StdLib/LibC/Uefi/InteractiveIO/CanonRead.c

   1 /** @file
   2   Canonical Interactive Input Function.
   3
   4   The functions assume that isatty() is TRUE at the time they are called.
   5
   6   Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php.
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14 **/
  15 #include  <Uefi.h>
  16
  17 #include  <LibConfig.h>
  18
  19 #include  <errno.h>
  20 #include  <sys/syslimits.h>
  21 #include  <sys/termios.h>
  22 #include  <Device/IIO.h>
  23 #include  <MainData.h>
  24 #include  "IIOutilities.h"
  25 #include  "IIOechoCtrl.h"
  26
  27 /** Read a line from the input file in canonical mode.
  28     Perform echoing and input processing as directed by the termios flags.
  29
  30     @param[in]    filp      A pointer to a file descriptor structure.
  31
  32     @return     The number of characters in the input buffer, or -1 if there
  33                 was an error.
  34 **/
  35 ssize_t
  36 IIO_CanonRead (
  37   struct __filedes *filp
  38   )
  39 {
  40   cIIO             *This;
  41   cFIFO            *InBuf;
  42   struct termios   *Termio;
  43   struct __filedes *fpOut;
  44   size_t            NumRead;
  45   wint_t            InChar;
  46   tcflag_t          IFlag;
  47   tcflag_t          LFlag;
  48   BOOLEAN           EchoIsOK;
  49   BOOLEAN           Activate;
  50   BOOLEAN           FirstRead;
  51   int               OutMode;
  52   UINTN             MaxColumn;
  53   UINTN             MaxRow;
  54
  55   NumRead   = MAX_INPUT;    // Workaround "potentially uninitialized" warning
  56   EchoIsOK  = FALSE;
  57   FirstRead = TRUE;
  58   This      = filp->devdata;
  59   Termio    = &This->Termio;
  60   InBuf     = This->InBuf;
  61
  62   // Get a copy of the flags we are going to use
  63   IFlag = Termio->c_iflag;
  64   LFlag = Termio->c_lflag;
  65
  66   /* Determine what the current screen size is. Also validates the output device. */
  67   OutMode = IIO_GetOutputSize(STDOUT_FILENO, &MaxColumn, &MaxRow);
  68   if(OutMode >= 0) {
  69     /*  Set the maximum screen dimensions. */
  70     This->MaxColumn = MaxColumn;
  71     This->MaxRow    = MaxRow;
  72
  73     /*  Record where the cursor is at the beginning of this Input operation.
  74         The currently set stdout device is used to determine this.  If there is
  75         no stdout, or stdout is not an interactive device, nothing is recorded.
  76     */
  77     if (IIO_GetCursorPosition(STDOUT_FILENO, &This->InitialXY.Column, &This->InitialXY.Row) >= 0) {
  78       This->CurrentXY.Column  = This->InitialXY.Column;
  79       This->CurrentXY.Row     = This->InitialXY.Row;
  80       EchoIsOK  = TRUE;   // Can only echo to stdout
  81     }
  82   }
  83
  84   // For now, we only echo to stdout.
  85   fpOut = &gMD->fdarray[STDOUT_FILENO];
  86
  87   //  Input and process characters until BufferSize is exhausted.
  88   do {
  89     InChar = IIO_GetInChar(filp, FirstRead);
  90     FirstRead = FALSE;
  91     Activate  = TRUE;
  92     if(InChar == CHAR_CARRIAGE_RETURN) {
  93       if((IFlag & IGNCR) != 0) {
  94         continue;   // Restart the do loop, discarding the CR
  95       }
  96       else if((IFlag & ICRNL) != 0) {
  97         InChar = L'\n';
  98       }
  99     }
 100     else if(InChar == CHAR_LINEFEED) {
 101       if((IFlag & INLCR) != 0) {
 102         InChar = L'\r';
 103       }
 104     }
 105     else if(CCEQ(Termio->c_cc[VINTR], InChar)) {
 106       if((LFlag & ISIG) != 0) {
 107         // Raise Signal
 108         // Flush Input Buffer
 109         // Return to caller
 110         InChar = IIO_ECHO_DISCARD;
 111         errno = EINTR;
 112       }
 113       else {
 114         Activate = FALSE;
 115       }
 116     }
 117     else if(CCEQ(Termio->c_cc[VQUIT], InChar)) {
 118       if((LFlag & ISIG) != 0) {
 119         // Raise Signal
 120         // Flush Input Buffer
 121         // Return to caller
 122         InChar = IIO_ECHO_DISCARD;
 123         errno = EINTR;
 124       }
 125       else {
 126         Activate = FALSE;
 127       }
 128     }
 129     else if(CCEQ(Termio->c_cc[VEOF], InChar)) {
 130       InChar = WEOF;
 131     }
 132     else if(CCEQ(Termio->c_cc[VEOL], InChar)) {
 133       EchoIsOK = FALSE;   // Buffer, but don't echo this character
 134     }
 135     else if(CCEQ(Termio->c_cc[VERASE], InChar)) {
 136       InChar = IIO_ECHO_ERASE;
 137       Activate = FALSE;
 138     }
 139     else if(CCEQ(Termio->c_cc[VKILL], InChar)) {
 140       InChar = IIO_ECHO_KILL;
 141       Activate = FALSE;
 142     }
 143     else {
 144       if((InChar < TtySpecKeyMin) || (InChar >= TtyFunKeyMax)) {
 145         Activate = FALSE;
 146       }
 147     }
 148     /** The Echo function is responsible for:
 149           * Adding the character to the input buffer, if appropriate.
 150           * Removing characters from the input buffer for ERASE and KILL processing.
 151           * Visually removing characters from the screen if ECHOE is set.
 152           * Ensuring one can not backspace beyond the beginning of the input text.
 153           * Sending final echo strings to output.
 154     **/
 155     (void)This->Echo(fpOut, (wchar_t)InChar, EchoIsOK);
 156     NumRead = InBuf->Count(InBuf, AsElements);
 157   } while((NumRead < MAX_INPUT) &&
 158           (Activate == FALSE));
 159
 160   return (ssize_t)NumRead;
 161 }