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authorJustus Winter <4winter@informatik.uni-hamburg.de>2014-01-12 15:47:17 +0100
committerJustus Winter <4winter@informatik.uni-hamburg.de>2014-01-12 15:59:23 +0100
commitc31404533f2fb70efd40d7b56d8165e2ab8bd160 (patch)
tree886f9e95cbd8e788c37f180d22e48623eef29906 /trans
parentdda3d358224c334c8fa4902b3e20c75caf8bddbc (diff)
trans/mtab: properly lock mtab objects
* trans/mtab.c (struct mtab): Add lock. (open_hook): Initialize lock. (close_hook): Destroy lock. (trivfs_S_io_read): Lock mtab object, adjust error handling accordingly. (trivfs_S_io_seek): Likewise. (trivfs_S_io_readable): Likewise.
Diffstat (limited to 'trans')
-rw-r--r--trans/mtab.c44
1 files changed, 32 insertions, 12 deletions
diff --git a/trans/mtab.c b/trans/mtab.c
index 0bcd52b4..5a5a07df 100644
--- a/trans/mtab.c
+++ b/trans/mtab.c
@@ -27,6 +27,7 @@
#include <hurd/trivfs.h>
#include <inttypes.h>
#include <mntent.h>
+#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
@@ -47,6 +48,7 @@ struct trivfs_control *control;
They keep track of the content and file position of the client. */
struct mtab
{
+ pthread_mutex_t lock;
char *contents;
size_t contents_len;
off_t offs;
@@ -569,6 +571,7 @@ open_hook (struct trivfs_peropen *peropen)
peropen->hook = mtab;
/* Initialize the fields. */
+ pthread_mutex_init (&mtab->lock, NULL);
mtab->offs = 0;
mtab->contents = NULL;
mtab->contents_len = 0;
@@ -602,8 +605,10 @@ open_hook (struct trivfs_peropen *peropen)
static void
close_hook (struct trivfs_peropen *peropen)
{
- free (((struct mtab *) peropen->hook)->contents);
- free (peropen->hook);
+ struct mtab *op = peropen->hook;
+ pthread_mutex_destroy (&op->lock);
+ free (op->contents);
+ free (op);
}
/* Read data from an IO object. If offset is -1, read from the object
@@ -615,6 +620,7 @@ trivfs_S_io_read (struct trivfs_protid *cred,
char **data, mach_msg_type_number_t *data_len,
loff_t offs, mach_msg_type_number_t amount)
{
+ error_t err = 0;
struct mtab *op;
/* Deny access if they have bad credentials. */
@@ -626,12 +632,13 @@ trivfs_S_io_read (struct trivfs_protid *cred,
/* Get the offset. */
op = cred->po->hook;
+ pthread_mutex_lock (&op->lock);
if (op->contents == NULL)
{
- error_t err = mtab_populate (op, target_path, insecure);
+ err = mtab_populate (op, target_path, insecure);
if (err)
- return err;
+ goto out;
}
if (offs == -1)
@@ -650,7 +657,10 @@ trivfs_S_io_read (struct trivfs_protid *cred,
{
*data = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
if (*data == MAP_FAILED)
- return ENOMEM;
+ {
+ err = ENOMEM;
+ goto out;
+ }
}
/* Copy the constant data into the buffer. */
@@ -661,7 +671,9 @@ trivfs_S_io_read (struct trivfs_protid *cred,
}
*data_len = amount;
- return 0;
+ out:
+ pthread_mutex_unlock (&op->lock);
+ return err;
}
@@ -671,16 +683,18 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
mach_port_t reply, mach_msg_type_name_t reply_type,
off_t offs, int whence, off_t *new_offs)
{
+ error_t err = 0;
if (! cred)
return EOPNOTSUPP;
struct mtab *op = cred->po->hook;
+ pthread_mutex_lock (&op->lock);
if (op->contents == NULL)
{
- error_t err = mtab_populate (op, target_path, insecure);
+ err = mtab_populate (op, target_path, insecure);
if (err)
- return err;
+ goto out;
}
switch (whence)
@@ -698,10 +712,12 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
break;
}
default:
- return EINVAL;
+ err = EINVAL;
}
- return 0;
+ out:
+ pthread_mutex_unlock (&op->lock);
+ return err;
}
/* If this variable is set, it is called every time a new peropen
@@ -720,6 +736,7 @@ trivfs_S_io_readable (struct trivfs_protid *cred,
mach_port_t reply, mach_msg_type_name_t replytype,
mach_msg_type_number_t *amount)
{
+ error_t err = 0;
if (!cred)
return EOPNOTSUPP;
@@ -727,16 +744,19 @@ trivfs_S_io_readable (struct trivfs_protid *cred,
return EINVAL;
struct mtab *op = cred->po->hook;
+ pthread_mutex_lock (&op->lock);
if (op->contents == NULL)
{
error_t err = mtab_populate (op, target_path, insecure);
if (err)
- return err;
+ goto out;
}
*amount = op->contents_len - op->offs;
- return 0;
+ out:
+ pthread_mutex_unlock (&op->lock);
+ return err;
}
/* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG.