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relogin: Add relogin utility

master
Jake Wakeling 5 months ago
parent
commit
60762e4948
  1. 5
      CMakeLists.txt
  2. 3
      README.md
  3. 81
      src/relogin.c

5
CMakeLists.txt

@ -1,11 +1,11 @@
cmake_minimum_required(VERSION 3.12)
cmake_minimum_required(VERSION 3.14)
project(coreutils LANGUAGES C)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/bin)
set(CMAKE_STATIC_LIBRARY_PREFIX "")
file(GLOB SRC_UTIL ${PROJECT_SOURCE_DIR}/src/util/*)
file(GLOB SRC_UTIL CONFIGURE_DEPENDS ${PROJECT_SOURCE_DIR}/src/util/*)
add_library(libutil STATIC ${SRC_UTIL})
@ -32,6 +32,7 @@ add_executable(od ${PROJECT_SOURCE_DIR}/src/od.c)
add_executable(pwd ${PROJECT_SOURCE_DIR}/src/pwd.c)
add_executable(rand ${PROJECT_SOURCE_DIR}/src/rand.c)
add_executable(realpath ${PROJECT_SOURCE_DIR}/src/realpath.c)
add_executable(relogin ${PROJECT_SOURCE_DIR}/src/relogin.c)
add_executable(rmdir ${PROJECT_SOURCE_DIR}/src/rmdir.c)
add_executable(sleep ${PROJECT_SOURCE_DIR}/src/sleep.c)
add_executable(sum ${PROJECT_SOURCE_DIR}/src/sum.c)

3
README.md

@ -27,6 +27,7 @@ A collection of general software utilities commonly found on UNIX systems.
| pwd | Print working directory | POSIX |
| rand | Generate random string | |
| realpath | Resolve an absolute pathname | |
| relogin | Invoke a command as a specified user | |
| rmdir | Remove directories | POSIX |
| sleep | Suspend execution for an interval | POSIX |
| sum | Write file checksums and block counts | |
@ -49,7 +50,7 @@ A collection of general software utilities commonly found on UNIX systems.
### Dependencies
- CMake >= 3.12, to build
- CMake >= 3.14, to build
### Building

81
src/relogin.c

@ -0,0 +1,81 @@
// relogin.c, version 0.1.0
// OMKOV coreutils relogin
// Copyright (C) 2022, Jakob Wakeling
// MIT Licence
#include "util/error.h"
#include "util/optget.h"
#include <grp.h>
#include <pwd.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdnoreturn.h>
#include <string.h>
#define VERSION "0.1.0"
static struct lop lops[] = {
{ "help", ARG_NUL, 256 },
{ "version", ARG_NUL, 257 },
{ NULL, 0, 0 }
};
static inline int relogin(const char *user, char *av[]);
static void hlp(void);
static void ver(void);
int main(int ac, char *av[]) { A0 = av[0];
struct opt opt = OPTGET_INIT; opt.str = ""; opt.lops = lops;
for (int o; (o = optget(&opt, av, 1)) != -1;) switch (o) {
case 256: { hlp(); return 0; }
case 257: { ver(); return 0; }
default: { return 1; }
}
if (opt.ind + 0 >= ac) { error(1, "missing user operand"); }
if (opt.ind + 1 >= ac) { error(1, "missing command operand"); }
if (relogin(av[1], &av[2])) { error(1, "%s: %s\n", av[1], serr()); }
return 0;
}
static inline int relogin(const char *user, char *av[]) {
struct passwd *pw;
if ((pw = getpwnam(user)) == NULL) { error(1, "%s", serr()); }
if (initgroups(pw->pw_name, pw->pw_gid) == -1) { error(1, "%s", serr()); }
if (setgid(pw->pw_gid) == -1) { error(1, "%s", serr()); }
if (setuid(pw->pw_uid) == -1) { error(1, "%s", serr()); }
setenv("HOME", pw->pw_dir, 1); setenv("LOGNAME", pw->pw_name, 1);
setenv("USER", pw->pw_name, 1); unsetenv("MAIL");
unsetenv("DOAS_USER"); unsetenv("SUDO_UID"); unsetenv("SUDO_GID");
unsetenv("SUDO_USER"); unsetenv("SUDO_COMMAND");
if (execvp(av[0], &av[0]) == -1) { error(1, "%s", serr()); }
return 0;
}
static void hlp(void) {
puts("relogin - invoke a command as a specified user\n");
puts("usage: relogin user command [argument...]\n");
puts("options:");
puts(" --help Display help information");
puts(" --version Display version information");
}
static void ver() {
puts("OMKOV coreutils relogin, version " VERSION);
puts("Copyright (C) 2022, Jakob Wakeling");
puts("MIT Licence (https://opensource.org/licenses/MIT)");
}
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