argv_split() is a helper function which takes a string, splits it at
whitespace, and returns a NULL-terminated argv vector. This is
deliberately simple - it does no quote processing of any kind.
[ Seems to me that this is something which is already being done in
the kernel, but I couldn't find any other implementations, either to
steal or replace. Keep an eye out. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
---
include/linux/string.h | 3 +
lib/Makefile | 2
lib/argv_split.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 110 insertions(+), 1 deletion(-)
===================================================================
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -108,6 +108,9 @@ extern char *kstrndup(const char *s, siz
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
+extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
+extern void argv_free(char **argv);
+
#ifdef __cplusplus
}
#endif
===================================================================
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,7 +5,7 @@ lib-y := ctype.o string.o vsprintf.o cmd
lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o dump_stack.o \
idr.o int_sqrt.o bitmap.o extable.o prio_tree.o \
- sha1.o irq_regs.o reciprocal_div.o
+ sha1.o irq_regs.o reciprocal_div.o argv_split.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
===================================================================
--- /dev/null
+++ b/lib/argv_split.c
@@ -0,0 +1,106 @@
+/*
+ * Helper function for splitting a string into an argv-like array.
+ */
+
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/bug.h>
+
+static const char *skip_sep(const char *cp)
+{
+ while (*cp && isspace(*cp))
+ cp++;
+
+ return cp;
+}
+
+static const char *skip_arg(const char *cp)
+{
+ while (*cp && !isspace(*cp))
+ cp++;
+
+ return cp;
+}
+
+static int count_argc(const char *str)
+{
+ int count = 0;
+
+ while (*str) {
+ str = skip_sep(str);
+ if (*str) {
+ count++;
+ str = skip_arg(str);
+ }
+ }
+
+ 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)
+{
+ char **p;
+ for (p = argv; *p; p++)
+ kfree(*p);
+
+ 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.
+ */
+char **argv_split(gfp_t gfp, const char *str, int *argcp)
+{
+ int argc = count_argc(str);
+ char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp);
+ char **argvp;
+
+ if (argv == NULL)
+ goto out;
+
+ *argcp = argc;
+ argvp = argv;
+
+ while (*str) {
+ str = skip_sep(str);
+
+ if (*str) {
+ const char *p = str;
+ char *t;
+
+ str = skip_arg(str);
+
+ t = kstrndup(p, str-p, gfp);
+ if (t == NULL)
+ goto fail;
+ *argvp++ = t;
+ }
+ }
+ *argvp = NULL;
+
+ out:
+ return argv;
+
+ fail:
+ argv_free(argv);
+ return NULL;
+}
+EXPORT_SYMBOL(argv_split);
--
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