project: core -> packer

Signed-off-by: Chloe M <chloe@faracom.org>

1 files changed, 453 insertions, 0 deletions

diff --git a/packer/rdar.c b/packer/rdar.c
new file mode 100644
index 0000000..ba67c69
--- /dev/null
+++ b/packer/rdar.c
@@ -0,0 +1,453 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ */
+
+#define _DEFAULT_SOURCE
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/queue.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <dirent.h>
+#include <string.h>
+
+/* Forward declarations */
+struct idata_desc;
+
+/* Data descriptor constants */
+#define RDAR_MAX_PATHLEN 32
+#define RDAR_MAGIC       ">RDAR!"
+#define RDAR_MAGIC_LEN   6
+
+/* Data descriptor file flags */
+#define DATA_ROOT (1 << 0)    /* Is root data descriptor */
+#define DATA_AVL  (1 << 1)    /* Available to consumer software; not touched by us */
+
+/* Version conversion macros */
+#define VERSION_U16(MAJOR, MINOR)   \
+    (((MINOR) << 8) | (MAJOR))
+#define VERSION_MAJOR(VERSION)      \
+    ((VERSION) & 0xFF)
+#define VERSION_MINOR(VERSION)      \
+    (((VERSION) >> 8) & 0xFF)
+
+/* Pushes idata descriptor to table */
+#define IDATA_PUSH(IDATA_P)                             \
+    ++d_desc_count;                                     \
+    TAILQ_INSERT_TAIL(&d_desc_table, (IDATA_P), link);
+
+/*
+ * Software version
+ *
+ * XXX: We encode it as a U16 so that we may bundle it
+ *      with the file data as binary.
+ */
+#define RDAR_VERSION VERSION_U16(1, 0)  /* v1.0 */
+
+/* Fallback path if '-o' is not specified */
+#define FALLBACK_OUTPUT_PATH "out.rdar"
+
+/* Globals */
+static const char *input_dir = NULL;
+static const char *output_path = NULL;
+static TAILQ_HEAD(, idata_desc) d_desc_table;
+static size_t d_desc_count = 0;
+
+/*
+ * The root data region (RDR) contains information about the
+ * entire archive.
+ *
+ * @desc_count:  Number of descriptors
+ * @revision:    Format revision
+ */
+struct root_data_region {
+    size_t desc_count;
+    uint16_t revision;
+};
+
+/*
+ * Represents a file that has been mapped into memory
+ *
+ * @data:     File data
+ * @length:   Length of data
+ */
+struct file_view {
+    char *data;
+    size_t length;
+};
+
+/*
+ * A data descriptor holds information about a specific
+ * file along with an offset to which it is located at
+ * in the offset.
+ *
+ * @magic:  Format magic
+ * @path:   File path
+ * @off:    File data offset
+ * @flags:  File flags
+ * @length: File length in bytes
+ */
+struct data_desc {
+    char magic[RDAR_MAGIC_LEN];
+    char path[RDAR_MAX_PATHLEN];
+    off_t off;
+    uint16_t flags;
+    size_t length;
+};
+
+/*
+ * Internal data descriptor, used to hold data
+ * before being flushed to the archive
+ *
+ * @data:  Actual data descriptor
+ * @file:  File view this descriptor references
+ * @link:  TAILQ link
+ */
+struct idata_desc {
+    struct data_desc data;
+    struct file_view file;
+    TAILQ_ENTRY(idata_desc) link;
+};
+
+static void
+help(void)
+{
+    printf("usage: ./rdar <... flags>\n");
+    printf("[-h]    Display this help menu\n");
+    printf("[-v]    Display the program version\n");
+    printf("[-i]    Input directory to pack\n");
+    printf("[-o]    Output path for archive file\n");
+}
+
+static void
+version(void)
+{
+    uint16_t Major, Minor;
+
+    Major = VERSION_MAJOR(RDAR_VERSION);
+    Minor = VERSION_MINOR(RDAR_VERSION);
+    printf("Version v%d.%d\n", Major, Minor);
+}
+
+/*
+ * Destroy a file view
+ *
+ * @view: View to destory
+ */
+static void
+view_destroy(struct file_view *view)
+{
+    munmap(view->data, view->length);
+    view->data = NULL;
+    view->length = 0;
+}
+
+/*
+ * Create a mapped file view from a file path
+ */
+static int
+view_from_path(const char *path, struct file_view *result)
+{
+    struct stat sb;
+    int fd;
+
+    if (path == NULL || result == NULL) {
+        return -1;
+    }
+
+    fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        printf("fatal: failed to open '%s'\n", path);
+        perror("open");
+        return -1;
+    }
+
+    if (stat(path, &sb) < 0) {
+        printf("fatal: failed to stat '%s'\n", path);
+        perror("stat");
+        close(fd);
+        return -1;
+    }
+
+    result->data = mmap(
+        NULL,
+        sb.st_size,
+        PROT_READ,
+        MAP_SHARED,
+        fd,
+        0
+    );
+
+    if (result->data == NULL) {
+        printf("fatal: failed to map '%s'\n", path);
+        perror("mmap");
+        close(fd);
+        return -1;
+    }
+
+    result->length = sb.st_size;
+    close(fd);
+    return 0;
+}
+
+/*
+ * Allocate an internal data descriptor
+ *
+ * @path:     Path of file
+ * @is_root:  If set, don't create a view
+ */
+static struct idata_desc *
+idata_from_file(const char *path, bool is_root)
+{
+    struct idata_desc *idata_desc;
+    struct data_desc *data_desc;
+    size_t path_len;
+    const char *p;
+
+    path_len = strlen(path);
+    if (path_len >= RDAR_MAX_PATHLEN - 1) {
+        printf("fatal: path '%s' is too long!\n", path);
+        return NULL;
+    }
+
+    idata_desc = malloc(sizeof(*idata_desc));
+    if (idata_desc == NULL) {
+        printf("fatal: failed to allocate idata_desc\n");
+        printf("* last file processed: %s\n", path);
+        return NULL;
+    }
+
+    if (!is_root) {
+        if (view_from_path(path, &idata_desc->file) < 0) {
+            free(idata_desc);
+            return NULL;
+        }
+    }
+
+    p = path;
+
+    /* Strip leading path stuff */
+    while (*p == '.' && *p != '\0')
+        ++p;
+    while (*p == '/' && *p != '\0')
+        ++p;
+
+    /* Initialize the data descriptor */
+    data_desc = &idata_desc->data;
+    memcpy(data_desc->magic, RDAR_MAGIC, RDAR_MAGIC_LEN);
+    memcpy(data_desc->path, p, strlen(p));
+    data_desc->path[path_len] = '\0';
+    data_desc->flags = 0;
+    data_desc->off = 0;
+    return idata_desc;
+}
+
+/*
+ * Push the root descriptor to the table.
+ *
+ * The root descriptor is to contain an offset into a special
+ * %root% file entry which contains data (e.g., version, file count)
+ * encoded within.
+ */
+static int
+idata_push_root(void)
+{
+    struct idata_desc *root;
+    struct data_desc *desc;
+
+    root = idata_from_file("%root%", true);
+    if (root == NULL) {
+        return -1;
+    }
+
+    desc = &root->data;
+    desc->length = sizeof(struct root_data_region);
+    desc->flags = DATA_ROOT;
+    IDATA_PUSH(root);
+    return 0;
+}
+
+static void
+idata_table_destroy(void)
+{
+    struct idata_desc *desc, *next;
+
+    desc = TAILQ_FIRST(&d_desc_table);
+    while (desc != NULL) {
+        view_destroy(&desc->file);
+        next = TAILQ_NEXT(desc, link);
+        TAILQ_REMOVE(&d_desc_table, desc, link);
+        desc = next;
+    }
+}
+
+static void
+flush_root_desc(struct data_desc *d_desc, int out_fd)
+{
+    struct root_data_region rdr = {
+        .desc_count = d_desc_count,
+        .revision = RDAR_VERSION
+    };
+
+    d_desc->off = lseek(out_fd, 0, SEEK_CUR);
+    write(out_fd, &rdr, sizeof(rdr));
+}
+
+static void
+idata_table_flush(void)
+{
+    const struct file_view *view;
+    struct idata_desc *desc_iter;
+    struct data_desc *d_desc;
+    off_t new_off;
+    int fd;
+
+    fd = open(output_path, O_WRONLY | O_TRUNC | O_CREAT, 0666);
+    if (fd < 0) {
+        printf("fatal: failed to open output path\n");
+        perror("open");
+        return;
+    }
+
+    new_off = d_desc_count * sizeof(struct data_desc);
+    lseek(fd, new_off, SEEK_SET);
+
+    /* First pass write the file data */
+    TAILQ_FOREACH(desc_iter, &d_desc_table, link) {
+        view = &desc_iter->file;
+        d_desc = &desc_iter->data;
+
+        /*
+         * Check if we need to flush the root descriptor, we ignore any files that start
+         * with the '%' modifier.
+         */
+        if (d_desc->path[0] == '%') {
+            if (strcmp(d_desc->path, "%root%") == 0)
+                flush_root_desc(d_desc, fd);
+
+            continue;
+        }
+
+        d_desc->off = lseek(fd, 0, SEEK_CUR);
+        d_desc->length = view->length;
+        write(fd, view->data, view->length);
+    }
+
+    /* Data descriptors go at the start */
+    lseek(fd, 0, SEEK_SET);
+
+    /* Second pass write the data descriptors */
+    TAILQ_FOREACH(desc_iter, &d_desc_table, link) {
+        view = &desc_iter->file;
+        d_desc = &desc_iter->data;
+        write(fd, d_desc, sizeof(*d_desc));
+    }
+
+    close(fd);
+}
+
+static void
+recurse_dir(const char *dirpath)
+{
+    DIR *dir;
+    struct dirent *dirent;
+    struct idata_desc *idata_desc;
+    char pathbuf[264];
+
+    dir = opendir(dirpath);
+    if (dir == NULL) {
+        printf("fatal: failed to open '%s'\n", input_dir);
+        perror("opendir");
+        return;
+    }
+
+    while ((dirent = readdir(dir)) != NULL) {
+        if (dirent->d_name[0] == '.') {
+            continue;
+        }
+
+        switch (dirent->d_type) {
+        case DT_REG:
+            snprintf(pathbuf, sizeof(pathbuf), "%s/%s", dirpath, dirent->d_name);
+            printf("[f] %s\n", pathbuf);
+
+            idata_desc = idata_from_file(pathbuf, false);
+            if (idata_desc == NULL) {
+                printf("warn: ignoring '%s'\n", pathbuf);
+                break;
+            }
+
+            IDATA_PUSH(idata_desc);
+            break;
+        case DT_DIR:
+            snprintf(pathbuf, sizeof(pathbuf), "%s/%s", dirpath, dirent->d_name);
+            printf("[d] %s\n", pathbuf);
+            recurse_dir(pathbuf);
+            break;
+        }
+    }
+
+    closedir(dir);
+}
+
+int
+main(int argc, char **argv)
+{
+    int opt;
+
+    if (argc < 2) {
+        printf("fatal: too few arguments\n");
+        help();
+        return -1;
+    }
+
+    while ((opt = getopt(argc, argv, "hvi:o:")) != -1) {
+        switch (opt) {
+        case 'h':
+            help();
+            return -1;
+        case 'v':
+            version();
+            return -1;
+        case 'i':
+            input_dir = strdup(optarg);
+            if (input_dir == NULL) {
+                printf("fatal: failed to allocate input_dir\n");
+                return -1;
+            }
+
+            break;
+        case 'o':
+            output_path = strdup(optarg);
+            if (output_path == NULL) {
+                printf("fatal: failed to allocate output dir\n");
+                return -1;
+            }
+
+            break;
+        }
+    }
+
+    if (input_dir == NULL) {
+        printf("fatal: input path not specified\n");
+        help();
+        return -1;
+    }
+
+    if (output_path == NULL) {
+        output_path = FALLBACK_OUTPUT_PATH;
+    }
+
+    TAILQ_INIT(&d_desc_table);
+    idata_push_root();
+    recurse_dir(input_dir);
+    idata_table_flush();
+    idata_table_destroy();
+    return 0;
+}