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winerror_to_errno implementation #81886

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eryksun opened this issue Jul 29, 2019 · 10 comments
Closed

winerror_to_errno implementation #81886

eryksun opened this issue Jul 29, 2019 · 10 comments
Labels
3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) OS-windows type-feature A feature request or enhancement

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@eryksun
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eryksun commented Jul 29, 2019

BPO 37705
Nosy @pfmoore, @tjguk, @zware, @eryksun, @zooba, @ZackerySpytz, @miss-islington, @arhadthedev
PRs
  • bpo-37705: Improve the implementation of winerror_to_errno() #15623
  • [3.8] bpo-37705: Improve the implementation of winerror_to_errno() (GH-15623) #15749
  • [3.7] bpo-37705: Improve the implementation of winerror_to_errno() (GH-15623) #15750
  • bpo-37705: Remove orphaned PC/errmap.mak #29724
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
    closed_at = <Date 2019-09-09.12:17:30.886>
    created_at = <Date 2019-07-29.13:41:00.656>
    labels = ['interpreter-core', '3.7', '3.8', '3.9', 'type-feature', 'OS-windows']
    title = 'winerror_to_errno implementation'
    updated_at = <Date 2022-02-02.16:23:46.658>
    user = 'https://github.com/eryksun'

    bugs.python.org fields:

    activity = <Date 2022-02-02.16:23:46.658>
    actor = 'miss-islington'
    assignee = 'none'
    closed = True
    closed_date = <Date 2019-09-09.12:17:30.886>
    closer = 'steve.dower'
    components = ['Interpreter Core', 'Windows']
    creation = <Date 2019-07-29.13:41:00.656>
    creator = 'eryksun'
    dependencies = []
    files = []
    hgrepos = []
    issue_num = 37705
    keywords = ['patch']
    message_count = 10.0
    messages = ['348661', '348768', '350552', '350585', '350889', '351378', '351380', '351415', '351417', '412373']
    nosy_count = 8.0
    nosy_names = ['paul.moore', 'tim.golden', 'zach.ware', 'eryksun', 'steve.dower', 'ZackerySpytz', 'miss-islington', 'arhadthedev']
    pr_nums = ['15623', '15749', '15750', '29724']
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'enhancement'
    url = 'https://bugs.python.org/issue37705'
    versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

    @eryksun
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    eryksun commented Jul 29, 2019

    OSError and _Py_fstat_noraise rely on winerror_to_errno() in PC/errmap.h in order to translate a Windows system error code into a POSIX errno value. PC/errmap.h is supposed to be generated by PC/generrmap.c, which is based on the old CRT's _dosmapperr() function. However, this function isn't implemented in the Universal CRT, and ucrt's corresponding function, __acrt_errno_from_os_error, isn't exported for public use.

    If generrmap.c is effectively dead, then it's no longer possible to add custom mappings there, as was done for bpo-12802 (ERROR_DIRECTORY -> ENOTDIR) and bpo-13063 (ERROR_NO_DATA -> EPIPE). Also, errmap.h hasn't been regenerated in 8 years, and since then the CRT added a new mapped value: ERROR_NO_UNICODE_TRANSLATION (1113) -> EILSEQ.

    Unless someone can suggest a way to continue automatically generating errmap.h via generrmap.c, then I think winerror_to_errno should be manually implemented in a more readable and maintainable way, and updated from the ucrt source (ucrt\misc\errno.cpp) with each major Python release. The implementation could use a switch statement like it currently does, but with named error codes, grouped by result. For example:

        int
        winerror_to_errno(int winerror)
        {
            switch(winerror) {
            case ERROR_FILE_NOT_FOUND:            //    2
            case ERROR_PATH_NOT_FOUND:            //    3
            case ERROR_INVALID_DRIVE:             //   15
            case ERROR_NO_MORE_FILES:             //   18
            case ERROR_BAD_NETPATH:               //   53
            case ERROR_BAD_NET_NAME:              //   67
            case ERROR_BAD_PATHNAME:              //  161
            case ERROR_FILENAME_EXCED_RANGE:      //  206
                return ENOENT;
        case ERROR_BAD_ENVIRONMENT:           //   10
            return E2BIG;
    
        case ERROR_BAD_FORMAT:                //   11
        case ERROR_INVALID_STARTING_CODESEG:  //  188
        case ERROR_INVALID_STACKSEG:          //  189
        case ERROR_INVALID_MODULETYPE:        //  190
        case ERROR_INVALID_EXE_SIGNATURE:     //  191
        case ERROR_EXE_MARKED_INVALID:        //  192
        case ERROR_BAD_EXE_FORMAT:            //  193
        case ERROR_ITERATED_DATA_EXCEEDS_64k: //  194
        case ERROR_INVALID_MINALLOCSIZE:      //  195
        case ERROR_DYNLINK_FROM_INVALID_RING: //  196
        case ERROR_IOPL_NOT_ENABLED:          //  197
        case ERROR_INVALID_SEGDPL:            //  198
        case ERROR_AUTODATASEG_EXCEEDS_64k:   //  199
        case ERROR_RING2SEG_MUST_BE_MOVABLE:  //  200
        case ERROR_RELOC_CHAIN_XEEDS_SEGLIM:  //  201
        case ERROR_INFLOOP_IN_RELOC_CHAIN:    //  202
            return ENOEXEC;
    
        case ERROR_INVALID_HANDLE:            //    6
        case ERROR_INVALID_TARGET_HANDLE:     //  114
        case ERROR_DIRECT_ACCESS_HANDLE:      //  130
            return EBADF;
    
        case ERROR_WAIT_NO_CHILDREN:          //  128
        case ERROR_CHILD_NOT_COMPLETE:        //  129
            return ECHILD;
    
        case ERROR_NO_PROC_SLOTS:             //   89
        case ERROR_MAX_THRDS_REACHED:         //  164
        case ERROR_NESTING_NOT_ALLOWED:       //  215
            return EAGAIN;
    
        case ERROR_ARENA_TRASHED:             //    7
        case ERROR_NOT_ENOUGH_MEMORY:         //    8
        case ERROR_INVALID_BLOCK:             //    9
        case ERROR_NOT_ENOUGH_QUOTA:          // 1816
            return ENOMEM;
    
        case ERROR_ACCESS_DENIED:             //    5
        case ERROR_CURRENT_DIRECTORY:         //   16
        case ERROR_WRITE_PROTECT:             //   19
        case ERROR_BAD_UNIT:                  //   20
        case ERROR_NOT_READY:                 //   21
        case ERROR_BAD_COMMAND:               //   22
        case ERROR_CRC:                       //   23
        case ERROR_BAD_LENGTH:                //   24
        case ERROR_SEEK:                      //   25
        case ERROR_NOT_DOS_DISK:              //   26
        case ERROR_SECTOR_NOT_FOUND:          //   27
        case ERROR_OUT_OF_PAPER:              //   28
        case ERROR_WRITE_FAULT:               //   29
        case ERROR_READ_FAULT:                //   30
        case ERROR_GEN_FAILURE:               //   31
        case ERROR_SHARING_VIOLATION:         //   32
        case ERROR_LOCK_VIOLATION:            //   33
        case ERROR_WRONG_DISK:                //   34
        case ERROR_SHARING_BUFFER_EXCEEDED:   //   36
        case ERROR_NETWORK_ACCESS_DENIED:     //   65
        case ERROR_CANNOT_MAKE:               //   82
        case ERROR_FAIL_I24:                  //   83
        case ERROR_DRIVE_LOCKED:              //  108
        case ERROR_SEEK_ON_DEVICE:            //  132
        case ERROR_NOT_LOCKED:                //  158
        case ERROR_LOCK_FAILED:               //  167
        case 35:                              //   35 [undefined]
            return EACCES;
    
        case ERROR_FILE_EXISTS:               //   80
        case ERROR_ALREADY_EXISTS:            //  183
            return EEXIST;
    
        case ERROR_NOT_SAME_DEVICE:           //   17
            return EXDEV;
    
        case ERROR_DIRECTORY:                 //  267 [bpo-12802]
            return ENOTDIR;
    
        case ERROR_TOO_MANY_OPEN_FILES:       //    4
            return EMFILE;
    
        case ERROR_DISK_FULL:                 //  112
            return ENOSPC;
    
        case ERROR_BROKEN_PIPE:               //  109
        case ERROR_NO_DATA:                   //  232 [bpo-13063]
            return EPIPE;
    
        case ERROR_DIR_NOT_EMPTY:             //  145
            return ENOTEMPTY;
    
        case ERROR_NO_UNICODE_TRANSLATION:    // 1113
            return EILSEQ;
    
            case ERROR_INVALID_FUNCTION:          //    1
            case ERROR_INVALID_ACCESS:            //   12
            case ERROR_INVALID_DATA:              //   13
            case ERROR_INVALID_PARAMETER:         //   87
            case ERROR_NEGATIVE_SEEK:             //  131
            default:
                return EINVAL;
            }
        }

    @eryksun eryksun added 3.8 only security fixes 3.9 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) OS-windows type-feature A feature request or enhancement labels Jul 29, 2019
    @eryksun
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    eryksun commented Jul 30, 2019

    Special casing of Winsock error codes should be handled in winerror_to_errno rather than in oserror_parse_args, so it's consistently applied everywhere. And it should use the proper range for Winsock, 10000-11999 -- not 10000-2147483647. Codes above the Winsock range should map to EINVAL. It's not a non-issue since this range has the following blocks allocated:

    IPSEC     13000-13999
    SXS       14000-14999
    EVT       15000-15079
    EC        15080-15099
    MUI       15100-15199
    MCA       15200-15249
    SYSPART   15250-15299
    VORTEX    15300-15320
    GPIO      15321-15340
    RUNLEVEL  15400-15500
    COMTASK   15501-15510
    APPX      15600-15699
    APPMODEL  15700-15720
    APPXSTATE 15800-15840
    API       15841-15860
    STORE     15861-15880
    

    Another thing winerror_to_errno should do is unwrap HRESULT codes for Win32 errors (0x80070000-0x8007FFFF). In other words, 0x80070005 is effectively the same as ERROR_ACCESS_DENIED (5). It should be mapped to EACCES and raise PermissionError.

    For example:

        int
        winerror_to_errno(int winerror)
        {
            /* Unwrap FACILITY_WIN32 HRESULT errors. */
            if ((winerror & 0xFFFF0000) == 0x80070000) {
                winerror &= 0x0000FFFF;
            }
    
            /* Winsock error codes (10000-11999) are errno values. */
            if (winerror >= 10000 && winerror < 12000) {
                return winerror;
            }
    
            switch(winerror) {
            
            /* ... */
            
            }
        }

    @zooba
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    zooba commented Aug 26, 2019

    While I'm inclined to think it's okay to find the CRT sources (e.g. "C:\Program Files (x86)\Windows Kits\10\Source\10.0.18362.0\ucrt\misc\errno.cpp") and extract the table from there as part of build, the problem I have is that it is woefully incomplete.

    I'd much rather have a manually managed table. It'd also be nice to expose it through the errno module somehow, probably just as a dict.

    It also seems like at least some of the WSA* constants (e.g. WSAEBADF==10009) are the equivalent errno plus 10000 (e.g.EBADF==9). Should we be mapping those back to the errno value?

    @eryksun
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    eryksun commented Aug 27, 2019

    It also seems like at least some of the WSA* constants (e.g.
    WSAEBADF==10009) are the equivalent errno plus 10000
    (e.g.EBADF==9). Should we be mapping those back to the
    errno value?

    Mapping WSAEINTR (10004) -> EINTR (4) and WSAEACCES (10013) -> EACCES (13) would allow special casing them as InterruptedError and PermissionError. This is different from the aliases such as EWOULDBLOCK = WSAEWOULDBLOCK, but it should be fine since the six affected values are singled out in WinSock2.h as C errno values.

    So the Winsock section becomes a switch:

            /* Winsock error codes (10000-11999) are errno values. */
            if (winerror >= 10000 && winerror < 12000) {
                switch(winerror) {
                case WSAEINTR:
                case WSAEBADF:
                case WSAEACCES:
                case WSAEFAULT:
                case WSAEINVAL:
                case WSAEMFILE:
                    /* Winsock definitions of errno values. See WinSock2.h */
                    return winerror - 10000;
                default:
                    return winerror;
                }
            }

    @ZackerySpytz
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    ZackerySpytz mannequin commented Aug 30, 2019

    I have created a pull request for this issue. Please take a look.

    @ZackerySpytz ZackerySpytz mannequin removed the 3.8 only security fixes label Aug 30, 2019
    @zooba
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    zooba commented Sep 9, 2019

    I'm going to merge and backport this all the way to 3.7. Adding a publicly accessible dict for use in Python code should be 3.9 only.

    @zooba zooba added 3.7 (EOL) end of life 3.8 only security fixes labels Sep 9, 2019
    @zooba
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    zooba commented Sep 9, 2019

    New changeset 19052a1 by Steve Dower (Zackery Spytz) in branch 'master':
    bpo-37705: Improve the implementation of winerror_to_errno() (GH-15623)
    19052a1

    @miss-islington
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    New changeset 68e401f by Miss Islington (bot) in branch '3.8':
    bpo-37705: Improve the implementation of winerror_to_errno() (GH-15623)
    68e401f

    @miss-islington
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    New changeset c257591 by Miss Islington (bot) in branch '3.7':
    bpo-37705: Improve the implementation of winerror_to_errno() (GH-15623)
    c257591

    @zooba zooba closed this as completed Sep 9, 2019
    @miss-islington
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    New changeset 38e0b9e by Oleg Iarygin in branch 'main':
    bpo-37705: Remove orphaned PC/errmap.mak (GH-29724)
    38e0b9e

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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    Labels
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