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 1.18 1999/01/29 22:59:43 dillon 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 #define MAXSHELLCMDLEN 64 43 44 static int exec_shell_imgact __P((struct image_params *imgp)); 45 46 /* 47 * Shell interpreter image activator. A interpreter name beginning 48 * at imgp->stringbase is the minimal successful exit requirement. 49 */ 50 static int 51 exec_shell_imgact(imgp) 52 struct image_params *imgp; 53 { 54 const char *image_header = imgp->image_header; 55 const char *ihp, *line_endp; 56 char *interp; 57 58 /* a shell script? */ 59 if (((const short *) image_header)[0] != SHELLMAGIC) 60 return(-1); 61 62 /* 63 * Don't allow a shell script to be the shell for a shell 64 * script. :-) 65 */ 66 if (imgp->interpreted) 67 return(ENOEXEC); 68 69 imgp->interpreted = 1; 70 71 /* 72 * Copy shell name and arguments from image_header into string 73 * buffer. 74 */ 75 76 /* 77 * Find end of line; return if the line > MAXSHELLCMDLEN long. 78 */ 79 for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) { 80 if (ihp >= &image_header[MAXSHELLCMDLEN]) 81 return(ENOEXEC); 82 } 83 line_endp = ihp; 84 85 /* reset for another pass */ 86 ihp = &image_header[2]; 87 88 /* Skip over leading spaces - until the interpreter name */ 89 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 90 91 /* copy the interpreter name */ 92 interp = imgp->interpreter_name; 93 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 94 *interp++ = *ihp++; 95 *interp = '\0'; 96 97 /* Disallow a null interpreter filename */ 98 if (*imgp->interpreter_name == '\0') 99 return(ENOEXEC); 100 101 /* reset for another pass */ 102 ihp = &image_header[2]; 103 104 /* copy the interpreter name and arguments */ 105 while (ihp < line_endp) { 106 /* Skip over leading spaces */ 107 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 108 109 if (ihp < line_endp) { 110 /* 111 * Copy to end of token. No need to watch stringspace 112 * because this is at the front of the string buffer 113 * and the maximum shell command length is tiny. 114 */ 115 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 116 *imgp->stringp++ = *ihp++; 117 imgp->stringspace--; 118 } 119 120 *imgp->stringp++ = 0; 121 imgp->stringspace--; 122 123 imgp->argc++; 124 } 125 } 126 127 imgp->argv0 = imgp->uap->fname; 128 129 return(0); 130 } 131 132 /* 133 * Tell kern_execve.c about it, with a little help from the linker. 134 */ 135 static struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 136 EXEC_SET(shell, shell_execsw); 137