util.c

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/****************************************************************************
 * util.c ***************************************************************
 ****************************************************************************
 */

#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "lirc/lirc_log.h"
#include "util.h"


const char* drop_sudo_root(int (*set_some_uid)(uid_t))
{
        struct passwd* pw;
        char* user;
        int r;

        if (getuid() != 0)
                return "";
        user = getenv("SUDO_USER");
        if (user == NULL)
                return "root";
        pw = getpwnam(user);
        if (pw == NULL) {
                logperror(LIRC_ERROR, "Can't run getpwnam() for %s", user);
                return "";
        }
        r = set_some_uid(pw->pw_uid);
        if (r == -1) {
                logperror(LOG_WARNING, "Cannot change UID to %d", pw->pw_uid);
                return "";
        }
        setenv("HOME", pw->pw_dir, 1);
        logprintf(LOG_NOTICE, "Running as user %s", pw->pw_name);
        return pw->pw_name;
}


void drop_root_cli(int (*set_some_uid)(uid_t))
{
        const char* new_user;

        new_user = drop_sudo_root(set_some_uid);
        if (strcmp("root", new_user) == 0)
                puts("Warning: Running as root.");
        else if (strlen(new_user) == 0)
                puts("Warning: Cannot change uid.");
        else
                printf("Running as regular user %s\n", new_user);
}