diff options
Diffstat (limited to 'msdos/is_exec.c')
| -rw-r--r-- | msdos/is_exec.c | 238 |
1 files changed, 0 insertions, 238 deletions
diff --git a/msdos/is_exec.c b/msdos/is_exec.c deleted file mode 100644 index 16b01c59a0b..00000000000 --- a/msdos/is_exec.c +++ /dev/null @@ -1,238 +0,0 @@ -/* IS_EXEC.C - * - * Copyright (C) 1995 DJ Delorie - * Copyright (C) 1994 Eli Zaretskii <eliz@is.elta.co.il> - * - * (See the README file in this directory for the copyright and license - * history of this file.) - * - * This file is free software: you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation, either version 3 of the License, or - * (at your option) any later version. - * - * This file is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this file. If not, see <http://www.gnu.org/licenses/>. - * - * Commentary: - * - * Given a filename or a file handle, and the extension of the file, - * determine if the file is executable. - * First, the file extension is checked in case it uniquely identifies - * the file as either an executable or not. Failing this, the first - * two bytes of the file are tested for known signatures of executable - * files. - * - */ - -#include <libc/stubs.h> -#include <stdio.h> -#include <string.h> -#include <ctype.h> -#include <errno.h> -#include <dpmi.h> -#include <go32.h> -#include <io.h> -#include <libc/farptrgs.h> -#include <libc/dosio.h> - -extern unsigned short _djstat_flags; -unsigned short _get_magic(const char *, int); -int _is_executable(const char *, int, const char *); - -/* - * Read a MAGIC NUMBER from a given file. These are the first - * two bytes of the file, if we look at them as an unsigned short. */ - -#define _STAT_EXEC_EXT 2 /* get execute bits from file extension? */ -#define _STAT_EXEC_MAGIC 4 /* get execute bits from magic signature? */ - -unsigned short -_get_magic(const char *s, int fh) -{ - __dpmi_regs regs; - unsigned short retval; - unsigned short fpos_high = 0, fpos_low = 0; - int read_fail = 0; - - /* If given a pathname, open the file. */ - if (s) - { - int handle; - if((handle = _open(s,0)) == -1) - return 0; - regs.x.bx = handle; - } - /* Else file already open. Remember its current file position - and move to beginning of file. */ - else - { - regs.x.ax = 0x4201; /* set pointer from current position */ - regs.x.bx = fh; - regs.x.cx = regs.x.dx = 0; /* move 0 bytes (i.e., stay put) */ - __dpmi_int(0x21, ®s); - if (regs.x.flags & 1) - { - errno = __doserr_to_errno(regs.x.ax); - return 0; - } - fpos_high = regs.x.dx; /* got current position */ - fpos_low = regs.x.ax; - - regs.x.ax = 0x4200; /* set pointer from the beginning of file */ - regs.x.cx = regs.x.dx = 0; /* move to beginning of file */ - __dpmi_int(0x21, ®s); - if (regs.x.flags & 1) - { - errno = __doserr_to_errno(regs.x.ax); - return 0; - } - } - regs.x.ds = __tb_segment; - regs.x.dx = __tb_offset; - - /* Read 2 bytes from the file. */ - regs.x.ax = 0x3f00; - regs.x.cx = 2; - __dpmi_int(0x21, ®s); - - /* We can either (1) succeed, (2) read less than 2 bytes, - or (3) fail to read at all. */ - if (regs.x.ax != 2) - read_fail = (regs.x.flags & 1) ? regs.x.ax : -1; - - /* If called with filename, close the file. */ - if (s) - { - regs.x.ax = 0x3e00; - __dpmi_int(0x21, ®s); - if (regs.x.flags & 1) - errno = __doserr_to_errno(regs.x.ax); - } - /* Else leave file pointer where we found it. */ - else - { - regs.x.ax = 0x4200; /* set pointer from the beginning of file */ - regs.x.bx = fh; - regs.x.cx = fpos_high; - regs.x.dx = fpos_low; - __dpmi_int(0x21, ®s); - if (regs.x.flags & 1) - { - errno = __doserr_to_errno(regs.x.ax); - return 0; - } - } - - if (read_fail == 0) - retval = _farpeekw(_dos_ds, __tb); - else - { - /* The file couldn't be read: assume non-executable. If the file - *is* executable, but was passed as a file-handle, and the user - opened it in write-only mode, they lose... */ - retval = 0; - if (read_fail != -1) - errno = __doserr_to_errno(read_fail); - } - - return retval; -} - -/* A list of extensions which designate executable files. These - are NOT tested for the magic number. */ -static char executables[] = "|EXE|COM|BAT|BTM|DLL|VXD|"; - -/* A list of extensions which belong to files known to NEVER be - executables. These exist to minimize read()'ing files while - detecting executables by magic number. You are welcome to - add to this list, but remember: only extensions which could - NEVER be present in executables should go here. */ -static char non_executables[] = "\ -|A|A01|A02|A03|A04|A05|ADL|ARC|ARJ|ASC|ASM|AUX|AWK\ -|BAS|BIB|BGI|BMP\ -|C|CC|CFG|CGZ|CH3|CHR|CI|CLP|CMF|CPI|CPP|CXX\ -|DAT|DBF|DIZ|DOC|DVI\ -|E|EL|ELC\ -|F77|FN3\ -|GIF|GZ\ -|H|HLP|HPP|HXX\ -|ICO|IN|INC|INF|INI\ -|JPG\ -|L|LEX|LF|LIB|LOG|LST|LZH\ -|M|MAK|MAP|MF|MID|MPG\ -|O|OBJ\ -|PAK|PAS|PBM|PCD|PCX|PDS|PIC|PIF|PN3|PRJ|PS\ -|RAS|RGB|RLE\ -|S|SND|SY3\ -|TAR|TAZ|TEX|TGA|TGZ|TIF|TXH|TXI|TXT\ -|VOC\ -|WAV|WK1|WK3|WKB|WQ1|WQ3|WQ4|WQ5|WQ6|WQ!\ -|XBM\ -|Y\ -|ZIP|ZOO|"; - -int -_is_executable(const char *filename, int fhandle, const char *extension) -{ - if (!extension && filename) - { - const char *cp, *ep=0; - for (cp=filename; *cp; cp++) - { - if (*cp == '.') - ep = cp; - if (*cp == '/' || *cp == '\\' || *cp == ':') - ep = 0; - } - extension = ep; - } - if ((_djstat_flags & _STAT_EXEC_EXT) == 0 - && extension - && *extension - && strlen(extension) <= ((extension[0]=='.') ? 4 : 3)) - { - /* Search the list of extensions in executables[]. */ - char tmp_buf[6], *tp = tmp_buf; - - *tp++ = '|'; - if (*extension == '.') - extension++; - while (*extension) - *tp++ = toupper (*extension++); - *tp++ = '|'; - *tp = '\0'; - if (strstr(non_executables, tmp_buf)) - return 0; - else if (strstr(executables, tmp_buf)) - return 1; - } - - /* No extension, or extension doesn't define execute - bits unambiguously. We are in for some dirty work. - Read the first two bytes of the file and see if they - are any of the known magic numbers which designate - executable files. - Unix-like shells, which have executable shell scripts - without extensions and DON'T have "#!" as their FIRST - TWO CHARACTERS, lose here. Sorry, folks. */ - if ( (_djstat_flags & _STAT_EXEC_MAGIC) == 0 ) - { - switch (_get_magic(filename, fhandle)) - { - case 0x5a4d: /* "MZ" */ - case 0x010b: - case 0x014c: - case 0x2123: /* "#!" */ - return 1; - } - } - - return 0; -} - |