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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/sysproto.h> 33 #include <sys/exec.h> 34 #include <sys/imgact.h> 35 #include <sys/kernel.h> 36 37 #if BYTE_ORDER == LITTLE_ENDIAN 38 #define SHELLMAGIC 0x2123 /* #! */ 39 #else 40 #define SHELLMAGIC 0x2321 41 #endif 42 43 /* 44 * Shell interpreter image activator. An interpreter name beginning 45 * at imgp->stringbase is the minimal successful exit requirement. 46 */ 47 int 48 exec_shell_imgact(imgp) 49 struct image_params *imgp; 50 { 51 const char *image_header = imgp->image_header; 52 const char *ihp, *line_endp; 53 char *interp; 54 55 /* a shell script? */ 56 if (((const short *) image_header)[0] != SHELLMAGIC) 57 return(-1); 58 59 /* 60 * Don't allow a shell script to be the shell for a shell 61 * script. :-) 62 */ 63 if (imgp->interpreted) 64 return(ENOEXEC); 65 66 imgp->interpreted = 1; 67 68 /* 69 * Copy shell name and arguments from image_header into string 70 * buffer. 71 */ 72 73 /* 74 * Find end of line; return if the line > MAXSHELLCMDLEN long. 75 */ 76 for (ihp = &image_header[2]; *ihp != '\n' && *ihp != '#'; ++ihp) { 77 if (ihp >= &image_header[MAXSHELLCMDLEN]) 78 return(ENAMETOOLONG); 79 } 80 line_endp = ihp; 81 82 /* reset for another pass */ 83 ihp = &image_header[2]; 84 85 /* Skip over leading spaces - until the interpreter name */ 86 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 87 88 /* copy the interpreter name */ 89 interp = imgp->interpreter_name; 90 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) 91 *interp++ = *ihp++; 92 *interp = '\0'; 93 94 /* Disallow a null interpreter filename */ 95 if (*imgp->interpreter_name == '\0') 96 return(ENOEXEC); 97 98 /* reset for another pass */ 99 ihp = &image_header[2]; 100 101 /* copy the interpreter name and arguments */ 102 while (ihp < line_endp) { 103 /* Skip over leading spaces */ 104 while ((*ihp == ' ') || (*ihp == '\t')) ihp++; 105 106 if (ihp < line_endp) { 107 /* 108 * Copy to end of token. No need to watch stringspace 109 * because this is at the front of the string buffer 110 * and the maximum shell command length is tiny. 111 */ 112 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { 113 *imgp->stringp++ = *ihp++; 114 imgp->stringspace--; 115 } 116 117 *imgp->stringp++ = 0; 118 imgp->stringspace--; 119 120 imgp->argc++; 121 } 122 } 123 124 imgp->argv0 = imgp->fname; 125 126 return(0); 127 } 128 129 /* 130 * Tell kern_execve.c about it, with a little help from the linker. 131 */ 132 static struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 133 EXEC_SET(shell, shell_execsw); 134