1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Helper function for splitting a string into an argv-like array.
4 */
5
6 #include <stdlib.h>
7 #include <linux/kernel.h>
8 #include <linux/ctype.h>
9 #include <linux/string.h>
10
11 static const char *skip_arg(const char *cp)
12 {
13 while (*cp && !isspace(*cp))
14 cp++;
15
16 return cp;
17 }
18
19 static 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 */
40 void argv_free(char **argv)
41 {
42 char **p;
43 for (p = argv; *p; p++) {
44 free(*p);
45 *p = NULL;
46 }
47
48 free(argv);
49 }
50
51 /**
52 * argv_split - split a string at whitespace, returning an argv
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 */
63 char **argv_split(const char *str, int *argcp)
64 {
65 int argc = count_argc(str);
66 char **argv = calloc(argc + 1, sizeof(*argv));
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 = strndup(p, str-p);
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 }