iOS sandbox directory structure resolution

Transferred from: http://blog.csdn.net/wzzvictory/article/details/18269713

for security reasons, the sandbox mechanism of the iOS system stipulates that each app can access only the files under the current sandbox directory (with exceptions, such as the ability of the system contacts to be accessed by third-party apps under user authorization), a rule that reveals the closeness of the iOS system. first, a few major directories in the sandboxEach sandbox has a similar directory structure, as shown (from Apple's official documentation):the sandbox catalogs for each app are similar, mainly containing the 4 directories shown in the figure:1, Myapp.app① Content: This directory contains data for the application itself, including resource files and executables. after the program starts, the code or resources are dynamically loaded into memory from the directory as needed, and lazy loading is used here. ② The entire directory is read-only: To prevent tampering, the application will sign the directory when it is installed. In the case of non-jailbreak, the contents of this directory cannot be changed, and if the contents of the directory are changed on the jailbreak device, the corresponding signature will be changed, in which case the result of the Apple website description is that the application will not start and I have not practiced it. Whether ③ will be synced by itunes: no 2. Documents① Store Content: We can save the application's data file in this directory. However, these data types are limited to non-renewable data, and renewable data files should be stored in the Library/cache directory. Whether the ② will be synced by itunes: Yes 3, Documents/inbox① Store Content: This directory is used to hold files opened by external applications requesting the current application. For example, our application is called a, several open file formats are registered to the system, B is applied with a file F in a supported format, and application call a opens F. Since F is currently in the sandbox of the B application, we know that the sandbox mechanism is not allowed A to access the files in the B sandbox, so Apple's solution is to speak F copy a copy of the Documents/inbox directory to the A application , and then let a open f. Whether the ② will be synced by itunes: Yes 4. Library① Store Content: Apple is recommended to store default settings or other status information. ② will be synced with itunes: Yes, but except for caches subdirectories5, Library/caches① Storage content: Mainly cache files, users in the process of using the cache can be saved in this directory. As mentioned earlier, the documents directory is used to store non-renewable files, so this directory is used to hold those renewable files, such as data requested by the network. For this reason, the application usually also needs to be responsible for deleting these files. whether ② will be synced by itunes: No. 6, Library/preferences① Store Content: Application Preferences file. The settings data we write with Nsuserdefaults will be saved to a plist file in that directory, which is called Write Plist! Whether the ② will be synced by itunes: Yes 7. tmp① Store content: Various temporary files, save files that are not needed when the app starts again. Moreover, when the application no longer needs these files should be actively deleted, because the contents of the directory can be removed from the system at any time, the current known one possible reason is that the system disk storage space is insufficient. Whether ② will be synced by itunes: no second, the way to get the main directory path

1. Sandbox directory

NSLog (@ "%@", Nshomedirectory ());

Output result :

/var/mobile/applications/326640A7-6E27-4C63-ba5e- 7391F203659A

2. tmp

NSLog (@ "%@", Nstemporarydirectory ());

Output Result:

/private/var/mobile/applications/326640A7-6E27-4C6 3-ba5e-7391F203659a/tmp/

3, Myapp.app

NSLog (@ "%@", [[NSBundle Mainbundle] Bundlepath]);

Output Result:
/var/mobile/applications/326640A7-6E27-4C63-ba5e-7391F 203659a/phonecall. App 4. Documents

1. Nsarray *paths = Nssearchpathfordirectoriesindomains (NSDocumentDirectory, Nsuserdomainmask, YES);
2. NSString *path = [Paths Objectatindex:0];
3. NSLog (@ "%@", Path);

Output Result:

          /var/mobile/applications/326640a7-6E27-4c63-ba5e-7391f203659A/Documents   

here the Nssearchpathfordirectoriesindomains method needs to be explained, and its declaration is as follows:

1. Foundation_export nsarray *nssearchpathfordirectoriesindomains (nssearchpathdirectory directory,  Nssearchpathdomainmask Domainmask, BOOL Expandtilde);

The method is used to return a collection of paths for the specified name in the specified range of directories. There are three parameters:

• Directory

the enum value of the Nssearchpathdirectory type, indicating the name of the directory we are searching for, such as here with nsdocumentdirectory that we are searching for the documents directory. If we change it to nscachesdirectory it means that we are searching for the Library/caches directory.

• Domainmask

An enum value of type Nssearchpathdomainmask that specifies the search scope, where nsuserdomainmask indicates that the scope of the search is limited to the currently applied sandbox directory. It can also be written as Nslocaldomainmask (representing/library), Nsnetworkdomainmask (for/network), etc.

• Expandtilde

a bool value that indicates whether wavy lines are expanded ~. We know that in iOS the full-write form is/user/username, the value of Yes is written as a full-written form, for No is directly written as "~".

iOS sandbox directory structure resolution (RPM)