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SETFSGID |
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!!!SETFSGID |
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NAME |
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SYNOPSIS |
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DESCRIPTION |
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RETURN VALUE |
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CONFORMING TO |
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BUGS |
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NOTE |
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SEE ALSO |
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---- |
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!!NAME |
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setfsgid - set group identity used for file system checks |
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!!SYNOPSIS |
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__#include __ /* glibc uses |
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__ |
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__int setfsgid(uid_t__ ''fsgid''__);__ |
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!!DESCRIPTION |
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__setfsgid__ sets the group ID that the Linux kernel uses |
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to check for all accesses to the file system. Normally, the |
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value of ''fsgid'' will shadow the value of the effective |
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group ID. In fact, whenever the effective group ID is |
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changed, ''fsgid'' will also be changed to new value of |
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effective group ID. |
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An explicit call to __setfsgid__ is usually only used by |
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programs such as the Linux NFS server that need to change |
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what group ID is used for file access without a |
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corresponding change in the real and effective group IDs. A |
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change in the normal group IDs for a program such as the NFS |
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server is a security hole that can expose it to unwanted |
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signals from other group IDs. |
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__setfsgid__ will only succeed if the caller is the |
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superuser or if ''fsgid'' matches either the real group |
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ID, effective group ID, saved set-group-ID, or the current |
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value of ''fsgid''. |
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!!RETURN VALUE |
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On success, the previous value of ''fsgid'' is returned. |
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On error, the current value of ''fsgid'' is |
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returned. |
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!!CONFORMING TO |
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__setfsgid__ is Linux specific and should not be used in |
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programs intended to be portable. |
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!!BUGS |
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No error messages of any kind are returned to the caller. At |
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the very least, __EPERM__ should be returned when the |
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call fails. |
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!!NOTE |
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When glibc determines that the argument is not a valid gid, |
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it will return -1 and set ''errno'' to EINVAL without |
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attempting the system call. |
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!!SEE ALSO |
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setfsuid(2) |
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---- |
