Re: [PATCH] Add getdents32t syscall

[Randy.Dunlap]

On Thu, 26 Feb 2004 20:38:19 +0100 Jakub Jelinek wrote:

| glibc struct dirent has d_type field (similarly to struct dirent64).
| Because no 32-bit getdents syscall provides this field to userland,
| glibc needs to use getdents64 syscall even for 32-bit getdents
| (and readdir etc.) and convert dirent entries from struct dirent64
| to struct dirent.  The code is quite complicated and as the former
| is bigger and the size of 64-bit dirents cannot be predicted accurately,
| it can happen that glibc reads too many entries and has to seek back
| on the dir etc.
| 
| The following patch introduces a new syscall (on 32-bit architectures),
| which fills in 32-bit struct dirent with d_type member.
| With this syscall glibc can simply call this syscall in 32-bit getdents
| and be done with it, no seeking, issues with NFS zero extended d_ino values,
| buffer translation etc.  sys_getdents32t (the t in there is for type,
| to differentiate it from compatibility sys_getdents32 which don't provide
| d_type) function should be usable both on 32-bit arches and in 32-bit
| compatibility layers on 64-bit arches (on most arches directly, if
| the arguments are zero extended in assembly).
| 

| +asmlinkage long sys_getdents32t(unsigned int fd, struct linux_dirent32t __user * dirent, unsigned int count)
| +{

Please add function prototype for that to include/linux/syscalls.h.

Thanks,
--
~Randy
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