Begin zyb/extract

.gitignore

@@ -1,2 +0,0 @@
-# Meson build output
-build

include/zyb/extract.h

@@ -0,0 +1,28 @@
+#ifndef ZYB_EXTRACT_H
+#define ZYB_EXTRACT_H
+
+// libc
+#include <stdio.h>
+
+// libzyb
+#include <zyb/header.h>
+
+// Extract leader from an open zyb
+int zyb_extract_leader(FILE *fptr, struct lead *leader);
+
+// Extract (next) dependency from an open zyb
+int zyb_extract_dependency(FILE *fptr, struct dependency *dep);
+
+// Extract full header from an open zyb
+int zyb_extract_header(FILE *fptr, struct zyb_header *header);
+
+// Extract (next) file from an open zyb
+int zyb_extract_file(FILE *fptr, char *dir);
+
+// Extract full zyb archive
+int zyb_extract_FILE(FILE *fptr, char *dir);
+
+// Extract full zyb archive at `file`
+int zyb_extract(char *file, char *dir);
+
+#endif

include/zyb/header.h

@@ -0,0 +1,58 @@
+#ifndef ZYB_HEADERS_H
+#define ZYB_HEADERS_H
+
+// libc
+#include <sys/types.h>
+
+#define ZYB_MAGIC "ZYB\0"
+#define ZYB_DEP_MAGIC "DEP\0"
+#define ZYB_FILE_MAGIC "ZIP\0"
+#define ZYB_FORMAT_VER 1
+#define ZYB_NAME_LENGTH 100
+
+/*
+ * This struct is the very first thing in any .zyb file.
+ * It contains package metadata, such as the name and dependencies.
+ */
+struct __attribute__((__packed__, aligned(2))) zyb_header {
+	/*
+	 * This struct is the first part of the header,
+	 * containing critical information about the package.
+	 */
+	struct __attribute__((__packed__, aligned(2))) lead {
+		char magic[4];				// Magic (ZYB_MAGIC)
+		unsigned short version;			// Format version (ZYB_FORMAT_VER)
+		char arch[6];				// Magic identifying arch
+		char os[6];				// Magic identifying os
+		char name[ZYB_NAME_LENGTH];		// Name of the package
+		unsigned short major, minor, patch;	// SemVer
+		unsigned short dependencies;		// Number of dependencies
+		unsigned char reserved[2];		// Padding
+	} leader;
+	/*
+	 * This struct contains information about each dependency.
+	 * The number of these struct should EXACTLY be lead.dependencies.
+	 */
+	struct __attribute__((__packed__, aligned(2))) dependency {
+		char magic[4];				// Magic (ZYB_DEP_MAGIC)
+		char name[ZYB_NAME_LENGTH];		// Name of the dependency
+		unsigned short major, minor, patch;	// Minimum SemVer
+		unsigned char reserved[2];		// Padding
+	} dependencies[0];
+};
+
+/*
+ * This struct appends every single file in the .zyb.
+ * It contains metadata for the individual files in the package.
+ * WARNING: CHECKSUM IS FOR THE UNZIPPED FILE.
+ */
+struct __attribute__((__packed__, aligned(2))) zyb_file_header {
+	char magic[4];					// Magic (ZYB_FILE_MAGIC)
+	char *path;					// Destination path of the file
+	mode_t permissions;				// UNIX permission attributes (32 bits)
+	off_t length;					// File length (64 bits)
+	unsigned char checksum[32];			// Checksum of the unzipped file
+	unsigned char reserved[2];			// Padding
+};
+
+#endif

meson.build

@@ -1,4 +1,5 @@
-project('libzepkg', 'c')
+project('libzepkg', 'c',
+  version : '0.1.0')
 
 cmake = import('cmake')
 pkg = import('pkgconfig')
@@ -6,19 +7,26 @@ pkg = import('pkgconfig')
 # The minizip-ng project, used for gzipping files
 minizip_ng = cmake.subproject('minizip-ng').dependency('minizip')
 
+# External dependencies
+glib = dependency('glib-2.0', method : 'pkg-config', required : true)
+gio = dependency('gio-unix-2.0', method : 'pkg-config', required : true)
+ostree = dependency('ostree-1', method : 'pkg-config', required : true)
+
 files = files(
-  'src/crypt/sha256.c',
+  'source/crypt/sha256.c',
-  'src/crypt/utils.c')
+  'source/crypt/utils.c',
+
+  'source/zyb/extract.c')
 include = include_directories('include')
 
-# Build the library (statically)
+# Build the library
 libzepkg = static_library('zepkg', files,
   include_directories : include,
-  dependencies : [minizip_ng])
+  dependencies : [ minizip_ng, glib, gio, ostree ])
 
 # Generate a pkg-config file
 pkg.generate(
   libraries : [ libzepkg ],
-  version : '0.1.0',
+  subdirs : [ 'zyb' ],
   name : 'libzepkg',
   description : 'Library for extracting zyb files, and interacting with the zepkg database.')

source/zyb/extract.c

@@ -0,0 +1,119 @@
+#include <zyb/extract.h>
+
+// libc
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+// libzepkg
+#include <crypt/sha256.h>
+
+int zyb_extract_leader(FILE *fptr, struct lead *leader) {
+	if (fptr == NULL)
+		return 1;
+
+	char magic[4];
+	size_t bytes = fread(magic, 1, 4, fptr);
+	if (bytes != 4)
+		return 1;
+
+	if (strcmp(magic, ZYB_MAGIC))
+		return 1;
+
+	bytes = fread(&leader + 4, 1, sizeof(struct lead) - 4, fptr);
+	if (bytes != sizeof(struct lead) - 4)
+		return 1;
+
+	if (leader->version != ZYB_FORMAT_VER)
+		return 1;
+
+	return 0;
+}
+
+int zyb_extract_dependency(FILE *fptr, struct dependency *dep) {
+	if (fptr == NULL)
+		return 1;
+
+	char magic[4];
+	size_t bytes = fread(magic, 1, 4, fptr);
+	if (bytes != 4)
+		return 1;
+
+	if (strcmp(magic, ZYB_DEP_MAGIC))
+		return 1;
+
+	bytes = fread(&dep + 4, 1, sizeof(struct dependency) - 4, fptr);
+	if (bytes != sizeof(struct dependency) - 4)
+		return 1;
+
+	return 0;
+}
+
+int zyb_extract_header(FILE *fptr, struct zyb_header *header) {
+	if (fptr == NULL)
+		return 1;
+
+	struct lead leader;
+	int ret;
+	if ((ret = zyb_extract_leader(fptr, &leader)))
+		return ret;
+	header->leader = leader;
+
+	if (header->leader.dependencies > 0) {
+		for (int i = 0; i < header->leader.dependencies; i++) {
+			header = realloc(header, sizeof(header) + sizeof(struct dependency));
+
+			struct dependency dep;
+			if ((ret = zyb_extract_dependency(fptr, &dep)))
+				return ret;
+			header->dependencies[i] = dep;
+		}
+	}
+
+	return 0;
+}
+
+int zyb_extract_file(FILE *fptr, char *dir) {
+	if (fptr == NULL)
+		return 1;
+
+	char magic[4];
+	size_t bytes = fread(magic, 1, 4, fptr);
+	if (bytes != 4)
+		return 1;
+
+	if (strcmp(magic, ZYB_FILE_MAGIC))
+		return 1;
+
+	// Read path in chunks of 2 bytes (to account for alignment)
+	char *path = malloc(PATH_MAX);
+	for (int i = 0; i < PATH_MAX; i += 2) {
+		fread(path + i, 1, 2, fptr);
+		if (path[i] == '\0' || path[i + 1] == '\0')
+			goto eos;
+	}
+	// If it reaches this point, means the string is longer than PATH_MAX
+	return 1;
+
+eos:	// End of string;
+	// Read rest of header
+	mode_t permissions;
+	bytes = fread(&permissions, sizeof(mode_t), 1, fptr);
+	if (bytes != sizeof(mode_t))
+		return 1;
+
+	off_t size;
+	bytes = fread(&size, sizeof(off_t), 1, fptr);
+	if (bytes != sizeof(off_t))
+		return 1;
+
+	unsigned char checksum[32];
+	bytes = fread(&checksum, 1, 32, fptr);
+	if (bytes != 32)
+		return 1;
+
+	// Move pointer 2 bytes to account for padding
+	fseek(fptr, 2, SEEK_CUR);
+
+	return 0;
+}