Line data    Source code

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