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.
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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
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21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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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 1.5 2005/02/25 08:49:10 dillon Exp $
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. A interpreter name beginning
45 * at imgp->args->begin_argv is the minimal successful exit requirement.
48 exec_shell_imgact(struct image_params *imgp)
50 const char *image_header = imgp->image_header;
52 int error, length, offset;
55 if (((const short *) image_header)[0] != SHELLMAGIC)
59 * Don't allow a shell script to be the shell for a shell
62 if (imgp->interpreted)
65 imgp->interpreted = 1;
68 * Figure out the number of bytes that need to be reserved in the
69 * argument string to copy the contents of the interpreter's command
70 * line into the argument string.
72 ihp = &image_header[2];
74 while (ihp < &image_header[MAXSHELLCMDLEN]) {
75 /* Skip any whitespace */
76 if (*ihp == ' ' || *ihp == '\t') {
82 if (*ihp == '\n' || *ihp == '#')
89 } while (ihp < &image_header[MAXSHELLCMDLEN] &&
90 *ihp != ' ' && *ihp != '\t' &&
91 *ihp != '\n' && *ihp != '#');
93 /* Take into account the \0 that will terminate the token */
97 /* If the script gives a null line as the interpreter, we bail */
101 /* It should not be possible for offset to exceed MAXSHELLCMDLEN */
102 KKASSERT(offset <= MAXSHELLCMDLEN);
105 * The full path name of the original script file must be tagged
106 * onto the end, adjust the offset to deal with it.
108 * The original argv0 is being replaced, set 'length' to the number
109 * of bytes being removed. So 'offset' is the number of bytes being
110 * added and 'length' is the number of bytes being removed.
112 offset += strlen(imgp->args->fname) + 1; /* add fname */
113 length = strlen(imgp->args->begin_argv) + 1; /* bytes to delete */
115 if (offset - length > imgp->args->space)
118 bcopy(imgp->args->begin_argv + length, imgp->args->begin_argv + offset,
119 imgp->args->endp - (imgp->args->begin_argv + length));
121 offset -= length; /* calculate actual adjustment */
122 imgp->args->begin_envv += offset;
123 imgp->args->endp += offset;
124 imgp->args->space -= offset;
125 /* decr argc remove old argv[0], incr argc for fname add, net 0 */
128 * Loop through the interpreter name yet again, copying as
131 ihp = &image_header[2];
133 while (ihp < &image_header[MAXSHELLCMDLEN]) {
134 /* Skip whitespace */
135 if ((*ihp == ' ' || *ihp == '\t')) {
141 if ((*ihp == '\n') || (*ihp == '#'))
144 /* Found a token, copy it */
146 imgp->args->begin_argv[offset] = *ihp;
149 } while (ihp < &image_header[MAXSHELLCMDLEN] &&
150 *ihp != ' ' && *ihp != '\t' &&
151 *ihp != '\n' && *ihp != '#');
153 /* And terminate the argument */
154 imgp->args->begin_argv[offset] = '\0';
160 * Finally, add the filename onto the end for the interpreter to
161 * use and copy the interpreter's name to imgp->interpreter_name
164 error = copystr(imgp->args->fname, imgp->args->buf + offset,
165 imgp->args->space, &length);
168 error = copystr(imgp->args->begin_argv, imgp->interpreter_name,
169 MAXSHELLCMDLEN, &length);
175 * Tell kern_execve.c about it, with a little help from the linker.
177 static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
178 EXEC_SET(shell, shell_execsw);