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 AUTHOR 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 1.9 1995/11/06 12:52:31 davidg Exp $ 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/sysproto.h> 37 #include <sys/resourcevar.h> 38 #include <sys/exec.h> 39 #include <sys/imgact.h> 40 #include <sys/kernel.h> 41 #include <machine/endian.h> 42 43 #if BYTE_ORDER == LITTLE_ENDIAN 44 #define SHELLMAGIC 0x2123 /* #! */ 45 #else 46 #define SHELLMAGIC 0x2321 47 #endif 48 49 #define MAXSHELLCMDLEN 64 50 51 static int exec_shell_imgact __P((struct image_params *imgp)); 52 53 /* 54 * Shell interpreter image activator. A interpreter name beginning 55 * at imgp->stringbase is the minimal successful exit requirement. 56 */ 57 static int 58 exec_shell_imgact(imgp) 59 struct image_params *imgp; 60 { 61 const char *image_header = imgp->image_header; 62 const char *ihp, *line_endp; 63 char *interp; 64 65 /* a shell script? */ 66 if (((short *) image_header)[0] != SHELLMAGIC) 67 return(-1); 68 69 /* 70 * Don't allow a shell script to be the shell for a shell 71 * script. :-) 72 */ 73 if (imgp->interpreted) 74 return(ENOEXEC); 75 76 imgp->interpreted = 1; 77 78 /* 79 * Copy shell name and arguments from image_header into string 80 * buffer. 81 */ 82 83 /* 84 * Find end of line; return if the line > MAXSHELLCMDLEN long. 85 */ 86 for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) { 87 if (ihp >= &image_header[MAXSHELLCMDLEN]) 88 return(ENOEXEC); 89 } 90 line_endp = ihp; 91 92 /* reset for another pass */ 93 ihp = &image_header[2]; 94 95 /* Skip over leading spaces - until the interpreter name */ 96 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 97 98 /* copy the interpreter name */ 99 interp = imgp->interpreter_name; 100 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 101 *interp++ = *ihp++; 102 *interp = '\0'; 103 104 /* Disallow a null interpreter filename */ 105 if (*imgp->interpreter_name == '\0') 106 return(ENOEXEC); 107 108 /* reset for another pass */ 109 ihp = &image_header[2]; 110 111 /* copy the interpreter name and arguments */ 112 while (ihp < line_endp) { 113 /* Skip over leading spaces */ 114 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 115 116 if (ihp < line_endp) { 117 /* 118 * Copy to end of token. No need to watch stringspace 119 * because this is at the front of the string buffer 120 * and the maximum shell command length is tiny. 121 */ 122 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 123 *imgp->stringp++ = *ihp++; 124 imgp->stringspace--; 125 } 126 127 *imgp->stringp++ = 0; 128 imgp->stringspace--; 129 130 imgp->argc++; 131 } 132 } 133 134 /* set argv[0] to point to original file name */ 135 suword(imgp->uap->argv, (int)imgp->uap->fname); 136 137 return(0); 138 } 139 140 /* 141 * Tell kern_execve.c about it, with a little help from the linker. 142 * Since `const' objects end up in the text segment, TEXT_SET is the 143 * correct directive to use. 144 */ 145 static const struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 146 TEXT_SET(execsw_set, shell_execsw); 147