tarfs.c, as well as an incomplete ramfs.c:

1 files changed, 233 insertions, 208 deletions

diff --git a/kernel/fs/tar.c b/kernel/fs/tar.c
index 8beebc6..b844ed2 100644
--- a/kernel/fs/tar.c
+++ b/kernel/fs/tar.c
@@ -1,188 +1,222 @@
-#include "lib/kio.h"
 #include <comus/fs.h>
 #include <lib.h>
+#include <comus/tar.h>
 
-struct tar_hdr {
-	char name[100];
-	char mode[8];
-	char uid[8];
-	char gid[8];
-	char size[12];
-	char mtime[12];
-	char chksum[8];
-	char typeflag;
-	char linkname[100];
-	char magic[6];
-	char version[2];
-	char uname[32];
-	char gname[32];
-	char devmajor[8];
-	char devminor[8];
-	char prefix[155];
-	char unused[12];
+// 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
 };
-
-struct tar_file {
-	struct file file;
-	struct file_system *fs;
-	size_t len;
-	size_t offset;
-	size_t sect;
-};
-
-#define TAR_SECT_SIZE 512
-
-#define TMAGIC "ustar"
-#define TMAGLEN 6
-#define TVERSION "00"
+#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'
-#define DIRTYPE '5'
+#define REGTYPE  '0'            /* regular file */
+#define DIRTYPE  '5'            /* directory */
 
-static int read_tar_hdr(struct disk *disk, uint32_t sect, struct tar_hdr *hdr)
-{
-	if (disk_read(disk, sect * TAR_SECT_SIZE, TAR_SECT_SIZE, hdr) <
-		TAR_SECT_SIZE)
-		return 1;
 
-	// check magic
-	if (memcmp(hdr->magic, TMAGIC, TMAGLEN) != 0)
-		return 1;
-
-	// check version
-	if (memcmp(hdr->version, TVERSION, TVERSLEN) != 0)
-		return 1;
-
-	return 0;
+struct tar_file {
+    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;
+    
 }
 
-static int tar_to_fs_type(char typeflag)
-{
-	switch (typeflag) {
-	case REGTYPE:
-		return F_REG;
-	case DIRTYPE:
-		return F_DIR;
-	default:
-		return -1;
-	}
+/// @brief 
+/// @param f 
+/// @param buffer 
+/// @param len 
+/// @return 
+int tar_read(struct file *f, char *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;
+        }
 
-static int tar_locate(struct file_system *fs, const char *path,
-					  struct tar_hdr *out_hdr, size_t *out_sect,
-					  size_t *in_sect, bool partial)
-{
-	struct tar_hdr hdr;
-	size_t sect = 0;
+    }
+    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;
 
-	if (in_sect != NULL)
-		sect = *in_sect;
+        }
 
-	while (1) {
-		size_t filesize, sects;
-		int cmp;
+    }
+    return ERROR_TAR; // it should never actually reach here.
 
-		if (read_tar_hdr(fs->fs_disk, sect, &hdr))
-			return 1;
+}
 
-		filesize = strtoull(hdr.size, NULL, 8);
-		sects = (filesize + TAR_SECT_SIZE - 1) / TAR_SECT_SIZE;
 
-		if (partial) {
-			size_t len = MIN(strlen(path), strlen(hdr.name));
-			cmp = memcmp(hdr.name, path, len);
-		} else {
-			cmp = memcmp(hdr.name, path, strlen(path) + 1);
-		}
+void tar_close(struct file *f) {
+    kfree(f); 
+}
 
-		if (cmp) {
-			// not our file, goto next
-			sect += sects + 1;
-			continue;
-		}
+int tar_seek(struct file *f, int offsetAdd, int theSeek) {
+    struct tar_file *tf = (struct tar_file*) f;
+    if(theSeek == SEEK_SET) {
+        tf->offset = offsetAdd;
+    } else if(theSeek == SEEK_CUR) {
+        tf->offset = tf->offset + offsetAdd;
+    } else if(theSeek ==SEEK_END) {
+        tf->offset = tf->len + offsetAdd;
+    } else {
+        return ERROR_TAR;
+    }
+    return NOERROR_TAR;
 
-		// we found our file!
-		*out_hdr = hdr;
-		*out_sect = sect;
-		if (in_sect != NULL)
-			*in_sect = sect + sects + 1;
-		return 0;
-	}
 
-	return 1;
 }
 
-int tar_read(struct file *in, void *buf, size_t len)
-{
-	struct tar_file *file = (struct tar_file *)in;
-	size_t max_bytes = file->len - file->offset;
-	long bytes = MIN(max_bytes, len);
-
-	if (file->file.f_type != F_REG)
-		return 1;
-
-	if (bytes < 1)
-		return 0;
+int tar_write(struct file *f, const char *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;
+}
 
-	bytes = disk_read(file->fs->fs_disk,
-					  (file->sect + 1) * TAR_SECT_SIZE + file->offset, bytes,
-					  buf);
-	if (bytes < 0)
-		return bytes; // return err code
+/*int tar_ents(struct file *f, struct dirent *d, size_t dIndex) {
+    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;
+    }
+    while(1 == 1) {
+        if(find_file_redux(tf->fs, dir.name, &sect_off, &sect, &dir) != 0) {
+            return ERROR_TAR;
+        }
+        if(curr_index < dIndex) {
+            curr_index += 1;
+        } else if(curr_index > dIndex) {
+            // something went seriously wrong
+            return ERROR_TAR;
+        } 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);
+            return NOERROR_TAR;
+        }
 
-	file->offset += bytes;
-	return bytes;
-}
 
-int tar_write(struct file *in, const void *buf, size_t len)
-{
-	(void)in;
-	(void)buf;
-	(void)len;
+    }
 
-	// cannot write to tar balls
-	return -1;
-}
+    
+}*/
 
-int tar_seek(struct file *in, long int off, int whence)
-{
-	struct tar_file *file = (struct tar_file *)in;
-	switch (whence) {
-	case SEEK_SET:
-		file->offset = off;
-		return file->offset;
-	case SEEK_CUR:
-		file->offset += off;
-		return file->offset;
-	case SEEK_END:
-		file->offset = file->len + off;
-		return file->offset;
-	default:
-		return -1;
-	}
-}
 
-int tar_ents(struct file *in, struct dirent *ent, size_t entry)
+int tar_ents(struct file *f, struct dirent *ent, size_t entry)
 {
-	struct tar_file *file;
-	struct tar_hdr dir, hdr;
+	struct tar_file *tf;
+	struct tar_header dir, hdr;
 	size_t sect;
 	size_t sect_off = 0;
 	size_t idx = 0;
 
-	file = (struct tar_file *)in;
+	tf = (struct tar_file *)f;
 	sect = 0;
 
-	if (file->file.f_type != F_DIR)
+	if (tf->file.f_type != F_DIR)
 		return -1;
 
-	if (read_tar_hdr(file->fs->fs_disk, sect, &dir))
-		return 1;
+	if (read_tar_header(tf->fs->fs_disk, sect, &dir)) {
+        return ERROR_TAR;
+    }
 
 	while (1) {
-		if (tar_locate(file->fs, dir.name, &hdr, &sect, &sect_off, true))
-			return 1;
+		if (find_file_redux(tf->fs, dir.name, &sect_off, &sect, &hdr))
+			return ERROR_TAR;
 
 		if (idx != entry) {
 			idx++;
@@ -192,77 +226,68 @@ int tar_ents(struct file *in, struct dirent *ent, size_t entry)
 		ent->d_offset = entry;
 		ent->d_namelen = strlen(hdr.name);
 		memcpy(ent->d_name, hdr.name, ent->d_namelen + 1);
-		return 0;
+		return NOERROR_TAR;
 	}
 
-	return 1;
-}
-
-void tar_close(struct file *file)
-{
-	kfree(file);
+	return ERROR_TAR;
 }
 
-int tar_open(struct file_system *fs, const char *path, int flags,
-			 struct file **out)
-{
-	struct tar_file *file;
-	struct tar_hdr hdr;
-	size_t sect;
+// opens up the tar file at fullpath, and puts it in out.
+int tar_open(struct file_system *fs, const char *fullpath, struct file **out) {
+    struct tar_header hdr;
+    struct tar_file *newFile;
+    size_t sect_result;
+    find_file(fs, fullpath, NULL, &sect_result, &hdr);
+    newFile = kalloc(sizeof(struct tar_file));
+    //newFile->file = idk;
+    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;
 
-	// cannot create or write files
-	if (flags != O_RDONLY)
-		return 1;
+    *out = (struct file *)newFile;
+    return NOERROR_TAR;
+    
 
-	if (tar_locate(fs, path, &hdr, &sect, NULL, false))
-		return 1;
 
-	file = kalloc(sizeof(struct tar_file));
-	if (file == NULL)
-		return 1;
-
-	file->file.f_type = tar_to_fs_type(hdr.typeflag);
-	file->file.read = tar_read;
-	file->file.write = tar_write;
-	file->file.seek = tar_seek;
-	file->file.ents = tar_ents;
-	file->file.close = tar_close;
-	file->fs = fs;
-	file->len = strtoull(hdr.size, NULL, 8);
-	file->offset = 0;
-	file->sect = sect;
-	*out = (struct file *)file;
-
-	return 0;
+    
 }
 
-int tar_stat(struct file_system *fs, const char *path, struct stat *stat)
-{
-	struct tar_hdr hdr;
-	size_t sect;
-
-	if (tar_locate(fs, path, &hdr, &sect, NULL, false))
-		return 1;
-
-	stat->s_length = strtoull(hdr.size, NULL, 8);
-	stat->s_type = tar_to_fs_type(hdr.typeflag);
-
-	return 0;
+// 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;
 }
 
-int tar_mount(struct file_system *fs)
-{
-	struct tar_hdr hdr;
-
-	// if first tar hdr is valid, assume valid tarball
-	if (read_tar_hdr(fs->fs_disk, 0, &hdr))
-		return 1;
-
-	fs->fs_present = true;
-	fs->fs_name = "tar";
-	fs->open = tar_open;
-	fs->stat = tar_stat;
-
-	INFO("loaded tarfs on disk %d", fs->fs_disk->d_id);
-	return 0;
+// 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;
 }
+
+// no need to unmount, since mount just overrides whatever it was using previously.
\ No newline at end of file