guestfs-inspect/guestfs-inspectd.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <czmq.h>
#include <zmsg.h>
#include <zactor.h>
#include <guestfs.h>

#include "libguestfs-inspect.h"

#define STREQ(a, b) (strcmp((a), (b)) == 0)

static void worker_task(zsock_t*, const char*);

static int compare_key_len(const void*, const void*);
static int count_mountpoints(char *const *argv);

static int compare_key_len(const void *p1, const void *p2) {
  const char *key1 = *(char* const*) p1;
  const char *key2 = *(char* const*) p2;
  return strlen(key1) - strlen(key2);
}

static int count_mountpoints(char *const *argv) {
  size_t c;
  for (c = 0; argv[c]; c++) {}
  return c;
}

static void cat_file(guestfs_h *g, const char *file_path, char **file_content, size_t *file_size) {
  assert((*file_content) == NULL);
  if (guestfs_is_file_opts(g, file_path, GUESTFS_IS_FILE_OPTS_FOLLOWSYMLINKS, 1, -1) > 0) {
    (*file_content) = guestfs_read_file(g, file_path, file_size);
    if ((*file_content) == NULL) {
      exit(EXIT_FAILURE);
    }
  }
  return;
}

static guestfs_h* init_guestfs(const char *disk_path) {
  guestfs_h *g = NULL;
  char **roots, **mountpoints;
  char *root;
  size_t i, j;

  // Create a connection handle
  g = guestfs_create();
  if (g == NULL) {
    exit(EXIT_FAILURE);
  }

  // Adding disk_path to connection handle
  if (guestfs_add_drive_opts(g, disk_path, GUESTFS_ADD_DRIVE_OPTS_READONLY, 1, -1) == -1) {
    exit(EXIT_FAILURE);
  }

  // Launching connection handle
  if (guestfs_launch(g) == -1) {
    exit(EXIT_FAILURE);
  }

  // Pulling rootfs information
  roots = guestfs_inspect_os(g);
  if (roots == NULL) {
    exit(EXIT_FAILURE);
  }

  // Looping through roots to mount mountpoints
  for (j = 0; roots[j] != NULL; j++) {
    root = roots[j];
    mountpoints = guestfs_inspect_get_mountpoints(g, root);
    if (mountpoints == NULL) {
      exit(EXIT_FAILURE);
    }
    // Sorting mountpoints to be in {'${device_path}', '${mount_path}'} format
    qsort(mountpoints, count_mountpoints(mountpoints) / 2, 2 * sizeof (char*), compare_key_len);
      for (i = 0; mountpoints[i] != NULL; i += 2) {
        guestfs_mount_ro(g, mountpoints[i+1], mountpoints[i]);
        free(mountpoints[i]);
        free(mountpoints[i+1]);
      }
      free(mountpoints);
      free(root);
  }
  free(roots);

  printf("Finished initializing guestfs\n");
  return g;
}

static void worker_task(zsock_t *pipe, const char *disk_path) {
  guestfs_h *g;
  g = init_guestfs(disk_path);

  zsock_t *worker = zsock_new_dealer("inproc://workers");

  // ZeroMQ Opens here
  zsock_signal(pipe, 0);

  while (true) {
    zmsg_t *msg = zmsg_recv(pipe);
    if (!msg) {
      break;
    }
    zframe_t *client_id = zmsg_pop(msg);

    struct guestfs_inpsect_command *command = guestfs_inspect_zmsg_to_command(msg);
    zmsg_t *reply = zmsg_new();
    if (!reply) {
      printf("wuddahec\n");
      exit(EXIT_FAILURE);
    }

    switch (command->command) {
      case GUESTFS_COMMAND_LS:;
        zmsg_pushstr(reply, "From worker! -- not implemented");
        break;
      case GUESTFS_COMMAND_CAT:;
        char *res = NULL;
        size_t s = 0;
        cat_file(g, command->args.cat.paths[0], &res, &s);
        zmsg_addmem(reply, res, s);
        free(res);
        break;
      default:;
        zmsg_pushstr(reply, "Unknown command");
        break;
    }

    // Sending reply
    zmsg_pushstr(reply, "");
    zmsg_prepend(reply, &client_id);
    zmsg_send(&reply, worker);

    guestfs_inspect_command_destroy(&command);
    zframe_destroy(&client_id);
    zmsg_destroy(&msg);
    zmsg_destroy(&reply);
  }

  zsock_destroy(&worker);
  guestfs_close(g);
  exit(EXIT_SUCCESS);
}

typedef struct {
  char *name;
  zactor_t *worker;
} zactor_worker_map;

char *strdup(const char *);
void mapping_zactor_worker(const char *name, zactor_t *worker, zactor_worker_map **map, size_t mapper_size) {
  map[mapper_size - 1] = malloc(sizeof(zactor_worker_map));
  (*map[mapper_size - 1]).name = strdup(name);
  (*map[mapper_size - 1]).worker = worker;
  return;
}

zactor_t * zactor_worker_lookup(char *name, zactor_worker_map **map, size_t mapper_size) {
  size_t i = 0;
  for (i = 0; i < mapper_size; i++) {
    if (strcmp((*map[i]).name, name) == 0) {
	    return map[i]->worker;
    }
  }
  return NULL;
}

int main(int argc, char **argv) {
  if (argc < 2) {
    printf("Usage: %s <disk-path>:<name> ...\n", argv[0]);
    return EXIT_FAILURE;
  }

  // Zactor setup
  size_t worker_map_size = 0;
  zactor_worker_map **worker_map = NULL;

  for (int i = 0; i < argc - 1; i++) {
    worker_map_size++;
    worker_map = realloc(worker_map, sizeof(zactor_worker_map *) * worker_map_size);
    char *path = strtok(argv[i+1], ":");
    char *name = strtok(NULL, ":");
    printf("--- Registering\n");
    printf("name: '%s'\n", name);
    printf("path: '%s'\n", path);
    mapping_zactor_worker(name, zactor_new((void *)worker_task, path), worker_map, worker_map_size);
  }

  if (worker_map == NULL) {
    exit(EXIT_FAILURE);
  }

  // Setup daemon ipc endpoint
  char *ep = guestfs_inspect_endpoint();
  printf("ep: %s\n", ep);

  // Setup ZMQ routers
  zsock_t *frontend = zsock_new(ZMQ_ROUTER);
  zsock_bind(frontend, "%s", ep);
  free(ep);

  zsock_t *backend = zsock_new(ZMQ_ROUTER);
  zsock_bind(backend, "inproc://workers");

  // Connecting frontend to backend
  zpoller_t *poller = zpoller_new(frontend, backend, NULL);
  assert(poller);

  while (true) {
    void *sock = zpoller_wait(poller, -1);

    if (!sock) {
      break;
    }

    if (sock == frontend) {
      zmsg_t *msg = zmsg_recv(frontend);
      // reply id
      zframe_t *identity = zmsg_pop(msg);
      // Null frame
      zmsg_pop(msg);

      struct guestfs_inpsect_command *c = guestfs_inspect_zmsg_to_command(msg);
      if (c == NULL) {
        printf("Error creating inspect command\n");
        zmsg_destroy(&msg);
        zframe_destroy(&identity);
        continue;
      }

      zactor_t *zactor_tmp = zactor_worker_lookup(c->name, worker_map, worker_map_size);
      if (zactor_tmp != NULL) {
        // send request to worker
        zmsg_prepend(msg, &identity);
        zactor_send(zactor_tmp, &msg);
      } else {
        // add failure responce
      }

      zactor_tmp = NULL;
      guestfs_inspect_command_destroy(&c);
      zmsg_destroy(&msg);
      zframe_destroy(&identity);
    } else if (sock == backend) {
      zmsg_t *msg = zmsg_recv(backend);
      zmsg_pop(msg); // Removing backend id
      zmsg_send(&msg, frontend);
      zmsg_destroy(&msg);
    } else {
      printf("Recieved unknown message\n");
    }
  }

  // Cleanup
  for (size_t i = 0; i < worker_map_size; i++) {
    zactor_destroy(&worker_map[i]->worker);
    free(worker_map[i]);
  }
  free(worker_map);

  return EXIT_SUCCESS;
}