1 /* 2 * Copyright (c) 1993, David Greenman 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by David Greenman 16 * 4. The name of the developer may be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $Id: imgact_shell.c,v 1.5 1994/08/18 22:34:56 wollman Exp $ 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/resourcevar.h> 37 #include <sys/exec.h> 38 #include <sys/imgact.h> 39 #include <sys/kernel.h> 40 #include <machine/endian.h> 41 42 #if BYTE_ORDER == LITTLE_ENDIAN 43 #define SHELLMAGIC 0x2123 /* #! */ 44 #else 45 #define SHELLMAGIC 0x2321 46 #endif 47 48 #define MAXSHELLCMDLEN 64 49 50 /* 51 * Shell interpreter image activator. A interpreter name beginning 52 * at iparams->stringbase is the minimal successful exit requirement. 53 */ 54 int 55 exec_shell_imgact(iparams) 56 struct image_params *iparams; 57 { 58 const char *image_header = iparams->image_header; 59 const char *ihp, *line_endp; 60 char *interp; 61 62 /* a shell script? */ 63 if (((short *) image_header)[0] != SHELLMAGIC) 64 return(-1); 65 66 /* 67 * Don't allow a shell script to be the shell for a shell 68 * script. :-) 69 */ 70 if (iparams->interpreted) 71 return(ENOEXEC); 72 73 iparams->interpreted = 1; 74 75 /* 76 * Copy shell name and arguments from image_header into string 77 * buffer. 78 */ 79 80 /* 81 * Find end of line; return if the line > MAXSHELLCMDLEN long. 82 */ 83 for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) { 84 if (ihp >= &image_header[MAXSHELLCMDLEN]) 85 return(ENOEXEC); 86 } 87 line_endp = ihp; 88 89 /* reset for another pass */ 90 ihp = &image_header[2]; 91 92 /* Skip over leading spaces - until the interpreter name */ 93 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 94 95 /* copy the interpreter name */ 96 interp = iparams->interpreter_name; 97 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 98 *interp++ = *ihp++; 99 *interp = '\0'; 100 101 /* Disallow a null interpreter filename */ 102 if (*iparams->interpreter_name == '\0') 103 return(ENOEXEC); 104 105 /* reset for another pass */ 106 ihp = &image_header[2]; 107 108 /* copy the interpreter name and arguments */ 109 while (ihp < line_endp) { 110 /* Skip over leading spaces */ 111 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 112 113 if (ihp < line_endp) { 114 /* 115 * Copy to end of token. No need to watch stringspace 116 * because this is at the front of the string buffer 117 * and the maximum shell command length is tiny. 118 */ 119 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 120 *iparams->stringp++ = *ihp++; 121 iparams->stringspace--; 122 } 123 124 *iparams->stringp++ = 0; 125 iparams->stringspace--; 126 127 iparams->argc++; 128 } 129 } 130 131 /* set argv[0] to point to original file name */ 132 suword(iparams->uap->argv, (int)iparams->uap->fname); 133 134 return(0); 135 } 136 137 /* 138 * Tell kern_execve.c about it, with a little help from the linker. 139 * Since `const' objects end up in the text segment, TEXT_SET is the 140 * correct directive to use. 141 */ 142 static const struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 143 TEXT_SET(execsw_set, shell_execsw); 144