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-rw-r--r--lib/microtar/src/microtar.c434
1 files changed, 434 insertions, 0 deletions
diff --git a/lib/microtar/src/microtar.c b/lib/microtar/src/microtar.c
new file mode 100644
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--- /dev/null
+++ b/lib/microtar/src/microtar.c
@@ -0,0 +1,434 @@
+/*
+ * Copyright (c) 2017 rxi
+ * Copyright (c) 2024 Gaspartcho
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "microtar.h"
+
+typedef struct {
+ // Original tar header fields
+ char file_path[100];
+ char file_mode[8];
+ char owner_user_id[8];
+ char owner_group_id[8];
+ char file_size[12];
+ char file_mtime[12];
+ char header_checksum[8];
+ char file_type;
+ char link_path[100];
+
+ // New UStar fields
+ char magic_bytes[6];
+ char version[2];
+ char owner_user_name[32];
+ char owner_group_name[32];
+ char device_major_number[8];
+ char device_minor_number[8];
+ char prefix[155];
+
+ char padding[12];
+} mtar_raw_header_t;
+
+
+static unsigned round_up(unsigned n, unsigned incr) {
+ return n + (incr - n % incr) % incr;
+}
+
+
+static unsigned checksum(const mtar_raw_header_t* rh) {
+ unsigned i;
+ unsigned char *p = (unsigned char*) rh;
+ unsigned res = 256;
+ for (i = 0; i < offsetof(mtar_raw_header_t, header_checksum); i++) {
+ res += p[i];
+ }
+ for (i = offsetof(mtar_raw_header_t, file_type); i < sizeof(*rh); i++) {
+ res += p[i];
+ }
+ return res;
+}
+
+
+static int tread(mtar_t *tar, void *data, unsigned size) {
+ int err = tar->read(tar, data, size);
+ tar->pos += size;
+ return err;
+}
+
+
+static int twrite(mtar_t *tar, const void *data, unsigned size) {
+ int err = tar->write(tar, data, size);
+ tar->pos += size;
+ return err;
+}
+
+
+static int write_null_bytes(mtar_t *tar, int n) {
+ int i, err;
+ char nul = '\0';
+ for (i = 0; i < n; i++) {
+ err = twrite(tar, &nul, 1);
+ if (err) {
+ return err;
+ }
+ }
+ return MTAR_ESUCCESS;
+}
+
+static int read_filename(char *dest, const char *name, const char *prefix) {
+ // If there's no prefix, use name directly
+ if (prefix[0] == '\0') {
+ strcpy(dest, name);
+ dest[100] = '\0';
+ return MTAR_ESUCCESS;
+ }
+
+ // If there is a prefix, the path is: <prefix> '/' <path>
+ strcpy(dest, prefix);
+ strcat(dest, "/");
+ strcat(dest, name);
+ dest[256] = '\0';
+
+ return MTAR_ESUCCESS;
+}
+
+
+static int raw_to_header(mtar_header_t *h, const mtar_raw_header_t *rh) {
+ unsigned chksum1, chksum2;
+
+ /* If the checksum starts with a null byte we assume the record is NULL */
+ if (*rh->header_checksum == '\0') {
+ return MTAR_ENULLRECORD;
+ }
+
+ /* Build and compare checksum */
+ chksum1 = checksum(rh);
+ sscanf(rh->header_checksum, "%o", &chksum2);
+ if (chksum1 != chksum2) {
+ return MTAR_EBADCHKSUM;
+ }
+
+ /* Load raw header into header */
+ sscanf(rh->file_mode, "%o", &h->mode);
+ sscanf(rh->owner_user_id, "%o", &h->owner);
+ sscanf(rh->file_size, "%o", &h->size);
+ sscanf(rh->file_mtime, "%o", &h->mtime);
+ h->type = rh->file_type;
+ read_filename(h->name, rh->file_path, rh->prefix);
+ read_filename(h->linkname, rh->link_path, rh->prefix);
+
+ return MTAR_ESUCCESS;
+}
+
+
+static int header_to_raw(mtar_raw_header_t *rh, const mtar_header_t *h) {
+ unsigned chksum;
+
+ /* Load header into raw header */
+ memset(rh, 0, sizeof(*rh));
+ sprintf(rh->file_mode , "%o", h->mode);
+ sprintf(rh->owner_user_id, "%o", h->owner);
+ sprintf(rh->file_size, "%o", h->size);
+ sprintf(rh->file_mtime, "%o", h->mtime);
+ rh->file_type = h->type ? h->type : MTAR_TREG;
+ strcpy(rh->file_path, h->name);
+ strcpy(rh->link_path, h->linkname);
+
+
+ /* Calculate and write checksum */
+ chksum = checksum(rh);
+ sprintf(rh->header_checksum, "%06o", chksum);
+ rh->header_checksum[7] = ' ';
+
+ return MTAR_ESUCCESS;
+}
+
+
+const char* mtar_strerror(int err) {
+ switch (err) {
+ case MTAR_ESUCCESS : return "success";
+ case MTAR_EFAILURE : return "failure";
+ case MTAR_EOPENFAIL : return "could not open";
+ case MTAR_EREADFAIL : return "could not read";
+ case MTAR_EWRITEFAIL : return "could not write";
+ case MTAR_ESEEKFAIL : return "could not seek";
+ case MTAR_EBADCHKSUM : return "bad checksum";
+ case MTAR_ENULLRECORD : return "null record";
+ case MTAR_ENOTFOUND : return "file not found";
+ }
+ return "unknown error";
+}
+
+
+static int file_write(mtar_t *tar, const void *data, unsigned size) {
+ unsigned res = fwrite(data, 1, size, tar->stream);
+ return (res == size) ? MTAR_ESUCCESS : MTAR_EWRITEFAIL;
+}
+
+static int file_read(mtar_t *tar, void *data, unsigned size) {
+ unsigned res = fread(data, 1, size, tar->stream);
+ return (res == size) ? MTAR_ESUCCESS : MTAR_EREADFAIL;
+}
+
+static int file_seek(mtar_t *tar, unsigned offset) {
+ int res = fseek(tar->stream, offset, SEEK_SET);
+ return (res == 0) ? MTAR_ESUCCESS : MTAR_ESEEKFAIL;
+}
+
+static int file_close(mtar_t *tar) {
+ fclose(tar->stream);
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_open(mtar_t *tar, const char *filename, const char *mode) {
+ int err;
+ mtar_header_t h;
+
+ /* Init tar struct and functions */
+ memset(tar, 0, sizeof(*tar));
+ tar->write = file_write;
+ tar->read = file_read;
+ tar->seek = file_seek;
+ tar->close = file_close;
+
+ /* Assure mode is always binary */
+ if ( strchr(mode, 'r') ) mode = "rb";
+ if ( strchr(mode, 'w') ) mode = "wb";
+ if ( strchr(mode, 'a') ) mode = "ab";
+ /* Open file */
+ tar->stream = fopen(filename, mode);
+ if (!tar->stream) {
+ return MTAR_EOPENFAIL;
+ }
+ /* Read first header to check it is valid if mode is `r` */
+ if (*mode == 'r') {
+ err = mtar_read_header(tar, &h);
+ if (err != MTAR_ESUCCESS) {
+ mtar_close(tar);
+ return err;
+ }
+ }
+
+ /* Return ok */
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_close(mtar_t *tar) {
+ return tar->close(tar);
+}
+
+
+int mtar_seek(mtar_t *tar, unsigned pos) {
+ int err = tar->seek(tar, pos);
+ tar->pos = pos;
+ return err;
+}
+
+
+int mtar_rewind(mtar_t *tar) {
+ tar->remaining_data = 0;
+ tar->last_header = 0;
+ return mtar_seek(tar, 0);
+}
+
+
+int mtar_next(mtar_t *tar) {
+ int err, n;
+ mtar_header_t h;
+ /* Load header */
+ err = mtar_read_header(tar, &h);
+ if (err) {
+ return err;
+ }
+ /* Seek to next record */
+ n = round_up(h.size, 512) + sizeof(mtar_raw_header_t);
+ return mtar_seek(tar, tar->pos + n);
+}
+
+
+int mtar_find(mtar_t *tar, const char *name, mtar_header_t *h) {
+ int err;
+ mtar_header_t header;
+ /* Start at beginning */
+ err = mtar_rewind(tar);
+ if (err) {
+ return err;
+ }
+ /* Iterate all files until we hit an error or find the file */
+ while ( (err = mtar_read_header(tar, &header)) == MTAR_ESUCCESS ) {
+ if ( !strcmp(header.name, name) ) {
+ if (h) {
+ *h = header;
+ }
+ return MTAR_ESUCCESS;
+ }
+ mtar_next(tar);
+ }
+ /* Return error */
+ if (err == MTAR_ENULLRECORD) {
+ err = MTAR_ENOTFOUND;
+ }
+ return err;
+}
+
+
+int mtar_read_header(mtar_t *tar, mtar_header_t *h) {
+ int err;
+ mtar_raw_header_t rh;
+ /* Save header position */
+ tar->last_header = tar->pos;
+ /* Read raw header */
+ err = tread(tar, &rh, sizeof(rh));
+ if (err) {
+ return err;
+ }
+ /* Seek back to start of header */
+ err = mtar_seek(tar, tar->last_header);
+ if (err) {
+ return err;
+ }
+ /* Load raw header into header struct and return */
+ return raw_to_header(h, &rh);
+}
+
+
+int mtar_update_header(mtar_header_t *h, mtar_header_t *oh) {
+ if (oh->mode) h->mode = oh->mode;
+ if (oh->owner) h->owner = oh->owner;
+ if (oh->size) h->size = oh->size;
+ if (oh->mtime) h->mtime = oh->mtime;
+ if (oh->type) h->type = oh->type;
+
+ if (oh->name[0] != '\0') strcpy(h->name, oh->name);
+ if (oh->linkname[0] != '\0') strcpy(h->linkname, oh->linkname);
+
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_clear_header(mtar_header_t *h){
+ h->mode = 0;
+ h->owner = 0;
+ h->size = 0;
+ h->mtime = 0;
+ h->type = 0;
+ bzero(h->name, strlen(h->name));
+ bzero(h->linkname, strlen(h->linkname));
+
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_read_data(mtar_t *tar, void *ptr, unsigned size) {
+ int err;
+ /* If we have no remaining data then this is the first read, we get the size,
+ * set the remaining data and seek to the beginning of the data */
+ if (tar->remaining_data == 0) {
+ mtar_header_t h;
+ /* Read header */
+ err = mtar_read_header(tar, &h);
+ if (err) {
+ return err;
+ }
+ /* Seek past header and init remaining data */
+ err = mtar_seek(tar, tar->pos + sizeof(mtar_raw_header_t));
+ if (err) {
+ return err;
+ }
+ tar->remaining_data = h.size;
+ }
+ /* Read data */
+ err = tread(tar, ptr, size);
+ if (err) {
+ return err;
+ }
+ tar->remaining_data -= size;
+ /* If there is no remaining data we've finished reading and seek back to the
+ * header */
+ if (tar->remaining_data == 0) {
+ return mtar_seek(tar, tar->last_header);
+ }
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_write_header(mtar_t *tar, const mtar_header_t *h) {
+ mtar_raw_header_t rh;
+ /* Build raw header and write */
+ header_to_raw(&rh, h);
+ tar->remaining_data = h->size;
+ return twrite(tar, &rh, sizeof(rh));
+}
+
+
+int mtar_write_file_header(mtar_t *tar, const char *name, unsigned size) {
+ mtar_header_t h;
+ /* Build header */
+ memset(&h, 0, sizeof(h));
+ strcpy(h.name, name);
+ h.size = size;
+ h.type = MTAR_TREG;
+ h.mode = 0664;
+ /* Write header */
+ return mtar_write_header(tar, &h);
+}
+
+
+int mtar_write_dir_header(mtar_t *tar, const char *name) {
+ mtar_header_t h;
+ /* Build header */
+ memset(&h, 0, sizeof(h));
+ strcpy(h.name, name);
+ h.type = MTAR_TDIR;
+ h.mode = 0775;
+ /* Write header */
+ return mtar_write_header(tar, &h);
+}
+
+
+int mtar_write_data(mtar_t *tar, const void *data, unsigned size) {
+ int err;
+ /* Write data */
+ err = twrite(tar, data, size);
+ if (err) {
+ return err;
+ }
+ tar->remaining_data -= size;
+ /* Write padding if we've written all the data for this file */
+ if (tar->remaining_data == 0) {
+ return write_null_bytes(tar, round_up(tar->pos, 512) - tar->pos);
+ }
+ return MTAR_ESUCCESS;
+}
+
+
+int mtar_finalize(mtar_t *tar) {
+ /* Write two NULL records */
+ return write_null_bytes(tar, sizeof(mtar_raw_header_t) * 2);
+}
+
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