Made small modifications
This commit is contained in:
332
src/backing.c
332
src/backing.c
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#include "backing.h"
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#include "disk.h"
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#include "entry.h"
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <libgen.h>
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#include <sys/stat.h>
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bool IsBackingIdentifierValid(const char* backing_identifier) {
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if (backing_identifier == NULL)
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return false;
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// Check that the identifier is not empty or too long
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size_t length = strlen(backing_identifier);
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if (length == 0 || length > 64)
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return false;
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// Check that the identifier does not contain any slashes
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for (size_t i = 0; i < length; i++)
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if (backing_identifier[i] == '/')
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return false;
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// Check that the identifier is not "." or ".."
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if (strcmp(backing_identifier, ".") == 0 || strcmp(backing_identifier, "..") == 0)
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return false;
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// Check that the identifier starts with a number
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if (backing_identifier[0] < '0' || backing_identifier[0] > '9')
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return false;
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return true;
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}
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int GetBackingIndex(const char* backing_identifier) {
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// Check that the identifier is valid
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if (!IsBackingIdentifierValid(backing_identifier))
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return -1;
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// Get the index
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return atoi(backing_identifier);
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}
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Status GetBackingPoolPath(char** _backing_pool_path) {
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return Format(_backing_pool_path, "/var/lib/sandbox/backings");
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}
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Status GetBackingPath(const char* backing_identifier, char** _backing_path) {
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// Check that the identifier is valid, as it will be used in a path
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if (!IsBackingIdentifierValid(backing_identifier)) {
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Log(LOG_LEVEL_ERROR, "Invalid backing identifier '%s'.", backing_identifier);
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return FAILURE;
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}
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// Get the backing pool path
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char* backing_pool_path = NULL;
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Status status = GetBackingPoolPath(&backing_pool_path);
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if (status != SUCCESS)
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return status;
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// Format the backing path
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status = Format(_backing_path, "%s/%s", backing_pool_path, backing_identifier);
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free(backing_pool_path);
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return status;
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}
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Status DoesBackingExist(const char* backing_identifier, bool* _result) {
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// Get the backing path
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char* backing_path = NULL;
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Status status = GetBackingPath(backing_identifier, &backing_path);
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if (status != SUCCESS)
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return status;
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// Check if the backing exists and is a regular file
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struct stat st;
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*_result = stat(backing_path, &st) == 0 && S_ISREG(st.st_mode);
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free(backing_path);
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return SUCCESS;
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}
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Status AddBacking(const char* backing_identifier, const char* entry_identifier) {
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// Check that the backing does not already exist
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bool exists;
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Status status = DoesBackingExist(backing_identifier, &exists);
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if (status != SUCCESS)
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return status;
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if (exists) {
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Log(LOG_LEVEL_ERROR, "The backing '%s' already exists.", backing_identifier);
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return FAILURE;
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}
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// Check that the entry disk exists
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status = DoesEntryDiskExist(entry_identifier, &exists);
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if (status != SUCCESS)
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return status;
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if (!exists) {
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Log(LOG_LEVEL_ERROR, "The entry disk '%s' does not exist. Cannot create backing from it.", entry_identifier);
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return FAILURE;
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}
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// Get information about the entry disk
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DiskInfo entry_info;
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status = GetEntryDiskInfo(entry_identifier, &entry_info);
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if (status != SUCCESS)
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return status;
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// Check that the backing used by the entry actually exists (broken backing chain)
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if (entry_info.backing_identifier != NULL) {
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status = DoesBackingExist(entry_info.backing_identifier, &exists);
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if (status != SUCCESS) {
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FreeDiskInfo(&entry_info);
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return status;
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}
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if (!exists) {
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Log(LOG_LEVEL_ERROR, "The backing '%s' of the entry disk '%s' does not exist.", entry_info.backing_identifier, entry_identifier);
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FreeDiskInfo(&entry_info);
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return FAILURE;
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}
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}
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// Copy the entry disk to the backing disk
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char* entry_disk_path = NULL;
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status = GetEntryDiskPath(entry_identifier, &entry_disk_path);
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if (status != SUCCESS) {
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FreeDiskInfo(&entry_info);
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return status;
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}
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char* backing_path = NULL;
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status = GetBackingPath(backing_identifier, &backing_path);
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if (status != SUCCESS) {
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free(entry_disk_path);
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FreeDiskInfo(&entry_info);
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return status;
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}
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status = CopyFile(entry_disk_path, backing_path);
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if (status != SUCCESS) {
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free(entry_disk_path);
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free(backing_path);
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FreeDiskInfo(&entry_info);
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return status;
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}
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free(entry_disk_path);
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// If the entry disk has a backing, rebase the backing to the new backing
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if (entry_info.backing_identifier != NULL) {
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status = RebaseDisk(backing_path, entry_info.backing_identifier);
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if (status != SUCCESS) {
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RemoveBacking(backing_identifier);
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free(backing_path);
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FreeDiskInfo(&entry_info);
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return status;
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}
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}
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free(backing_path);
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FreeDiskInfo(&entry_info);
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return SUCCESS;
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}
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Status RemoveBacking(const char* backing_identifier) {
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// Check that the backing exists
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bool exists;
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Status status = DoesBackingExist(backing_identifier, &exists);
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if (status != SUCCESS)
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return status;
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if (!exists) {
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Log(LOG_LEVEL_ERROR, "The backing '%s' does not exist.", backing_identifier);
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return FAILURE;
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}
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// Get the backing path
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char* backing_path = NULL;
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status = GetBackingPath(backing_identifier, &backing_path);
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if (status != SUCCESS)
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return status;
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// Remove the backing
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if (unlink(backing_path) != 0) {
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Log(LOG_LEVEL_ERROR, "Failed to remove the backing '%s' (%s).", backing_identifier, strerror(errno));
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free(backing_path);
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return FAILURE;
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}
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free(backing_path);
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// TODO: Remove all the backings that use this backing as a base
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return SUCCESS;
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}
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Status ListBackings(char*** _backings) {
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*_backings = NULL;
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// Open the backing pool directory
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char* backing_pool_path = NULL;
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Status status = GetBackingPoolPath(&backing_pool_path);
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if (status != SUCCESS)
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return status;
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DIR* dir = opendir(backing_pool_path);
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if (dir == NULL) {
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Log(LOG_LEVEL_ERROR, "Failed to open the backing pool directory %s (%s).", backing_pool_path, strerror(errno));
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free(backing_pool_path);
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return FAILURE;
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}
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free(backing_pool_path);
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// Allocate memory for at least one backing (the NULL terminator)
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*_backings = malloc(sizeof(char*));
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if (*_backings == NULL) {
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Log(LOG_LEVEL_ERROR, "Failed to allocate memory for the backings list (%s).", strerror(errno));
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closedir(dir);
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return FAILURE;
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}
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(*_backings)[0] = NULL;
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// Read the files in the backing pool directory
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size_t count = 0;
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struct dirent* file;
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while ((file = readdir(dir)) != NULL) {
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if (strcmp(file->d_name, ".") == 0 || strcmp(file->d_name, "..") == 0)
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continue;
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// Check if the backing exists (this checks for validity)
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bool exists;
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Status status = DoesBackingExist(file->d_name, &exists);
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if (status != SUCCESS || !exists)
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continue;
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// Allocate memory for the new backing list
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char** new_backings = realloc(*_backings, (count + 2) * sizeof(char*)); // +2 for the new entry and the NULL terminator
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if (new_backings == NULL) {
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Log(LOG_LEVEL_ERROR, "Failed to reallocate memory for the backing list (%s).", strerror(errno));
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closedir(dir);
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for (size_t i = 0; i < count; i++)
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free((*_backings)[i]);
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free(*_backings);
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return FAILURE;
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}
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*_backings = new_backings;
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// Duplicate the file name and add it to the list
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(*_backings)[count] = strdup(file->d_name);
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if ((*_backings)[count] == NULL) {
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Log(LOG_LEVEL_ERROR, "Failed to duplicate the backing name (%s).", strerror(errno));
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closedir(dir);
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for (size_t i = 0; i < count; i++)
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free((*_backings)[i]);
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free(*_backings);
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return FAILURE;
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}
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// Add the NULL terminator
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(*_backings)[count + 1] = NULL;
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count++;
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}
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closedir(dir);
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return SUCCESS;
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}
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Status GetLatestBacking(char** _backing_identifier) {
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// List the backings
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char** backings = NULL;
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Status status = ListBackings(&backings);
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if (status != SUCCESS)
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return status;
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// Find the latest backing
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int latest_identifier_index = -1;
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int latest_index = -1;
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for (int i = 0; backings[i] != NULL; i++) {
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int index = GetBackingIndex(backings[i]);
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if (index > latest_index) {
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latest_identifier_index = i;
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latest_index = index;
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}
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}
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// Return the latest backing
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if (latest_identifier_index == -1) {
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*_backing_identifier = NULL;
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} else {
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*_backing_identifier = strdup(backings[latest_identifier_index]);
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if (*_backing_identifier == NULL) {
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Log(LOG_LEVEL_ERROR, "Failed to duplicate the backing identifier (%s).", strerror(errno));
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status = FAILURE;
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}
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}
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// Free the backings list
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for (int i = 0; backings[i] != NULL; i++)
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free(backings[i]);
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free(backings);
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return status;
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}
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Status GetBackingDiskInfo(const char* backing_identifier, DiskInfo* _info) {
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*_info = (DiskInfo){0};
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// Get the backing path
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char* backing_path = NULL;
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Status status = GetBackingPath(backing_identifier, &backing_path);
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if (status != SUCCESS)
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return status;
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// Get the disk info
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status = GetDiskInfo(backing_path, _info);
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free(backing_path);
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return status;
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}
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