Change the user ID and group ID of a file or symbolic link
#include <sys/types.h> #include <unistd.h> int lchown( const char * path, uid_t owner, gid_t group );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The lchown() function changes the user ID and group ID of the file specified by path to be the numeric values contained in owner and group, respectively. It's similar to chown(), except in the case where the named file is a symbolic link. In this case, lchown() changes the ownership of the symbolic link file itself, while chown() changes the ownership of the file or directory to which the symbolic link refers.
Only processes with an effective user ID equal to the user ID of the file or with appropriate privileges (for example, the superuser) may change the ownership of a file.
In QNX Neutrino, the _POSIX_CHOWN_RESTRICTED flag is enforced. This means that only the superuser may change the ownership of a file. The group of a file may be changed by the superuser, or also by a process with the effective user ID equal to the user ID of the file, if (and only if) owner is equal to the user ID of the file and group is equal to the effective group ID of the calling process.
If the path argument refers to a regular file, the set-user-ID (S_ISUID) and set-group-ID (S_ISGID) bits of the file mode are cleared, if the function is successful.
If lchown() succeeds, the st_ctime field of the file is marked for update.
/* * Change the ownership of a list of files * to the current user/group */ #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <unistd.h> int main( int argc, char **argv ) { int i; int ecode = 0; for( i = 1; i < argc; i++ ) { if( lchown( argv[i], getuid(), getgid() ) == -1 ) { perror( argv[i] ); ecode++; } } return( ecode ); }
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | Yes |
Thread | Yes |