lib/dpkg/string.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * string.c - string handling routines
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2008-2015 Guillem Jover <guillem@debian.org>
   7  *
   8  * This is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <config.h>
  23 #include <compat.h>
  24
  25 #include <string.h>
  26
  27 #include <dpkg/c-ctype.h>
  28 #include <dpkg/string.h>
  29 #include <dpkg/dpkg.h>
  30
  31 char *
  32 str_concat(char *dst, ...)
  33 {
  34         va_list args;
  35         const char *src;
  36         size_t len;
  37
  38         va_start(args, dst);
  39         while ((src = va_arg(args, const char *))) {
  40                 len = strlen(src);
  41                 memcpy(dst, src, len);
  42                 dst += len;
  43         }
  44         va_end(args);
  45         *dst = '\0';
  46
  47         return dst;
  48 }
  49
  50 /**
  51  * Match the end of a string.
  52  *
  53  * @param str The string.
  54  * @param end The end to match in str.
  55  *
  56  * @return Whether the string was matched at the end.
  57  */
  58 bool
  59 str_match_end(const char *str, const char *end)
  60 {
  61         size_t str_len = strlen(str);
  62         size_t end_len = strlen(end);
  63         const char *str_end = str + str_len - end_len;
  64
  65         if (str_len >= end_len && strcmp(str_end, end) == 0)
  66                 return true;
  67         else
  68                 return false;
  69 }
  70
  71 /**
  72  * Print formatted output to an allocated string.
  73  *
  74  * @param fmt The format string.
  75  * @param ... The format arguments.
  76  *
  77  * @return The new allocated formatted output string (never NULL).
  78  */
  79 char *
  80 str_fmt(const char *fmt, ...)
  81 {
  82         va_list args;
  83         char *str;
  84
  85         va_start(args, fmt);
  86         m_vasprintf(&str, fmt, args);
  87         va_end(args);
  88
  89         return str;
  90 }
  91
  92 /**
  93  * Escape format characters from a string.
  94  *
  95  * @param dst The destination string.
  96  * @param src The source string.
  97  * @param n The size of the destination buffer.
  98  *
  99  * @return The end of the destination string.
 100  */
 101 char *
 102 str_escape_fmt(char *dst, const char *src, size_t n)
 103 {
 104         char *d = dst;
 105         const char *s = src;
 106
 107         if (n == 0)
 108                 return d;
 109
 110         while (*s) {
 111                 if (*s == '%') {
 112                         if (n-- <= 2)
 113                                 break;
 114                         *d++ = '%';
 115                 }
 116                 if (n-- <= 1)
 117                         break;
 118                 *d++ = *s++;
 119         }
 120
 121         *d = '\0';
 122
 123         return d;
 124 }
 125
 126 /**
 127  * Quote shell metacharacters in a string.
 128  *
 129  * This function allows passing strings to commands without splitting the
 130  * arguments, like in system(3)
 131  *
 132  * @param src The source string to escape.
 133  *
 134  * @return The new allocated string (never NULL).
 135  */
 136 char *
 137 str_quote_meta(const char *src)
 138 {
 139         char *new_dst, *dst;
 140
 141         new_dst = dst = m_malloc(strlen(src) * 2);
 142
 143         while (*src) {
 144                 if (!c_isdigit(*src) && !c_isalpha(*src))
 145                         *dst++ = '\\';
 146
 147                 *dst++ = *src++;
 148         }
 149
 150         *dst = '\0';
 151
 152         return new_dst;
 153 }
 154
 155 /**
 156  * Check and strip possible surrounding quotes in string.
 157  *
 158  * @param str The string to act on.
 159  *
 160  * @return A pointer to str or NULL if the quotes were unbalanced.
 161  */
 162 char *
 163 str_strip_quotes(char *str)
 164 {
 165         if (str[0] == '"' || str[0] == '\'') {
 166                 size_t str_len = strlen(str);
 167
 168                 if (str[0] != str[str_len - 1])
 169                         return NULL;
 170
 171                 /* Remove surrounding quotes. */
 172                 str[str_len - 1] = '\0';
 173                 str++;
 174         }
 175
 176         return str;
 177 }
 178
 179 /**
 180  * Trim possible ending spaces in string.
 181  *
 182  * @param str The string to act on.
 183  *
 184  * @return A pointer to the end of the trimmed string.
 185  */
 186 char *
 187 str_rtrim_spaces(const char *str, char *str_end)
 188 {
 189         while (str_end > str && c_isspace(str_end[-1]))
 190                 str_end--;
 191         if (str_end >= str)
 192                 *str_end = '\0';
 193         return str_end;
 194 }