plash data

Usage

plash usage: plash data [CMD1 [CMD2 ...]]

Description

Prints the location of the build data.
if arguments are given, these arguments will be execed insite the build data.

Example

$ plash data
home/myuser/.plashdata

$ plash data ls
id_counter  index  layer  map  mnt  tmp

Tested Behaviour

#!/bin/sh

set -eux

• argument is executed

test hi = "$(plash data printf "hi")"

• argument is executed in plash data

plash data ls | grep mnt

plash data ls | grep tmp

plash data ls | grep layer

• argument is executed in directory returned by invocation with no arguments

out1=$(plash data pwd)

out2=$(plash data)

test "$out1" = "$out2"

• HOME influences the plash data

test $(

unset PLASH_DATA

HOME=xx

plash data

) = "xx/.plashdata"

• PLASH_DATA is the plash data if set

test $(PLASH_DATA=xx plash data) = xx

• home directory in /etc/passwd is consulted as fallback

homedir=$(getent passwd "$(id -u)" | cut -d: -f6)

test "$(

unset HOME

unset PLASH_DATA

plash data

)" = "$homedir"/.plashdata

Source Code

#define USAGE "usage: plash usage: plash data [CMD1 [CMD2 ...]]\n"

#define _GNU_SOURCE

#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <plash.h>

char *get_home_dir() {
  struct passwd *pwd;
  char *home_env;
  if (!(home_env = getenv("HOME"))) {
    pwd = getpwuid(getuid());
    if (!pwd)
      pl_fatal("could not determine your home directory");
    return pwd->pw_dir;
  }
  return home_env;
}

char *get_plash_data() {
  char *plash_data;
  if (!(plash_data = getenv("PLASH_DATA"))) {
    if (asprintf(&plash_data, "%s/.plashdata", get_home_dir()) == -1)
      pl_fatal("asprintf");
  }
  return plash_data;
}

int data_main(int argc, char *argv[]) {
  char *plash_data = get_plash_data();

  // if no arguments, print the plash data directory
  if (argc == 1) {
    puts(plash_data);
    return EXIT_SUCCESS;
  }

  // if arguments given, cd to plash data and exec the arguments
  if (chdir(plash_data) == -1)
    pl_fatal("chdir %s", plash_data);
  argv++;
  pl_unshare_user(); // because some files here might be from a subuid
                     // (different uid)
  execvp(argv[0], argv);
  pl_fatal("exec %s", argv[0]);
  return EXIT_FAILURE;
}