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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_MAC_AUTHORIZATION_UTIL_H_
      6 #define BASE_MAC_AUTHORIZATION_UTIL_H_
      7 
      8 // AuthorizationExecuteWithPrivileges fork()s and exec()s the tool, but it
      9 // does not wait() for it.  It also doesn't provide the caller with access to
     10 // the forked pid.  If used irresponsibly, zombie processes will accumulate.
     11 //
     12 // Apple's really gotten us between a rock and a hard place, here.
     13 //
     14 // Fortunately, AuthorizationExecuteWithPrivileges does give access to the
     15 // tool's stdout (and stdin) via a FILE* pipe.  The tool can output its pid
     16 // to this pipe, and the main program can read it, and then have something
     17 // that it can wait() for.
     18 //
     19 // The contract is that any tool executed by the wrappers declared in this
     20 // file must print its pid to stdout on a line by itself before doing anything
     21 // else.
     22 //
     23 // http://developer.apple.com/library/mac/#samplecode/BetterAuthorizationSample/Listings/BetterAuthorizationSampleLib_c.html
     24 // (Look for "What's This About Zombies?")
     25 
     26 #include <CoreFoundation/CoreFoundation.h>
     27 #include <Security/Authorization.h>
     28 #include <stdio.h>
     29 #include <sys/types.h>
     30 
     31 #include "base/base_export.h"
     32 
     33 namespace base {
     34 namespace mac {
     35 
     36 // Obtains an AuthorizationRef for the rights indicated by |rights|.  If
     37 // necessary, prompts the user for authentication. If the user is prompted,
     38 // |prompt| will be used as the prompt string and an icon appropriate for the
     39 // application will be displayed in a prompt dialog. Note that the system
     40 // appends its own text to the prompt string. |extraFlags| will be ORed
     41 // together with the default flags. Returns NULL on failure.
     42 BASE_EXPORT
     43 AuthorizationRef GetAuthorizationRightsWithPrompt(
     44     AuthorizationRights* rights,
     45     CFStringRef prompt,
     46     AuthorizationFlags extraFlags);
     47 
     48 // Obtains an AuthorizationRef (using |GetAuthorizationRightsWithPrompt|) that
     49 // can be used to run commands as root.
     50 BASE_EXPORT
     51 AuthorizationRef AuthorizationCreateToRunAsRoot(CFStringRef prompt);
     52 
     53 // Calls straight through to AuthorizationExecuteWithPrivileges.  If that
     54 // call succeeds, |pid| will be set to the pid of the executed tool.  If the
     55 // pid can't be determined, |pid| will be set to -1.  |pid| must not be NULL.
     56 // |pipe| may be NULL, but the tool will always be executed with a pipe in
     57 // order to read the pid from its stdout.
     58 BASE_EXPORT
     59 OSStatus ExecuteWithPrivilegesAndGetPID(AuthorizationRef authorization,
     60                                         const char* tool_path,
     61                                         AuthorizationFlags options,
     62                                         const char** arguments,
     63                                         FILE** pipe,
     64                                         pid_t* pid);
     65 
     66 // Calls ExecuteWithPrivilegesAndGetPID, and if that call succeeds, calls
     67 // waitpid() to wait for the process to exit.  If waitpid() succeeds, the
     68 // exit status is placed in |exit_status|, otherwise, -1 is stored.
     69 // |exit_status| may be NULL and this function will still wait for the process
     70 // to exit.
     71 BASE_EXPORT
     72 OSStatus ExecuteWithPrivilegesAndWait(AuthorizationRef authorization,
     73                                       const char* tool_path,
     74                                       AuthorizationFlags options,
     75                                       const char** arguments,
     76                                       FILE** pipe,
     77                                       int* exit_status);
     78 
     79 }  // namespace mac
     80 }  // namespace base
     81 
     82 #endif  // BASE_MAC_AUTHORIZATION_UTIL_H_
     83