environment grooming
[exim.git] / src / src / environment.c
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
5/* Copyright (c) Heiko Schlittermann 2016
6 * hs@schlittermann.de
7 * See the file NOTICE for conditions of use and distribution.
8 */
9
10#include "exim.h"
11
2478dbdf 12extern char **environ;
2478dbdf 13
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14/* The cleanup_environment() function is used during the startup phase
15of the Exim process, right after reading the configurations main
16part, before any expansions take place. It retains the environment
17variables we trust (via the keep_environment option) and allows to
18set additional variables (via add_environment).
19
20Returns: TRUE if successful
21 FALSE otherwise
22*/
23
24BOOL
25cleanup_environment()
26{
27if (!keep_environment || *keep_environment == '\0')
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28 {
29 /* From: https://github.com/dovecot/core/blob/master/src/lib/env-util.c#L55
30 Try to clear the environment.
31 a) environ = NULL crashes on OS X.
32 b) *environ = NULL doesn't work on FreeBSD 7.0.
33 c) environ = emptyenv doesn't work on Haiku OS
34 d) environ = calloc() should work everywhere */
35
36 if (environ) *environ = NULL;
37
38 }
bc3c7bb7 39else if (Ustrcmp(keep_environment, "*") != 0)
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40 {
41 rmark reset_point = store_mark();
d7978c0f 42 if (environ) for (uschar ** p = USS environ; *p; /* see below */)
bc3c7bb7 43 {
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44 /* It's considered broken if we do not find the '=', according to
45 Florian Weimer. For now we ignore such strings. unsetenv() would complain,
46 getenv() would complain. */
93a680e4 47 uschar * eqp = Ustrchr(*p, '=');
bc3c7bb7 48
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49 if (eqp)
50 {
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51 uschar * name = string_copyn(*p, eqp - *p);
52
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53 if (OK != match_isinlist(name, CUSS &keep_environment,
54 0, NULL, NULL, MCL_NOEXPAND, FALSE, NULL))
271019bd 55 if (os_unsetenv(name) < 0) return FALSE;
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56 else p = USS environ; /* RESTART from the beginning */
57 else p++;
2478dbdf 58 }
bc3c7bb7 59 }
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60 store_reset(reset_point);
61 }
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62#ifndef DISABLE_TLS
63tls_clean_env();
64#endif
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65if (add_environment)
66 {
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67 uschar * p;
68 int sep = 0;
69 const uschar * envlist = add_environment;
93a680e4 70
f3ebb786 71 while ((p = string_nextinlist(&envlist, &sep, NULL, 0))) putenv(CS p);
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72 }
73
f3ebb786 74return TRUE;
bc3c7bb7 75}