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1 /* xputenv.c: set an environment variable without return. |
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2 |
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3 Copyright (C) 1993, 94 Karl Berry. |
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4 |
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5 This program is free software; you can redistribute it and/or modify |
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6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 2, or (at your option) |
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8 any later version. |
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9 |
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10 This program is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 GNU General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU General Public License |
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16 along with this program; if not, write to the Free Software |
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17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
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18 |
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19 #include <kpathsea/config.h> |
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20 |
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21 /* Avoid implicit declaration warning. */ |
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22 extern int putenv (); |
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23 |
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24 /* This `x' function is different from the others in that it takes |
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25 different parameters than the standard function; but I find it much |
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26 more convenient to pass the variable and the value separately. Also, |
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27 this way we can guarantee that the environment value won't become |
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28 garbage. Also, putenv just overwrites old entries with |
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29 the new, and we want to reclaim that space -- this may be called |
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30 hundreds of times on a run. |
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31 |
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32 But naturally, some systems do it differently. In this case, it's |
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33 net2 that is smart and does its own saving/freeing. If you can write |
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34 a test for configure to check this, please send it to me. Until then, |
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35 you'll have to define SMART_PUTENV yourself. */ |
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36 |
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37 void |
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38 xputenv P2C(const_string, var_name, const_string, value) |
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39 { |
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40 static const_string *saved_env_items = NULL; |
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41 static unsigned saved_len; |
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42 string old_item = NULL; |
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43 string new_item = concat3 (var_name, "=", value); |
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44 |
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45 #ifndef SMART_PUTENV |
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46 /* Check if we have saved anything yet. */ |
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47 if (!saved_env_items) |
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48 { |
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49 saved_env_items = XTALLOC1 (const_string); |
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50 saved_env_items[0] = var_name; |
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51 saved_len = 1; |
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52 } |
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53 else |
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54 { |
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55 /* Check if we've assigned VAR_NAME before. */ |
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56 unsigned i; |
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57 unsigned len = strlen (var_name); |
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58 for (i = 0; i < saved_len && !old_item; i++) |
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59 { |
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60 if (STREQ (saved_env_items[i], var_name)) |
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61 { |
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62 old_item = getenv (var_name); |
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63 assert (old_item); |
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64 /* Back up to the `NAME=' in the environment before the |
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65 value that getenv returns. */ |
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66 old_item -= (len + 1); |
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67 } |
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68 } |
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69 |
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70 if (!old_item) |
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71 { |
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72 /* If we haven't seen VAR_NAME before, save it. Assume it is |
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73 in safe storage. */ |
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74 saved_len++; |
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75 XRETALLOC (saved_env_items, saved_len, const_string); |
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76 saved_env_items[saved_len - 1] = var_name; |
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77 } |
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78 } |
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79 #endif /* not SMART_PUTENV */ |
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80 |
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81 /* As far as I can see there's no way to distinguish between the |
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82 various errors; putenv doesn't have errno values. */ |
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83 if (putenv (new_item) < 0) |
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84 FATAL1 ("putenv (%s) failed", new_item); |
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85 |
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86 #ifndef SMART_PUTENV |
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87 /* Can't free `new_item' because its contained value is now in |
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88 `environ', but we can free `old_item', since it's been replaced. */ |
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89 if (old_item) |
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90 free (old_item); |
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91 #endif /* not SMART_PUTENV */ |
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92 } |
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93 |
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94 |
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95 /* A special case for setting a variable to a numeric value |
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96 (specifically, KPATHSEA_DPI). We don't need to dynamically allocate |
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97 and free the string for the number, since it's saved as part of the |
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98 environment value. */ |
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99 |
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100 void |
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101 xputenv_int P2C(const_string, var_name, int, num) |
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102 { |
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103 char str[MAX_INT_LENGTH]; |
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104 sprintf (str, "%d", num); |
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105 |
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106 xputenv (var_name, str); |
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107 } |
