealing with winpath.

The heart of the change is include/ncpathmgmt.h, which provides
alternate operations such as NCfopen or NCaccess and which properly
parse and rebuild path arguments to work for the platform on which
the code is executing. This mostly matters for Windows because of the
way that it uses backslash and drive letters, as compared to *nix*.
One important feature is that the user can do string manipulations
on a file path without having to worry too much about the platform
because the path management code will properly handle most mixed cases.
So one can for example concatenate a path suffix that uses forward
slashes to a Windows path and have it work correctly.

The conversion code is in libdispatch/dpathmgr.c, and the
important function there is NCpathcvt which does the proper
conversions to the local path format.

As a rule, most code should just replace their file operations with
the corresponding NCxxx ones defined in include/ncpathmgmt.h. These
NCxxx functions all call NCpathcvt on their path arguments before
executing the actual file operation.

In some rare cases, the client may need to directly use NCpathcvt,
but this should be avoided as much as possible. If there is a need
for supporting a new file operation not already in ncpathmgmt.h, then
use the code in dpathmgr.c as a template. Also please notify Unidata
so we can include it as a formal part or our supported operations.
Also, if you see an operation in the library that is not using the
NCxxx form, then please submit an issue so we can fix it.

Misc. Changes:
* Clean up the utf8 testing code; it is impossible to get some
  tests to work under windows using shell scripts; the args do
  not pass as utf8 but as some other encoding.
* Added an extra utf8 test case: test_unicode_path.sh
* Add a true test for HDF5 1.10.6 or later because as noted in
  PR https://github.com/Unidata/netcdf-c/pull/1794,
  HDF5 changed its Windows file path handling.
2021-03-04 13:41:31 -07:00
Dennis Heimbigner
25d2e05444 Prepare for the path management code
Rename some files in prep for eventual implementation
of more comprehensive cross-platform file path management.
2020-10-13 19:12:15 -06:00
Ward Fisher
31dee0c4da
Revert "Revert "Fix nczarr-experimental: improve build support, disengage hdf5 vs netcdf4 flags, and find AWS libraries"" 2020-08-17 19:15:47 -06:00
Ward Fisher
16c27ca13f
Revert "Fix nczarr-experimental: improve build support, disengage hdf5 vs netcdf4 flags, and find AWS libraries" 2020-08-17 15:51:01 -06:00
Dennis Heimbigner
931f6d0ad4 Define isnan and isinf for OSX 2020-08-04 19:22:42 -06:00
Dennis Heimbigner
59e04ae071 This PR adds EXPERIMENTAL support for accessing data in the
cloud using a variant of the Zarr protocol and storage
format. This enhancement is generically referred to as "NCZarr".

The data model supported by NCZarr is netcdf-4 minus the user-defined
types and the String type. In this sense it is similar to the CDF-5
data model.

More detailed information about enabling and using NCZarr is
described in the document NUG/nczarr.md and in a
[Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in).

WARNING: this code has had limited testing, so do use this version
for production work. Also, performance improvements are ongoing.
Note especially the following platform matrix of successful tests:

Platform | Build System | S3 support
------------------------------------
Linux+gcc      | Automake     | yes
Linux+gcc      | CMake        | yes
Visual Studio  | CMake        | no

Additionally, and as a consequence of the addition of NCZarr,
major changes have been made to the Filter API. NOTE: NCZarr
does not yet support filters, but these changes are enablers for
that support in the future.  Note that it is possible
(probable?) that there will be some accidental reversions if the
changes here did not correctly mimic the existing filter testing.

In any case, previously filter ids and parameters were of type
unsigned int. In order to support the more general zarr filter
model, this was all converted to char*.  The old HDF5-specific,
unsigned int operations are still supported but they are
wrappers around the new, char* based nc_filterx_XXX functions.
This entailed at least the following changes:
1. Added the files libdispatch/dfilterx.c and include/ncfilter.h
2. Some filterx utilities have been moved to libdispatch/daux.c
3. A new entry, "filter_actions" was added to the NCDispatch table
   and the version bumped.
4. An overly complex set of structs was created to support funnelling
   all of the filterx operations thru a single dispatch
   "filter_actions" entry.
5. Move common code to from libhdf5 to libsrc4 so that it is accessible
   to nczarr.

Changes directly related to Zarr:
1. Modified CMakeList.txt and configure.ac to support both C and C++
   -- this is in support of S3 support via the awd-sdk libraries.
2. Define a size64_t type to support nczarr.
3. More reworking of libdispatch/dinfermodel.c to
   support zarr and to regularize the structure of the fragments
   section of a URL.

Changes not directly related to Zarr:
1. Make client-side filter registration be conditional, with default off.
2. Hack include/nc4internal.h to make some flags added by Ed be unique:
   e.g. NC_CREAT, NC_INDEF, etc.
3. cleanup include/nchttp.h and libdispatch/dhttp.c.
4. Misc. changes to support compiling under Visual Studio including:
   * Better testing under windows for dirent.h and opendir and closedir.
5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags
   and to centralize error reporting.
6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them.
7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible.

Changes Left TO-DO:
1. fix provenance code, it is too HDF5 specific.
2020-06-28 18:02:47 -06:00
Dennis Heimbigner
44d0dcaad2 Add support for multiple filters per variable.
re: https://github.com/Unidata/netcdf-c/issues/1584

Support has been added for multiple filters per variable.  This
affects a number of components in netcdf. The new APIs are
documented in NUG/filters.md.

The primary changes are:
* A set of new functions are provided (see __include/netcdf_filter.h__).
    - Obtain a list of the filters associated with a variable
    - Obtain the parameters for a specific filter.
* The existing __nc_inq_var_filter__ function now returns info
  about the first defined filter.
* The utilities (ncgen, ncdump, and nccopy) now support
  an extended format for specifying a sequence of filters.
  The general form is __<filter>|<filter>..._.
* The ncdump **_Filter** attribute now dumps a list of all the
  filters associated with a variable using the above new format.
* Filter specifications can now use a filter name instead of number
  for filters known to the netcdf library, which in turn is taken
  from the HDF5 filter registration page.
* New errors are defined: NC_EFILTER and NC_ENOFILTER. The latter
  is returned if an attempt is made to access an unknown filter.
* Internally, the dispatch table has been extended to add a function
  to handle all of the filter functions.
* New, filter-related, tests were added to nc_test4.
* A new plugin was added to the plugins directory to help with testing.

Notes:
1. The shuffle and fletcher32 filters are not part of the multifilter system.

Misc. changes:
1. A debug module was added to libhdf5 to help catch error locations.
2020-02-16 12:59:33 -07:00
Dennis Heimbigner
f1506d552e Change (again), and hopefully simplify, the file model inference algorithm.
* For URL paths, the new approach essentially centralizes all information
  in the URL into the "#mode=" fragment key and uses that value
  to determine the dispatcher for (most) URLs.

* The new approach has the following steps:

  1. canonicalize the path if it is a URL.
  2. use the mode= fragment key to determine the dispatcher
  3. if dispatcher still not determined, then use the mode flags
     argument to nc_open/nc_create to determine the dispatcher.
  4. if the path points to something readable, attempt to read the
     magic number at the front, and use that to determine the dispatcher.
     this case may override all previous cases.

* Misc changes.

  1. Update documentation
  2. Moved some unit tests from libdispatch to unit_test directory.
  3. Fixed use of wrong #ifdef macro in test_filter_reg.c
     [I think this may fix an previously reported esupport query].
2019-09-29 12:59:28 -06:00
Ward Fisher
688c06d50c
Merge branch 'master' into fix-warnings 2019-01-23 15:12:20 -07:00
Ben Boeckel
94a0259f0e NC_mktmp: pass the remaining space to strncat
This could overflow if `tmp` only had a few bytes left in its space
given its current contents.
2019-01-16 15:55:33 -05:00
Dennis Heimbigner
735ae80928 merge master and fix conflicts 2018-12-12 11:47:54 -07:00
Ward Fisher
25417880f7 Updated libdispatch/ files with copyright notice. 2018-12-06 14:29:57 -07:00
Dennis Heimbigner
1a7531392f Make the netcdf-c library compile with gcc -ansi.
Primary fixes to get -ansi to work.
1. Convert all '//' C++ style comments to /*...*/ or to use #if 0...#endif
2. It turns out that when -ansi is specified, then a number of
   functions no longer are defined in the header -- but they are still
   in the .so file.<br>
   The big example is strdup(). So, added code to include/ncconfig.h to define
   externs for those missing functions that occur in more than one place.
   These are enabled if !_WIN32 && __STDC__ == 1 (__STDC__ is supposed to
   be the equivalent compile time flag to -ansi). Note that this requires
   config.h (which references ncconfig.h) to be included in files where it is
   currently not included. Single uses will be only in the file that uses them.
3. Added mmap test for the MAP_ANONYMOUS flag to configure.ac. Apparently
   this is not always defined with -ansi.
4. fix some large integer constants in nc_test4/tst_atts3.c and nc_test4/tst_filterparser.c
   to avoid compiler complaints.
5. fix a double constant in nc_test4/tst_filterparser.c to avoid compiler complaints.

[Note I suspect #4 and #5 will be a problem on big-endian machines, but we have no way to test]

Misc. Changes:
1. convert more instances of _MSC_VER to _WIN32.
2. added some debugging code to include/nctestserver.h
3. added comment about libdispatch/drc.c always being compiled.
4. modify parser generation in ncgen to remove unneeded files.
2018-12-05 19:20:43 -07:00
Dennis Heimbigner
4636584d5b Revert/Improve nc_create + NC_DISKLESS behavior
re: https://github.com/Unidata/netcdf-c/issues/1154

Inadvertently, the behavior of NC_DISKLESS with nc_create() was
changed in release 4.6.1. Previously, the NC_WRITE flag needed
to be explicitly used with NC_DISKLESS in order to cause the
created file to be persisted to disk.

Additional analyis indicated that the current NC_DISKLESS
implementation was seriously flawed.

This PR attempts to clean up and regularize the situation with
respect to NC_DISKLESS control. One important aspect of diskless
operation is that there are two different notions of write.

1. The file is read-write vs read-only when using the netcdf API.
2. The file is persisted or not to disk at nc_close().

Previously, these two were conflated. The rules now are
as follows.

1. NC_DISKLESS + NC_WRITE means that the file is read/write using the netcdf API
2. NC_DISKLESS + NC_PERSIST means that the file is persisted to a disk file at nc_close.
3. NC_DISKLESS + NC_PERSIST + NC_WRITE means both 1 and 2.

The NC_PERSIST flag is new and takes over the obsolete NC_MPIPOSIX flag.
NC_MPIPOSIX is still defined, but is now an alias for the NC_MPIIO flag.

It is also now the case that for netcdf-4, NC_DISKLESS is independent
of NC_INMEMORY and in fact it is an error to specify both flags
simultaneously.

Finally, the MMAP code was fixed to use NC_PERSIST as well.
Also marked MMAP as deprecated.

Also added a test case to test various combinations of NC_DISKLESS,
NC_PERSIST, and NC_WRITE.

This PR affects a number of files and especially test cases
that used NC_DISKLESS.

Misc. Unrelated fixes
1. fixed some warnings in ncdump/dumplib.c
2018-10-10 13:32:17 -06:00
Dennis Heimbigner
ccc70d640b re: esupport MQO-415619
and https://github.com/Unidata/netcdf-c/issues/708

Expand the NC_INMEMORY capabilities to support writing and accessing
the final modified memory.

Three new functions have been added:
nc_open_memio, nc_create_mem, and nc_close_memio.

The following new capabilities were added.
1. nc_open_memio() allows the NC_WRITE mode flag
   so a chunk of memory can be passed in and be modified
2. nc_create_mem() allows the NC_INMEMORY flag to be set
   to cause the created file to be kept in memory.
3. nc_close_mem() allows the final in-memory contents to be
   retrieved at the time the file is closed.
4. A special flag, NC_MEMIO_LOCK, is provided to ensure that
   the provided memory will not be freed or reallocated.

Note the following.
1. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is not set,
   then the netcdf-c library will take control of the incoming memory.
   This means that the original memory block should not be freed
   but the block returned by nc_close_mem() must be freed.
2. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is set,
   then modifications to the original memory may fail if the space available
   is insufficient.

Documentation is provided in the file docs/inmemory.md.
A test case is provided: nc_test/tst_inmemory.c driven by
nc_test/run_inmemory.sh

WARNING: changes were made to the dispatch table for
the close entry. From int (*close)(int) to int (*close)(int,void*).
2018-02-25 21:45:31 -07:00
Greg Sjaardema
cdec707429
Eliminate potential buffer overflow
I realize strncat is being eliminated, but in case the elimination isn't done prior to release, this patch should be applied.
2018-01-11 10:28:18 -07:00
Dennis Heimbigner
4db4393e69 Begin changing over to use strlcat instead of strncat because
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.
2017-11-23 10:55:24 -07:00
Dennis Heimbigner
a2e0f069ec This pr should probably be delayed until after Version 4.5.
Primary change is to cleanup code and remove duplicated code.

1. Unify the rc file reading into libdispatch/drc.c. Eventually extend
   if we need rc file for netcdf itself as opposed to the dap code.
2. Unify the extraction from the rc file of DAP authorization info.
3. Misc. other small unifications: make temp file, read file.
4. Avoid use of libcurl when reading file:// because
   there is some kind of problem with the Visual Studio version.
   Might be related to the winpath problem.
   In any case, do direct read instead.
5. Add new error code NC_ERCFILE for errors in reading RC file.
6. Complete documentation cleanup as indicated in this comment
   https://github.com/Unidata/netcdf-c/pull/472#issuecomment-325926426
7. Convert some occurrences of #ifdef _WIN32 to #ifdef _MSC_VER
2017-09-02 18:09:36 -06:00
Dennis Heimbigner
a17fa2ed2a add dutil.c 2017-08-31 14:36:54 -06:00