syscall.c

   1 /*
   2  * Syscall wrappers to ensure that nothing gets done in dry_run mode
   3  * and to handle system peculiarities.
   4  *
   5  * Copyright (C) 1998 Andrew Tridgell
   6  * Copyright (C) 2002 Martin Pool
   7  * Copyright (C) 2003-2009 Wayne Davison
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, visit the http://fsf.org website.
  21  */
  22
  23 #include "rsync.h"
  24
  25 #if !defined MKNOD_CREATES_SOCKETS && defined HAVE_SYS_UN_H
  26 #include <sys/un.h>
  27 #endif
  28 #ifdef HAVE_SYS_ATTR_H
  29 #include <sys/attr.h>
  30 #endif
  31
  32 extern int dry_run;
  33 extern int am_root;
  34 extern int read_only;
  35 extern int list_only;
  36 extern int preserve_perms;
  37 extern int preserve_executability;
  38
  39 #define RETURN_ERROR_IF(x,e) \
  40         do { \
  41                 if (x) { \
  42                         errno = (e); \
  43                         return -1; \
  44                 } \
  45         } while (0)
  46
  47 #define RETURN_ERROR_IF_RO_OR_LO RETURN_ERROR_IF(read_only || list_only, EROFS)
  48
  49 int do_unlink(const char *fname)
  50 {
  51         if (dry_run) return 0;
  52         RETURN_ERROR_IF_RO_OR_LO;
  53         return unlink(fname);
  54 }
  55
  56 int do_symlink(const char *fname1, const char *fname2)
  57 {
  58         if (dry_run) return 0;
  59         RETURN_ERROR_IF_RO_OR_LO;
  60         return symlink(fname1, fname2);
  61 }
  62
  63 #ifdef HAVE_LINK
  64 int do_link(const char *fname1, const char *fname2)
  65 {
  66         if (dry_run) return 0;
  67         RETURN_ERROR_IF_RO_OR_LO;
  68         return link(fname1, fname2);
  69 }
  70 #endif
  71
  72 int do_lchown(const char *path, uid_t owner, gid_t group)
  73 {
  74         if (dry_run) return 0;
  75         RETURN_ERROR_IF_RO_OR_LO;
  76 #ifndef HAVE_LCHOWN
  77 #define lchown chown
  78 #endif
  79         return lchown(path, owner, group);
  80 }
  81
  82 int do_mknod(const char *pathname, mode_t mode, dev_t dev)
  83 {
  84         if (dry_run) return 0;
  85         RETURN_ERROR_IF_RO_OR_LO;
  86
  87         /* For --fake-super, we create a normal file with mode 0600. */
  88         if (am_root < 0) {
  89                 int fd = open(pathname, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR|S_IRUSR);
  90                 if (fd < 0 || close(fd) < 0)
  91                         return -1;
  92                 return 0;
  93         }
  94
  95 #if !defined MKNOD_CREATES_FIFOS && defined HAVE_MKFIFO
  96         if (S_ISFIFO(mode))
  97                 return mkfifo(pathname, mode);
  98 #endif
  99 #if !defined MKNOD_CREATES_SOCKETS && defined HAVE_SYS_UN_H
 100         if (S_ISSOCK(mode)) {
 101                 int sock;
 102                 struct sockaddr_un saddr;
 103 #ifdef HAVE_SOCKADDR_UN_LEN
 104                 unsigned int len =
 105 #endif
 106                     strlcpy(saddr.sun_path, pathname, sizeof saddr.sun_path);
 107 #ifdef HAVE_SOCKADDR_UN_LEN
 108                 saddr.sun_len = len >= sizeof saddr.sun_path
 109                               ? sizeof saddr.sun_path : len + 1;
 110 #endif
 111                 saddr.sun_family = AF_UNIX;
 112
 113                 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0
 114                     || (unlink(pathname) < 0 && errno != ENOENT)
 115                     || (bind(sock, (struct sockaddr*)&saddr, sizeof saddr)) < 0)
 116                         return -1;
 117                 close(sock);
 118 #ifdef HAVE_CHMOD
 119                 return do_chmod(pathname, mode);
 120 #else
 121                 return 0;
 122 #endif
 123         }
 124 #endif
 125 #ifdef HAVE_MKNOD
 126         return mknod(pathname, mode, dev);
 127 #else
 128         return -1;
 129 #endif
 130 }
 131
 132 int do_rmdir(const char *pathname)
 133 {
 134         if (dry_run) return 0;
 135         RETURN_ERROR_IF_RO_OR_LO;
 136         return rmdir(pathname);
 137 }
 138
 139 int do_open(const char *pathname, int flags, mode_t mode)
 140 {
 141         if (flags != O_RDONLY) {
 142                 RETURN_ERROR_IF(dry_run, 0);
 143                 RETURN_ERROR_IF_RO_OR_LO;
 144         }
 145
 146         return open(pathname, flags | O_BINARY, mode);
 147 }
 148
 149 #ifdef HAVE_CHMOD
 150 int do_chmod(const char *path, mode_t mode)
 151 {
 152         int code;
 153         if (dry_run) return 0;
 154         RETURN_ERROR_IF_RO_OR_LO;
 155         if (S_ISLNK(mode)) {
 156 #ifdef HAVE_LCHMOD
 157                 code = lchmod(path, mode & CHMOD_BITS);
 158 #elif defined HAVE_SETATTRLIST
 159                 struct attrlist attrList;
 160                 uint32_t m = mode & CHMOD_BITS; /* manpage is wrong: not mode_t! */
 161
 162                 memset(&attrList, 0, sizeof attrList);
 163                 attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
 164                 attrList.commonattr = ATTR_CMN_ACCESSMASK;
 165                 code = setattrlist(path, &attrList, &m, sizeof m, FSOPT_NOFOLLOW);
 166 #else
 167                 code = 1;
 168 #endif
 169         } else
 170                 code = chmod(path, mode & CHMOD_BITS); /* DISCOURAGED FUNCTION */
 171         if (code != 0 && (preserve_perms || preserve_executability))
 172                 return code;
 173         return 0;
 174 }
 175 #endif
 176
 177 int do_rename(const char *fname1, const char *fname2)
 178 {
 179         if (dry_run) return 0;
 180         RETURN_ERROR_IF_RO_OR_LO;
 181         return rename(fname1, fname2);
 182 }
 183
 184 void trim_trailing_slashes(char *name)
 185 {
 186         int l;
 187         /* Some BSD systems cannot make a directory if the name
 188          * contains a trailing slash.
 189          * <http://www.opensource.apple.com/bugs/X/BSD%20Kernel/2734739.html> */
 190
 191         /* Don't change empty string; and also we can't improve on
 192          * "/" */
 193
 194         l = strlen(name);
 195         while (l > 1) {
 196                 if (name[--l] != '/')
 197                         break;
 198                 name[l] = '\0';
 199         }
 200 }
 201
 202 int do_mkdir(char *fname, mode_t mode)
 203 {
 204         if (dry_run) return 0;
 205         RETURN_ERROR_IF_RO_OR_LO;
 206         trim_trailing_slashes(fname);
 207         return mkdir(fname, mode);
 208 }
 209
 210 /* like mkstemp but forces permissions */
 211 int do_mkstemp(char *template, mode_t perms)
 212 {
 213         RETURN_ERROR_IF(dry_run, 0);
 214         RETURN_ERROR_IF(read_only, EROFS);
 215         perms |= S_IWUSR;
 216
 217 #if defined HAVE_SECURE_MKSTEMP && defined HAVE_FCHMOD && (!defined HAVE_OPEN64 || defined HAVE_MKSTEMP64)
 218         {
 219                 int fd = mkstemp(template);
 220                 if (fd == -1)
 221                         return -1;
 222                 if (fchmod(fd, perms) != 0 && preserve_perms) {
 223                         int errno_save = errno;
 224                         close(fd);
 225                         unlink(template);
 226                         errno = errno_save;
 227                         return -1;
 228                 }
 229 #if defined HAVE_SETMODE && O_BINARY
 230                 setmode(fd, O_BINARY);
 231 #endif
 232                 return fd;
 233         }
 234 #else
 235         if (!mktemp(template))
 236                 return -1;
 237         return do_open(template, O_RDWR|O_EXCL|O_CREAT, perms);
 238 #endif
 239 }
 240
 241 int do_stat(const char *fname, STRUCT_STAT *st)
 242 {
 243 #ifdef USE_STAT64_FUNCS
 244         return stat64(fname, st);
 245 #else
 246         return stat(fname, st);
 247 #endif
 248 }
 249
 250 int do_lstat(const char *fname, STRUCT_STAT *st)
 251 {
 252 #ifdef SUPPORT_LINKS
 253 # ifdef USE_STAT64_FUNCS
 254         return lstat64(fname, st);
 255 # else
 256         return lstat(fname, st);
 257 # endif
 258 #else
 259         return do_stat(fname, st);
 260 #endif
 261 }
 262
 263 int do_fstat(int fd, STRUCT_STAT *st)
 264 {
 265 #ifdef USE_STAT64_FUNCS
 266         return fstat64(fd, st);
 267 #else
 268         return fstat(fd, st);
 269 #endif
 270 }
 271
 272 OFF_T do_lseek(int fd, OFF_T offset, int whence)
 273 {
 274 #ifdef HAVE_LSEEK64
 275 #if !SIZEOF_OFF64_T
 276         OFF_T lseek64();
 277 #else
 278         off64_t lseek64();
 279 #endif
 280         return lseek64(fd, offset, whence);
 281 #else
 282         return lseek(fd, offset, whence);
 283 #endif
 284 }