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 * $FreeBSD: src/sys/kern/imgact_shell.c,v 1.21.2.2 2001/12/22 01:21:39 jwd Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/sysproto.h> 32 #include <sys/exec.h> 33 #include <sys/imgact.h> 34 #include <sys/kernel.h> 35 36 #if BYTE_ORDER == LITTLE_ENDIAN 37 #define SHELLMAGIC 0x2123 /* #! */ 38 #else 39 #define SHELLMAGIC 0x2321 40 #endif 41 42 /* 43 * Shell interpreter image activator. A interpreter name beginning 44 * at imgp->stringbase is the minimal successful exit requirement. 45 */ 46 int 47 exec_shell_imgact(imgp) 48 struct image_params *imgp; 49 { 50 const char *image_header = imgp->image_header; 51 const char *ihp, *line_endp; 52 char *interp; 53 54 /* a shell script? */ 55 if (((const short *) image_header)[0] != SHELLMAGIC) 56 return(-1); 57 58 /* 59 * Don't allow a shell script to be the shell for a shell 60 * script. :-) 61 */ 62 if (imgp->interpreted) 63 return(ENOEXEC); 64 65 imgp->interpreted = 1; 66 67 /* 68 * Copy shell name and arguments from image_header into string 69 * buffer. 70 */ 71 72 /* 73 * Find end of line; return if the line > MAXSHELLCMDLEN long. 74 */ 75 for (ihp = &image_header[2]; *ihp != '\n' && *ihp != '#'; ++ihp) { 76 if (ihp >= &image_header[MAXSHELLCMDLEN]) 77 return(ENAMETOOLONG); 78 } 79 line_endp = ihp; 80 81 /* reset for another pass */ 82 ihp = &image_header[2]; 83 84 /* Skip over leading spaces - until the interpreter name */ 85 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 86 87 /* copy the interpreter name */ 88 interp = imgp->interpreter_name; 89 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 90 *interp++ = *ihp++; 91 *interp = '\0'; 92 93 /* Disallow a null interpreter filename */ 94 if (*imgp->interpreter_name == '\0') 95 return(ENOEXEC); 96 97 /* reset for another pass */ 98 ihp = &image_header[2]; 99 100 /* copy the interpreter name and arguments */ 101 while (ihp < line_endp) { 102 /* Skip over leading spaces */ 103 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 104 105 if (ihp < line_endp) { 106 /* 107 * Copy to end of token. No need to watch stringspace 108 * because this is at the front of the string buffer 109 * and the maximum shell command length is tiny. 110 */ 111 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 112 *imgp->stringp++ = *ihp++; 113 imgp->stringspace--; 114 } 115 116 *imgp->stringp++ = 0; 117 imgp->stringspace--; 118 119 imgp->argc++; 120 } 121 } 122 123 imgp->argv0 = imgp->uap->fname; 124 125 return(0); 126 } 127 128 /* 129 * Tell kern_execve.c about it, with a little help from the linker. 130 */ 131 static struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 132 EXEC_SET(shell, shell_execsw); 133