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 | |
12 | static 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 | */ |
35 | void argv_free(char **argv) |
36 | { |
37 | argv--; |
38 | kfree(objp: argv[0]); |
39 | kfree(objp: argv); |
40 | } |
41 | EXPORT_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 | */ |
60 | char **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(s: str, KMALLOC_MAX_SIZE - 1, gfp); |
68 | if (!argv_str) |
69 | return NULL; |
70 | |
71 | argc = count_argc(str: argv_str); |
72 | argv = kmalloc_array(n: argc + 2, size: sizeof(*argv), flags: gfp); |
73 | if (!argv) { |
74 | kfree(objp: 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 | } |
95 | EXPORT_SYMBOL(argv_split); |
96 |