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authorAl Viro <viro@zeniv.linux.org.uk>2022-08-16 17:57:56 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2022-08-17 23:25:04 +0200
commit25885a35a72007cf28ec5f9ba7169c5c798f7167 (patch)
tree948589bcdf9420b67123d83eab2cf7f7d8bdbcf8 /fs/readdir.c
parentlocks: fix TOCTOU race when granting write lease (diff)
downloadlinux-25885a35a72007cf28ec5f9ba7169c5c798f7167.tar.xz
linux-25885a35a72007cf28ec5f9ba7169c5c798f7167.zip
Change calling conventions for filldir_t
filldir_t instances (directory iterators callbacks) used to return 0 for "OK, keep going" or -E... for "stop". Note that it's *NOT* how the error values are reported - the rules for those are callback-dependent and ->iterate{,_shared}() instances only care about zero vs. non-zero (look at emit_dir() and friends). So let's just return bool ("should we keep going?") - it's less confusing that way. The choice between "true means keep going" and "true means stop" is bikesheddable; we have two groups of callbacks - do something for everything in directory, until we run into problem and find an entry in directory and do something to it. The former tended to use 0/-E... conventions - -E<something> on failure. The latter tended to use 0/1, 1 being "stop, we are done". The callers treated anything non-zero as "stop", ignoring which non-zero value did they get. "true means stop" would be more natural for the second group; "true means keep going" - for the first one. I tried both variants and the things like if allocation failed something = -ENOMEM; return true; just looked unnatural and asking for trouble. [folded suggestion from Matthew Wilcox <willy@infradead.org>] Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/readdir.c')
-rw-r--r--fs/readdir.c68
1 files changed, 34 insertions, 34 deletions
diff --git a/fs/readdir.c b/fs/readdir.c
index 09e8ed7d4161..9c53edb60c03 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -140,7 +140,7 @@ struct readdir_callback {
int result;
};
-static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
+static bool fillonedir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct readdir_callback *buf =
@@ -149,14 +149,14 @@ static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
unsigned long d_ino;
if (buf->result)
- return -EINVAL;
+ return false;
buf->result = verify_dirent_name(name, namlen);
- if (buf->result < 0)
- return buf->result;
+ if (buf->result)
+ return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->result = -EOVERFLOW;
- return -EOVERFLOW;
+ return false;
}
buf->result++;
dirent = buf->dirent;
@@ -169,12 +169,12 @@ static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
- return 0;
+ return true;
efault_end:
user_write_access_end();
efault:
buf->result = -EFAULT;
- return -EFAULT;
+ return false;
}
SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
@@ -219,7 +219,7 @@ struct getdents_callback {
int error;
};
-static int filldir(struct dir_context *ctx, const char *name, int namlen,
+static bool filldir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent __user *dirent, *prev;
@@ -232,18 +232,18 @@ static int filldir(struct dir_context *ctx, const char *name, int namlen,
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
- return buf->error;
+ return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
- return -EINVAL;
+ return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->error = -EOVERFLOW;
- return -EOVERFLOW;
+ return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
- return -EINTR;
+ return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
@@ -260,12 +260,12 @@ static int filldir(struct dir_context *ctx, const char *name, int namlen,
buf->current_dir = (void __user *)dirent + reclen;
buf->prev_reclen = reclen;
buf->count -= reclen;
- return 0;
+ return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
- return -EFAULT;
+ return false;
}
SYSCALL_DEFINE3(getdents, unsigned int, fd,
@@ -307,7 +307,7 @@ struct getdents_callback64 {
int error;
};
-static int filldir64(struct dir_context *ctx, const char *name, int namlen,
+static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent64 __user *dirent, *prev;
@@ -319,13 +319,13 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen,
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
- return buf->error;
+ return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
- return -EINVAL;
+ return false;
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
- return -EINTR;
+ return false;
dirent = buf->current_dir;
prev = (void __user *)dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
@@ -342,13 +342,13 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen,
buf->prev_reclen = reclen;
buf->current_dir = (void __user *)dirent + reclen;
buf->count -= reclen;
- return 0;
+ return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
- return -EFAULT;
+ return false;
}
SYSCALL_DEFINE3(getdents64, unsigned int, fd,
@@ -397,7 +397,7 @@ struct compat_readdir_callback {
int result;
};
-static int compat_fillonedir(struct dir_context *ctx, const char *name,
+static bool compat_fillonedir(struct dir_context *ctx, const char *name,
int namlen, loff_t offset, u64 ino,
unsigned int d_type)
{
@@ -407,14 +407,14 @@ static int compat_fillonedir(struct dir_context *ctx, const char *name,
compat_ulong_t d_ino;
if (buf->result)
- return -EINVAL;
+ return false;
buf->result = verify_dirent_name(name, namlen);
- if (buf->result < 0)
- return buf->result;
+ if (buf->result)
+ return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->result = -EOVERFLOW;
- return -EOVERFLOW;
+ return false;
}
buf->result++;
dirent = buf->dirent;
@@ -427,12 +427,12 @@ static int compat_fillonedir(struct dir_context *ctx, const char *name,
unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
- return 0;
+ return true;
efault_end:
user_write_access_end();
efault:
buf->result = -EFAULT;
- return -EFAULT;
+ return false;
}
COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
@@ -471,7 +471,7 @@ struct compat_getdents_callback {
int error;
};
-static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
+static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct compat_linux_dirent __user *dirent, *prev;
@@ -484,18 +484,18 @@ static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
- return buf->error;
+ return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
- return -EINVAL;
+ return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->error = -EOVERFLOW;
- return -EOVERFLOW;
+ return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
- return -EINTR;
+ return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
@@ -511,12 +511,12 @@ static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
buf->prev_reclen = reclen;
buf->current_dir = (void __user *)dirent + reclen;
buf->count -= reclen;
- return 0;
+ return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
- return -EFAULT;
+ return false;
}
COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,