stdlib/FreeBSD/realpath.c.patch

   1 --- realpath.c.orig     2008-04-04 14:39:39.000000000 -0700
   2 +++ realpath.c  2008-04-04 19:59:19.000000000 -0700
   3 @@ -35,13 +35,41 @@ __FBSDID("$FreeBSD: src/lib/libc/stdlib/
   4  #include "namespace.h"
   5  #include <sys/param.h>
   6  #include <sys/stat.h>
   7 +#include <sys/mount.h>
   8
   9  #include <errno.h>
  10  #include <stdlib.h>
  11  #include <string.h>
  12  #include <unistd.h>
  13 +#include <sys/attr.h>
  14 +#include <sys/vnode.h>
  15  #include "un-namespace.h"
  16
  17 +struct attrs {
  18 +       u_int32_t len;
  19 +       attrreference_t name;
  20 +       dev_t dev;
  21 +       fsobj_type_t type;
  22 +       fsobj_id_t id;
  23 +       char buf[PATH_MAX];
  24 +};
  25 +
  26 +#ifndef BUILDING_VARIANT
  27 +__private_extern__ struct attrlist _rp_alist = {
  28 +       ATTR_BIT_MAP_COUNT,
  29 +       0,
  30 +       ATTR_CMN_NAME | ATTR_CMN_DEVID | ATTR_CMN_OBJTYPE | ATTR_CMN_OBJID,
  31 +       0,
  32 +       0,
  33 +       0,
  34 +       0,
  35 +};
  36 +#else /* BUILDING_VARIANT */
  37 +__private_extern__ struct attrlist _rp_alist;
  38 +#endif /* BUILDING_VARIANT */
  39 +
  40 +extern char * __private_getcwd(char *, size_t, int);
  41 +
  42  /*
  43   * char *realpath(const char *path, char resolved[PATH_MAX]);
  44   *
  45 @@ -50,26 +78,67 @@ __FBSDID("$FreeBSD: src/lib/libc/stdlib/
  46   * in which case the path which caused trouble is left in (resolved).
  47   */
  48  char *
  49 -realpath(const char *path, char resolved[PATH_MAX])
  50 +realpath(const char *path, char inresolved[PATH_MAX])
  51  {
  52 +       struct attrs attrs;
  53         struct stat sb;
  54         char *p, *q, *s;
  55 -       size_t left_len, resolved_len;
  56 +       size_t left_len, resolved_len, save_resolved_len;
  57         unsigned symlinks;
  58 -       int serrno, slen;
  59 +       int serrno, slen, useattrs, islink;
  60         char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
  61 +       dev_t dev, lastdev;
  62 +       struct statfs sfs;
  63 +       static dev_t rootdev;
  64 +       static int rootdev_inited = 0;
  65 +       ino_t inode;
  66 +       char *resolved;
  67
  68 +       if (path == NULL) {
  69 +               errno = EINVAL;
  70 +               return (NULL);
  71 +       }
  72 +#if __DARWIN_UNIX03
  73 +       if (*path == 0) {
  74 +               errno = ENOENT;
  75 +               return (NULL);
  76 +       }
  77 +#endif /* __DARWIN_UNIX03 */
  78 +       /*
  79 +        * Extension to the standard; if inresolved == NULL, allocate memory
  80 +        * (first on the stack, then use strdup())
  81 +        */
  82 +       if (!inresolved) {
  83 +           if ((resolved = alloca(PATH_MAX)) == NULL) return (NULL);
  84 +       } else {
  85 +           resolved = inresolved;
  86 +       }
  87 +       if (!rootdev_inited) {
  88 +               rootdev_inited = 1;
  89 +               if (stat("/", &sb) < 0) {
  90 +                       return (NULL);
  91 +                       }
  92 +               rootdev = sb.st_dev;
  93 +       }
  94         serrno = errno;
  95         symlinks = 0;
  96         if (path[0] == '/') {
  97                 resolved[0] = '/';
  98                 resolved[1] = '\0';
  99 -               if (path[1] == '\0')
 100 +               if (path[1] == '\0') {
 101                         return (resolved);
 102 +               }
 103                 resolved_len = 1;
 104                 left_len = strlcpy(left, path + 1, sizeof(left));
 105         } else {
 106 -               if (getcwd(resolved, PATH_MAX) == NULL) {
 107 +#if !defined(VARIANT_DARWINEXTSN) && __DARWIN_UNIX03
 108 +               /* 4447159: don't use GETPATH, so this will fail if */
 109 +               /* if parent directories are not readable, as per POSIX */
 110 +               if (__private_getcwd(resolved, PATH_MAX, 0) == NULL)
 111 +#else /* VARIANT_DARWINEXTSN || !__DARWIN_UNIX03 */
 112 +               if (__private_getcwd(resolved, PATH_MAX, 1) == NULL)
 113 +#endif /* !VARIANT_DARWINEXTSN && __DARWIN_UNIX03 */
 114 +               {
 115                         strlcpy(resolved, ".", PATH_MAX);
 116                         return (NULL);
 117                 }
 118 @@ -80,6 +149,13 @@ realpath(const char *path, char resolved
 119                 errno = ENAMETOOLONG;
 120                 return (NULL);
 121         }
 122 +       if (resolved_len > 1) {
 123 +               if (stat(resolved, &sb) < 0) {
 124 +                       return (NULL);
 125 +               }
 126 +               lastdev = sb.st_dev;
 127 +       } else
 128 +               lastdev = rootdev;
 129
 130         /*
 131          * Iterate over path components in `left'.
 132 @@ -127,6 +203,13 @@ realpath(const char *path, char resolved
 133                 }
 134
 135                 /*
 136 +                * Save resolved_len, so that we can later null out
 137 +                * the the appended next_token, and replace with the
 138 +                * real name (matters on case-insensitive filesystems).
 139 +                */
 140 +               save_resolved_len = resolved_len;
 141 +
 142 +               /*
 143                  * Append the next path component and lstat() it. If
 144                  * lstat() fails we still can return successfully if
 145                  * there are no more path components left.
 146 @@ -136,25 +219,87 @@ realpath(const char *path, char resolved
 147                         errno = ENAMETOOLONG;
 148                         return (NULL);
 149                 }
 150 -               if (lstat(resolved, &sb) != 0) {
 151 +               if (getattrlist(resolved, &_rp_alist, &attrs, sizeof(attrs), FSOPT_NOFOLLOW) == 0) {
 152 +                       useattrs = 1;
 153 +                       islink = (attrs.type == VLNK);
 154 +                       dev = attrs.dev;
 155 +                       inode = attrs.id.fid_objno;
 156 +               } else if (errno == ENOTSUP || errno == EINVAL) {
 157 +                       if ((useattrs = lstat(resolved, &sb)) == 0) {
 158 +                               islink = S_ISLNK(sb.st_mode);
 159 +                               dev = sb.st_dev;
 160 +                               inode = sb.st_ino;
 161 +                       }
 162 +               } else
 163 +                       useattrs = -1;
 164 +               if (useattrs < 0) {
 165 +#if !__DARWIN_UNIX03
 166                         if (errno == ENOENT && p == NULL) {
 167                                 errno = serrno;
 168                                 return (resolved);
 169                         }
 170 +#endif /* !__DARWIN_UNIX03 */
 171                         return (NULL);
 172                 }
 173 -               if (S_ISLNK(sb.st_mode)) {
 174 +               if (dev != lastdev) {
 175 +                       /*
 176 +                        * We have crossed a mountpoint.  For volumes like UDF
 177 +                        * the getattrlist name may not match the actual
 178 +                        * mountpoint, so we just copy the mountpoint directly.
 179 +                        * (3703138).  However, the mountpoint may not be
 180 +                        * accessible, as when chroot-ed, so check first.
 181 +                        * There may be a file on the chroot-ed volume with
 182 +                        * the same name as the mountpoint, so compare device
 183 +                        * and inode numbers.
 184 +                        */
 185 +                       lastdev = dev;
 186 +                       if (statfs(resolved, &sfs) == 0 && lstat(sfs.f_mntonname, &sb) == 0 && dev == sb.st_dev && inode == sb.st_ino) {
 187 +                               /*
 188 +                                * However, it's possible that the mountpoint
 189 +                                * path matches, even though it isn't the real
 190 +                                * path in the chroot-ed environment, so check
 191 +                                * that each component of the mountpoint
 192 +                                * is a directory (and not a symlink)
 193 +                                */
 194 +                               char temp[sizeof(sfs.f_mntonname)];
 195 +                               char *cp;
 196 +                               int ok = 1;
 197 +
 198 +                               strcpy(temp, sfs.f_mntonname);
 199 +                               for(;;) {
 200 +                                       if ((cp = strrchr(temp, '/')) == NULL) {
 201 +                                               ok = 0;
 202 +                                               break;
 203 +                                       }
 204 +                                       if (cp <= temp)
 205 +                                               break;
 206 +                                       *cp = 0;
 207 +                                       if (lstat(temp, &sb) < 0 || (sb.st_mode & S_IFMT) != S_IFDIR) {
 208 +                                               ok = 0;
 209 +                                               break;
 210 +                                       }
 211 +                               }
 212 +                               if (ok) {
 213 +                                       resolved_len = strlcpy(resolved, sfs.f_mntonname, PATH_MAX);
 214 +                                       continue;
 215 +                               }
 216 +                       }
 217 +                       /* if we fail, use the other methods. */
 218 +               }
 219 +               if (islink) {
 220                         if (symlinks++ > MAXSYMLINKS) {
 221                                 errno = ELOOP;
 222                                 return (NULL);
 223                         }
 224                         slen = readlink(resolved, symlink, sizeof(symlink) - 1);
 225 -                       if (slen < 0)
 226 +                       if (slen < 0) {
 227                                 return (NULL);
 228 +                       }
 229                         symlink[slen] = '\0';
 230                         if (symlink[0] == '/') {
 231                                 resolved[1] = 0;
 232                                 resolved_len = 1;
 233 +                               lastdev = rootdev;
 234                         } else if (resolved_len > 1) {
 235                                 /* Strip the last path component. */
 236                                 resolved[resolved_len - 1] = '\0';
 237 @@ -184,7 +329,30 @@ realpath(const char *path, char resolved
 238                                 }
 239                         }
 240                         left_len = strlcpy(left, symlink, sizeof(left));
 241 +               } else if (useattrs) {
 242 +                       /*
 243 +                        * attrs already has the real name.
 244 +                        */
 245 +
 246 +                       resolved[save_resolved_len] = '\0';
 247 +                       resolved_len = strlcat(resolved, (const char *)&attrs.name + attrs.name.attr_dataoffset, PATH_MAX);
 248 +                       if (resolved_len >= PATH_MAX) {
 249 +                               errno = ENAMETOOLONG;
 250 +                               return (NULL);
 251 +                       }
 252                 }
 253 +               /*
 254 +                * For the case of useattrs == 0, we could scan the directory
 255 +                * and try to match the inode.  There are many problems with
 256 +                * this: (1) the directory may not be readable, (2) for multiple
 257 +                * hard links, we would find the first, but not necessarily
 258 +                * the one specified in the path, (3) we can't try to do
 259 +                * a case-insensitive search to match the right one in (2),
 260 +                * because the underlying filesystem may do things like
 261 +                * decompose composed characters.  For most cases, doing
 262 +                * nothing is the right thing when useattrs == 0, so we punt
 263 +                * for now.
 264 +                */
 265         }
 266
 267         /*
 268 @@ -193,5 +361,6 @@ realpath(const char *path, char resolved
 269          */
 270         if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
 271                 resolved[resolved_len - 1] = '\0';
 272 +       if (!inresolved) resolved = strdup(resolved);
 273         return (resolved);
 274  }