summaryrefslogtreecommitdiff
path: root/tests/setenv.c
blob: 7505716ef6669b86741a41eb5c76646a3c2aeafb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
/* Copyright (C) 1992, 1995-2003, 2005-2024 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#if !_LIBC
/* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
   optimizes away the name == NULL test below.  */
# define _GL_ARG_NONNULL(params)

# define _GL_USE_STDLIB_ALLOC 1
# include <config.h>
#endif

#include <alloca.h>

/* Specification.  */
#include <stdlib.h>

#include <errno.h>
#ifndef __set_errno
# define __set_errno(ev) ((errno) = (ev))
#endif

#include <string.h>
#if _LIBC || HAVE_UNISTD_H
# include <unistd.h>
#endif

#if defined _WIN32 && ! defined __CYGWIN__
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif

#if !_LIBC
# include "malloca.h"
#endif

#if defined _WIN32 && ! defined __CYGWIN__
/* Don't assume that UNICODE is not defined.  */
# undef SetEnvironmentVariable
# define SetEnvironmentVariable SetEnvironmentVariableA
#endif

#if _LIBC || !HAVE_SETENV
#if !HAVE_DECL__PUTENV

#if !_LIBC
# define __environ      environ
#endif

#if _LIBC
/* This lock protects against simultaneous modifications of 'environ'.  */
# include <bits/libc-lock.h>
__libc_lock_define_initialized (static, envlock)
# define LOCK   __libc_lock_lock (envlock)
# define UNLOCK __libc_lock_unlock (envlock)
#else
# define LOCK
# define UNLOCK
#endif

/* In the GNU C library we must keep the namespace clean.  */
#ifdef _LIBC
# define setenv __setenv
# define clearenv __clearenv
# define tfind __tfind
# define tsearch __tsearch
#endif

/* In the GNU C library implementation we try to be more clever and
   allow arbitrarily many changes of the environment given that the used
   values are from a small set.  Outside glibc this will eat up all
   memory after a while.  */
#if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
                      && (defined __GNUC__ || defined __clang__))
# define USE_TSEARCH    1
# include <search.h>
typedef int (*compar_fn_t) (const void *, const void *);

/* This is a pointer to the root of the search tree with the known
   values.  */
static void *known_values;

# define KNOWN_VALUE(Str) \
  __extension__                                                               \
  ({                                                                          \
    void *value = tfind (Str, &known_values, (compar_fn_t) strcmp);           \
    value != NULL ? *(char **) value : NULL;                                  \
  })
# define STORE_VALUE(Str) \
  tsearch (Str, &known_values, (compar_fn_t) strcmp)

#else
# undef USE_TSEARCH

# define KNOWN_VALUE(Str) NULL
# define STORE_VALUE(Str) do { } while (0)

#endif


/* If this variable is not a null pointer we allocated the current
   environment.  */
static char **last_environ;


/* This function is used by 'setenv' and 'putenv'.  The difference between
   the two functions is that for the former must create a new string which
   is then placed in the environment, while the argument of 'putenv'
   must be used directly.  This is all complicated by the fact that we try
   to reuse values once generated for a 'setenv' call since we can never
   free the strings.  */
int
__add_to_environ (const char *name, const char *value, const char *combined,
                  int replace)
{
  char **ep;
  size_t size;
  const size_t namelen = strlen (name);
  const size_t vallen = value != NULL ? strlen (value) + 1 : 0;

  LOCK;

  /* We have to get the pointer now that we have the lock and not earlier
     since another thread might have created a new environment.  */
  ep = __environ;

  size = 0;
  if (ep != NULL)
    {
      for (; *ep != NULL; ++ep)
        if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
          break;
        else
          ++size;
    }

  if (ep == NULL || *ep == NULL)
    {
      char **new_environ;
#ifdef USE_TSEARCH
      char *new_value;
#endif

      /* We allocated this space; we can extend it.  */
      new_environ =
        (char **) (last_environ == NULL
                   ? malloc ((size + 2) * sizeof (char *))
                   : realloc (last_environ, (size + 2) * sizeof (char *)));
      if (new_environ == NULL)
        {
          /* It's easier to set errno to ENOMEM than to rely on the
             'malloc-posix' and 'realloc-posix' gnulib modules.  */
          __set_errno (ENOMEM);
          UNLOCK;
          return -1;
        }

      /* If the whole entry is given add it.  */
      if (combined != NULL)
        /* We must not add the string to the search tree since it belongs
           to the user.  */
        new_environ[size] = (char *) combined;
      else
        {
          /* See whether the value is already known.  */
#ifdef USE_TSEARCH
# ifdef _LIBC
          new_value = (char *) alloca (namelen + 1 + vallen);
          __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
                     value, vallen);
# else
          new_value = (char *) malloca (namelen + 1 + vallen);
          if (new_value == NULL)
            {
              __set_errno (ENOMEM);
              UNLOCK;
              return -1;
            }
          memcpy (new_value, name, namelen);
          new_value[namelen] = '=';
          memcpy (&new_value[namelen + 1], value, vallen);
# endif

          new_environ[size] = KNOWN_VALUE (new_value);
          if (new_environ[size] == NULL)
#endif
            {
              new_environ[size] = (char *) malloc (namelen + 1 + vallen);
              if (new_environ[size] == NULL)
                {
#if defined USE_TSEARCH && !defined _LIBC
                  freea (new_value);
#endif
                  __set_errno (ENOMEM);
                  UNLOCK;
                  return -1;
                }

#ifdef USE_TSEARCH
              memcpy (new_environ[size], new_value, namelen + 1 + vallen);
#else
              memcpy (new_environ[size], name, namelen);
              new_environ[size][namelen] = '=';
              memcpy (&new_environ[size][namelen + 1], value, vallen);
#endif
              /* And save the value now.  We cannot do this when we remove
                 the string since then we cannot decide whether it is a
                 user string or not.  */
              STORE_VALUE (new_environ[size]);
            }
#if defined USE_TSEARCH && !defined _LIBC
          freea (new_value);
#endif
        }

      if (__environ != last_environ)
        memcpy (new_environ, __environ, size * sizeof (char *));

      new_environ[size + 1] = NULL;

      last_environ = __environ = new_environ;
    }
  else if (replace)
    {
      char *np;

      /* Use the user string if given.  */
      if (combined != NULL)
        np = (char *) combined;
      else
        {
#ifdef USE_TSEARCH
          char *new_value;
# ifdef _LIBC
          new_value = alloca (namelen + 1 + vallen);
          __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
                     value, vallen);
# else
          new_value = malloca (namelen + 1 + vallen);
          if (new_value == NULL)
            {
              __set_errno (ENOMEM);
              UNLOCK;
              return -1;
            }
          memcpy (new_value, name, namelen);
          new_value[namelen] = '=';
          memcpy (&new_value[namelen + 1], value, vallen);
# endif

          np = KNOWN_VALUE (new_value);
          if (np == NULL)
#endif
            {
              np = (char *) malloc (namelen + 1 + vallen);
              if (np == NULL)
                {
#if defined USE_TSEARCH && !defined _LIBC
                  freea (new_value);
#endif
                  __set_errno (ENOMEM);
                  UNLOCK;
                  return -1;
                }

#ifdef USE_TSEARCH
              memcpy (np, new_value, namelen + 1 + vallen);
#else
              memcpy (np, name, namelen);
              np[namelen] = '=';
              memcpy (&np[namelen + 1], value, vallen);
#endif
              /* And remember the value.  */
              STORE_VALUE (np);
            }
#if defined USE_TSEARCH && !defined _LIBC
          freea (new_value);
#endif
        }

      *ep = np;
    }

  UNLOCK;

  return 0;
}

int
setenv (const char *name, const char *value, int replace)
{
  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
    {
      __set_errno (EINVAL);
      return -1;
    }

  return __add_to_environ (name, value, NULL, replace);
}

/* The 'clearenv' was planned to be added to POSIX.1 but probably
   never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
   for Fortran 77) requires this function.  */
int
clearenv (void)
{
  LOCK;

  if (__environ == last_environ && __environ != NULL)
    {
      /* We allocated this environment so we can free it.  */
      free (__environ);
      last_environ = NULL;
    }

  /* Clear the environment pointer removes the whole environment.  */
  __environ = NULL;

  UNLOCK;

  return 0;
}

#ifdef _LIBC
static void
free_mem (void)
{
  /* Remove all traces.  */
  clearenv ();

  /* Now remove the search tree.  */
  __tdestroy (known_values, free);
  known_values = NULL;
}
text_set_element (__libc_subfreeres, free_mem);


# undef setenv
# undef clearenv
weak_alias (__setenv, setenv)
weak_alias (__clearenv, clearenv)
#endif

#else /* HAVE_DECL__PUTENV */
/* Native Windows */

int
setenv (const char *name, const char *value, int replace)
{
  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
    {
      errno = EINVAL;
      return -1;
    }

  /* The Microsoft documentation
     <https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/putenv-wputenv>
     says:
       "Don't change an environment entry directly: instead,
        use _putenv or _wputenv to change it."
     Note: Microsoft's _putenv updates not only the contents of _environ but
     also the contents of _wenviron, so that both are in kept in sync.  */
  const char *existing_value = getenv (name);
  if (existing_value != NULL)
    {
      if (replace)
        {
          if (strcmp (existing_value, value) == 0)
            /* No need to allocate memory.  */
            return 0;
        }
      else
        /* Keep the existing value.  */
        return 0;
    }
  /* Allocate a new environment entry in the heap.  */
  /* _putenv ("NAME=") unsets NAME, so if VALUE is the empty string, invoke
     _putenv ("NAME= ") and fix up the result afterwards.  */
  const char *value_ = (value[0] == '\0' ? " " : value);
  size_t name_len = strlen (name);
  size_t value_len = strlen (value_);
  char *string = (char *) malloc (name_len + 1 + value_len + 1);
  if (string == NULL)
    return -1;
  memcpy (string, name, name_len);
  string[name_len] = '=';
  memcpy (&string[name_len + 1], value_, value_len + 1);
  /* Use _putenv.  */
  if (_putenv (string) < 0)
    return -1;
  if (value[0] == '\0')
    {
      /* Fix up the result.  */
      char *new_value = getenv (name);
      if (new_value != NULL && new_value[0] == ' ' && new_value[1] == '\0')
        new_value[0] = '\0';
# if defined _WIN32 && ! defined __CYGWIN__
      /* _putenv propagated "NAME= " into the subprocess environment;
         fix that by calling SetEnvironmentVariable directly.  */
      /* Documentation:
         <https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setenvironmentvariable>  */
      if (!SetEnvironmentVariable (name, ""))
        {
          switch (GetLastError ())
            {
            case ERROR_NOT_ENOUGH_MEMORY:
            case ERROR_OUTOFMEMORY:
              errno = ENOMEM;
              break;
            default:
              errno = EINVAL;
              break;
            }
          return -1;
        }
# endif
    }
  return 0;
}

#endif /* HAVE_DECL__PUTENV */
#endif /* _LIBC || !HAVE_SETENV */

/* The rest of this file is called into use when replacing an existing
   but buggy setenv.  Known bugs include failure to diagnose invalid
   name, and consuming a leading '=' from value.  */
#if HAVE_SETENV

# undef setenv
# if !HAVE_DECL_SETENV
extern int setenv (const char *, const char *, int);
# endif
# define STREQ(a, b) (strcmp (a, b) == 0)

int
rpl_setenv (const char *name, const char *value, int replace)
{
  int result;
  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
    {
      errno = EINVAL;
      return -1;
    }
  /* Call the real setenv even if replace is 0, in case implementation
     has underlying data to update, such as when environ changes.  */
  result = setenv (name, value, replace);
  if (result == 0 && replace && *value == '=')
    {
      char *tmp = getenv (name);
      if (!STREQ (tmp, value))
        {
          int saved_errno;
          size_t len = strlen (value);
          tmp = malloca (len + 2);
          if (tmp == NULL)
            {
              errno = ENOMEM;
              return -1;
            }
          /* Since leading '=' is eaten, double it up.  */
          *tmp = '=';
          memcpy (tmp + 1, value, len + 1);
          result = setenv (name, tmp, replace);
          saved_errno = errno;
          freea (tmp);
          errno = saved_errno;
        }
    }
  return result;
}

#endif /* HAVE_SETENV */