1  //    Copyright 2005-2014, various authors
  2  //
  3  //    This program is free software; you can redistribute it and/or modify
  4  //    it under the terms of the GNU General Public License as published by
  5  //    the Free Software Foundation; either version 2 of the License, or
  6  //    (at your option) any later version.
  7  //
  8  //    This program is distributed in the hope that it will be useful,
  9  //    but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  //    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  //    GNU General Public License for more details.
 12  //
 13  //    You should have received a copy of the GNU General Public License
 14  //    along with this program; if not, write to the Free Software
 15  //    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 16  
 17  //
 18  // This file contains some handy string parsing functions lifted from Linux
 19  // 2.6.27.44, from the files mm/util.c and lib/argv_split.c.
 20  //
 21  // It gets compiled into the hostmot2 driver if the kernel does not provide
 22  // its own versions of these functions: argv_split(), argv_free(), and
 23  // kstrndup().
 24  //
 25  
 26  
 27  #include <rtapi_ctype.h>
 28  #include <rtapi_slab.h>
 29  #include <rtapi_string.h>
 30  
 31  /**
 32   * rtapi_kstrndup - allocate space for and copy an existing string
 33   * @s: the string to duplicate
 34   * @max: read at most @max chars from @s
 35   * @gfp: the GFP mask used in the rtapi_kmalloc() call when allocating memory
 36   */
 37  char *rtapi_kstrndup(const char *s, size_t max, rtapi_gfp_t gfp)
 38  {
 39  	size_t len;
 40  	char *buf;
 41  
 42  	if (!s)
 43  		return NULL;
 44  
 45  	len = strnlen(s, max);
 46  	buf = rtapi_kmalloc(len+1, gfp);
 47  	if (buf) {
 48  		memcpy(buf, s, len);
 49  		buf[len] = '\0';
 50  	}
 51  	return buf;
 52  }
 53  
 54  
 55  /*
 56   * Helper function for splitting a string into an argv-like array.
 57   */
 58  
 59  static const char *skip_sep(const char *cp)
 60  {
 61  	while (*cp && isspace(*cp))
 62  		cp++;
 63  
 64  	return cp;
 65  }
 66  
 67  static const char *skip_arg(const char *cp)
 68  {
 69  	while (*cp && !isspace(*cp))
 70  		cp++;
 71  
 72  	return cp;
 73  }
 74  
 75  static int count_argc(const char *str)
 76  {
 77  	int count = 0;
 78  
 79  	while (*str) {
 80  		str = skip_sep(str);
 81  		if (*str) {
 82  			count++;
 83  			str = skip_arg(str);
 84  		}
 85  	}
 86  
 87  	return count;
 88  }
 89  
 90  /**
 91   * rtapi_argv_free - free an argv
 92   * @argv - the argument vector to be freed
 93   *
 94   * Frees an argv and the strings it points to.
 95   */
 96  void rtapi_argv_free(char **argv)
 97  {
 98  	char **p;
 99  	for (p = argv; *p; p++)
100  		rtapi_kfree(*p);
101  
102  	rtapi_kfree(argv);
103  }
104  
105  /**
106   * rtapi_argv_split - split a string at whitespace, returning an argv
107   * @gfp: the GFP mask used to allocate memory
108   * @str: the string to be split
109   * @argcp: returned argument count
110   *
111   * Returns an array of pointers to strings which are split out from
112   * @str.  This is performed by strictly splitting on white-space; no
113   * quote processing is performed.  Multiple whitespace characters are
114   * considered to be a single argument separator.  The returned array
115   * is always NULL-terminated.  Returns NULL on memory allocation
116   * failure.
117   */
118  char **rtapi_argv_split(rtapi_gfp_t gfp, const char *str, int *argcp)
119  {
120  	int argc = count_argc(str);
121  	char **argv = rtapi_kzalloc(sizeof(*argv) * (argc+1), gfp);
122  	char **argvp;
123  
124  	if (argv == NULL)
125  		goto out;
126  
127  	if (argcp)
128  		*argcp = argc;
129  
130  	argvp = argv;
131  
132  	while (*str) {
133  		str = skip_sep(str);
134  
135  		if (*str) {
136  			const char *p = str;
137  			char *t;
138  
139  			str = skip_arg(str);
140  
141  			t = rtapi_kstrndup(p, str-p, gfp);
142  			if (t == NULL)
143  				goto fail;
144  			*argvp++ = t;
145  		}
146  	}
147  	*argvp = NULL;
148  
149    out:
150  	return argv;
151  
152    fail:
153  	rtapi_argv_free(argv);
154  	return NULL;
155  }
156  
157  EXPORT_SYMBOL(rtapi_kstrndup);
158  EXPORT_SYMBOL(rtapi_argv_split);
159  EXPORT_SYMBOL(rtapi_argv_free);