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Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -07001/*
2 * Helper function for splitting a string into an argv-like array.
3 */
4
5#include <linux/kernel.h>
6#include <linux/ctype.h>
André Goddard Rosae7d28602009-12-14 18:01:06 -08007#include <linux/string.h>
Robert P. J. Day5a56db12007-10-20 00:25:12 +02008#include <linux/slab.h>
9#include <linux/module.h>
Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -070010
Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -070011static 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) {
André Goddard Rosae7d28602009-12-14 18:01:06 -080024 str = skip_spaces(str);
Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -070025 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
Neil Horman8e2b7052007-10-16 23:26:33 -070072 if (argcp)
73 *argcp = argc;
74
Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -070075 argvp = argv;
76
77 while (*str) {
André Goddard Rosae7d28602009-12-14 18:01:06 -080078 str = skip_spaces(str);
Jeremy Fitzhardinged84d1cc2007-07-17 18:37:02 -070079
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);