| 0,0 → 1,140 |
|---|
| |
| #include "doserr.h" |
| #include "helpers.h" |
| |
| #include "redir.h" |
| |
| static unsigned short oldstdout = 0xffff; |
| |
| /* parse commandline and performs necessary redirections. cmdline is |
| * modified so all redirections are cut out. |
| * returns 0 on success, non-zero otherwise */ |
| int redir_parsecmd(char far *cmdline, char *BUFFER) { |
| unsigned short i; |
| unsigned short rediroffset_stdin = 0; |
| unsigned short rediroffset_stdout = 0; |
| unsigned short pipesoffsets[16]; |
| unsigned short pipescount = 0; |
| |
| /* NOTE: |
| * |
| * 1. while it is possible to type a command with multiple |
| * redirections, MSDOS executes only the last redirection. |
| * |
| * 2. the order in which >, < and | are provided on the command line does |
| * not seem to matter for MSDOS. piped commands are executed first (in |
| * the order they appear) and the result of the last one is redirected to |
| * whenever the last > points at. |
| */ |
| |
| /* preset oldstdout to 0xffff in case no redirection is required */ |
| oldstdout = 0xffff; |
| |
| for (i = 0;; i++) { |
| if (cmdline[i] == '>') { |
| cmdline[i] = 0; |
| rediroffset_stdout = i + 1; |
| } else if (cmdline[i] == '<') { |
| cmdline[i] = 0; |
| rediroffset_stdin = i + 1; |
| } else if (cmdline[i] == '|') { |
| cmdline[i] = 0; |
| pipesoffsets[pipescount++] = i + 1; |
| } else if (cmdline[i] == 0) { |
| break; |
| } |
| } |
| |
| if (rediroffset_stdin != 0) { |
| outputnl("ERROR: stdin redirection is not supported yet"); |
| return(-1); |
| } |
| |
| if (pipescount != 0) { |
| outputnl("ERROR: pipe redirections are not supported yet"); |
| return(-1); |
| } |
| |
| if (rediroffset_stdout != 0) { |
| unsigned short openflag = 0x12; /* used during the int 21h,ah=6c call */ |
| unsigned short errcode = 0; |
| unsigned short handle = 0; |
| char far *ptr; |
| /* append? */ |
| if (cmdline[rediroffset_stdout] == '>') { |
| openflag = 0x11; |
| rediroffset_stdout++; |
| } |
| |
| /* copy dst file to BUFFER */ |
| ptr = cmdline + rediroffset_stdout; |
| while (*ptr == ' ') ptr++; /* skip leading white spaces */ |
| for (i = 0;; i++) { |
| BUFFER[i] = ptr[i]; |
| if ((BUFFER[i] == ' ') || (BUFFER[i] == 0)) break; |
| } |
| BUFFER[i] = 0; |
| |
| /* */ |
| _asm { |
| push ax |
| push bx |
| push cx |
| push dx |
| push si |
| mov ax, 0x6c00 /* Extended Open/Create */ |
| mov bx, 1 /* access mode (0=read, 1=write, 2=r+w */ |
| xor cx, cx /* attributes when(if) creating the file (0=normal) */ |
| mov dx, [openflag] /* action if file exists (0x11=open, 0x12=truncate)*/ |
| mov si, BUFFER /* ASCIIZ filename */ |
| int 0x21 /* AX=handle on success (CF clear), otherwise dos err */ |
| mov [handle], ax /* save the file handler */ |
| jnc DUPSTDOUT |
| mov [errcode], ax |
| jmp DONE |
| DUPSTDOUT: |
| /* save (duplicate) current stdout so I can revert it later */ |
| mov ah, 0x45 /* duplicate file handle */ |
| mov bx, 1 /* handle to dup (1=stdout) */ |
| int 0x21 /* ax = new file handle */ |
| mov [oldstdout], ax |
| /* redirect the stdout handle */ |
| mov bx, [handle] /* dst handle */ |
| mov cx, 1 /* src handle (1=stdout) */ |
| mov ah, 0x46 /* redirect a handle */ |
| int 0x21 |
| /* close the original file handle (no longer needed) */ |
| mov ah, 0x3e /* close a file handle (handle in BX) */ |
| int 0x21 |
| DONE: |
| pop si |
| pop dx |
| pop cx |
| pop bx |
| pop ax |
| } |
| if (errcode != 0) { |
| outputnl(doserr(errcode)); |
| return(-1); |
| } |
| } |
| |
| return(0); |
| } |
| |
| |
| /* restores previous stdout/stdin handlers if they have been redirected */ |
| void redir_revert(void) { |
| _asm { |
| /* if oldstdout is 0xffff then not redirected */ |
| cmp word ptr [oldstdout], 0xffff |
| je DONE |
| /* redirect the stdout handle */ |
| mov bx, [oldstdout] /* dst handle */ |
| mov cx, 1 /* src handle (1=stdout) */ |
| mov ah, 0x46 /* redirect a handle */ |
| int 0x21 |
| mov [oldstdout], 0xffff |
| DONE: |
| } |
| } |