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Date: Tue, 2 Jun 2009 03:00:47 -0400
From: Mike Frysinger <vapier@...too.org>
To: linux-kernel@...r.kernel.org
Cc: Greg KH <gregkh@...e.de>, Robin Getz <rgetz@...ckfin.uclinux.org>,
Bryan Wu <cooloney@...nel.org>
Subject: [PATCH] debugfs: use specified mode to possibly mark files read/write only
From: Robin Getz <rgetz@...ckfin.uclinux.org>
In many SoC implementations there are hardware registers can be read or
write only. This extends the debugfs to enforce the file permissions for
these types of registers by providing a set of fops which are read or
write only. This assumes that the kernel developer knows more about the
hardware than the user (even root users) -- which is normally true.
Signed-off-by: Robin Getz <rgetz@...ckfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier@...too.org>
Signed-off-by: Bryan Wu <cooloney@...nel.org>
---
you mention debugfs header file changes, but i don't see what would need
changing ? the mode checking is all done internally ...
fs/debugfs/file.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 63 insertions(+), 0 deletions(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 33a9012..f10091f 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -67,6 +67,8 @@ static int debugfs_u8_get(void *data, u64 *val)
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
/**
* debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
@@ -95,6 +97,13 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
struct dentry *debugfs_create_u8(const char *name, mode_t mode,
struct dentry *parent, u8 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u8_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u8_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_u8);
}
EXPORT_SYMBOL_GPL(debugfs_create_u8);
@@ -110,6 +119,8 @@ static int debugfs_u16_get(void *data, u64 *val)
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
/**
* debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
@@ -138,6 +149,13 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
struct dentry *debugfs_create_u16(const char *name, mode_t mode,
struct dentry *parent, u16 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u16_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u16_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_u16);
}
EXPORT_SYMBOL_GPL(debugfs_create_u16);
@@ -153,6 +171,8 @@ static int debugfs_u32_get(void *data, u64 *val)
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
/**
* debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
@@ -181,6 +201,13 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
struct dentry *debugfs_create_u32(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u32_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u32_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_u32);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32);
@@ -197,6 +224,8 @@ static int debugfs_u64_get(void *data, u64 *val)
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
/**
* debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
@@ -225,15 +254,28 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
struct dentry *debugfs_create_u64(const char *name, mode_t mode,
struct dentry *parent, u64 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u64_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_u64);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);
DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
/*
* debugfs_create_x{8,16,32} - create a debugfs file that is used to read and write an unsigned {8,16,32}-bit value
@@ -256,6 +298,13 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n"
struct dentry *debugfs_create_x8(const char *name, mode_t mode,
struct dentry *parent, u8 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x8_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x8_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_x8);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);
@@ -273,6 +322,13 @@ EXPORT_SYMBOL_GPL(debugfs_create_x8);
struct dentry *debugfs_create_x16(const char *name, mode_t mode,
struct dentry *parent, u16 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x16_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x16_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_x16);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);
@@ -290,6 +346,13 @@ EXPORT_SYMBOL_GPL(debugfs_create_x16);
struct dentry *debugfs_create_x32(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x32_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file(name, mode, parent, value, &fops_x32_wo);
+
return debugfs_create_file(name, mode, parent, value, &fops_x32);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);
--
1.6.3.1
--
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