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 * $DragonFly: src/sys/kern/imgact_shell.c,v 1.3 2003/11/12 01:00:33 daver Exp $ 28 */ 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. A interpreter name beginning 45 * at imgp->args->begin_argv is the minimal successful exit requirement. 46 */ 47 int 48 exec_shell_imgact(struct image_params *imgp) 49 { 50 const char *image_header = imgp->image_header; 51 const char *ihp; 52 int error, length, offset; 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 * We must determine how far to offset the contents of the buffer 69 * to make room for the interpreter + args and the full path of 70 * the interpreted file while overwriting the first argument 71 * currently in the buffer. 72 */ 73 ihp = &image_header[2]; 74 offset = 0; 75 while (ihp < &image_header[MAXSHELLCMDLEN]) { 76 /* Skip any whitespace */ 77 while ((*ihp == ' ') || (*ihp == '\t')) 78 ihp++; 79 80 /* End of line? */ 81 if ((*ihp == '\n') || (*ihp == '#')) 82 break; 83 84 /* Found a token */ 85 while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') && 86 (*ihp != '#')) { 87 offset++; 88 ihp++; 89 } 90 /* Include terminating nulls in the offset */ 91 offset++; 92 } 93 94 /* If the script gives a null line as the interpreter, we bail */ 95 if (offset == 0) 96 return (ENOEXEC); 97 98 /* Check that we aren't too big */ 99 if (offset > MAXSHELLCMDLEN) 100 return (ENAMETOOLONG); 101 102 /* The file name is used to replace argv[0] */ 103 offset += strlen(imgp->args->fname) + 1; 104 offset -= strlen(imgp->args->begin_argv) + 1; 105 106 if (offset > imgp->args->space) 107 return (E2BIG); 108 109 /* Move the contents of imgp->args->buf by offset bytes. */ 110 bcopy(imgp->args->buf, imgp->args->buf + offset, 111 ARG_MAX - imgp->args->space); 112 113 /* 114 * Loop through the interpreter name yet again, copying as 115 * we go. 116 */ 117 ihp = &image_header[2]; 118 offset = 0; 119 while (ihp < &image_header[MAXSHELLCMDLEN]) { 120 /* Skip whitespace */ 121 while ((*ihp == ' ' || *ihp == '\t')) 122 ihp++; 123 124 /* End of line? */ 125 if ((*ihp == '\n') || (*ihp == '#')) 126 break; 127 128 /* Found a token, copy it */ 129 while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') && 130 (*ihp != '#')) 131 imgp->args->buf[offset++] = *ihp++; 132 133 imgp->args->buf[offset++] = '\0'; 134 imgp->args->argc++; 135 } 136 137 error = copystr(imgp->args->fname, imgp->args->buf + offset, 138 imgp->args->space, &length); 139 140 if (error == 0) 141 error = copystr(imgp->args->begin_argv, 142 imgp->interpreter_name, MAXSHELLCMDLEN, &length); 143 144 return (error); 145 } 146 147 /* 148 * Tell kern_execve.c about it, with a little help from the linker. 149 */ 150 static struct execsw shell_execsw = { exec_shell_imgact, "#!" }; 151 EXEC_SET(shell, shell_execsw); 152