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
  37         va_start(args, dst);
  38         while ((src = va_arg(args, const char *))) {
  39                 size_t len;
  40
  41                 len = strlen(src);
  42                 memcpy(dst, src, len);
  43                 dst += len;
  44         }
  45         va_end(args);
  46         *dst = '\0';
  47
  48         return dst;
  49 }
  50
  51 /**
  52  * Match the end of a string.
  53  *
  54  * @param str The string.
  55  * @param end The end to match in str.
  56  *
  57  * @return Whether the string was matched at the end.
  58  */
  59 bool
  60 str_match_end(const char *str, const char *end)
  61 {
  62         size_t str_len = strlen(str);
  63         size_t end_len = strlen(end);
  64         const char *str_end = str + str_len - end_len;
  65
  66         if (str_len >= end_len && strcmp(str_end, end) == 0)
  67                 return true;
  68         else
  69                 return false;
  70 }
  71
  72 /**
  73  * Print formatted output to an allocated string.
  74  *
  75  * @param fmt The format string.
  76  * @param ... The format arguments.
  77  *
  78  * @return The new allocated formatted output string (never NULL).
  79  */
  80 char *
  81 str_fmt(const char *fmt, ...)
  82 {
  83         va_list args;
  84         char *str;
  85
  86         va_start(args, fmt);
  87         m_vasprintf(&str, fmt, args);
  88         va_end(args);
  89
  90         return str;
  91 }
  92
  93 /**
  94  * Escape format characters from a string.
  95  *
  96  * @param dst The destination string.
  97  * @param src The source string.
  98  * @param n The size of the destination buffer.
  99  *
 100  * @return The end of the destination string.
 101  */
 102 char *
 103 str_escape_fmt(char *dst, const char *src, size_t n)
 104 {
 105         char *d = dst;
 106         const char *s = src;
 107
 108         if (n == 0)
 109                 return d;
 110
 111         while (*s) {
 112                 if (*s == '%') {
 113                         if (n-- <= 2)
 114                                 break;
 115                         *d++ = '%';
 116                 }
 117                 if (n-- <= 1)
 118                         break;
 119                 *d++ = *s++;
 120         }
 121
 122         *d = '\0';
 123
 124         return d;
 125 }
 126
 127 /**
 128  * Quote shell metacharacters in a string.
 129  *
 130  * This function allows passing strings to commands without splitting the
 131  * arguments, like in system(3)
 132  *
 133  * @param src The source string to escape.
 134  *
 135  * @return The new allocated string (never NULL).
 136  */
 137 char *
 138 str_quote_meta(const char *src)
 139 {
 140         char *new_dst, *dst;
 141
 142         new_dst = dst = m_malloc(strlen(src) * 2);
 143
 144         while (*src) {
 145                 if (!c_isdigit(*src) && !c_isalpha(*src))
 146                         *dst++ = '\\';
 147
 148                 *dst++ = *src++;
 149         }
 150
 151         *dst = '\0';
 152
 153         return new_dst;
 154 }
 155
 156 /**
 157  * Check and strip possible surrounding quotes in string.
 158  *
 159  * @param str The string to act on.
 160  *
 161  * @return A pointer to str or NULL if the quotes were unbalanced.
 162  */
 163 char *
 164 str_strip_quotes(char *str)
 165 {
 166         if (str[0] == '"' || str[0] == '\'') {
 167                 size_t str_len = strlen(str);
 168
 169                 if (str[0] != str[str_len - 1])
 170                         return NULL;
 171
 172                 /* Remove surrounding quotes. */
 173                 str[str_len - 1] = '\0';
 174                 str++;
 175         }
 176
 177         return str;
 178 }
 179
 180 /**
 181  * Trim possible ending spaces in string.
 182  *
 183  * @param str The string to act on.
 184  * @param str_end The end of the string to act on.
 185  *
 186  * @return A pointer to the end of the trimmed string.
 187  */
 188 char *
 189 str_rtrim_spaces(const char *str, char *str_end)
 190 {
 191         while (str_end > str && c_isspace(str_end[-1]))
 192                 str_end--;
 193         if (str_end >= str)
 194                 *str_end = '\0';
 195         return str_end;
 196 }