external/ibm-public/postfix/dist/src/util/lstat_as.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      lstat_as 3
   6 /* SUMMARY
   7 /*      lstat file as user
   8 /* SYNOPSIS
   9 /*      #include <sys/stat.h>
  10 /*      #include <lstat_as.h>
  11 /*
  12 /*      int     lstat_as(path, st, euid, egid)
  13 /*      const char *path;
  14 /*      struct stat *st;
  15 /*      uid_t   euid;
  16 /*      gid_t   egid;
  17 /* DESCRIPTION
  18 /*      lstat_as() looks up the file status of the named \fIpath\fR,
  19 /*      using the effective rights specified by \fIeuid\fR
  20 /*      and \fIegid\fR, and stores the result into the structure pointed
  21 /*      to by \fIst\fR.  A -1 result means the lookup failed.
  22 /*      This call does not follow symbolic links.
  23 /* DIAGNOSTICS
  24 /*      Fatal error: no permission to change privilege level.
  25 /* SEE ALSO
  26 /*      set_eugid(3) switch effective rights
  27 /* LICENSE
  28 /* .ad
  29 /* .fi
  30 /*      The Secure Mailer license must be distributed with this software.
  31 /* AUTHOR(S)
  32 /*      Wietse Venema
  33 /*      IBM T.J. Watson Research
  34 /*      P.O. Box 704
  35 /*      Yorktown Heights, NY 10598, USA
  36 /*--*/
  37
  38 /* System library. */
  39
  40 #include <sys_defs.h>
  41 #include <sys/stat.h>
  42 #include <unistd.h>
  43
  44 /* Utility library. */
  45
  46 #include "msg.h"
  47 #include "set_eugid.h"
  48 #include "lstat_as.h"
  49
  50 /* lstat_as - lstat file as user */
  51
  52 int     lstat_as(const char *path, struct stat * st, uid_t euid, gid_t egid)
  53 {
  54     uid_t   saved_euid = geteuid();
  55     gid_t   saved_egid = getegid();
  56     int     status;
  57
  58     /*
  59      * Switch to the target user privileges.
  60      */
  61     set_eugid(euid, egid);
  62
  63     /*
  64      * Lstat that file.
  65      */
  66     status = lstat(path, st);
  67
  68     /*
  69      * Restore saved privileges.
  70      */
  71     set_eugid(saved_euid, saved_egid);
  72
  73     return (status);
  74 }