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argv_split.c
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argv_split.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Helper function for splitting a string into an argv-like array.
*/
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/export.h>
static int count_argc(const char *str)
{
int count = 0;
bool was_space;
for (was_space = true; *str; str++) {
if (isspace(*str)) {
was_space = true;
} else if (was_space) {
was_space = false;
count++;
}
}
return count;
}
/**
* argv_free - free an argv
* @argv - the argument vector to be freed
*
* Frees an argv and the strings it points to.
*/
void argv_free(char **argv)
{
argv--;
kfree(argv[0]);
kfree(argv);
}
EXPORT_SYMBOL(argv_free);
/**
* argv_split - split a string at whitespace, returning an argv
* @gfp: the GFP mask used to allocate memory
* @str: the string to be split
* @argcp: returned argument count
*
* Returns an array of pointers to strings which are split out from
* @str. This is performed by strictly splitting on white-space; no
* quote processing is performed. Multiple whitespace characters are
* considered to be a single argument separator. The returned array
* is always NULL-terminated. Returns NULL on memory allocation
* failure.
*
* The source string at `str' may be undergoing concurrent alteration via
* userspace sysctl activity (at least). The argv_split() implementation
* attempts to handle this gracefully by taking a local copy to work on.
*/
char **argv_split(gfp_t gfp, const char *str, int *argcp)
{
char *argv_str;
bool was_space;
char **argv, **argv_ret;
int argc;
argv_str = kstrndup(str, KMALLOC_MAX_SIZE - 1, gfp);
if (!argv_str)
return NULL;
argc = count_argc(argv_str);
argv = kmalloc_array(argc + 2, sizeof(*argv), gfp);
if (!argv) {
kfree(argv_str);
return NULL;
}
*argv = argv_str;
argv_ret = ++argv;
for (was_space = true; *argv_str; argv_str++) {
if (isspace(*argv_str)) {
was_space = true;
*argv_str = 0;
} else if (was_space) {
was_space = false;
*argv++ = argv_str;
}
}
*argv = NULL;
if (argcp)
*argcp = argc;
return argv_ret;
}
EXPORT_SYMBOL(argv_split);