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1// SPDX-License-Identifier: GPL-2.02/*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 12static 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 argv31 * @argv: the argument vector to be freed32 *33 * Frees an argv and the strings it points to.34 */35void argv_free(char **argv)36{37 argv--;38 kfree(argv[0]);39 kfree(argv);40}41EXPORT_SYMBOL(argv_free);42 43/**44 * argv_split - split a string at whitespace, returning an argv45 * @gfp: the GFP mask used to allocate memory46 * @str: the string to be split47 * @argcp: returned argument count48 *49 * Returns: an array of pointers to strings which are split out from50 * @str. This is performed by strictly splitting on white-space; no51 * quote processing is performed. Multiple whitespace characters are52 * considered to be a single argument separator. The returned array53 * is always NULL-terminated. Returns NULL on memory allocation54 * failure.55 *56 * The source string at `str' may be undergoing concurrent alteration via57 * userspace sysctl activity (at least). The argv_split() implementation58 * attempts to handle this gracefully by taking a local copy to work on.59 */60char **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(str, KMALLOC_MAX_SIZE - 1, gfp);68 if (!argv_str)69 return NULL;70 71 argc = count_argc(argv_str);72 argv = kmalloc_array(argc + 2, sizeof(*argv), gfp);73 if (!argv) {74 kfree(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}95EXPORT_SYMBOL(argv_split);96