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

 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);