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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $Id: imgact_shell.c,v 1.15 1997/04/23 22:07:04 ache Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/sysproto.h> 31 #include <sys/exec.h> 32 #include <sys/imgact.h> 33 #include <sys/kernel.h> 34 35 #if BYTE_ORDER == LITTLE_ENDIAN 36 #define SHELLMAGIC 0x2123 /* #! */ 37 #else 38 #define SHELLMAGIC 0x2321 39 #endif 40 41 #define MAXSHELLCMDLEN 64 42 43 static int exec_shell_imgact __P((struct image_params *imgp)); 44 45 /* 46 * Shell interpreter image activator. A interpreter name beginning 47 * at imgp->stringbase is the minimal successful exit requirement. 48 */ 49 static int 50 exec_shell_imgact(imgp) 51 struct image_params *imgp; 52 { 53 const char *image_header = imgp->image_header; 54 const char *ihp, *line_endp; 55 char *interp; 56 57 /* a shell script? */ 58 if (((const short *) image_header)[0] != SHELLMAGIC) 59 return(-1); 60 61 /* 62 * Don't allow a shell script to be the shell for a shell 63 * script. :-) 64 */ 65 if (imgp->interpreted) 66 return(ENOEXEC); 67 68 imgp->interpreted = 1; 69 70 /* 71 * Copy shell name and arguments from image_header into string 72 * buffer. 73 */ 74 75 /* 76 * Find end of line; return if the line > MAXSHELLCMDLEN long. 77 */ 78 for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) { 79 if (ihp >= &image_header[MAXSHELLCMDLEN]) 80 return(ENOEXEC); 81 } 82 line_endp = ihp; 83 84 /* reset for another pass */ 85 ihp = &image_header[2]; 86 87 /* Skip over leading spaces - until the interpreter name */ 88 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 89 90 /* copy the interpreter name */ 91 interp = imgp->interpreter_name; 92 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 93 *interp++ = *ihp++; 94 *interp = '\0'; 95 96 /* Disallow a null interpreter filename */ 97 if (*imgp->interpreter_name == '\0') 98 return(ENOEXEC); 99 100 /* reset for another pass */ 101 ihp = &image_header[2]; 102 103 /* copy the interpreter name and arguments */ 104 while (ihp < line_endp) { 105 /* Skip over leading spaces */ 106 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 107 108 if (ihp < line_endp) { 109 /* 110 * Copy to end of token. No need to watch stringspace 111 * because this is at the front of the string buffer 112 * and the maximum shell command length is tiny. 113 */ 114 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 115 *imgp->stringp++ = *ihp++; 116 imgp->stringspace--; 117 } 118 119 *imgp->stringp++ = 0; 120 imgp->stringspace--; 121 122 imgp->argc++; 123 } 124 } 125 126 imgp->argv0 = imgp->uap->fname; 127 128 return(0); 129 } 130 131 /* 132 * Tell kern_execve.c about it, with a little help from the linker. 133 * Since `const' objects end up in the text segment, TEXT_SET is the 134 * correct directive to use. 135 */ 136 static const struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 137 TEXT_SET(execsw_set, shell_execsw); 138