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Update thread and syscall to use local fd counter instead global one, preventing overflow

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This commit is contained in:
sBubshait
2024-11-15 15:48:56 +00:00
parent 7daf4fb079
commit 6b1dbdd34f
4 changed files with 8 additions and 6 deletions
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1
src/threads/thread.c
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@@ -688,6 +688,7 @@ init_thread (struct thread *t, const char *name, int nice, int priority,
t->recent_cpu = recent_cpu; t->recent_cpu = recent_cpu;
t->priority = t->base_priority; t->priority = t->base_priority;
t->fd_counter = MINIMUM_USER_FD;
t->exit_status = -1; t->exit_status = -1;
list_init (&t->child_results); list_init (&t->child_results);

7
src/threads/thread.h
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@@ -32,6 +32,9 @@ typedef int tid_t;
#define NICE_DEFAULT 0 /* Default niceness. */ #define NICE_DEFAULT 0 /* Default niceness. */
#define NICE_MAX 20 /* Highest niceness. */ #define NICE_MAX 20 /* Highest niceness. */
/* File Descriptors. */
#define MINIMUM_USER_FD 2 /* Minimum file descriptor for user programs. */
/* A process result, synchronised between parent and child. */ /* A process result, synchronised between parent and child. */
struct process_result struct process_result
{ {
@@ -137,7 +140,9 @@ struct thread
#ifdef USERPROG #ifdef USERPROG
/* Owned by userprog/process.c. */ /* Owned by userprog/process.c. */
uint32_t *pagedir; /* Page directory. */ uint32_t *pagedir; /* Page directory. */
struct hash open_files; /* Hash Table of FD -> Struct File */ unsigned int fd_counter; /* File descriptor counter for thread's
open files. */
struct hash open_files; /* Hash Table of FD -> Struct File. */
#endif #endif
/* Owned by thread.c. */ /* Owned by thread.c. */

4
src/userprog/syscall.c
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@@ -16,8 +16,6 @@
#define MAX_SYSCALL_ARGS 3 #define MAX_SYSCALL_ARGS 3
#define EXIT_FAILURE -1 #define EXIT_FAILURE -1
static unsigned fd_counter = MIN_USER_FD;
struct open_file struct open_file
{ {
int fd; /* File Descriptor / Identifier */ int fd; /* File Descriptor / Identifier */
@@ -224,7 +222,7 @@ syscall_open (const char *file)
} }
/* Populate the above struct, with a unique FD and the current open file */ /* Populate the above struct, with a unique FD and the current open file */
file_info->fd = fd_counter++; file_info->fd = thread_current ()->fd_counter++;
file_info->file = ptr; file_info->file = ptr;
/* Add the new FD->file mapping to the hashtable for the current thread */ /* Add the new FD->file mapping to the hashtable for the current thread */

2
src/userprog/syscall.h
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@@ -4,8 +4,6 @@
#include <hash.h> #include <hash.h>
#include "threads/synch.h" #include "threads/synch.h"
#define MIN_USER_FD 2
typedef int pid_t; typedef int pid_t;
struct lock filesys_lock; struct lock filesys_lock;