external/ibm-public/postfix/dist/src/global/dot_lockfile_as.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      dot_lockfile_as 3
   6 /* SUMMARY
   7 /*      dotlock file as user
   8 /* SYNOPSIS
   9 /*      #include <dot_lockfile_as.h>
  10 /*
  11 /*      int     dot_lockfile_as(path, why, euid, egid)
  12 /*      const char *path;
  13 /*      VSTRING *why;
  14 /*      uid_t   euid;
  15 /*      gid_t   egid;
  16 /*
  17 /*      void    dot_unlockfile_as(path, euid, egid)
  18 /*      const char *path;
  19 /*      uid_t   euid;
  20 /*      gid_t   egid;
  21 /* DESCRIPTION
  22 /*      dot_lockfile_as() and dot_unlockfile_as() are wrappers around
  23 /*      the dot_lockfile() and dot_unlockfile() routines. The routines
  24 /*      change privilege to the designated privilege, perform the
  25 /*      requested operation, and restore privileges.
  26 /* DIAGNOSTICS
  27 /*      Fatal error: no permission to change privilege level.
  28 /* SEE ALSO
  29 /*      dot_lockfile(3) dotlock file management
  30 /*      set_eugid(3) switch effective rights
  31 /* LICENSE
  32 /* .ad
  33 /* .fi
  34 /*      The Secure Mailer license must be distributed with this software.
  35 /* AUTHOR(S)
  36 /*      Wietse Venema
  37 /*      IBM T.J. Watson Research
  38 /*      P.O. Box 704
  39 /*      Yorktown Heights, NY 10598, USA
  40 /*--*/
  41
  42 /* System library. */
  43
  44 #include <sys_defs.h>
  45 #include <unistd.h>
  46
  47 /* Utility library. */
  48
  49 #include "msg.h"
  50 #include "set_eugid.h"
  51 #include "dot_lockfile.h"
  52 #include "dot_lockfile_as.h"
  53
  54 /* dot_lockfile_as - dotlock file as user */
  55
  56 int     dot_lockfile_as(const char *path, VSTRING *why, uid_t euid, gid_t egid)
  57 {
  58     uid_t   saved_euid = geteuid();
  59     gid_t   saved_egid = getegid();
  60     int     result;
  61
  62     /*
  63      * Switch to the target user privileges.
  64      */
  65     set_eugid(euid, egid);
  66
  67     /*
  68      * Lock that file.
  69      */
  70     result = dot_lockfile(path, why);
  71
  72     /*
  73      * Restore saved privileges.
  74      */
  75     set_eugid(saved_euid, saved_egid);
  76
  77     return (result);
  78 }
  79
  80 /* dot_unlockfile_as - dotlock file as user */
  81
  82 void     dot_unlockfile_as(const char *path, uid_t euid, gid_t egid)
  83 {
  84     uid_t   saved_euid = geteuid();
  85     gid_t   saved_egid = getegid();
  86
  87     /*
  88      * Switch to the target user privileges.
  89      */
  90     set_eugid(euid, egid);
  91
  92     /*
  93      * Lock that file.
  94      */
  95     dot_unlockfile(path);
  96
  97     /*
  98      * Restore saved privileges.
  99      */
 100     set_eugid(saved_euid, saved_egid);
 101 }