imgact_shell.c revision 886
1284990Scy/* 2284990Scy * Copyright (c) 1993, David Greenman 3284990Scy * All rights reserved. 4289997Sglebius * 5284990Scy * Redistribution and use in source and binary forms, with or without 6284990Scy * modification, are permitted provided that the following conditions 7284990Scy * are met: 8284990Scy * 1. Redistributions of source code must retain the above copyright 9289997Sglebius * notice, this list of conditions and the following disclaimer. 10289997Sglebius * 2. Redistributions in binary form must reproduce the above copyright 11289997Sglebius * notice, this list of conditions and the following disclaimer in the 12289997Sglebius * documentation and/or other materials provided with the distribution. 13289997Sglebius * 3. All advertising materials mentioning features or use of this software 14289997Sglebius * must display the following acknowledgement: 15289997Sglebius * This product includes software developed by David Greenman 16289997Sglebius * 4. The name of the developer may be used to endorse or promote products 17289997Sglebius * derived from this software without specific prior written permission. 18284990Scy * 19289997Sglebius * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20289997Sglebius * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21284990Scy * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22289997Sglebius * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23289997Sglebius * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24284990Scy * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25284990Scy * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26284990Scy * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27289997Sglebius * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28289997Sglebius * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29284990Scy * SUCH DAMAGE. 30289997Sglebius * 31289997Sglebius * $Id: imgact_shell.c,v 1.1 1993/12/20 16:16:46 wollman Exp $ 32284990Scy */ 33284990Scy 34284990Scy#include "param.h" 35284990Scy#include "systm.h" 36284990Scy#include "resourcevar.h" 37284990Scy#include "imgact.h" 38289997Sglebius#include "kernel.h" 39289997Sglebius#include "machine/endian.h" 40284990Scy 41284990Scy#if BYTE_ORDER == LITTLE_ENDIAN 42284990Scy#define SHELLMAGIC 0x2123 /* #! */ 43284990Scy#else 44284990Scy#define SHELLMAGIC 0x2321 45284990Scy#endif 46284990Scy 47284990Scy#define MAXSHELLCMDLEN 64 48284990Scy 49284990Scy/* 50284990Scy * Shell interpreter image activator. A interpreter name beginning 51284990Scy * at iparams->stringbase is the minimal successful exit requirement. 52284990Scy */ 53289997Sglebiusint 54289997Sglebiusexec_shell_imgact(iparams) 55289997Sglebius struct image_params *iparams; 56284990Scy{ 57284990Scy const char *image_header = iparams->image_header; 58284990Scy const char *ihp, *line_endp; 59284990Scy int length; 60284990Scy char *interp; 61284990Scy char **argv; 62284990Scy 63284990Scy /* a shell script? */ 64284990Scy if (((short *) image_header)[0] != SHELLMAGIC) 65284990Scy return(-1); 66284990Scy 67284990Scy /* 68289997Sglebius * Don't allow a shell script to be the shell for a shell 69289997Sglebius * script. :-) 70284990Scy */ 71284990Scy if (iparams->interpreted) 72284990Scy return(ENOEXEC); 73284990Scy 74284990Scy iparams->interpreted = 1; 75284990Scy 76284990Scy /* 77284990Scy * Copy shell name and arguments from image_header into string 78284990Scy * buffer. 79284990Scy */ 80284990Scy 81 /* 82 * Find end of line; return if the line > MAXSHELLCMDLEN long. 83 */ 84 for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) { 85 if (ihp >= &image_header[MAXSHELLCMDLEN]) 86 return(ENOEXEC); 87 } 88 line_endp = ihp; 89 90 /* reset for another pass */ 91 ihp = &image_header[2]; 92 93 /* Skip over leading spaces - until the interpreter name */ 94 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 95 96 /* copy the interpreter name */ 97 interp = iparams->interpreter_name; 98 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 99 *interp++ = *ihp++; 100 *interp = '\0'; 101 102 /* Disallow a null interpreter filename */ 103 if (*iparams->interpreter_name == '\0') 104 return(ENOEXEC); 105 106 /* reset for another pass */ 107 ihp = &image_header[2]; 108 109 /* copy the interpreter name and arguments */ 110 while (ihp < line_endp) { 111 /* Skip over leading spaces */ 112 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 113 114 if (ihp < line_endp) { 115 /* 116 * Copy to end of token. No need to watch stringspace 117 * because this is at the front of the string buffer 118 * and the maximum shell command length is tiny. 119 */ 120 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 121 *iparams->stringp++ = *ihp++; 122 iparams->stringspace--; 123 } 124 125 *iparams->stringp++ = 0; 126 iparams->stringspace--; 127 128 iparams->argc++; 129 } 130 } 131 132 /* set argv[0] to point to original file name */ 133 suword(iparams->uap->argv, (int)iparams->uap->fname); 134 135 return(0); 136} 137 138/* 139 * Tell kern_execve.c about it, with a little help from the linker. 140 * Since `const' objects end up in the text segment, TEXT_SET is the 141 * correct directive to use. 142 */ 143static const struct execsw shell_execsw = { exec_shell_imgact }; 144TEXT_SET(execsw_set, shell_execsw); 145