8e2b705649
It would be nice if the argv_split library function could gracefully handle a NULL pointer in the argcp parameter, so as to allow functions using it that did not care about the value of argc to not have to declare a useless variable. This patch accomplishes that. Tested by me, with successful results. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Satyam Sharma <satyam@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
108 lines
1.8 KiB
C
108 lines
1.8 KiB
C
/*
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* Helper function for splitting a string into an argv-like array.
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*/
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#include <linux/kernel.h>
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#include <linux/ctype.h>
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#include <linux/bug.h>
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static const char *skip_sep(const char *cp)
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{
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while (*cp && isspace(*cp))
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cp++;
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return cp;
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}
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static const char *skip_arg(const char *cp)
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{
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while (*cp && !isspace(*cp))
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cp++;
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return cp;
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}
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static int count_argc(const char *str)
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{
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int count = 0;
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while (*str) {
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str = skip_sep(str);
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if (*str) {
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count++;
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str = skip_arg(str);
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}
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}
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return count;
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}
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/**
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* argv_free - free an argv
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* @argv - the argument vector to be freed
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*
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* Frees an argv and the strings it points to.
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*/
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void argv_free(char **argv)
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{
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char **p;
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for (p = argv; *p; p++)
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kfree(*p);
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kfree(argv);
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}
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EXPORT_SYMBOL(argv_free);
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/**
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* argv_split - split a string at whitespace, returning an argv
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* @gfp: the GFP mask used to allocate memory
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* @str: the string to be split
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* @argcp: returned argument count
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*
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* Returns an array of pointers to strings which are split out from
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* @str. This is performed by strictly splitting on white-space; no
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* quote processing is performed. Multiple whitespace characters are
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* considered to be a single argument separator. The returned array
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* is always NULL-terminated. Returns NULL on memory allocation
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* failure.
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*/
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char **argv_split(gfp_t gfp, const char *str, int *argcp)
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{
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int argc = count_argc(str);
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char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp);
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char **argvp;
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if (argv == NULL)
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goto out;
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if (argcp)
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*argcp = argc;
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argvp = argv;
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while (*str) {
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str = skip_sep(str);
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if (*str) {
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const char *p = str;
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char *t;
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str = skip_arg(str);
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t = kstrndup(p, str-p, gfp);
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if (t == NULL)
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goto fail;
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*argvp++ = t;
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}
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}
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*argvp = NULL;
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out:
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return argv;
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fail:
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argv_free(argv);
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return NULL;
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}
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EXPORT_SYMBOL(argv_split);
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