From 3ecb5b9d66099e5e52ecb913f5e7cb7e77789b09 Mon Sep 17 00:00:00 2001 From: Mathieu Maret Date: Thu, 23 May 2024 00:21:41 +0200 Subject: [PATCH] VFS: design for the name cache system --- core/fs.c | 13 +++++ core/fs.h | 7 +++ core/fsEntry.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++++ core/fsEntry.h | 118 +++++++++++++++++++++++++++++++++++++++++++ core/main.c | 4 ++ tests/test.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 404 insertions(+) create mode 100644 core/fs.c create mode 100644 core/fs.h create mode 100644 core/fsEntry.c create mode 100644 core/fsEntry.h diff --git a/core/fs.c b/core/fs.c new file mode 100644 index 0000000..290b8c5 --- /dev/null +++ b/core/fs.c @@ -0,0 +1,13 @@ +#include "fs.h" + +int fsInodeUnref(struct inode *inode) +{ + (void)inode; + return 0; +}; + +int fsInodeRef(struct inode *inode) +{ + (void)inode; + return 0; +}; diff --git a/core/fs.h b/core/fs.h new file mode 100644 index 0000000..aa70ed1 --- /dev/null +++ b/core/fs.h @@ -0,0 +1,7 @@ +#pragma once + + +struct inode {//TODO + }; +int fsInodeUnref(struct inode *inode); +int fsInodeRef(struct inode *inode); diff --git a/core/fsEntry.c b/core/fsEntry.c new file mode 100644 index 0000000..1381652 --- /dev/null +++ b/core/fsEntry.c @@ -0,0 +1,133 @@ +#include "alloc.h" +#include "assert.h" +#include "fsEntry.h" +#include "errno.h" +#include "list.h" +#include "mem.h" +#include "stdint.h" + +bool_t pstringSplipPath(struct pstr *path, struct pstr *upper, struct pstr *lower) +{ + typeof(path->name) curPos = path->name; + typeof(path->len) curLen = path->len; + typeof(path->len) upperLen = 0; + + // Skip leading / + while (curLen > 0 && curPos[0] == '/') { + curPos++; + curLen--; + } + + upper->name = curPos; + + // Find first non / + while (curLen > 0 && curPos[0] != '/') { + upperLen++; + curLen--; + curPos++; + } + upper->len = upperLen; + + while (curLen > 0 && curPos[0] == '/') { + curPos++; + curLen--; + } + lower->name = curPos; + lower->len = path->len - (lower->name - path->name); + + return lower->len > 0; +} + +bool_t pstringIsEq(struct pstr *p1, struct pstr *p2) +{ + return p1->len == p2->len && (memcmp(p1, p2, p1->len) == 0); +} + +int fsEntryRef(struct fsEntry *entry) +{ + entry->ref++; + return 0; +} + +int fsEntryUnref(struct fsEntry **entry) +{ + struct fsEntry *toDelete = NULL, *entryTmp; + + entryTmp = *entry; + *entry = NULL; + + while (entryTmp) { + assert(entryTmp->ref > 0); + entryTmp->ref--; + + if (entryTmp->ref > 0) + break; + + if (entryTmp == *entry) + entry = NULL; + + if (entryTmp->parent) { + struct fsEntry *parent = entryTmp->parent; + + assert(entryTmp->parent->ref >= 1); + + list_delete_named(parent->childs, entryTmp, prevSiblings, nextSiblings); + // At next iteration we will decrement parent's ref cnt + } + + // Avoid recursivity in kernel by using a list of entry to suppress + list_add_tail_named(toDelete, entryTmp, prevSiblings, nextSiblings); + + // now, unref parent + entryTmp = entryTmp->parent; + } + + // free 0 ref entries + while (!list_is_empty_named(toDelete, prevSiblings, nextSiblings)) { + entryTmp = list_pop_head_named(toDelete, prevSiblings, nextSiblings); + fsInodeUnref(entryTmp->node); + free(entryTmp); + } + + return 0; +} + +int fsEntryNewChild(struct fsEntry *parent, const struct pstr *name, struct inode *inode, + struct fsEntry **result) +{ + struct fsEntry *entry = malloc(sizeof(struct fsEntry)); + + if (!entry) + return -ENOMEM; + + if (name && name->len > 0) { + char *allocName = malloc(name->len); + + if (!allocName) { + free(entry); + return -ENOMEM; + } + + memcpy(allocName, name->name, name->len); + entry->name.len = name->len; + entry->name.name = allocName; + } + + entry->ref = 1; + entry->node = inode; + entry->parent = parent; + + fsInodeRef(inode); + if (parent) { + fsEntryRef(parent); + list_add_head_named(parent->childs, entry, prevSiblings, nextSiblings); + } + + *result = entry; + + return 0; +} + +int fsEntrySetup(void){ + return allocBookSlab(sizeof(struct fsEntry), PAGE_SIZE, 0, 0); +} diff --git a/core/fsEntry.h b/core/fsEntry.h new file mode 100644 index 0000000..7d3e924 --- /dev/null +++ b/core/fsEntry.h @@ -0,0 +1,118 @@ +#pragma once + +#include "fs.h" +#include "stdint.h" +#include "stddef.h" + +/** + * Those structures aimes to represent VFS directory entries in memory. + * It's the equivalent of the Linux dentry or SimpleOs sos_fs_nscache_node. + */ + +/** + * Path or Pascal String + * */ +struct pstr { + size_t len; + const char *name; +}; + +#define PSTR_INIT(n, l) \ + { \ + .len = l, .name = n \ + } + + +/** + * @brief Structure representing a file system entry. + * + * This structure holds information about a file system entry, + * including its name, associated inode, relationships within + * the file system hierarchy, and reference count. + */ +struct fsEntry { + struct pstr name; + struct inode *node; + + struct fsEntry *parent; // parent directory + struct fsEntry *mountpoint; // if this is a mounted fs, point to mountpoint + struct fsEntry *mountedFs; // Fs possibly mounted on this fsEntry + + struct fsEntry *childs; // point to the list of children + struct fsEntry *nextSiblings, *prevSiblings; // Sibling at the same level + + uint ref; // reference counter +}; + +/** + * @brief Splits a pstr path into upper and lower components. + * + * This function takes a path and splits it into an upper component + * (the first segment of the path) and a lower component (the rest of the path). + * + * @param path Pointer to the input pstr structure representing the path. + * @param upper Pointer to the pstr structure to store the upper component. + * @param lower Pointer to the pstr structure to store the lower component. + * @return bool_t Returns true if there is a lower component, false otherwise. + */ +bool_t pstringSplipPath(struct pstr *path, struct pstr *upper, struct pstr *lower); + +/** + * @brief Compares two pstr structures to check if they are equal. + * + * This function compares the length and the content of the strings + * in the two provided pstr structures. + * + * @param a Pointer to the first pstr structure. + * @param b Pointer to the second pstr structure. + * @return int Returns 1 if the structures are equal, 0 otherwise. + */ +bool_t pstringIsEq(struct pstr *p1, struct pstr *p2); + +/** + * @brief Increments the reference count of a file system entry. + * + * This function increments the reference count of the given file system + * entry. It is typically used to manage the lifecycle of file system + * entries, ensuring that they are not prematurely deallocated. + * + * @param entry Pointer to the fsEntry structure whose reference count will be incremented. + * @return int Returns 0 on success. + */ +int fsEntryRef(struct fsEntry *entry); + +/** + * @brief Decrements the reference count of a file system entry. + * + * This function decrements the reference count of the given file system + * entry. It is typically used to manage the lifecycle of file system + * entries, ensuring that they are not prematurely deallocated. + * + * @param entry Pointer to the fsEntry structure whose reference count will be incremented. + * @return int Returns 0 on success. + */ +int fsEntryUnref(struct fsEntry **entry); + +/** + * @brief Creates a new child fsEntry under the specified parent. + * + * This function allocates and initializes a new fsEntry structure + * representing a file system entry. The new entry is added as a child + * of the specified parent. It also handles reference counting for + * the parent entry and the associated inode. + * + * @param parent Pointer to the parent fsEntry. Can be NULL if the new entry has no parent. + * @param name Pointer to the pstr structure representing the name of the new entry. Can be NULL. + * @param inode Pointer to the inode associated with the new entry. + * @param result Pointer to a location where the pointer to the newly created fsEntry will be stored. + * @return int Returns 0 on success, or a negative error code on failure. + * -ENOMEM if memory allocation fails. + */ +int fsEntryNewChild(struct fsEntry *parent, const struct pstr *name, struct inode *inode, + struct fsEntry **result); + +/** + * @brief Setup the fsEntry subsystem + * + */ +int fsEntrySetup(void); diff --git a/core/main.c b/core/main.c index c3a188f..24312a5 100644 --- a/core/main.c +++ b/core/main.c @@ -3,6 +3,7 @@ #include "ata.h" #include "elf.h" #include "exception.h" +#include "fsEntry.h" #include "gdt.h" #include "idt.h" #include "interrupt.h" @@ -259,6 +260,9 @@ void kmain(unsigned long magic, unsigned long addr) irqSetRoutine(IRQ_TIMER, pit_handler); ATAInit(); + + // VFS name caching + fsEntrySetup(); #ifdef RUN_TEST run_test(); #endif diff --git a/tests/test.c b/tests/test.c index 4f7d964..1f1a70f 100644 --- a/tests/test.c +++ b/tests/test.c @@ -3,8 +3,11 @@ #include "ata.h" #include "assert.h" #include "cpu_context.h" +#include "fsEntry.h" #include "kernel.h" #include "klibc.h" +#include "stddef.h" +#include "stdint.h" #include "thread.h" #include "list.h" #include "mem.h" @@ -493,8 +496,134 @@ void testRingBuffer() ringbufferDestroy(inst); } +void printPstr(struct pstr *str){ + for(uint i = 0; i < str->len; i++){ + putc(str->name[i]); + } +} +void printPstrln(struct pstr *str){ + printPstr(str); + putc('\n'); +} + +void testFsPstring() +{ + bool_t result; + struct pstr path, upper, lower, lower2, lower3; + + // Test 1 + path.name = "/usr/local/bin"; + path.len = 14; + result = pstringSplipPath(&path, &upper, &lower); + printf("Test 1:\n"); + printPstrln(&path); + printPstrln(&upper); + printPstrln(&lower); + printf("Result: %s\n\n", result ? "true" : "false"); + + // Test 2 + path.name = "/home/user"; + path.len = 10; + result = pstringSplipPath(&path, &upper, &lower); + printf("Test 2:\n"); + printPstrln(&path); + printPstrln(&upper); + printPstrln(&lower); + printf("Result: %s\n\n", result ? "true" : "false"); + + // Test 3 + path.name = "/tmp"; + path.len = 4; + result = pstringSplipPath(&path, &upper, &lower); + printf("Test 3:\n"); + printPstrln(&path); + printPstrln(&upper); + printPstrln(&lower); + printf("Result: %s\n\n", result ? "true" : "false"); + + // Test 4 + path.name = "/var/log/"; + path.len = 9; + result = pstringSplipPath(&path, &upper, &lower); + printf("Test 4:\n"); + printPstrln(&path); + printPstrln(&upper); + printPstrln(&lower); + printf("Result: %s\n\n", result ? "true" : "false"); + + // Test 5 + path.name = "/"; + path.len = 1; + result = pstringSplipPath(&path, &upper, &lower); + printf("Test 5:\n"); + printPstrln(&path); + printPstrln(&upper); + printPstrln(&lower); + printf("Result: %s\n\n", result ? "true" : "false"); + + // Test 6 + const char *tmp = "///home///file/test///"; + const char *testS = "test"; + path.name = tmp; + path.len = strlen(tmp); + struct pstr test = PSTR_INIT(testS, strlen(testS)); + struct pstr empty = PSTR_INIT("", 0); + struct pstr slash = PSTR_INIT("/", 1); + struct pstr dot = PSTR_INIT("..", 2); + + printf("Test 6:\n"); + printPstr(&path); + assert(pstringSplipPath(&path, &upper, &lower)); + printf("\nUpper: "); + printPstr(&upper); + printf("\nLower: "); + printPstr(&lower); + printf("\n"); + assert(pstringSplipPath(&lower, &upper, &lower2)); + printf("\nUpper: "); + printPstr(&upper); + printf("\nLower: "); + printPstr(&lower2); + printf("\n"); + assert(pstringSplipPath(&lower2, &upper, &lower3) == 0); + printf("\nUpper: "); + printPstr(&upper); + printf("\nLower: "); + printPstr(&lower3); + printf("\n"); + assert(pstringIsEq(&upper, &test)); + assert(pstringSplipPath(&empty, &upper, &lower) == FALSE); + assert(pstringSplipPath(&slash, &upper, &lower) == FALSE); + assert(pstringIsEq(&empty, &test) == FALSE); + assert(pstringIsEq(&dot, &test) == FALSE); + + +} + +void testFsEntry() +{ + printf("Test fsEntry: create tree\n"); + struct inode node; + struct fsEntry *root, *home, *usr; + struct pstr rootname = PSTR_INIT("root", 4); + struct pstr homename = PSTR_INIT("home", 4); + struct pstr usrname = PSTR_INIT("usr", 3); + assert(fsEntryNewChild(NULL, &rootname, &node, &root) == 0); + assert(fsEntryNewChild(root, &homename, &node, &home) == 0); + assert(fsEntryNewChild(root, &usrname, &node, &usr) == 0); + + printf("Test fsEntry: free tree\n"); + fsEntryUnref(&usr); + assert(root->ref > 0); + assert(usr == NULL); + fsEntryUnref(&home); + assert(usr == NULL); +} + void run_test(void) { + testFsPstring(); + testFsEntry(); // Example of checking thx to access attributs //int a[4] = {0}; //int b[3] = {0};