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 1.3 2003/11/12 01:00:33 daver 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 * 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.
73 ihp = &image_header[2];
75 while (ihp < &image_header[MAXSHELLCMDLEN]) {
76 /* Skip any whitespace */
77 while ((*ihp == ' ') || (*ihp == '\t'))
81 if ((*ihp == '\n') || (*ihp == '#'))
85 while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
90 /* Include terminating nulls in the offset */
94 /* If the script gives a null line as the interpreter, we bail */
98 /* Check that we aren't too big */
99 if (offset > MAXSHELLCMDLEN)
100 return (ENAMETOOLONG);
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;
106 if (offset > imgp->args->space)
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);
114 * Loop through the interpreter name yet again, copying as
117 ihp = &image_header[2];
119 while (ihp < &image_header[MAXSHELLCMDLEN]) {
120 /* Skip whitespace */
121 while ((*ihp == ' ' || *ihp == '\t'))
125 if ((*ihp == '\n') || (*ihp == '#'))
128 /* Found a token, copy it */
129 while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
131 imgp->args->buf[offset++] = *ihp++;
133 imgp->args->buf[offset++] = '\0';
137 error = copystr(imgp->args->fname, imgp->args->buf + offset,
138 imgp->args->space, &length);
141 error = copystr(imgp->args->begin_argv,
142 imgp->interpreter_name, MAXSHELLCMDLEN, &length);
148 * Tell kern_execve.c about it, with a little help from the linker.
150 static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
151 EXEC_SET(shell, shell_execsw);