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/*-
* Copyright (c) 1993, David Greenman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#if BYTE_ORDER == LITTLE_ENDIAN
#define SHELLMAGIC 0x2123 /* #! */
#else
#define SHELLMAGIC 0x2321
#endif
/*
* Shell interpreter image activator. An interpreter name beginning
* at imgp->args->begin_argv is the minimal successful exit requirement.
*/
int
exec_shell_imgact(imgp)
struct image_params *imgp;
{
const char *image_header = imgp->image_header;
const char *ihp;
int error, offset;
size_t length, clength;
struct vattr vattr;
/* a shell script? */
if (((const short *) image_header)[0] != SHELLMAGIC)
return(-1);
/*
* Don't allow a shell script to be the shell for a shell
* script. :-)
*/
if (imgp->interpreted)
return(ENOEXEC);
imgp->interpreted = 1;
/*
* At this point we have the first page of the file mapped.
* However, we don't know how far into the page the contents are
* valid -- the actual file might be much shorter than the page.
* So find out the file size.
*/
error = VOP_GETATTR(imgp->vp, &vattr, imgp->proc->p_ucred, curthread);
if (error)
return (error);
clength = (vattr.va_size > MAXSHELLCMDLEN) ?
MAXSHELLCMDLEN : vattr.va_size;
/*
* Figure out the number of bytes that need to be reserved in the
* argument string to copy the contents of the interpreter's command
* line into the argument string.
*/
ihp = &image_header[2];
offset = 0;
while (ihp < &image_header[clength]) {
/* Skip any whitespace */
if ((*ihp == ' ') || (*ihp == '\t')) {
ihp++;
continue;
}
/* End of line? */
if ((*ihp == '\n') || (*ihp == '#') || (*ihp == '\0'))
break;
/* Found a token */
do {
offset++;
ihp++;
} while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
(*ihp != '#') && (*ihp != '\0') &&
(ihp < &image_header[clength]));
/* Include terminating nulls in the offset */
offset++;
}
/* If the script gives a null line as the interpreter, we bail */
if (offset == 0)
return (ENOEXEC);
/* Check that we aren't too big */
if (ihp == &image_header[MAXSHELLCMDLEN])
return (ENAMETOOLONG);
/*
* The full path name of the original script file must be tagged
* onto the end, adjust the offset to deal with it.
*
* The original argv[0] is being replaced, set 'length' to the number
* of bytes being removed. So 'offset' is the number of bytes being
* added and 'length' is the number of bytes being removed.
*/
offset += strlen(imgp->args->fname) + 1; /* add fname */
length = (imgp->args->argc == 0) ? 0 :
strlen(imgp->args->begin_argv) + 1; /* bytes to delete */
if (offset - length > imgp->args->stringspace)
return (E2BIG);
bcopy(imgp->args->begin_argv + length, imgp->args->begin_argv + offset,
imgp->args->endp - (imgp->args->begin_argv + length));
offset -= length; /* calculate actual adjustment */
imgp->args->begin_envv += offset;
imgp->args->endp += offset;
imgp->args->stringspace -= offset;
/*
* If there were no arguments then we've added one, otherwise
* decr argc remove old argv[0], incr argc for fname add, net 0
*/
if (imgp->args->argc == 0)
imgp->args->argc = 1;
/*
* Loop through the interpreter name yet again, copying as
* we go.
*/
ihp = &image_header[2];
offset = 0;
while (ihp < &image_header[clength]) {
/* Skip whitespace */
if ((*ihp == ' ') || (*ihp == '\t')) {
ihp++;
continue;
}
/* End of line? */
if ((*ihp == '\n') || (*ihp == '#') || (*ihp == '\0'))
break;
/* Found a token, copy it */
do {
imgp->args->begin_argv[offset++] = *ihp++;
} while ((*ihp != ' ') && (*ihp != '\t') && (*ihp != '\n') &&
(*ihp != '#') && (*ihp != '\0') &&
(ihp < &image_header[MAXSHELLCMDLEN]));
imgp->args->begin_argv[offset++] = '\0';
imgp->args->argc++;
}
/*
* Finally, add the filename onto the end for the interpreter to
* use and copy the interpreter's name to imgp->interpreter_name
* for exec to use.
*/
error = copystr(imgp->args->fname, imgp->args->buf + offset,
imgp->args->stringspace, &length);
if (error == 0)
error = copystr(imgp->args->begin_argv, imgp->interpreter_name,
MAXSHELLCMDLEN, &length);
return (error);
}
/*
* Tell kern_execve.c about it, with a little help from the linker.
*/
static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
EXEC_SET(shell, shell_execsw);
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