~% cd Desktop/V3 V3% gcc -o extract_file extract_file.c V3%./extract_file disk1.img CONFIG.SYS File not found in root directory. V3%./extract_file DISK1.img CONFIG.SYS File not found in root directory. DISK1 V3 % 1s disk1.img V3% extract_file extract_file.c > Name < > DISK1 Date Modified » a Size .fseventsd ATTRIB.EXE AUTOEXEC.BAT CHKDSK.EXE COMMAND.COM CONFIG.SYS COUNTRY.SYS COUNTRY.TX Yesterday at 7:37 PM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM 37 37 DEBUG.EXE May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM 1 5 13B 2 DEFRAG.EXE May 31, 1994 at 6:22 AM DEFRAG.HL May 31, 1994 at 6:22 AM DOSSETUP.INI May 31, 1994 at 6:22 AM DRVSPACE.BIN May 31, 1994 at 6:22 AM EDIT.COM EGA.CP_ EGA2.CP_ May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM 413 b 1 EGA3.CP May 31, 1994 at 6:22 AM 1 EMM386.EX_ May 31, 1994 at 6:22 AM 5 EXPAND.EXE FDISK.EXE FORMAT.COM IO.SYS May 31, 1994 at 6:22 AM 1 May 31, 1994 at 6:22 AM 2 May 31, 1994 at 6:22 AM 2 < > V3 Name DISK1 disk1.img extract_file extract_file.c QBASIC.EXE iCloud Drive > I Desktop ISO.CP_ KEYB.COM KEYBOARD.SYS KEYBRD2.SY_ MEM.EX_ MSCDEX.EXE MSDOS.SYS NETWORKS.TXT May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM 1 May 31, 1994 at 6:22 AM 3 May 31, 1994 at 6:22 AM 1 May 31, 1994 at 6:22 AM 2 May 31, 1994 at 6:22 AM 2 May 31, 1994 at 6:22 AM 3 May 31, 1994 at 6:22 AM NLSFUNC.EXE PACKING.LST May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM May 31, 1994 at 6:22 AM 19 V3 > DISK1

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Question

code is still not working!! please help me ! idk why it wont work. I was following directions as given. #include #include #include #include #include #pragma pack(push, 1) typedef struct { int8_tjump_to_bootstrap[3]; int8_toem_id[8]; uint16_tbytes_per_sector; uint8_tsectors_per_cluster; uint16_treserved_sectors; uint8_tfat_copies; uint16_troot_dir_entries; uint16_ttotal_sectors; uint8_tmedia_descriptor_type; uint16_tsectors_per_fat; uint16_tsectors_per_track; uint16_theads; uint32_thidden_sectors; uint32_ttotal_sectors2; uint8_tdrive_index; uint8_t_stuff; uint8_tsignature; uint32_tid; int8_tlabel[11]; int8_ttype[8]; int8_t_more_stuff[448]; uint16_tsig; } boot_t; typedef struct { int8_tfilename[8]; int8_textension[3]; int8_tattributes; int8_t_reserved[10]; uint16_tupdate_time; uint16_tupdate_date; uint16_tstarting_cluster; uint32_tfile_size; } dir_entry_t; #pragma pack(pop) void readSector(FILE *disk, uint32_t sectorNumber, uint8_t *buffer, uint16_t bytesPerSector) { if (disk==NULL) { fprintf(stderr, "Invalid file pointer.\n"); return; } if (buffer==NULL) { fprintf(stderr, "Invalid buffer pointer.\n"); return; } if (fseek(disk, sectorNumber*bytesPerSector, SEEK_SET) !=0) { perror("Error seeking file"); return; } size_tbytesRead=fread(buffer, 1, bytesPerSector, disk); if (bytesRead!=bytesPerSector) { if (feof(disk)) { fprintf(stderr, "End of file reached unexpectedly.\n"); } else if (ferror(disk)) { perror("Error reading file"); } return; } } void readMBR(FILE *disk, boot_t *bootSector) { uint8_tbuffer[512]; readSector(disk, 0, buffer, 512); memcpy(bootSector, buffer, sizeof(boot_t)); } dir_entry_t* getRootDirEntries(FILE *disk, boot_t *bootSector) { uint16_trootDirSectors= ((bootSector->root_dir_entries*32) + (bootSector->bytes_per_sector-1)) /bootSector->bytes_per_sector; uint8_t*buffer= (uint8_t*)malloc(rootDirSectors*bootSector->bytes_per_sector); readSector(disk, bootSector->reserved_sectors+ (bootSector->fat_copies*bootSector->sectors_per_fat), buffer, rootDirSectors*bootSector->bytes_per_sector); return (dir_entry_t*)buffer; } dir_entry_t* findRootDirEntry(const char *filename, dir_entry_t *entries, uint16_t numEntries) { for (inti=0; ireserved_sectors+ (bootSector->fat_copies*bootSector->sectors_per_fat) + ((bootSector->root_dir_entries * 32 + bootSector->bytes_per_sector - 1) / bootSector->bytes_per_sector); uint32_tfirstSectorOfCluster= ((clusterNumber-2) *bootSector->sectors_per_cluster) +firstDataSector; for (inti=0; isectors_per_cluster; i++) { readSector(disk, firstSectorOfCluster+i, buffer+ (i*bootSector->bytes_per_sector), bootSector->bytes_per_sector); } } void extractFile(FILE *disk, dir_entry_t *entry, boot_t *bootSector) { uint8_t*buffer= (uint8_t*)malloc(entry->file_size); uint32_tcluster=entry->starting_cluster; uint32_tbytesRead=0; while (bytesReadfile_size) { readCluster(disk, cluster, buffer+bytesRead, bootSector); bytesRead+=bootSector->bytes_per_sector*bootSector->sectors_per_cluster; // In a real implementation, follow the FAT to find the next cluster cluster++; } FILE*output=fopen("output_file", "wb"); fwrite(buffer, 1, entry->file_size, output); fclose(output); free(buffer); } int main(int argc, char *argv[]) { if (argc!=3) { fprintf(stderr, "Usage: %s \n", argv[0]); return1; } constchar*diskImage=argv[1]; constchar*filename=argv[2]; FILE*disk=fopen(diskImage, "rb"); if (disk==NULL) { perror("Error opening disk image"); return1; } boot_tbootSector; readMBR(disk, &bootSector); dir_entry_t*entries=getRootDirEntries(disk, &bootSector); dir_entry_t*entry=findRootDirEntry(filename, entries, bootSector.root_dir_entries); if (entry) { extractFile(disk, entry, &bootSector); printf("File extracted successfully.\n"); } else { fprintf(stderr, "File not found in root directory.\n"); } free(entries); fclose(disk); return0; }

~% cd Desktop/V3
V3% gcc -o extract_file extract_file.c
V3%./extract_file disk1.img CONFIG.SYS
File not found in root directory.
V3%./extract_file DISK1.img CONFIG.SYS
File not found in root directory.
DISK1
V3 % 1s
disk1.img
V3%
extract_file
extract_file.c

>
Name
< > DISK1
Date Modified
» a
Size
.fseventsd
ATTRIB.EXE
AUTOEXEC.BAT
CHKDSK.EXE
COMMAND.COM
CONFIG.SYS
COUNTRY.SYS
COUNTRY.TX
Yesterday at 7:37 PM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
37
37
DEBUG.EXE
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
1
5
13B
2
DEFRAG.EXE
May 31, 1994 at 6:22 AM
DEFRAG.HL
May 31, 1994 at 6:22 AM
DOSSETUP.INI
May 31, 1994 at 6:22 AM
DRVSPACE.BIN
May 31, 1994 at 6:22 AM
EDIT.COM
EGA.CP_
EGA2.CP_
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
413 b
1
EGA3.CP
May 31, 1994 at 6:22 AM
1
EMM386.EX_
May 31, 1994 at 6:22 AM
5
EXPAND.EXE
FDISK.EXE
FORMAT.COM
IO.SYS
May 31, 1994 at 6:22 AM
1
May 31, 1994 at 6:22 AM
2
May 31, 1994 at 6:22 AM
2
< > V3
Name
DISK1
disk1.img
extract_file
extract_file.c
QBASIC.EXE
iCloud Drive > I Desktop
ISO.CP_
KEYB.COM
KEYBOARD.SYS
KEYBRD2.SY_
MEM.EX_
MSCDEX.EXE
MSDOS.SYS
NETWORKS.TXT
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
1
May 31, 1994 at 6:22 AM
3
May 31, 1994 at 6:22 AM
1
May 31, 1994 at 6:22 AM
2
May 31, 1994 at 6:22 AM
2
May 31, 1994 at 6:22 AM
3
May 31, 1994 at 6:22 AM
NLSFUNC.EXE
PACKING.LST
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
May 31, 1994 at 6:22 AM
19
V3 > DISK1

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