[PATCH 3/3] proc: make UTS-related sysctls utsns aware

From: Sam Vilain
Date: Mon May 22 2006 - 21:23:01 EST


From: Sam Vilain <sam.vilain@xxxxxxxxxxxxxxx>

Add a new function proc_do_utsns_string, that derives the pointer
into the uts_namespace->name structure, currently based on the
filename of the dentry in /proc, and calls _proc_do_string()
---
RFC only - not tested yet. builds, though.

kernel/sysctl.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 104 insertions(+), 0 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cf053fc..37dc17f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -141,8 +141,13 @@ #endif

static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
ctl_table *, void **);
+#ifndef CONFIG_UTS_NS
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);
+#else
+static int proc_do_utsns_string(ctl_table *table, int write, struct file *filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
+#endif

static ctl_table root_table[];
static struct ctl_table_header root_table_header =
@@ -238,6 +243,7 @@ #endif
};

static ctl_table kern_table[] = {
+#ifndef CONFIG_UTS_NS
{
.ctl_name = KERN_OSTYPE,
.procname = "ostype",
@@ -283,6 +289,54 @@ static ctl_table kern_table[] = {
.proc_handler = &proc_do_uts_string,
.strategy = &sysctl_string,
},
+#else /* !CONFIG_UTS_NS */
+ {
+ .ctl_name = KERN_OSTYPE,
+ .procname = "ostype",
+ .data = NULL,
+ /* could maybe use __NEW_UTS_LEN here? */
+ .maxlen = sizeof(current->nsproxy->uts_ns->name.sysname),
+ .mode = 0444,
+ .proc_handler = &proc_do_utsns_string,
+ .strategy = &sysctl_string,
+ },
+ {
+ .ctl_name = KERN_OSRELEASE,
+ .procname = "osrelease",
+ .data = NULL,
+ .maxlen = sizeof(current->nsproxy->uts_ns->name.release),
+ .mode = 0444,
+ .proc_handler = &proc_do_utsns_string,
+ .strategy = &sysctl_string,
+ },
+ {
+ .ctl_name = KERN_VERSION,
+ .procname = "version",
+ .data = NULL,
+ .maxlen = sizeof(current->nsproxy->uts_ns->name.version),
+ .mode = 0444,
+ .proc_handler = &proc_do_utsns_string,
+ .strategy = &sysctl_string,
+ },
+ {
+ .ctl_name = KERN_NODENAME,
+ .procname = "hostname",
+ .data = NULL,
+ .maxlen = sizeof(current->nsproxy->uts_ns->name.nodename),
+ .mode = 0644,
+ .proc_handler = &proc_do_utsns_string,
+ .strategy = &sysctl_string,
+ },
+ {
+ .ctl_name = KERN_DOMAINNAME,
+ .procname = "domainname",
+ .data = NULL,
+ .maxlen = sizeof(current->nsproxy->uts_ns->name.domainname),
+ .mode = 0644,
+ .proc_handler = &proc_do_utsns_string,
+ .strategy = &sysctl_string,
+ },
+#endif /* !CONFIG_UTS_NS */
{
.ctl_name = KERN_PANIC,
.procname = "panic",
@@ -1684,6 +1738,7 @@ int proc_dostring(ctl_table *table, int
* to observe. Should this be in kernel/sys.c ????
*/

+#ifndef CONFIG_UTS_NS
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@@ -1700,6 +1755,55 @@ static int proc_do_uts_string(ctl_table
}
return r;
}
+#else /* !CONFIG_UTS_NS */
+static int proc_do_utsns_string(ctl_table *table, int write, struct file *filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int r;
+ struct uts_namespace* uts_ns = current->nsproxy->uts_ns;
+ char* which;
+
+ /* map the filename to the pointer. perhaps it would be better
+ to put struct offset pointers in table->data ? */
+ switch (filp->f_dentry->d_name.name[3]) {
+ case 'y': /* ostYpe */
+ which = uts_ns->name.sysname;
+ break;
+ case 't': /* hosTname */
+ which = uts_ns->name.nodename;
+ break;
+ case 'e': /* osrElease */
+ which = uts_ns->name.release;
+ break;
+ case 's': /* verSion */
+ which = uts_ns->name.version;
+ break;
+ case 'x': /* XXX - unreachable */
+ which = uts_ns->name.machine;
+ break;
+ case 'a': /* domAinname */
+ which = uts_ns->name.domainname;
+ break;
+ default:
+ printk("procfs: impossible uts part '%s'",
+ (char*)filp->f_dentry->d_name.name);
+ r = -EINVAL;
+ goto out;
+ }
+
+ if (!write) {
+ down_read(&uts_sem);
+ r=_proc_do_string(which,table->maxlen,0,filp,buffer,lenp, ppos);
+ up_read(&uts_sem);
+ } else {
+ down_write(&uts_sem);
+ r=_proc_do_string(which,table->maxlen,1,filp,buffer,lenp, ppos);
+ up_write(&uts_sem);
+ }
+ out:
+ return r;
+}
+#endif /* !CONFIG_UTS_NS */

static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
int *valp,

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