chrome/installer/gcapi_mac/gcapi.mm - chromium/src - Git at Google

 // Copyright 2012 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "chrome/installer/gcapi_mac/gcapi.h"

 #import <Cocoa/Cocoa.h>
 #include <grp.h>
 #include <pwd.h>
 #include <stddef.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/utsname.h>

 namespace {

 // The "~~" prefixes are replaced with the home directory of the
 // console owner (i.e. not the home directory of the euid).
 NSString* const kChromeInstallPath = @"/Applications/Google Chrome.app";

 NSString* const kBrandKey = @"KSBrandID";
 NSString* const kUserBrandPath = @"~~/Library/Google/Google Chrome Brand.plist";

 // ksadmin moved from MacOS to Helpers in Keystone 1.2.13.112, 2019-11-12. A
 // symbolic link from the old location was left in place, but may not remain
 // indefinitely. Try the new location first, falling back to the old if needed.
 NSString* const kSystemKsadminPath =
     @"/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
      "Contents/Helpers/ksadmin";
 NSString* const kSystemKsadminPathOld =
     @"/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
      "Contents/MacOS/ksadmin";
 NSString* const kUserKsadminPath =
     @"~~/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
      "Contents/Helpers/ksadmin";
 NSString* const kUserKsadminPathOld =
     @"~~/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
      "Contents/MacOS/ksadmin";

 NSString* const kSystemMasterPrefsPath =
     @"/Library/Google/Google Chrome Master Preferences";
 NSString* const kUserMasterPrefsPath =
     @"~~/Library/Application Support/Google/Chrome/"
      "Google Chrome Master Preferences";

 // Condensed from chromium's base/mac/mac_util.mm.
 bool IsMacOSVersionSupported() {
   // base::OperatingSystemVersionNumbers() at one time called Gestalt(), which
   // was observed to be able to spawn threads (see https://crbug.com/53200).
   // Nowadays that function calls -[NSProcessInfo operatingSystemVersion], whose
   // current implementation does things like hit the file system, which is
   // possibly a blocking operation. Either way, it's overkill for what needs to
   // be done here.
   //
   // uname, on the other hand, is implemented as a simple series of sysctl
   // system calls to obtain the relevant data from the kernel. The data is
   // compiled right into the kernel, so no threads or blocking or other
   // funny business is necessary.

   struct utsname uname_info;
   if (uname(&uname_info) != 0) {
     return false;
   }
   if (strcmp(uname_info.sysname, "Darwin") != 0) {
     return false;
   }

   char* dot = strchr(uname_info.release, '.');
   if (!dot) {
     return false;
   }

   int darwin_major_version = atoi(uname_info.release);
   if (darwin_major_version < 6) {
     return false;
   }

   int macos_version;
   // Darwin major versions 6 through 19 corresponded to macOS versions 10.2
   // through 10.15. Darwin major version 20 corresponds to macOS version 11.0.
   // Assume a correspondence between Darwin's major version numbers and macOS
   // major version numbers.
   if (darwin_major_version <= 19) {
     macos_version = 1000 + darwin_major_version - 4;
   } else {
     macos_version = 100 * (darwin_major_version - 9);
   }

   // Chrome is known to work on 10.13 - 13.x.
   return macos_version >= 1013 && macos_version < 1400;
 }

 // Returns the pid/gid of the logged-in user, even if getuid() claims that the
 // current user is root.
 // Returns nullptr on error.
 passwd* GetRealUserId() {
   CFDictionaryRef session_info = CGSessionCopyCurrentDictionary();
   CFAutorelease(session_info);
   if (!session_info) {
     return nullptr;  // Possibly no screen plugged in.
   }

   CFNumberRef ns_uid =
       (CFNumberRef)CFDictionaryGetValue(session_info, kCGSessionUserIDKey);
   if (CFGetTypeID(ns_uid) != CFNumberGetTypeID()) {
     return nullptr;
   }

   uid_t uid;
   BOOL success = CFNumberGetValue(ns_uid, kCFNumberSInt32Type, &uid);
   if (!success) {
     return nullptr;
   }

   return getpwuid(uid);
 }

 enum TicketKind { kSystemTicket, kUserTicket };

 // Replaces "~~" with |home_dir|.
 NSString* AdjustHomedir(NSString* s, const char* home_dir) {
   if (![s hasPrefix:@"~~"]) {
     return s;
   }
   NSString* ns_home_dir = @(home_dir);
   return [ns_home_dir stringByAppendingString:[s substringFromIndex:2]];
 }

 // If |chrome_path| is not 0, |*chrome_path| is set to the path where chrome
 // is according to keystone. It's only set if that path exists on disk.
 BOOL FindChromeTicket(TicketKind kind,
                       const passwd* user,
                       NSString** chrome_path) {
   if (chrome_path) {
     *chrome_path = nil;
   }

   NSMutableArray<NSString*>* keystone_paths = [NSMutableArray
       arrayWithObjects:kSystemKsadminPath, kSystemKsadminPathOld, nil];
   if (kind == kUserTicket) {
     [keystone_paths insertObject:AdjustHomedir(kUserKsadminPath, user->pw_dir)
                          atIndex:0];
     [keystone_paths
         insertObject:AdjustHomedir(kUserKsadminPathOld, user->pw_dir)
              atIndex:1];
   }

   for (NSString* path in keystone_paths) {
     if (![NSFileManager.defaultManager fileExistsAtPath:path]) {
       continue;
     }

     NSString* string = nil;
     bool ksadmin_ran_successfully = false;

     @try {
       NSTask* task = [[NSTask alloc] init];
       task.launchPath = path;

       NSArray* arguments = @[
         kind == kUserTicket ? @"--user-store" : @"--system-store",
         @"--print-tickets",
         @"--productid",
         @"com.google.Chrome",
       ];
       if (geteuid() == 0 && kind == kUserTicket) {
         NSString* run_as = @(user->pw_name);
         task.launchPath = @"/usr/bin/sudo";
         arguments =
             [@[ @"-u", run_as, path ] arrayByAddingObjectsFromArray:arguments];
       }
       task.arguments = arguments;

       NSPipe* pipe = [NSPipe pipe];
       task.standardOutput = pipe;

       NSFileHandle* file = pipe.fileHandleForReading;

       [task launch];

       NSData* data = [file readDataToEndOfFile];
       [task waitUntilExit];

       ksadmin_ran_successfully = task.terminationStatus == 0;
       string = [[NSString alloc] initWithData:data
                                      encoding:NSUTF8StringEncoding];
     } @catch (id exception) {
       // Most likely, ks_path didn't exist.
     }

     if (ksadmin_ran_successfully && string.length > 0) {
       // If the user deleted chrome, it doesn't get unregistered in keystone.
       // Check if the path keystone thinks chrome is at still exists, and if not
       // treat this as "chrome isn't installed". Sniff for
       //   xc=<KSPathExistenceChecker:1234 path=/Applications/Google Chrome.app>
       // in the output. But don't mess with system tickets, since reinstalling
       // a user chrome on top of a system ticket produces a non-autoupdating
       // chrome.
       NSRange start = [string rangeOfString:@"\n\txc=<KSPathExistenceChecker:"];
       if (start.location == NSNotFound && start.length == 0) {
         return YES;  // Err on the cautious side.
       }
       string = [string substringFromIndex:start.location];

       start = [string rangeOfString:@"path="];
       if (start.location == NSNotFound && start.length == 0) {
         return YES;  // Err on the cautious side.
       }
       string = [string substringFromIndex:start.location];

       NSRange end = [string rangeOfString:@".app>\n\t"];
       if (end.location == NSNotFound && end.length == 0) {
         return YES;
       }

       string = [string substringToIndex:NSMaxRange(end) - [@">\n\t" length]];
       string = [string substringFromIndex:start.length];

       BOOL exists = [NSFileManager.defaultManager fileExistsAtPath:string];
       if (exists && chrome_path) {
         *chrome_path = string;
       }
       // Don't allow reinstallation over a system ticket, even if chrome doesn't
       // exist on disk.
       if (kind == kSystemTicket) {
         return YES;
       }
       return exists;
     }
   }

   return NO;
 }

 // File permission mask for files created by gcapi.
 const mode_t kUserPermissions = 0755;
 const mode_t kAdminPermissions = 0775;

 BOOL CreatePathToFile(NSString* path, const passwd* user) {
   path = [path stringByDeletingLastPathComponent];

   // Default owner, group, permissions:
   // * Permissions are set according to the umask of the current process. For
   //   more information, see umask.
   // * The owner ID is set to the effective user ID of the process.
   // * The group ID is set to that of the parent directory.
   // The default group ID is fine. Owner ID is fine if creating a system path,
   // but when creating a user path explicitly set the owner in case euid is 0.
   // Do set permissions explicitly; for admin paths all admins can write, for
   // user paths just the owner may.
   NSMutableDictionary* attributes = [NSMutableDictionary dictionary];
   if (user) {
     attributes[NSFilePosixPermissions] = @(kUserPermissions);
     attributes[NSFileOwnerAccountID] = @(user->pw_uid);
   } else {
     attributes[NSFilePosixPermissions] = @(kAdminPermissions);
     attributes[NSFileGroupOwnerAccountName] = @"admin";
   }

   return [NSFileManager.defaultManager createDirectoryAtPath:path
                                  withIntermediateDirectories:YES
                                                   attributes:attributes
                                                        error:nil];
 }

 // Tries to write |data| at |user_path|.
 // Returns the path where it wrote, or nil on failure.
 NSString* WriteUserData(NSData* data, NSString* user_path, const passwd* user) {
   user_path = AdjustHomedir(user_path, user->pw_dir);
   if (CreatePathToFile(user_path, user) && [data writeToFile:user_path
                                                   atomically:YES]) {
     chmod(user_path.fileSystemRepresentation, kUserPermissions & ~0111);
     chown(user_path.fileSystemRepresentation, user->pw_uid, user->pw_gid);
     return user_path;
   }
   return nil;
 }

 // Tries to write |data| at |system_path| or if that fails at |user_path|.
 // Returns the path where it wrote, or nil on failure.
 NSString* WriteData(NSData* data,
                     NSString* system_path,
                     NSString* user_path,
                     const passwd* user) {
   // Try system first.
   if (CreatePathToFile(system_path, nullptr) && [data writeToFile:system_path
                                                        atomically:YES]) {
     chmod(system_path.fileSystemRepresentation, kAdminPermissions & ~0111);
     // Make sure the file is owned by group admin.
     if (group* group = getgrnam("admin")) {
       chown(system_path.fileSystemRepresentation, 0, group->gr_gid);
     }
     return system_path;
   }

   // Failed, try user.
   return WriteUserData(data, user_path, user);
 }

 NSString* WriteBrandCode(const char* brand_code, const passwd* user) {
   NSDictionary* brand_dict = @{
     kBrandKey : @(brand_code),
   };
   NSData* contents = [NSPropertyListSerialization
       dataWithPropertyList:brand_dict
                     format:NSPropertyListBinaryFormat_v1_0
                    options:0
                      error:nil];

   return WriteUserData(contents, kUserBrandPath, user);
 }

 BOOL WriteMasterPrefs(const char* master_prefs_contents,
                       size_t master_prefs_contents_size,
                       const passwd* user) {
   NSData* contents = [NSData dataWithBytes:master_prefs_contents
                                     length:master_prefs_contents_size];
   return WriteData(contents, kSystemMasterPrefsPath, kUserMasterPrefsPath,
                    user) != nil;
 }

 NSString* PathToFramework(NSString* app_path, NSDictionary* info_plist) {
   NSString* version = info_plist[@"CFBundleShortVersionString"];
   if (!version) {
     return nil;
   }
   return [NSString pathWithComponents:@[
     app_path, @"Contents", @"Frameworks", @"Google Chrome Framework.framework",
     @"Versions", version
   ]];
 }

 NSString* PathToInstallScript(NSString* app_path, NSDictionary* info_plist) {
   return [PathToFramework(app_path, info_plist)
       stringByAppendingPathComponent:@"Resources/install.sh"];
 }

 bool isbrandchar(int c) {
   // Always four upper-case alpha chars.
   return c >= 'A' && c <= 'Z';
 }

 }  // namespace

 int GoogleChromeCompatibilityCheck(unsigned* reasons) {
   unsigned local_reasons = 0;
   @autoreleasepool {
     if (!IsMacOSVersionSupported()) {
       local_reasons |= GCCC_ERROR_OSNOTSUPPORTED;
     }

     NSString* path;
     if (FindChromeTicket(kSystemTicket, nullptr, &path)) {
       local_reasons |= GCCC_ERROR_ALREADYPRESENT;
       if (!path) {  // Ticket points to nothingness.
         local_reasons |= GCCC_ERROR_ACCESSDENIED;
       }
     }

     passwd* user = GetRealUserId();
     if (!user) {
       local_reasons |= GCCC_ERROR_ACCESSDENIED;
     } else if (FindChromeTicket(kUserTicket, user, nullptr)) {
       local_reasons |= GCCC_ERROR_ALREADYPRESENT;
     }

     if ([NSFileManager.defaultManager fileExistsAtPath:kChromeInstallPath]) {
       local_reasons |= GCCC_ERROR_ALREADYPRESENT;
     }

     if ((local_reasons & GCCC_ERROR_ALREADYPRESENT) == 0) {
       if (![NSFileManager.defaultManager
               isWritableFileAtPath:@"/Applications"]) {
         local_reasons |= GCCC_ERROR_ACCESSDENIED;
       }
     }
   }

   if (reasons != nullptr) {
     *reasons = local_reasons;
   }
   return local_reasons == 0;
 }

 int InstallGoogleChrome(const char* source_path,
                         const char* brand_code,
                         const char* master_prefs_contents,
                         unsigned master_prefs_contents_size) {
   if (!GoogleChromeCompatibilityCheck(nullptr)) {
     return 0;
   }

   @autoreleasepool {
     passwd* user = GetRealUserId();
     if (!user) {
       return 0;
     }

     NSString* app_path = @(source_path);
     NSString* info_plist_path =
         [app_path stringByAppendingPathComponent:@"Contents/Info.plist"];
     NSDictionary* info_plist =
         [NSDictionary dictionaryWithContentsOfFile:info_plist_path];

     // Use install.sh from the Chrome app bundle to copy Chrome to its
     // destination.
     NSString* install_script = PathToInstallScript(app_path, info_plist);
     if (!install_script) {
       return 0;
     }

     @try {
       NSTask* task = [[NSTask alloc] init];

       // install.sh tries to make the installed app admin-writable, but
       // only when it's not run as root.
       if (geteuid() == 0) {
         // Use |su $(whoami)| instead of sudo -u. If the current user is in more
         // than 16 groups, |sudo -u $(whoami)| will drop all but the first 16
         // groups, which can lead to problems (e.g. if "admin" is one of the
         // dropped groups).
         // Since geteuid() is 0, su won't prompt for a password.
         NSString* run_as = @(user->pw_name);
         task.launchPath = @"/usr/bin/su";

         NSString* single_quote_escape = @"'\"'\"'";
         NSString* install_script_quoted = [install_script
             stringByReplacingOccurrencesOfString:@"'"
                                       withString:single_quote_escape];
         NSString* app_path_quoted =
             [app_path stringByReplacingOccurrencesOfString:@"'"
                                                 withString:single_quote_escape];
         NSString* install_path_quoted = [kChromeInstallPath
             stringByReplacingOccurrencesOfString:@"'"
                                       withString:single_quote_escape];

         NSString* install_script_execution = [NSString
             stringWithFormat:@"exec '%@' '%@' '%@'", install_script_quoted,
                              app_path_quoted, install_path_quoted];
         task.arguments = @[ run_as, @"-c", install_script_execution ];
       } else {
         task.launchPath = install_script;
         task.arguments = @[ app_path, kChromeInstallPath ];
       }

       [task launch];
       [task waitUntilExit];
       if (task.terminationStatus != 0) {
         return 0;
       }
     } @catch (id exception) {
       return 0;
     }

     // Set brand code. If Chrome's Info.plist contains a brand code, use that.
     NSString* info_plist_brand = info_plist[kBrandKey];
     if (info_plist_brand &&
         [info_plist_brand respondsToSelector:@selector(UTF8String)]) {
       brand_code = [info_plist_brand UTF8String];
     }

     BOOL valid_brand_code =
         brand_code && strlen(brand_code) == 4 && isbrandchar(brand_code[0]) &&
         isbrandchar(brand_code[1]) && isbrandchar(brand_code[2]) &&
         isbrandchar(brand_code[3]);

     if (valid_brand_code) {
       WriteBrandCode(brand_code, user);
     }

     // Write master prefs.
     if (master_prefs_contents) {
       WriteMasterPrefs(master_prefs_contents, master_prefs_contents_size, user);
     }

     // TODO Set default browser if requested.
   }
   return 1;
 }

 int LaunchGoogleChrome() {
   @autoreleasepool {
     passwd* user = GetRealUserId();
     if (!user) {
       return 0;
     }

     NSString* app_path;

     NSString* path;
     if (FindChromeTicket(kUserTicket, user, &path) && path) {
       app_path = path;
     } else if (FindChromeTicket(kSystemTicket, nullptr, &path) && path) {
       app_path = path;
     } else {
       app_path = kChromeInstallPath;
     }

     // NSWorkspace launches processes as the current console owner,
     // even when running with euid of 0.
     return [NSWorkspace.sharedWorkspace launchApplication:app_path];
   }
 }
	// Copyright 2012 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "chrome/installer/gcapi_mac/gcapi.h"

	#import <Cocoa/Cocoa.h>
	#include <grp.h>
	#include <pwd.h>
	#include <stddef.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/utsname.h>

	namespace {

	// The "~~" prefixes are replaced with the home directory of the
	// console owner (i.e. not the home directory of the euid).
	NSString* const kChromeInstallPath = @"/Applications/Google Chrome.app";

	NSString* const kBrandKey = @"KSBrandID";
	NSString* const kUserBrandPath = @"~~/Library/Google/Google Chrome Brand.plist";

	// ksadmin moved from MacOS to Helpers in Keystone 1.2.13.112, 2019-11-12. A
	// symbolic link from the old location was left in place, but may not remain
	// indefinitely. Try the new location first, falling back to the old if needed.
	NSString* const kSystemKsadminPath =
	@"/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
	"Contents/Helpers/ksadmin";
	NSString* const kSystemKsadminPathOld =
	@"/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
	"Contents/MacOS/ksadmin";
	NSString* const kUserKsadminPath =
	@"~~/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
	"Contents/Helpers/ksadmin";
	NSString* const kUserKsadminPathOld =
	@"~~/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/"
	"Contents/MacOS/ksadmin";

	NSString* const kSystemMasterPrefsPath =
	@"/Library/Google/Google Chrome Master Preferences";
	NSString* const kUserMasterPrefsPath =
	@"~~/Library/Application Support/Google/Chrome/"
	"Google Chrome Master Preferences";

	// Condensed from chromium's base/mac/mac_util.mm.
	bool IsMacOSVersionSupported() {
	// base::OperatingSystemVersionNumbers() at one time called Gestalt(), which
	// was observed to be able to spawn threads (see https://crbug.com/53200).
	// Nowadays that function calls -[NSProcessInfo operatingSystemVersion], whose
	// current implementation does things like hit the file system, which is
	// possibly a blocking operation. Either way, it's overkill for what needs to
	// be done here.
	//
	// uname, on the other hand, is implemented as a simple series of sysctl
	// system calls to obtain the relevant data from the kernel. The data is
	// compiled right into the kernel, so no threads or blocking or other
	// funny business is necessary.

	struct utsname uname_info;
	if (uname(&uname_info) != 0) {
	return false;
	}
	if (strcmp(uname_info.sysname, "Darwin") != 0) {
	return false;
	}

	char* dot = strchr(uname_info.release, '.');
	if (!dot) {
	return false;
	}

	int darwin_major_version = atoi(uname_info.release);
	if (darwin_major_version < 6) {
	return false;
	}

	int macos_version;
	// Darwin major versions 6 through 19 corresponded to macOS versions 10.2
	// through 10.15. Darwin major version 20 corresponds to macOS version 11.0.
	// Assume a correspondence between Darwin's major version numbers and macOS
	// major version numbers.
	if (darwin_major_version <= 19) {
	macos_version = 1000 + darwin_major_version - 4;
	} else {
	macos_version = 100 * (darwin_major_version - 9);
	}

	// Chrome is known to work on 10.13 - 13.x.
	return macos_version >= 1013 && macos_version < 1400;
	}

	// Returns the pid/gid of the logged-in user, even if getuid() claims that the
	// current user is root.
	// Returns nullptr on error.
	passwd* GetRealUserId() {
	CFDictionaryRef session_info = CGSessionCopyCurrentDictionary();
	CFAutorelease(session_info);
	if (!session_info) {
	return nullptr; // Possibly no screen plugged in.
	}

	CFNumberRef ns_uid =
	(CFNumberRef)CFDictionaryGetValue(session_info, kCGSessionUserIDKey);
	if (CFGetTypeID(ns_uid) != CFNumberGetTypeID()) {
	return nullptr;
	}

	uid_t uid;
	BOOL success = CFNumberGetValue(ns_uid, kCFNumberSInt32Type, &uid);
	if (!success) {
	return nullptr;
	}

	return getpwuid(uid);
	}

	enum TicketKind { kSystemTicket, kUserTicket };

	// Replaces "~~" with \|home_dir\|.
	NSString* AdjustHomedir(NSString* s, const char* home_dir) {
	if (![s hasPrefix:@"~~"]) {
	return s;
	}
	NSString* ns_home_dir = @(home_dir);
	return [ns_home_dir stringByAppendingString:[s substringFromIndex:2]];
	}

	// If \|chrome_path\| is not 0, \|*chrome_path\| is set to the path where chrome
	// is according to keystone. It's only set if that path exists on disk.
	BOOL FindChromeTicket(TicketKind kind,
	const passwd* user,
	NSString** chrome_path) {
	if (chrome_path) {
	*chrome_path = nil;
	}

	NSMutableArray<NSString> keystone_paths = [NSMutableArray
	arrayWithObjects:kSystemKsadminPath, kSystemKsadminPathOld, nil];
	if (kind == kUserTicket) {
	[keystone_paths insertObject:AdjustHomedir(kUserKsadminPath, user->pw_dir)
	atIndex:0];
	[keystone_paths
	insertObject:AdjustHomedir(kUserKsadminPathOld, user->pw_dir)
	atIndex:1];
	}

	for (NSString* path in keystone_paths) {
	if (![NSFileManager.defaultManager fileExistsAtPath:path]) {
	continue;
	}

	NSString* string = nil;
	bool ksadmin_ran_successfully = false;

	@try {
	NSTask* task = [[NSTask alloc] init];
	task.launchPath = path;

	NSArray* arguments = @[
	kind == kUserTicket ? @"--user-store" : @"--system-store",
	@"--print-tickets",
	@"--productid",
	@"com.google.Chrome",
	];
	if (geteuid() == 0 && kind == kUserTicket) {
	NSString* run_as = @(user->pw_name);
	task.launchPath = @"/usr/bin/sudo";
	arguments =
	[@[ @"-u", run_as, path ] arrayByAddingObjectsFromArray:arguments];
	}
	task.arguments = arguments;

	NSPipe* pipe = [NSPipe pipe];
	task.standardOutput = pipe;

	NSFileHandle* file = pipe.fileHandleForReading;

	[task launch];

	NSData* data = [file readDataToEndOfFile];
	[task waitUntilExit];

	ksadmin_ran_successfully = task.terminationStatus == 0;
	string = [[NSString alloc] initWithData:data
	encoding:NSUTF8StringEncoding];
	} @catch (id exception) {
	// Most likely, ks_path didn't exist.
	}

	if (ksadmin_ran_successfully && string.length > 0) {
	// If the user deleted chrome, it doesn't get unregistered in keystone.
	// Check if the path keystone thinks chrome is at still exists, and if not
	// treat this as "chrome isn't installed". Sniff for
	// xc=<KSPathExistenceChecker:1234 path=/Applications/Google Chrome.app>
	// in the output. But don't mess with system tickets, since reinstalling
	// a user chrome on top of a system ticket produces a non-autoupdating
	// chrome.
	NSRange start = [string rangeOfString:@"\n\txc=<KSPathExistenceChecker:"];
	if (start.location == NSNotFound && start.length == 0) {
	return YES; // Err on the cautious side.
	}
	string = [string substringFromIndex:start.location];

	start = [string rangeOfString:@"path="];
	if (start.location == NSNotFound && start.length == 0) {
	return YES; // Err on the cautious side.
	}
	string = [string substringFromIndex:start.location];

	NSRange end = [string rangeOfString:@".app>\n\t"];
	if (end.location == NSNotFound && end.length == 0) {
	return YES;
	}

	string = [string substringToIndex:NSMaxRange(end) - [@">\n\t" length]];
	string = [string substringFromIndex:start.length];

	BOOL exists = [NSFileManager.defaultManager fileExistsAtPath:string];
	if (exists && chrome_path) {
	*chrome_path = string;
	}
	// Don't allow reinstallation over a system ticket, even if chrome doesn't
	// exist on disk.
	if (kind == kSystemTicket) {
	return YES;
	}
	return exists;
	}
	}

	return NO;
	}

	// File permission mask for files created by gcapi.
	const mode_t kUserPermissions = 0755;
	const mode_t kAdminPermissions = 0775;

	BOOL CreatePathToFile(NSString* path, const passwd* user) {
	path = [path stringByDeletingLastPathComponent];

	// Default owner, group, permissions:
	// * Permissions are set according to the umask of the current process. For
	// more information, see umask.
	// * The owner ID is set to the effective user ID of the process.
	// * The group ID is set to that of the parent directory.
	// The default group ID is fine. Owner ID is fine if creating a system path,
	// but when creating a user path explicitly set the owner in case euid is 0.
	// Do set permissions explicitly; for admin paths all admins can write, for
	// user paths just the owner may.
	NSMutableDictionary* attributes = [NSMutableDictionary dictionary];
	if (user) {
	attributes[NSFilePosixPermissions] = @(kUserPermissions);
	attributes[NSFileOwnerAccountID] = @(user->pw_uid);
	} else {
	attributes[NSFilePosixPermissions] = @(kAdminPermissions);
	attributes[NSFileGroupOwnerAccountName] = @"admin";
	}

	return [NSFileManager.defaultManager createDirectoryAtPath:path
	withIntermediateDirectories:YES
	attributes:attributes
	error:nil];
	}

	// Tries to write \|data\| at \|user_path\|.
	// Returns the path where it wrote, or nil on failure.
	NSString* WriteUserData(NSData* data, NSString* user_path, const passwd* user) {
	user_path = AdjustHomedir(user_path, user->pw_dir);
	if (CreatePathToFile(user_path, user) && [data writeToFile:user_path
	atomically:YES]) {
	chmod(user_path.fileSystemRepresentation, kUserPermissions & ~0111);
	chown(user_path.fileSystemRepresentation, user->pw_uid, user->pw_gid);
	return user_path;
	}
	return nil;
	}

	// Tries to write \|data\| at \|system_path\| or if that fails at \|user_path\|.
	// Returns the path where it wrote, or nil on failure.
	NSString* WriteData(NSData* data,
	NSString* system_path,
	NSString* user_path,
	const passwd* user) {
	// Try system first.
	if (CreatePathToFile(system_path, nullptr) && [data writeToFile:system_path
	atomically:YES]) {
	chmod(system_path.fileSystemRepresentation, kAdminPermissions & ~0111);
	// Make sure the file is owned by group admin.
	if (group* group = getgrnam("admin")) {
	chown(system_path.fileSystemRepresentation, 0, group->gr_gid);
	}
	return system_path;
	}

	// Failed, try user.
	return WriteUserData(data, user_path, user);
	}

	NSString* WriteBrandCode(const char* brand_code, const passwd* user) {
	NSDictionary* brand_dict = @{
	kBrandKey : @(brand_code),
	};
	NSData* contents = [NSPropertyListSerialization
	dataWithPropertyList:brand_dict
	format:NSPropertyListBinaryFormat_v1_0
	options:0
	error:nil];

	return WriteUserData(contents, kUserBrandPath, user);
	}

	BOOL WriteMasterPrefs(const char* master_prefs_contents,
	size_t master_prefs_contents_size,
	const passwd* user) {
	NSData* contents = [NSData dataWithBytes:master_prefs_contents
	length:master_prefs_contents_size];
	return WriteData(contents, kSystemMasterPrefsPath, kUserMasterPrefsPath,
	user) != nil;
	}

	NSString* PathToFramework(NSString* app_path, NSDictionary* info_plist) {
	NSString* version = info_plist[@"CFBundleShortVersionString"];
	if (!version) {
	return nil;
	}
	return [NSString pathWithComponents:@[
	app_path, @"Contents", @"Frameworks", @"Google Chrome Framework.framework",
	@"Versions", version
	]];
	}

	NSString* PathToInstallScript(NSString* app_path, NSDictionary* info_plist) {
	return [PathToFramework(app_path, info_plist)
	stringByAppendingPathComponent:@"Resources/install.sh"];
	}

	bool isbrandchar(int c) {
	// Always four upper-case alpha chars.
	return c >= 'A' && c <= 'Z';
	}

	} // namespace

	int GoogleChromeCompatibilityCheck(unsigned* reasons) {
	unsigned local_reasons = 0;
	@autoreleasepool {
	if (!IsMacOSVersionSupported()) {
	local_reasons \|= GCCC_ERROR_OSNOTSUPPORTED;
	}

	NSString* path;
	if (FindChromeTicket(kSystemTicket, nullptr, &path)) {
	local_reasons \|= GCCC_ERROR_ALREADYPRESENT;
	if (!path) { // Ticket points to nothingness.
	local_reasons \|= GCCC_ERROR_ACCESSDENIED;
	}
	}

	passwd* user = GetRealUserId();
	if (!user) {
	local_reasons \|= GCCC_ERROR_ACCESSDENIED;
	} else if (FindChromeTicket(kUserTicket, user, nullptr)) {
	local_reasons \|= GCCC_ERROR_ALREADYPRESENT;
	}

	if ([NSFileManager.defaultManager fileExistsAtPath:kChromeInstallPath]) {
	local_reasons \|= GCCC_ERROR_ALREADYPRESENT;
	}

	if ((local_reasons & GCCC_ERROR_ALREADYPRESENT) == 0) {
	if (![NSFileManager.defaultManager
	isWritableFileAtPath:@"/Applications"]) {
	local_reasons \|= GCCC_ERROR_ACCESSDENIED;
	}
	}
	}

	if (reasons != nullptr) {
	*reasons = local_reasons;
	}
	return local_reasons == 0;
	}

	int InstallGoogleChrome(const char* source_path,
	const char* brand_code,
	const char* master_prefs_contents,
	unsigned master_prefs_contents_size) {
	if (!GoogleChromeCompatibilityCheck(nullptr)) {
	return 0;
	}

	@autoreleasepool {
	passwd* user = GetRealUserId();
	if (!user) {
	return 0;
	}

	NSString* app_path = @(source_path);
	NSString* info_plist_path =
	[app_path stringByAppendingPathComponent:@"Contents/Info.plist"];
	NSDictionary* info_plist =
	[NSDictionary dictionaryWithContentsOfFile:info_plist_path];

	// Use install.sh from the Chrome app bundle to copy Chrome to its
	// destination.
	NSString* install_script = PathToInstallScript(app_path, info_plist);
	if (!install_script) {
	return 0;
	}

	@try {
	NSTask* task = [[NSTask alloc] init];

	// install.sh tries to make the installed app admin-writable, but
	// only when it's not run as root.
	if (geteuid() == 0) {
	// Use \|su $(whoami)\| instead of sudo -u. If the current user is in more
	// than 16 groups, \|sudo -u $(whoami)\| will drop all but the first 16
	// groups, which can lead to problems (e.g. if "admin" is one of the
	// dropped groups).
	// Since geteuid() is 0, su won't prompt for a password.
	NSString* run_as = @(user->pw_name);
	task.launchPath = @"/usr/bin/su";

	NSString* single_quote_escape = @"'\"'\"'";
	NSString* install_script_quoted = [install_script
	stringByReplacingOccurrencesOfString:@"'"
	withString:single_quote_escape];
	NSString* app_path_quoted =
	[app_path stringByReplacingOccurrencesOfString:@"'"
	withString:single_quote_escape];
	NSString* install_path_quoted = [kChromeInstallPath
	stringByReplacingOccurrencesOfString:@"'"
	withString:single_quote_escape];

	NSString* install_script_execution = [NSString
	stringWithFormat:@"exec '%@' '%@' '%@'", install_script_quoted,
	app_path_quoted, install_path_quoted];
	task.arguments = @[ run_as, @"-c", install_script_execution ];
	} else {
	task.launchPath = install_script;
	task.arguments = @[ app_path, kChromeInstallPath ];
	}

	[task launch];
	[task waitUntilExit];
	if (task.terminationStatus != 0) {
	return 0;
	}
	} @catch (id exception) {
	return 0;
	}

	// Set brand code. If Chrome's Info.plist contains a brand code, use that.
	NSString* info_plist_brand = info_plist[kBrandKey];
	if (info_plist_brand &&
	[info_plist_brand respondsToSelector:@selector(UTF8String)]) {
	brand_code = [info_plist_brand UTF8String];
	}

	BOOL valid_brand_code =
	brand_code && strlen(brand_code) == 4 && isbrandchar(brand_code[0]) &&
	isbrandchar(brand_code[1]) && isbrandchar(brand_code[2]) &&
	isbrandchar(brand_code[3]);

	if (valid_brand_code) {
	WriteBrandCode(brand_code, user);
	}

	// Write master prefs.
	if (master_prefs_contents) {
	WriteMasterPrefs(master_prefs_contents, master_prefs_contents_size, user);
	}

	// TODO Set default browser if requested.
	}
	return 1;
	}

	int LaunchGoogleChrome() {
	@autoreleasepool {
	passwd* user = GetRealUserId();
	if (!user) {
	return 0;
	}

	NSString* app_path;

	NSString* path;
	if (FindChromeTicket(kUserTicket, user, &path) && path) {
	app_path = path;
	} else if (FindChromeTicket(kSystemTicket, nullptr, &path) && path) {
	app_path = path;
	} else {
	app_path = kChromeInstallPath;
	}

	// NSWorkspace launches processes as the current console owner,
	// even when running with euid of 0.
	return [NSWorkspace.sharedWorkspace launchApplication:app_path];
	}
	}