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/slab.h>
8 #include <linux/module.h>
9
10 static const char *skip_sep(const char *cp)
11 {
12 while (*cp && isspace(*cp))
13 cp++;
14
15 return cp;
16 }
17
18 static const char *skip_arg(const char *cp)
19 {
20 while (*cp && !isspace(*cp))
21 cp++;
22
23 return cp;
24 }
25
26 static int count_argc(const char *str)
27 {
28 int count = 0;
29
30 while (*str) {
31 str = skip_sep(str);
32 if (*str) {
33 count++;
34 str = skip_arg(str);
35 }
36 }
37
38 return count;
39 }
40
41 /**
42 * argv_free - free an argv
43 * @argv - the argument vector to be freed
44 *
45 * Frees an argv and the strings it points to.
46 */
47 void argv_free(char **argv)
48 {
49 char **p;
50 for (p = argv; *p; p++)
51 kfree(*p);
52
53 kfree(argv);
54 }
55 EXPORT_SYMBOL(argv_free);
56
57 /**
58 * argv_split - split a string at whitespace, returning an argv
59 * @gfp: the GFP mask used to allocate memory
60 * @str: the string to be split
61 * @argcp: returned argument count
62 *
63 * Returns an array of pointers to strings which are split out from
64 * @str. This is performed by strictly splitting on white-space; no
65 * quote processing is performed. Multiple whitespace characters are
66 * considered to be a single argument separator. The returned array
67 * is always NULL-terminated. Returns NULL on memory allocation
68 * failure.
69 */
70 char **argv_split(gfp_t gfp, const char *str, int *argcp)
71 {
72 int argc = count_argc(str);
73 char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp);
74 char **argvp;
75
76 if (argv == NULL)
77 goto out;
78
79 if (argcp)
80 *argcp = argc;
81
82 argvp = argv;
83
84 while (*str) {
85 str = skip_sep(str);
86
87 if (*str) {
88 const char *p = str;
89 char *t;
90
91 str = skip_arg(str);
92
93 t = kstrndup(p, str-p, gfp);
94 if (t == NULL)
95 goto fail;
96 *argvp++ = t;
97 }
98 }
99 *argvp = NULL;
100
101 out:
102 return argv;
103
104 fail:
105 argv_free(argv);
106 return NULL;
107 }
108 EXPORT_SYMBOL(argv_split);
109
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