1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Helper function for splitting a string into an argv-like array.
 4 */
 5
 6#include <linux/kernel.h>
 7#include <linux/ctype.h>
 8#include <linux/string.h>
 9#include <linux/slab.h>
10#include <linux/export.h>
 
 
 
 
 
 
 
 
11
12static int count_argc(const char *str)
13{
14	int count = 0;
15	bool was_space;
16
17	for (was_space = true; *str; str++) {
18		if (isspace(*str)) {
19			was_space = true;
20		} else if (was_space) {
21			was_space = false;
22			count++;
 
23		}
24	}
25
26	return count;
27}
28
29/**
30 * argv_free - free an argv
31 * @argv - the argument vector to be freed
32 *
33 * Frees an argv and the strings it points to.
34 */
35void argv_free(char **argv)
36{
37	argv--;
38	kfree(argv[0]);
 
 
39	kfree(argv);
40}
41EXPORT_SYMBOL(argv_free);
42
43/**
44 * argv_split - split a string at whitespace, returning an argv
45 * @gfp: the GFP mask used to allocate memory
46 * @str: the string to be split
47 * @argcp: returned argument count
48 *
49 * Returns an array of pointers to strings which are split out from
50 * @str.  This is performed by strictly splitting on white-space; no
51 * quote processing is performed.  Multiple whitespace characters are
52 * considered to be a single argument separator.  The returned array
53 * is always NULL-terminated.  Returns NULL on memory allocation
54 * failure.
55 *
56 * The source string at `str' may be undergoing concurrent alteration via
57 * userspace sysctl activity (at least).  The argv_split() implementation
58 * attempts to handle this gracefully by taking a local copy to work on.
59 */
60char **argv_split(gfp_t gfp, const char *str, int *argcp)
61{
62	char *argv_str;
63	bool was_space;
64	char **argv, **argv_ret;
65	int argc;
66
67	argv_str = kstrndup(str, KMALLOC_MAX_SIZE - 1, gfp);
68	if (!argv_str)
69		return NULL;
70
71	argc = count_argc(argv_str);
72	argv = kmalloc_array(argc + 2, sizeof(*argv), gfp);
73	if (!argv) {
74		kfree(argv_str);
75		return NULL;
76	}
77
78	*argv = argv_str;
79	argv_ret = ++argv;
80	for (was_space = true; *argv_str; argv_str++) {
81		if (isspace(*argv_str)) {
82			was_space = true;
83			*argv_str = 0;
84		} else if (was_space) {
85			was_space = false;
86			*argv++ = argv_str;
87		}
88	}
89	*argv = NULL;
90
91	if (argcp)
92		*argcp = argc;
93	return argv_ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
94}
95EXPORT_SYMBOL(argv_split);

 
  1/*
  2 * Helper function for splitting a string into an argv-like array.
  3 */
  4
  5#include <linux/kernel.h>
  6#include <linux/ctype.h>
  7#include <linux/string.h>
  8#include <linux/slab.h>
  9#include <linux/module.h>
 10
 11static const char *skip_arg(const char *cp)
 12{
 13	while (*cp && !isspace(*cp))
 14		cp++;
 15
 16	return cp;
 17}
 18
 19static int count_argc(const char *str)
 20{
 21	int count = 0;
 
 22
 23	while (*str) {
 24		str = skip_spaces(str);
 25		if (*str) {
 
 
 26			count++;
 27			str = skip_arg(str);
 28		}
 29	}
 30
 31	return count;
 32}
 33
 34/**
 35 * argv_free - free an argv
 36 * @argv - the argument vector to be freed
 37 *
 38 * Frees an argv and the strings it points to.
 39 */
 40void argv_free(char **argv)
 41{
 42	char **p;
 43	for (p = argv; *p; p++)
 44		kfree(*p);
 45
 46	kfree(argv);
 47}
 48EXPORT_SYMBOL(argv_free);
 49
 50/**
 51 * argv_split - split a string at whitespace, returning an argv
 52 * @gfp: the GFP mask used to allocate memory
 53 * @str: the string to be split
 54 * @argcp: returned argument count
 55 *
 56 * Returns an array of pointers to strings which are split out from
 57 * @str.  This is performed by strictly splitting on white-space; no
 58 * quote processing is performed.  Multiple whitespace characters are
 59 * considered to be a single argument separator.  The returned array
 60 * is always NULL-terminated.  Returns NULL on memory allocation
 61 * failure.
 
 
 
 
 62 */
 63char **argv_split(gfp_t gfp, const char *str, int *argcp)
 64{
 65	int argc = count_argc(str);
 66	char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp);
 67	char **argvp;
 
 
 
 
 
 
 
 
 
 
 
 
 68
 69	if (argv == NULL)
 70		goto out;
 
 
 
 
 
 
 
 
 
 
 71
 72	if (argcp)
 73		*argcp = argc;
 74
 75	argvp = argv;
 76
 77	while (*str) {
 78		str = skip_spaces(str);
 79
 80		if (*str) {
 81			const char *p = str;
 82			char *t;
 83
 84			str = skip_arg(str);
 85
 86			t = kstrndup(p, str-p, gfp);
 87			if (t == NULL)
 88				goto fail;
 89			*argvp++ = t;
 90		}
 91	}
 92	*argvp = NULL;
 93
 94  out:
 95	return argv;
 96
 97  fail:
 98	argv_free(argv);
 99	return NULL;
100}
101EXPORT_SYMBOL(argv_split);