code.delx.au - pulseaudio/blob - src/pulsecore/usergroup.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2009 Ted Percival
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation; either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <sys/types.h>
  27 #include <errno.h>
  28
  29 #ifdef HAVE_PWD_H
  30 #include <pwd.h>
  31 #endif
  32
  33 #ifdef HAVE_GRP_H
  34 #include <grp.h>
  35 #endif
  36
  37 #include <pulse/xmalloc.h>
  38 #include <pulsecore/macro.h>
  39
  40 #include "usergroup.h"
  41
  42 #ifdef HAVE_GRP_H
  43
  44 /* Returns a suitable starting size for a getgrnam_r() or getgrgid_r() buffer,
  45    plus the size of a struct group.
  46  */
  47 static size_t starting_getgr_buflen(void) {
  48     size_t full_size;
  49     long n;
  50 #ifdef _SC_GETGR_R_SIZE_MAX
  51     n = sysconf(_SC_GETGR_R_SIZE_MAX);
  52 #else
  53     n = -1;
  54 #endif
  55     if (n <= 0)
  56         n = 512;
  57
  58     full_size = (size_t) n + sizeof(struct group);
  59
  60     if (full_size < (size_t) n) /* check for integer overflow */
  61         return (size_t) n;
  62
  63     return full_size;
  64 }
  65
  66 /* Returns a suitable starting size for a getpwnam_r() or getpwuid_r() buffer,
  67    plus the size of a struct passwd.
  68  */
  69 static size_t starting_getpw_buflen(void) {
  70     long n;
  71     size_t full_size;
  72
  73 #ifdef _SC_GETPW_R_SIZE_MAX
  74     n = sysconf(_SC_GETPW_R_SIZE_MAX);
  75 #else
  76     n = -1;
  77 #endif
  78     if (n <= 0)
  79         n = 512;
  80
  81     full_size = (size_t) n + sizeof(struct passwd);
  82
  83     if (full_size < (size_t) n) /* check for integer overflow */
  84         return (size_t) n;
  85
  86     return full_size;
  87 }
  88
  89 /* Given a memory allocation (*bufptr) and its length (*buflenptr),
  90    double the size of the allocation, updating the given buffer and length
  91    arguments. This function should be used in conjunction with the pa_*alloc
  92    and pa_xfree functions.
  93
  94    Unlike realloc(), this function does *not* retain the original buffer's
  95    contents.
  96
  97    Returns 0 on success, nonzero on error. The error cause is indicated by
  98    errno.
  99  */
 100 static int expand_buffer_trashcontents(void **bufptr, size_t *buflenptr) {
 101     size_t newlen;
 102
 103     if (!bufptr || !*bufptr || !buflenptr) {
 104         errno = EINVAL;
 105         return -1;
 106     }
 107
 108     newlen = *buflenptr * 2;
 109
 110     if (newlen < *buflenptr) {
 111         errno = EOVERFLOW;
 112         return -1;
 113     }
 114
 115     /* Don't bother retaining memory contents; free & alloc anew */
 116     pa_xfree(*bufptr);
 117
 118     *bufptr = pa_xmalloc(newlen);
 119     *buflenptr = newlen;
 120
 121     return 0;
 122 }
 123
 124 #ifdef HAVE_GETGRGID_R
 125 /* Thread-safe getgrgid() replacement.
 126    Returned value should be freed using pa_getgrgid_free() when the caller is
 127    finished with the returned group data.
 128
 129    API is the same as getgrgid(), errors are indicated by a NULL return;
 130    consult errno for the error cause (zero it before calling).
 131  */
 132 struct group *pa_getgrgid_malloc(gid_t gid) {
 133     size_t buflen, getgr_buflen;
 134     int err;
 135     void *buf;
 136     void *getgr_buf;
 137     struct group *result = NULL;
 138
 139     buflen = starting_getgr_buflen();
 140     buf = pa_xmalloc(buflen);
 141
 142     getgr_buflen = buflen - sizeof(struct group);
 143     getgr_buf = (char *)buf + sizeof(struct group);
 144
 145     while ((err = getgrgid_r(gid, (struct group *)buf, getgr_buf,
 146                     getgr_buflen, &result)) == ERANGE)
 147     {
 148         if (expand_buffer_trashcontents(&buf, &buflen))
 149             break;
 150
 151         getgr_buflen = buflen - sizeof(struct group);
 152         getgr_buf = (char *)buf + sizeof(struct group);
 153     }
 154
 155     if (err || !result) {
 156         result = NULL;
 157         if (buf) {
 158             pa_xfree(buf);
 159             buf = NULL;
 160         }
 161     }
 162
 163     pa_assert(result == buf || result == NULL);
 164
 165     return result;
 166 }
 167
 168 void pa_getgrgid_free(struct group *grp) {
 169     pa_xfree(grp);
 170 }
 171
 172 #else /* !HAVE_GETGRGID_R */
 173
 174 struct group *pa_getgrgid_malloc(gid_t gid) {
 175     return getgrgid(gid);
 176 }
 177
 178 void pa_getgrgid_free(struct group *grp) {
 179     /* nothing */
 180     return;
 181 }
 182
 183 #endif /* !HAVE_GETGRGID_R */
 184
 185 #ifdef HAVE_GETGRNAM_R
 186 /* Thread-safe getgrnam() function.
 187    Returned value should be freed using pa_getgrnam_free() when the caller is
 188    finished with the returned group data.
 189
 190    API is the same as getgrnam(), errors are indicated by a NULL return;
 191    consult errno for the error cause (zero it before calling).
 192  */
 193 struct group *pa_getgrnam_malloc(const char *name) {
 194     size_t buflen, getgr_buflen;
 195     int err;
 196     void *buf;
 197     void *getgr_buf;
 198     struct group *result = NULL;
 199
 200     buflen = starting_getgr_buflen();
 201     buf = pa_xmalloc(buflen);
 202
 203     getgr_buflen = buflen - sizeof(struct group);
 204     getgr_buf = (char *)buf + sizeof(struct group);
 205
 206     while ((err = getgrnam_r(name, (struct group *)buf, getgr_buf,
 207                     getgr_buflen, &result)) == ERANGE)
 208     {
 209         if (expand_buffer_trashcontents(&buf, &buflen))
 210             break;
 211
 212         getgr_buflen = buflen - sizeof(struct group);
 213         getgr_buf = (char *)buf + sizeof(struct group);
 214     }
 215
 216     if (err || !result) {
 217         result = NULL;
 218         if (buf) {
 219             pa_xfree(buf);
 220             buf = NULL;
 221         }
 222     }
 223
 224     pa_assert(result == buf || result == NULL);
 225
 226     return result;
 227 }
 228
 229 void pa_getgrnam_free(struct group *group) {
 230     pa_xfree(group);
 231 }
 232
 233 #else /* !HAVE_GETGRNAM_R */
 234
 235 struct group *pa_getgrnam_malloc(const char *name) {
 236     return getgrnam(name);
 237 }
 238
 239 void pa_getgrnam_free(struct group *group) {
 240     /* nothing */
 241     return;
 242 }
 243
 244 #endif /* HAVE_GETGRNAM_R */
 245
 246 #endif /* HAVE_GRP_H */
 247
 248 #ifdef HAVE_PWD_H
 249
 250 #ifdef HAVE_GETPWNAM_R
 251 /* Thread-safe getpwnam() function.
 252    Returned value should be freed using pa_getpwnam_free() when the caller is
 253    finished with the returned passwd data.
 254
 255    API is the same as getpwnam(), errors are indicated by a NULL return;
 256    consult errno for the error cause (zero it before calling).
 257  */
 258 struct passwd *pa_getpwnam_malloc(const char *name) {
 259     size_t buflen, getpw_buflen;
 260     int err;
 261     void *buf;
 262     void *getpw_buf;
 263     struct passwd *result = NULL;
 264
 265     buflen = starting_getpw_buflen();
 266     buf = pa_xmalloc(buflen);
 267
 268     getpw_buflen = buflen - sizeof(struct passwd);
 269     getpw_buf = (char *)buf + sizeof(struct passwd);
 270
 271     while ((err = getpwnam_r(name, (struct passwd *)buf, getpw_buf,
 272                     getpw_buflen, &result)) == ERANGE)
 273     {
 274         if (expand_buffer_trashcontents(&buf, &buflen))
 275             break;
 276
 277         getpw_buflen = buflen - sizeof(struct passwd);
 278         getpw_buf = (char *)buf + sizeof(struct passwd);
 279     }
 280
 281     if (err || !result) {
 282         result = NULL;
 283         if (buf) {
 284             pa_xfree(buf);
 285             buf = NULL;
 286         }
 287     }
 288
 289     pa_assert(result == buf || result == NULL);
 290
 291     return result;
 292 }
 293
 294 void pa_getpwnam_free(struct passwd *passwd) {
 295     pa_xfree(passwd);
 296 }
 297
 298 #else /* !HAVE_GETPWNAM_R */
 299
 300 struct passwd *pa_getpwnam_malloc(const char *name) {
 301     return getpwnam(name);
 302 }
 303
 304 void pa_getpwnam_free(struct passwd *passwd) {
 305     /* nothing */
 306     return;
 307 }
 308
 309 #endif /* !HAVE_GETPWNAM_R */
 310
 311 #ifdef HAVE_GETPWUID_R
 312 /* Thread-safe getpwuid() function.
 313    Returned value should be freed using pa_getpwuid_free() when the caller is
 314    finished with the returned group data.
 315
 316    API is the same as getpwuid(), errors are indicated by a NULL return;
 317    consult errno for the error cause (zero it before calling).
 318  */
 319 struct passwd *pa_getpwuid_malloc(uid_t uid) {
 320     size_t buflen, getpw_buflen;
 321     int err;
 322     void *buf;
 323     void *getpw_buf;
 324     struct passwd *result = NULL;
 325
 326     buflen = starting_getpw_buflen();
 327     buf = pa_xmalloc(buflen);
 328
 329     getpw_buflen = buflen - sizeof(struct passwd);
 330     getpw_buf = (char *)buf + sizeof(struct passwd);
 331
 332     while ((err = getpwuid_r(uid, (struct passwd *)buf, getpw_buf,
 333                     getpw_buflen, &result)) == ERANGE)
 334     {
 335         if (expand_buffer_trashcontents(&buf, &buflen))
 336             break;
 337
 338         getpw_buflen = buflen - sizeof(struct passwd);
 339         getpw_buf = (char *)buf + sizeof(struct passwd);
 340     }
 341
 342     if (err || !result) {
 343         result = NULL;
 344         if (buf) {
 345             pa_xfree(buf);
 346             buf = NULL;
 347         }
 348     }
 349
 350     pa_assert(result == buf || result == NULL);
 351
 352     return result;
 353 }
 354
 355 void pa_getpwuid_free(struct passwd *passwd) {
 356     pa_xfree(passwd);
 357 }
 358
 359 #else /* !HAVE_GETPWUID_R */
 360
 361 struct passwd *pa_getpwuid_malloc(uid_t uid) {
 362     return getpwuid(uid);
 363 }
 364
 365 void pa_getpwuid_free(struct passwd *passwd) {
 366     /* nothing */
 367     return;
 368 }
 369
 370 #endif /* !HAVE_GETPWUID_R */
 371
 372 #endif /* HAVE_PWD_H */