| 1 | |
| 2 | * Helper function for splitting a string into an argv-like array.
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| 3 |
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| 4 |
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| 5 | #include <linux/kernel.h>
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| 6 | #include <linux/ctype.h>
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| 7 | #include <linux/string.h>
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| 8 | #include <linux/slab.h>
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| 9 | #include <linux/export.h>
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| 10 |
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| 11 | static int count_argc(const char *str)
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| 12 | {
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| 13 | int count = 0;
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| 14 | bool was_space;
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| 15 |
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| 16 | for (was_space = true; *str; str++) {
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| 17 | if (isspace(*str)) {
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| 18 | was_space = true;
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| 19 | } else if (was_space) {
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| 20 | was_space = false;
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| 21 | count++;
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| 22 | }
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| 23 | }
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| 24 |
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| 25 | return count;
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| 26 | }
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| 27 |
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| 28 | |
| 29 | * argv_free - free an argv
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| 30 | * @argv - the argument vector to be freed
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| 31 | *
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| 32 | * Frees an argv and the strings it points to.
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| 33 |
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| 34 | void argv_free(char **argv)
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| 35 | {
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| 36 | argv--;
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| 37 | kfree(argv[0]);
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| 38 | kfree(argv);
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| 39 | }
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| 40 | EXPORT_SYMBOL(argv_free);
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| 41 |
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| 42 | |
| 43 | * argv_split - split a string at whitespace, returning an argv
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| 44 | * @gfp: the GFP mask used to allocate memory
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| 45 | * @str: the string to be split
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| 46 | * @argcp: returned argument count
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| 47 | *
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| 48 | * Returns an array of pointers to strings which are split out from
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| 49 | * @str. This is performed by strictly splitting on white-space; no
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| 50 | * quote processing is performed. Multiple whitespace characters are
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| 51 | * considered to be a single argument separator. The returned array
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| 52 | * is always NULL-terminated. Returns NULL on memory allocation
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| 53 | * failure.
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| 54 | *
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| 55 | * The source string at `str' may be undergoing concurrent alteration via
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| 56 | * userspace sysctl activity (at least). The argv_split() implementation
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| 57 | * attempts to handle this gracefully by taking a local copy to work on.
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| 58 |
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| 59 | char **argv_split(gfp_t gfp, const char *str, int *argcp)
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| 60 | {
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| 61 | char *argv_str;
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| 62 | bool was_space;
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| 63 | char **argv, **argv_ret;
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| 64 | int argc;
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| 65 |
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| 66 | argv_str = kstrndup(str, KMALLOC_MAX_SIZE - 1, gfp);
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| 67 | if (!argv_str)
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| 68 | return NULL;
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| 69 |
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| 70 | argc = count_argc(argv_str);
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| 71 | argv = kmalloc(sizeof(*argv) * (argc + 2), gfp);
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| 72 | if (!argv) {
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| 73 | kfree(argv_str);
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| 74 | return NULL;
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| 75 | }
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| 76 |
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| 77 | *argv = argv_str;
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| 78 | argv_ret = ++argv;
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| 79 | for (was_space = true; *argv_str; argv_str++) {
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| 80 | if (isspace(*argv_str)) {
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| 81 | was_space = true;
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| 82 | *argv_str = 0;
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| 83 | } else if (was_space) {
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| 84 | was_space = false;
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| 85 | *argv++ = argv_str;
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| 86 | }
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| 87 | }
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| 88 | *argv = NULL;
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| 89 |
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| 90 | if (argcp)
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| 91 | *argcp = argc;
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| 92 | return argv_ret;
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| 93 | }
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| 94 | EXPORT_SYMBOL(argv_split);
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