bsd/man/man2/issetugid.2

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  34 .Dd August, 25 1996
  35 .Dt ISSETUGID 2
  36 .Os OpenBSD 2.0
  37 .Sh NAME
  38 .Nm issetugid
  39 .Nd is current executable running setuid or setgid
  40 .Sh SYNOPSIS
  41 .Fd #include <unistd.h>
  42 .Ft int
  43 .Fn issetugid void
  44 .Sh DESCRIPTION
  45 The
  46 .Fn issetugid
  47 function returns 1 if the process was made setuid or setgid as
  48 the result of the last
  49 .Fn execve
  50 system call.
  51 Otherwise it returns 0.
  52 .Pp
  53 This system call exists so that library routines (inside libc, libtermlib,
  54 or other libraries) can gaurantee safe behavior when used inside
  55 setuid or setgid programs.
  56 Some library routines may not be passed sufficient information to know
  57 if the current program was started setuid or setgid because higher level
  58 calling code may have made changes to the uid or the euid.
  59 In particular, it is wise to use this call to determine if a
  60 pathname returned from a
  61 .Fn getenv
  62 call may safely be used to
  63 .Fn open
  64 the specified file.
  65 .Pp
  66 .Fn issetugid
  67 is unaffected by calls to
  68 .Fn setuid ,
  69 .Fn fork ,
  70 and other such calls.  It is only controlled by
  71 .Fn execve .
  72 .Sh ERRORS
  73 The
  74 .Fn issetugid
  75 function is always successful, and no return value is reserved to
  76 indicate an error.
  77 .Sh SEE ALSO
  78 .Xr execve 2 ,
  79 .Xr setuid 2 ,
  80 .Xr seteuid 2,
  81 .Xr setgid 2 ,
  82 .Xr setegid 2
  83 .Sh HISTORY
  84 A
  85 .Fn lstat
  86 function call appeared in
  87 OpenBSD 2.0