First commit

src/comment.c

@@ -0,0 +1,17 @@
+#include "comment.h"
+#include <stdlib.h>
+
+CommentHeader *
+mk_comment_header(int reply_id, time_t creation_time, size_t text_length, char *user_sid, char *user_displayname)
+{
+    CommentHeader *header = malloc(sizeof(CommentHeader));
+    
+    header->reply_id = reply_id;
+    header->creation_time = creation_time;
+    header->text_length = text_length;
+
+    header->user_sid = user_sid;
+    header->user_displayname = user_displayname;
+
+    return header;
+}

src/drivers/unix_fs/unix_fs_driver.c

@@ -0,0 +1,234 @@
+#define _GNU_SOURCE /* ahh, didn't know asprintf is a GNU extension */
+/* TODO: remove this bullshit */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#include "comment.h"
+#include "drivers/unix_fs/unix_fs_driver.h"
+
+#define READ_BUF_SZ 256
+
+int
+is_valid_directory(const char *path)
+{
+    struct stat path_stat;
+    if (stat(path, &path_stat) != 0) {
+        return 0;
+    }
+    return S_ISDIR(path_stat.st_mode);
+}
+
+/* TODO: handle errors */
+int
+serialize_header(int fd, const CommentHeader *header)
+{
+    write(fd, &header->reply_id, sizeof(int));
+    write(fd, &header->creation_time, sizeof(time_t));
+    write(fd, &header->text_length, sizeof(size_t));
+    write(fd, header->user_sid, strlen(header->user_sid) + 1);
+    write(fd, header->user_displayname, strlen(header->user_displayname) + 1);
+    return 0;
+}
+
+/* TODO: handle errors */
+/* header string buffers must be long enough */
+int
+deserialize_header(int fd, CommentHeader *header)
+{
+    char buf[READ_BUF_SZ], *dst_bufs[2];
+    int bytes_read;
+    size_t len, dst_idx, i;
+
+    dst_bufs[0] = header->user_sid;
+    dst_bufs[1] = header->user_displayname;
+    dst_idx = 0;
+
+    read(fd, &header->reply_id, sizeof(int));
+    read(fd, &header->creation_time, sizeof(time_t));
+    read(fd, &header->text_length, sizeof(size_t));
+
+    while ((bytes_read = read(fd, buf, READ_BUF_SZ))) {
+        for (; i < bytes_read; ++i) {
+            if (buf[i] != '\0') {
+                *(dst_bufs[dst_idx]++) = buf[i];
+            } else {
+                dst_idx++;
+            }
+        }
+    }
+    return 0;
+}
+
+int
+unix_fs_driver_leave_comment(void *driver_data_ptr, CommentHeader *header, char *text)
+{
+    char *path, *header_file_path, *text_file_path, *id_ctrl_file_path;
+    FILE *id_ctrl_file;
+    size_t path_len, text_len;
+    int max_id;
+    int retval;
+    int header_fd, text_fd, id_ctrl_fd;
+    
+    /* assure safe free calls */
+    id_ctrl_file_path = header_file_path = text_file_path = NULL;
+    id_ctrl_file = NULL;
+
+    header_fd = text_fd = -1;
+
+    path = ((UnixFsDriverData*) driver_data_ptr)->path;
+    if (!is_valid_directory(path)) {
+        retval = -EINVAL;
+        goto defer;
+    }
+
+    path_len = strlen(path);
+    text_len = strlen(text);
+    
+    if (asprintf(&id_ctrl_file_path, "%s/%s", path, ID_CTRL_FILE) < 0) {
+        id_ctrl_file_path = NULL;
+        retval = -ENOMEM;
+        goto defer;
+    }
+
+    id_ctrl_file = fopen(id_ctrl_file_path, "r+");
+
+    if (!id_ctrl_file) {
+        retval = -EIO;
+        goto defer;
+    }
+
+    id_ctrl_fd = fileno(id_ctrl_file);
+    
+    if (lockf(id_ctrl_fd, F_LOCK, 0) < 0) {
+        id_ctrl_fd = -1;
+        retval = -EIO;
+        goto defer;
+    }
+    
+    if (fscanf(id_ctrl_file, "%d", &max_id) != 1) {
+        max_id = 1;
+    }
+
+    if (asprintf(&header_file_path, HEADER_FILE_FMT, path, max_id) < 0) {
+        header_file_path = NULL;
+        retval = -ENOMEM;
+        goto defer;
+    }
+    if (asprintf(&text_file_path, TEXT_FILE_FMT, path, max_id) < 0) {
+        text_file_path = NULL;
+        retval = -ENOMEM;
+        goto defer;
+    };
+
+    header_fd = open(header_file_path, O_RDWR | O_CREAT, 0644);
+    text_fd = open(text_file_path, O_RDWR | O_CREAT, 0644);
+
+    if (header_fd < 0 || text_fd < 0) {
+        retval = -EINVAL;
+        goto defer;
+    }
+   
+    if (write(text_fd, text, text_len) < text_len) {
+        retval = -EIO;
+        goto defer;
+    }
+    
+    retval = serialize_header(header_fd, header);
+    if (retval < 0) {
+        goto defer;
+    }
+    
+    if (!(id_ctrl_file = freopen(id_ctrl_file_path, "w+", id_ctrl_file))) {
+        retval = -EIO;
+        goto defer;
+    }
+    
+    fprintf(id_ctrl_file, "%d", max_id + 1); /* update id only on success */
+    retval = max_id + 1;
+defer:
+    if (id_ctrl_fd >= 0) {
+        if (lockf(id_ctrl_fd, F_ULOCK, 0) < 0) {
+            fprintf(stderr, "Failed to release id control lock, aborting...\n");
+            abort();
+        }
+    }
+    if (id_ctrl_file) fclose(id_ctrl_file);
+    free(id_ctrl_file_path);
+    free(header_file_path);
+    free(text_file_path);
+    if (header_fd >= 0) close(header_fd);
+    if (text_fd >= 0) close(text_fd);
+    return retval;
+}
+
+int
+unix_fs_driver_get_header(void *driver_data_ptr, CommentHeader *header, int id)
+{
+    char *path, *header_file_path;
+    int fd, retval;
+    
+    path = ((UnixFsDriverData*) driver_data_ptr)->path;
+    if (!asprintf(&header_file_path, HEADER_FILE_FMT, path, id)) {
+        return -ENOMEM;
+    }
+
+    fd = open(header_file_path, O_RDONLY);
+    if (fd < 0) {
+        free(header_file_path);
+        return -EIO;
+    }
+
+    retval = deserialize_header(fd, header);
+    free(header_file_path);
+    close(fd);
+    return retval;
+}
+
+int
+unix_fs_driver_get_text(void *driver_data_ptr, char *text, int id)
+{
+    char *path, *text_file_path;
+    int fd, retval;
+    off_t length;
+
+    path = ((UnixFsDriverData*) driver_data_ptr)->path;
+    if (!asprintf(&text_file_path, TEXT_FILE_FMT, path, id)) {
+        return -ENOMEM;
+    }
+
+    fd = open(text_file_path, O_RDONLY);
+    if (fd < 0) {
+        retval = -EIO;
+        goto defer;
+    }
+
+    length = lseek(fd, 0, SEEK_END);
+    if (length < 0) {
+        retval = -EIO;
+        goto defer;
+    }
+    if (lseek(fd, 0, SEEK_SET) < 0) {
+        retval = -EIO;
+        goto defer;
+    }
+
+    if (read(fd, text, length) < length) {
+        retval = -EIO;
+        goto defer;
+    }
+
+    text[length] = '\0';
+    retval = 0;
+
+defer:
+    free(text_file_path);
+    if (fd >= 0) close(fd);
+    return retval;
+}