src/basic/strxcpyx.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2013 Kay Sievers
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 /*
  22  * Concatenates/copies strings. In any case, terminates in all cases
  23  * with '\0' and moves the @dest pointer forward to the added '\0'.
  24  * Returns the remaining size, and 0 if the string was truncated.
  25  *
  26  * Due to the intended usage, these helpers silently noop invocations
  27  * having zero size.  This is technically an exception to the above
  28  * statement "terminates in all cases".  It's unexpected for such calls to
  29  * occur outside of a loop where this is the preferred behavior.
  30  */
  31
  32 #include <stdarg.h>
  33 #include <stdio.h>
  34 #include <string.h>
  35
  36 #include "strxcpyx.h"
  37
  38 size_t strpcpy(char **dest, size_t size, const char *src) {
  39         size_t len;
  40
  41         assert(dest);
  42         assert(src);
  43
  44         if (size == 0)
  45                 return 0;
  46
  47         len = strlen(src);
  48         if (len >= size) {
  49                 if (size > 1)
  50                         *dest = mempcpy(*dest, src, size-1);
  51                 size = 0;
  52         } else {
  53                 if (len > 0) {
  54                         *dest = mempcpy(*dest, src, len);
  55                         size -= len;
  56                 }
  57         }
  58         *dest[0] = '\0';
  59         return size;
  60 }
  61
  62 size_t strpcpyf(char **dest, size_t size, const char *src, ...) {
  63         va_list va;
  64         int i;
  65
  66         assert(dest);
  67         assert(src);
  68
  69         if (size == 0)
  70                 return 0;
  71
  72         va_start(va, src);
  73         i = vsnprintf(*dest, size, src, va);
  74         if (i < (int)size) {
  75                 *dest += i;
  76                 size -= i;
  77         } else {
  78                 size = 0;
  79         }
  80         va_end(va);
  81         return size;
  82 }
  83
  84 size_t strpcpyl(char **dest, size_t size, const char *src, ...) {
  85         va_list va;
  86
  87         assert(dest);
  88         assert(src);
  89
  90         va_start(va, src);
  91         do {
  92                 size = strpcpy(dest, size, src);
  93                 src = va_arg(va, char *);
  94         } while (src != NULL);
  95         va_end(va);
  96         return size;
  97 }
  98
  99 size_t strscpy(char *dest, size_t size, const char *src) {
 100         char *s;
 101
 102         assert(dest);
 103         assert(src);
 104
 105         s = dest;
 106         return strpcpy(&s, size, src);
 107 }
 108
 109 size_t strscpyl(char *dest, size_t size, const char *src, ...) {
 110         va_list va;
 111         char *s;
 112
 113         assert(dest);
 114         assert(src);
 115
 116         va_start(va, src);
 117         s = dest;
 118         do {
 119                 size = strpcpy(&s, size, src);
 120                 src = va_arg(va, char *);
 121         } while (src != NULL);
 122         va_end(va);
 123
 124         return size;
 125 }