Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/fs/binfmt_script.c
15109 views
1
/*

2
 *  linux/fs/binfmt_script.c

3
 *

4
 *  Copyright (C) 1996  Martin von Löwis

5
 *  original #!-checking implemented by tytso.

6
 */

7


8
#include <linux/module.h>

9
#include <linux/string.h>

10
#include <linux/stat.h>

11
#include <linux/binfmts.h>

12
#include <linux/init.h>

13
#include <linux/file.h>

14
#include <linux/err.h>

15
#include <linux/fs.h>

16


17
static int load_script(struct linux_binprm *bprm,struct pt_regs *regs)

18
{

19
	const char *i_arg, *i_name;

20
	char *cp;

21
	struct file *file;

22
	char interp[BINPRM_BUF_SIZE];

23
	int retval;

24


25
	if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') ||

26
	    (bprm->recursion_depth > BINPRM_MAX_RECURSION))

27
		return -ENOEXEC;

28
	/*

29
	 * This section does the #! interpretation.

30
	 * Sorta complicated, but hopefully it will work.  -TYT

31
	 */

32


33
	bprm->recursion_depth++;

34
	allow_write_access(bprm->file);

35
	fput(bprm->file);

36
	bprm->file = NULL;

37


38
	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';

39
	if ((cp = strchr(bprm->buf, '\n')) == NULL)

40
		cp = bprm->buf+BINPRM_BUF_SIZE-1;

41
	*cp = '\0';

42
	while (cp > bprm->buf) {

43
		cp--;

44
		if ((*cp == ' ') || (*cp == '\t'))

45
			*cp = '\0';

46
		else

47
			break;

48
	}

49
	for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);

50
	if (*cp == '\0') 

51
		return -ENOEXEC; /* No interpreter name found */

52
	i_name = cp;

53
	i_arg = NULL;

54
	for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)

55
		/* nothing */ ;

56
	while ((*cp == ' ') || (*cp == '\t'))

57
		*cp++ = '\0';

58
	if (*cp)

59
		i_arg = cp;

60
	strcpy (interp, i_name);

61
	/*

62
	 * OK, we've parsed out the interpreter name and

63
	 * (optional) argument.

64
	 * Splice in (1) the interpreter's name for argv[0]

65
	 *           (2) (optional) argument to interpreter

66
	 *           (3) filename of shell script (replace argv[0])

67
	 *

68
	 * This is done in reverse order, because of how the

69
	 * user environment and arguments are stored.

70
	 */

71
	retval = remove_arg_zero(bprm);

72
	if (retval)

73
		return retval;

74
	retval = copy_strings_kernel(1, &bprm->interp, bprm);

75
	if (retval < 0) return retval; 

76
	bprm->argc++;

77
	if (i_arg) {

78
		retval = copy_strings_kernel(1, &i_arg, bprm);

79
		if (retval < 0) return retval; 

80
		bprm->argc++;

81
	}

82
	retval = copy_strings_kernel(1, &i_name, bprm);

83
	if (retval) return retval; 

84
	bprm->argc++;

85
	bprm->interp = interp;

86


87
	/*

88
	 * OK, now restart the process with the interpreter's dentry.

89
	 */

90
	file = open_exec(interp);

91
	if (IS_ERR(file))

92
		return PTR_ERR(file);

93


94
	bprm->file = file;

95
	retval = prepare_binprm(bprm);

96
	if (retval < 0)

97
		return retval;

98
	return search_binary_handler(bprm,regs);

99
}

100


101
static struct linux_binfmt script_format = {

102
	.module		= THIS_MODULE,

103
	.load_binary	= load_script,

104
};

105


106
static int __init init_script_binfmt(void)

107
{

108
	return register_binfmt(&script_format);

109
}

110


111
static void __exit exit_script_binfmt(void)

112
{

113
	unregister_binfmt(&script_format);

114
}

115


116
core_initcall(init_script_binfmt);

117
module_exit(exit_script_binfmt);

118
MODULE_LICENSE("GPL");

119


120