#include <sys/types.h> #include <sys/stat.h>
int mknod(const char path, mode_t mode, dev_t dev);
The file type is specified in mode by the S_IFMT bits, which must be set to one of the following values:
For all file types other than
the calling process must have the P_FILESYS privilege.
The file access permissions are specified in mode by the 0007777 bits, and may be constructed by an OR of the following values:
|S_ISUID||04000||Set user ID on execution.|
|S_ISGID||020#0||Set group ID on execution if # is 7, 5, 3, or 1|
|Enable mandatory file/record locking if # is 6, 4, 2, or 0|
|S_ISVTX||01000||Save text image after execution.|
|S_IRWXU||00700||Read, write, execute by owner.|
|S_IRUSR||00400||Read by owner.|
|S_IWUSR||00200||Write by owner.|
|S_IXUSR||00100||Execute (search if a directory) by owner.|
|S_IRWXG||00070||Read, write, execute by group.|
|S_IRGRP||00040||Read by group.|
|S_IWGRP||00020||Write by group.|
|S_IXGRP||00010||Execute by group.|
|S_IRWXO||00007||Read, write, execute (search) by others.|
|S_IROTH||00004||Read by others.|
|S_IWOTH||00002||Write by others|
|S_IXOTH||00001||Execute by others.|
The owner ID of the file is set to the effective user ID of the process. The group ID of the file is set to the effective group ID of the process. However, if the S_ISGID bit is set in the parent directory, then the group ID of the file is inherited from the parent. If the group ID of the new file does not match the effective group ID or one of the supplementary group IDs, the S_ISGID bit is cleared.
The access permission bits of mode are modified by the process's file mode creation mask: all bits set in the process's file mode creation mask are cleared (see umask(2)). If mode indicates a block or character special file, dev is a configuration-dependent specification of a character or block I/O device. If mode does not indicate a block special or character special device, dev is ignored. See makedev(3C).
mknod checks to see if the driver has been installed and whether or not it is an old-style driver. If the driver is installed and it is an old-style driver, the minor number is limited to 255. If it's not an old-style driver, then it must be a new-style driver or uninstalled, and the minor number is limited to the current value of the MAXMINOR tunable. Of course, this tunable is set to 255 by default. If the range check fails, mknod fails with EINVAL.
If path is a symbolic link, it is not followed.
mknod fails and creates no new file if one or more of the following are true: