hw/virtio-9p-local.c

   1 /*
   2  * Virtio 9p Posix callback
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13 #include "virtio.h"
  14 #include "virtio-9p.h"
  15 #include <pwd.h>
  16 #include <grp.h>
  17
  18 static const char *rpath(FsContext *ctx, const char *path)
  19 {
  20     /* FIXME: so wrong... */
  21     static char buffer[4096];
  22     snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);
  23     return buffer;
  24 }
  25
  26 static int local_lstat(FsContext *ctx, const char *path, struct stat *stbuf)
  27 {
  28     return lstat(rpath(ctx, path), stbuf);
  29 }
  30
  31 static int local_setuid(FsContext *ctx, uid_t uid)
  32 {
  33     struct passwd *pw;
  34     gid_t groups[33];
  35     int ngroups;
  36     static uid_t cur_uid = -1;
  37
  38     if (cur_uid == uid) {
  39         return 0;
  40     }
  41
  42     if (setreuid(0, 0)) {
  43         return -1;
  44     }
  45
  46     pw = getpwuid(uid);
  47     if (pw == NULL) {
  48         return -1;
  49     }
  50
  51     ngroups = 33;
  52     if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups) == -1) {
  53         return -1;
  54     }
  55
  56     if (setgroups(ngroups, groups)) {
  57         return -1;
  58     }
  59
  60     if (setregid(-1, pw->pw_gid)) {
  61         return -1;
  62     }
  63
  64     if (setreuid(-1, uid)) {
  65         return -1;
  66     }
  67
  68     cur_uid = uid;
  69
  70     return 0;
  71 }
  72
  73 static ssize_t local_readlink(FsContext *ctx, const char *path,
  74                                 char *buf, size_t bufsz)
  75 {
  76     return readlink(rpath(ctx, path), buf, bufsz);
  77 }
  78
  79 static int local_close(FsContext *ctx, int fd)
  80 {
  81     return close(fd);
  82 }
  83
  84 static int local_closedir(FsContext *ctx, DIR *dir)
  85 {
  86     return closedir(dir);
  87 }
  88
  89 static int local_open(FsContext *ctx, const char *path, int flags)
  90 {
  91     return open(rpath(ctx, path), flags);
  92 }
  93
  94 static DIR *local_opendir(FsContext *ctx, const char *path)
  95 {
  96     return opendir(rpath(ctx, path));
  97 }
  98
  99 static void local_rewinddir(FsContext *ctx, DIR *dir)
 100 {
 101     return rewinddir(dir);
 102 }
 103
 104 static off_t local_telldir(FsContext *ctx, DIR *dir)
 105 {
 106     return telldir(dir);
 107 }
 108
 109 static struct dirent *local_readdir(FsContext *ctx, DIR *dir)
 110 {
 111     return readdir(dir);
 112 }
 113
 114 static void local_seekdir(FsContext *ctx, DIR *dir, off_t off)
 115 {
 116     return seekdir(dir, off);
 117 }
 118
 119 static ssize_t local_readv(FsContext *ctx, int fd, const struct iovec *iov,
 120                             int iovcnt)
 121 {
 122     return readv(fd, iov, iovcnt);
 123 }
 124
 125 static off_t local_lseek(FsContext *ctx, int fd, off_t offset, int whence)
 126 {
 127     return lseek(fd, offset, whence);
 128 }
 129
 130 FileOperations local_ops = {
 131     .lstat = local_lstat,
 132     .setuid = local_setuid,
 133     .readlink = local_readlink,
 134     .close = local_close,
 135     .closedir = local_closedir,
 136     .open = local_open,
 137     .opendir = local_opendir,
 138     .rewinddir = local_rewinddir,
 139     .telldir = local_telldir,
 140     .readdir = local_readdir,
 141     .seekdir = local_seekdir,
 142     .readv = local_readv,
 143     .lseek = local_lseek,
 144 };