2 * Copyright (c) 1993, David Greenman
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/sysproto.h>
34 #include <sys/imgact.h>
35 #include <sys/kernel.h>
37 #if BYTE_ORDER == LITTLE_ENDIAN
38 #define SHELLMAGIC 0x2123 /* #! */
40 #define SHELLMAGIC 0x2321
44 * Shell interpreter image activator. An interpreter name beginning
45 * at imgp->args->begin_argv is the minimal successful exit requirement.
48 exec_shell_imgact(imgp)
49 struct image_params *imgp;
51 const char *image_header = imgp->image_header;
57 if (((const short *) image_header)[0] != SHELLMAGIC)
61 * Don't allow a shell script to be the shell for a shell
64 if (imgp->interpreted)
67 imgp->interpreted = 1;
70 * Figure out the number of bytes that need to be reserved in the
71 * argument string to copy the contents of the interpreter's command
72 * line into the argument string.
74 ihp = &image_header[2];
76 while (ihp < &image_header[MAXSHELLCMDLEN]) {
77 /* Skip any whitespace */
78 while ((*ihp == ' ') || (*ihp == '\t')) {
84 if ((*ihp == '\n') || (*ihp == '#'))
88 while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
93 /* Include terminating nulls in the offset */
97 /* If the script gives a null line as the interpreter, we bail */
101 /* Check that we aren't too big */
102 if (offset > MAXSHELLCMDLEN)
103 return (ENAMETOOLONG);
106 * The full path name of the original script file must be tagged
107 * onto the end, adjust the offset to deal with it.
109 * The original argv[0] is being replaced, set 'length' to the number
110 * of bytes being removed. So 'offset' is the number of bytes being
111 * added and 'length' is the number of bytes being removed.
113 offset += strlen(imgp->args->fname) + 1; /* add fname */
114 length = (imgp->args->argc == 0) ? 0 :
115 strlen(imgp->args->begin_argv) + 1; /* bytes to delete */
117 if (offset - length > imgp->args->stringspace)
120 bcopy(imgp->args->begin_argv + length, imgp->args->begin_argv + offset,
121 imgp->args->endp - (imgp->args->begin_argv + length));
123 offset -= length; /* calculate actual adjustment */
124 imgp->args->begin_envv += offset;
125 imgp->args->endp += offset;
126 imgp->args->stringspace -= offset;
129 * If there were no arguments then we've added one, otherwise
130 * decr argc remove old argv[0], incr argc for fname add, net 0
132 if (imgp->args->argc == 0)
133 imgp->args->argc = 1;
136 * Loop through the interpreter name yet again, copying as
139 ihp = &image_header[2];
141 while (ihp < &image_header[MAXSHELLCMDLEN]) {
142 /* Skip whitespace */
143 while ((*ihp == ' ' || *ihp == '\t')) {
149 if ((*ihp == '\n') || (*ihp == '#'))
152 /* Found a token, copy it */
153 while ((*ihp != ' ') && (*ihp != '\t') &&
154 (*ihp != '\n') && (*ihp != '#')) {
155 imgp->args->begin_argv[offset++] = *ihp++;
157 imgp->args->begin_argv[offset++] = '\0';
162 * Finally, add the filename onto the end for the interpreter to
163 * use and copy the interpreter's name to imgp->interpreter_name
166 error = copystr(imgp->args->fname, imgp->args->buf + offset,
167 imgp->args->stringspace, &length);
170 error = copystr(imgp->args->begin_argv, imgp->interpreter_name,
171 MAXSHELLCMDLEN, &length);
177 * Tell kern_execve.c about it, with a little help from the linker.
179 static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
180 EXEC_SET(shell, shell_execsw);