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-rw-r--r--kernel/fs/tar.c453
1 files changed, 221 insertions, 232 deletions
diff --git a/kernel/fs/tar.c b/kernel/fs/tar.c
index 5f02c34..4e66944 100644
--- a/kernel/fs/tar.c
+++ b/kernel/fs/tar.c
@@ -2,210 +2,194 @@
#include <lib.h>
#include <comus/tar.h>
+
// the placements of these values mimics their placement in standard UStar
struct tar_header {
- char name[100]; // 0-99
- char mode[8]; // 100-107
- char ownerUID[8]; // 108-115
- char groupUID[8]; // 116-123
- char fileSize[12]; // 124-135
- char lastMod[12]; // 136-147
- char checksum[8]; // 148-155
- char type_flag; // 156
- char linked_name[100]; // 157-256
- char magic[6]; // 257-262
- char version[2]; // 263-264
- char username[32]; // 265-296
- char groupname[32]; // 297-328
- char majorNum[8]; // 329-336
- char minorNum[8]; // 337-344
- char prefix[155]; // 345-499
- char notUsed[12]; // 500-511
+ char name[100]; // 0-99
+ char mode[8]; // 100-107
+ char ownerUID[8]; // 108-115
+ char groupUID[8]; // 116-123
+ char fileSize[12]; // 124-135
+ char lastMod[12]; // 136-147
+ char checksum[8]; // 148-155
+ char type_flag; // 156
+ char linked_name[100]; // 157-256
+ char magic[6]; // 257-262
+ char version[2]; // 263-264
+ char username[32]; // 265-296
+ char groupname[32]; // 297-328
+ char majorNum[8]; // 329-336
+ char minorNum[8]; // 337-344
+ char prefix[155]; // 345-499
+ char notUsed[12]; // 500-511
};
-#define TAR_SIZE 512
-#define TMAGIC "ustar" /* ustar and a null */
-#define TMAGLEN 6
-#define TVERSION "00" /* 00 and no null */
+#define TAR_SIZE 512
+#define TMAGIC "ustar" /* ustar and a null */
+#define TMAGLEN 6
+#define TVERSION "00" /* 00 and no null */
#define TVERSLEN 2
#define ERROR_TAR 1
#define NOERROR_TAR 0
-#define REGTYPE '0' /* regular file */
-#define DIRTYPE '5' /* directory */
+#define REGTYPE '0' /* regular file */
+#define DIRTYPE '5' /* directory */
+
struct tar_file {
- struct file file;
- struct file_system *fs;
- size_t len;
- size_t offset;
- size_t sect;
+ struct file file;
+ struct file_system *fs;
+ size_t len;
+ size_t offset;
+ size_t sect;
};
-// read_tar_header reads what is in tar
-int read_tar_header(struct disk *disk, uint32_t sect, struct tar_header *hdr)
-{
- if (disk_read(disk, sect * TAR_SIZE, TAR_SIZE, hdr) < TAR_SIZE) {
- return ERROR_TAR;
- }
- if (memcmp(hdr->magic, TMAGIC, TMAGLEN) != 0 ||
- memcmp(hdr->version, TVERSION, TVERSLEN) != 0) {
- return ERROR_TAR;
- }
- return NOERROR_TAR;
+/// @brief reads from the disk into tar_header
+/// @param disk the disk used with disk_read
+/// @param sect the sector to read (used for disk_read offset)
+/// @param hdr the tar_header to read into. read_tar_header is essentially used to output this.
+/// @return NOERROR_TAR or ERROR_TAR
+int read_tar_header(struct disk *disk, uint32_t sect, struct tar_header *hdr) {
+ // makes sure it reads enough bytes.
+ if(disk_read(disk, sect * TAR_SIZE, TAR_SIZE, hdr) < TAR_SIZE) {
+ return ERROR_TAR;
+ }
+ // makes sure magic and version are correct for USTar.
+ if(memcmp(hdr->magic, TMAGIC, TMAGLEN) != 0 || memcmp(hdr->version, TVERSION, TVERSLEN) != 0) {
+ return ERROR_TAR;
+ }
+ return NOERROR_TAR;
+
}
-/// @brief
+/// @brief reads from the file, and puts it into buffer
/// @param f the file to be read
/// @param buffer the buffer that the content of the file is read into
-/// @param len
-/// @return
-int tar_read(struct file *f, void *buffer, size_t len)
-{
- struct tar_file *tf = (struct tar_file *)f;
- long size = MIN((tf->len - tf->offset), len);
- if (tf->file.f_type != F_REG || size < 1) {
- return ERROR_TAR;
- }
- size = disk_read(tf->fs->fs_disk, (tf->sect + 1) * TAR_SIZE + tf->offset,
- size, buffer);
- tf->offset += size;
- return size;
-}
-//static int read_tar()
-// we are assuming that things are formatted correctly.
-int find_file(struct file_system *fs, const char *filepath, size_t *sect,
- size_t *sect_return, struct tar_header *outHeader)
-{
- //char *tempFilePath = filepath;
- struct tar_header hdr;
- size_t curr_sect;
- if (sect == NULL) {
- curr_sect = 0;
- } else {
- curr_sect = *sect;
- }
- while (1 == 1) {
- if (read_tar_header(fs->fs_disk, curr_sect, &hdr) != 0) {
- return ERROR_TAR;
- }
- if (memcmp(hdr.name, filepath, strlen(filepath) + 1) != 0) {
- // didn't find it.
-
- curr_sect +=
- ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1) / TAR_SIZE) +
- 1;
- continue;
- } else {
- *outHeader = hdr;
- *sect_return = curr_sect;
- if (sect != NULL) {
- sect += curr_sect;
- }
- return NOERROR_TAR;
- }
- }
- return ERROR_TAR;
-}
-int find_file_redux(struct file_system *fs, const char *filepath, size_t *sect,
- size_t *sect_return, struct tar_header *outHeader)
-{
- struct tar_header hdr;
- size_t curr_sect;
- if (sect == NULL) {
- curr_sect = 0;
- } else {
- curr_sect = *sect;
- }
- while (1 == 1) {
- if (read_tar_header(fs->fs_disk, curr_sect, &hdr) != 0) {
- return ERROR_TAR;
- }
- if (memcmp(hdr.name, filepath,
- MIN(strlen(filepath), strlen(hdr.name))) != 0) {
- // didn't find it.
-
- curr_sect +=
- ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1) / TAR_SIZE) +
- 1;
- continue;
- } else {
- *outHeader = hdr;
- *sect_return = curr_sect;
- if (sect != NULL) {
- sect += curr_sect +
- ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1) /
- TAR_SIZE) +
- 1;
- }
- return NOERROR_TAR;
- }
- }
- return ERROR_TAR; // it should never actually reach here.
-}
-
-void tar_close(struct file *f)
-{
- kfree(f);
-}
-
-int tar_seek(struct file *f, long int offsetAdd, int theSeek)
-{
- struct tar_file *tf = (struct tar_file *)f;
- if (theSeek == SEEK_SET) {
- tf->offset = offsetAdd;
- return tf->offset;
- } else if (theSeek == SEEK_CUR) {
- tf->offset = tf->offset + offsetAdd;
- return tf->offset;
- } else if (theSeek == SEEK_END) {
- tf->offset = tf->len + offsetAdd;
- return tf->offset;
- } else {
- return -1;
- }
+/// @param len length of the buffer, which caps what can be read if the file has more data.
+/// @return size of what was read.
+int tar_read(struct file *f, void *buffer, size_t len) {
+ struct tar_file *tf = (struct tar_file*) f;
+ long size = MIN((tf->len - tf->offset), len);
+ if(tf->file.f_type != F_REG || size < 1) {
+ return ERROR_TAR;
+ }
+ size = disk_read(tf->fs->fs_disk, (tf->sect+1) * TAR_SIZE + tf->offset, size, buffer);
+ tf->offset += size;
+ return size;
}
+/// @brief used to locate files
+/// @param fs the file system being used
+/// @param filepath the path to the file
+/// @param sect the sector to begin at, defaults to 0 if NULL.
+/// @param sect_return the sector to be outputted
+/// @param outHeader tar_header output for file found.
+/// @return NOERROR_TAR or ERROR_TAR
+int find_file(struct file_system *fs, const char *filepath, size_t *sect, size_t *sect_return, struct tar_header *outHeader) {
+ struct tar_header hdr;
+ size_t curr_sect;
+ if(sect == NULL) {
+ curr_sect = 0;
+ } else {
+ curr_sect = *sect;
+ }
+ while (1 == 1) {
+ // if read_tar_header errors
+ if(read_tar_header(fs->fs_disk, curr_sect, &hdr) != 0) {
+ return ERROR_TAR;
+ }
+ if(memcmp(hdr.name, filepath, strlen(filepath) + 1) != 0) {
+ // didn't find it.
+ curr_sect += ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1)/TAR_SIZE) + 1;
+ continue;
+ } else {
+ *outHeader = hdr;
+ *sect_return = curr_sect;
+ if(sect != NULL) {
+ sect += curr_sect;
+ }
+ return NOERROR_TAR;
+ }
-int tar_write(struct file *f, const void *buffer, size_t len)
-{
- // tar doesn't do write lol. This is just here so there is something to send to write
- (void)f;
- (void)buffer;
- (void)len;
- return ERROR_TAR;
+ }
+ return ERROR_TAR;
}
-/*int tar_ents(struct file *f, struct dirent *d, size_t dIndex) {
+// similar to find_file, but with a partition
+int find_file_redux(struct file_system *fs, const char *filepath, size_t *sect, size_t *sect_return, struct tar_header *outHeader) {
struct tar_header hdr;
- struct tar_header dir;
- struct tar_file *tf = (struct tar_file*) f;
- size_t sect = 0;
- size_t sect_off = 0;
- size_t curr_index = 0;
- if(read_tar_header(tf->fs->fs_disk, sect, &hdr) != 0) {
- return ERROR_TAR;
+ size_t curr_sect;
+ if(sect == NULL) {
+ curr_sect = 0;
+ } else {
+ curr_sect = *sect;
}
- while(1 == 1) {
- if(find_file_redux(tf->fs, dir.name, &sect_off, &sect, &dir) != 0) {
+ while (1 == 1) {
+ if(read_tar_header(fs->fs_disk, curr_sect, &hdr) != 0) {
return ERROR_TAR;
}
- if(curr_index < dIndex) {
- curr_index += 1;
- } else if(curr_index > dIndex) {
- // something went seriously wrong
- return ERROR_TAR;
+ if(memcmp(hdr.name, filepath, MIN(strlen(filepath), strlen(hdr.name))) != 0) {
+ // didn't find it.
+
+ curr_sect += ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1)/TAR_SIZE) + 1;
+ continue;
} else {
- d->d_namelen = strlen(hdr.name);
- dir.type_flag = DIRTYPE;
- d->d_offset = dIndex;
- memcpy(d->d_name, hdr.name, d->d_namelen + 1);
+ *outHeader = hdr;
+ *sect_return = curr_sect;
+ if(sect != NULL) {
+ sect += curr_sect + ((strtoull(hdr.fileSize, NULL, 8) + TAR_SIZE - 1)/TAR_SIZE) + 1;
+ }
return NOERROR_TAR;
+
}
+ }
+ return ERROR_TAR; // it should never actually reach here.
+
+}
+/// @brief closes the file
+/// @param f the file to close, and free memory from.
+void tar_close(struct file *f) {
+ kfree(f);
+}
+/// @brief
+/// @param f the file to perform seek
+/// @param offsetAdd what to add/adjust to the offset
+/// @param theSeek what kind of seek we are doing
+/// @return the new offset, or -1 on error (we can't use 1 since that is a possible offset change).
+int tar_seek(struct file *f, long int offsetAdd, int theSeek) {
+ struct tar_file *tf = (struct tar_file*) f;
+ if(theSeek == SEEK_SET) {
+ tf->offset = offsetAdd;
+ return tf->offset;
+ } else if(theSeek == SEEK_CUR) {
+ tf->offset = tf->offset + offsetAdd;
+ return tf->offset;
+ } else if(theSeek ==SEEK_END) {
+ tf->offset = tf->len + offsetAdd;
+ return tf->offset;
+ } else {
+ return -1; // if seek has a bad value for some reason.
}
+}
-}*/
+/// @brief
+/// @param f the file to write to (in theory)
+/// @param buffer the buffer to write from (in theory)
+/// @param len the length of the buffer to be written into (in theory)
+/// @return ERROR_TAR or NOERROR_TAR (in this case always ERROR_TAR).
+int tar_write(struct file *f, const void *buffer, size_t len) {
+ // tar doesn't do write lol. This is just here so there is something to send to write
+ (void)f;
+ (void)buffer;
+ (void)len;
+ return ERROR_TAR;
+}
+/// @brief gets the directory entry for the given file
+/// @param f the file
+/// @param ent the directory entry is put into here
+/// @param entry where idx needs to reach
+/// @return NOERROR_TAR or ERROR_TAR
int tar_ents(struct file *f, struct dirent *ent, size_t entry)
{
struct tar_file *tf;
@@ -218,11 +202,11 @@ int tar_ents(struct file *f, struct dirent *ent, size_t entry)
sect = 0;
if (tf->file.f_type != F_DIR)
- return -1;
+ return ERROR_TAR;
if (read_tar_header(tf->fs->fs_disk, sect, &dir)) {
- return ERROR_TAR;
- }
+ return ERROR_TAR;
+ }
while (1) {
if (find_file_redux(tf->fs, dir.name, &sect_off, &sect, &hdr))
@@ -242,65 +226,70 @@ int tar_ents(struct file *f, struct dirent *ent, size_t entry)
return ERROR_TAR;
}
-// opens up the tar file at fullpath, and puts it in out.
-int tar_open(struct file_system *fs, const char *fullpath, int flags,
- struct file **out)
-{
- struct tar_header hdr;
- struct tar_file *newFile;
- size_t sect_result;
- find_file(fs, fullpath, NULL, &sect_result, &hdr);
- if (flags != O_RDONLY) {
- return ERROR_TAR;
- }
- newFile = kalloc(sizeof(struct tar_file));
-
- newFile->file.f_type = F_REG;
- newFile->fs = fs;
- newFile->file.read = tar_read;
- newFile->file.close = tar_close;
- newFile->file.write = tar_write; // doesn't actually work;
- newFile->file.ents = tar_ents;
- newFile->file.seek = tar_seek;
- newFile->offset = 0;
- newFile->len = strtoull(hdr.fileSize, NULL, 8);
- newFile->sect = sect_result;
+/// @brief opens up the file at the full file path, and prepares it for further action
+/// @param fs the file system being used
+/// @param fullpath the full file path to the file that needs to be opened
+/// @param flags in this case, just used to check whether the file is set to read only, to make sure it is correct
+/// @param out the file, ready to be acted upon, with the other functions loaded onto it.
+/// @return NOERROR_TAR or ERROR_TAR
+int tar_open(struct file_system *fs, const char *fullpath, int flags, struct file **out) {
+ struct tar_header hdr;
+ struct tar_file *newFile;
+ size_t sect_result;
+ find_file(fs, fullpath, NULL, &sect_result, &hdr);
+ if(flags != O_RDONLY) {
+ return ERROR_TAR;
+ }
+ newFile = kalloc(sizeof(struct tar_file));
- *out = (struct file *)newFile;
- return NOERROR_TAR;
-}
+ newFile->file.f_type = F_REG;
+ newFile->fs = fs;
+ newFile->file.read = tar_read;
+ newFile->file.close = tar_close;
+ newFile->file.write = tar_write; // doesn't actually work;
+ newFile->file.ents = tar_ents;
+ newFile->file.seek = tar_seek;
+ newFile->offset = 0;
+ newFile->len = strtoull(hdr.fileSize, NULL, 8);
+ newFile->sect = sect_result;
-// gets stats at the file at fullpath, putting them in out.
-int tar_stat(struct file_system *fs, const char *fullpath, struct stat *out)
-{
- struct tar_header hdr;
- size_t sect_result;
- find_file(fs, fullpath, NULL, &sect_result, &hdr);
- out->s_length = strtoull(hdr.fileSize, NULL, 8);
- if (hdr.type_flag == REGTYPE) {
- out->s_type = F_REG;
- } else if (hdr.type_flag == DIRTYPE) {
- out->s_type = F_DIR;
- } else {
- // wth
- return ERROR_TAR;
- }
- return NOERROR_TAR;
+ *out = (struct file *)newFile;
+ return NOERROR_TAR;
}
-// use tar for the filesystem.
-int tar_mount(struct file_system *fs)
-{
- struct tar_header hdr;
- // reads into hdr
- if (read_tar_header(fs->fs_disk, 0, &hdr) == 0) {
- fs->fs_name = "tar";
- fs->open = tar_open;
- fs->stat = tar_stat;
- fs->fs_present = true;
- return NOERROR_TAR;
- }
- return ERROR_TAR;
+/// @brief gets the stats for the file found at fullpath, putting them in out
+/// @param fs the file system being used
+/// @param fullpath the full filepath of the file
+/// @param out the stats for the file found
+/// @return NOERROR_TAR OR ERROR_TAR
+int tar_stat(struct file_system *fs, const char *fullpath, struct stat *out) {
+ struct tar_header hdr;
+ size_t sect_result;
+ find_file(fs, fullpath, NULL, &sect_result, &hdr);
+ out->s_length = strtoull(hdr.fileSize, NULL, 8);
+ if(hdr.type_flag == REGTYPE) {
+ out->s_type = F_REG;
+ } else if(hdr.type_flag == DIRTYPE) {
+ out->s_type = F_DIR;
+ } else {
+ // wth
+ return ERROR_TAR;
+ }
+ return NOERROR_TAR;
}
-// no need to unmount, since mount just overrides whatever it was using previously. \ No newline at end of file
+/// @brief use tar for the filesystem.
+/// @param fs the file system being used, and loading tar into it.
+/// @return NOERROR_TAR or ERROR_TAR
+int tar_mount(struct file_system *fs) {
+ struct tar_header hdr;
+ // reads into hdr
+ if(read_tar_header(fs->fs_disk, 0, &hdr) == 0) {
+ fs->fs_name = "tar";
+ fs->open = tar_open;
+ fs->stat = tar_stat;
+ fs->fs_present = true;
+ return NOERROR_TAR;
+ }
+ return ERROR_TAR;
+} \ No newline at end of file
generated by cgit v1.2.3-freya (git 2.51.0) at 2025-09-22 19:17:29 +0000