user.c

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/*-------------------------------------------------------------------------
 *
 * user.c
 *
 *        Wrapper functions for user and home directory lookup.
 *
 * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
 *
 * src/port/user.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "c.h"
 
#include <pwd.h>
 
#ifndef WIN32
 
/*
 * pg_get_user_name - get the name of the user with the given ID
 *
 * On success, the user name is returned into the buffer (of size buflen),
 * and "true" is returned.  On failure, a localized error message is
 * returned into the buffer, and "false" is returned.
 */
bool
pg_get_user_name(uid_t user_id, char *buffer, size_t buflen)
{
    char        pwdbuf[BUFSIZ];
    struct passwd pwdstr;
    struct passwd *pw = NULL;
    int         pwerr;
 
    pwerr = getpwuid_r(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
    if (pw != NULL)
    {
        strlcpy(buffer, pw->pw_name, buflen);
        return true;
    }
    if (pwerr != 0)
        snprintf(buffer, buflen,
                 _("could not look up local user ID %d: %s"),
                 (int) user_id,
                 strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
    else
        snprintf(buffer, buflen,
                 _("local user with ID %d does not exist"),
                 (int) user_id);
    return false;
}
 
/*
 * pg_get_user_home_dir - get the home directory of the user with the given ID
 *
 * On success, the directory path is returned into the buffer (of size buflen),
 * and "true" is returned.  On failure, a localized error message is
 * returned into the buffer, and "false" is returned.
 *
 * Note that this does not incorporate the common behavior of checking
 * $HOME first, since it's independent of which user_id is queried.
 */
bool
pg_get_user_home_dir(uid_t user_id, char *buffer, size_t buflen)
{
    char        pwdbuf[BUFSIZ];
    struct passwd pwdstr;
    struct passwd *pw = NULL;
    int         pwerr;
 
    pwerr = getpwuid_r(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
    if (pw != NULL)
    {
        strlcpy(buffer, pw->pw_dir, buflen);
        return true;
    }
    if (pwerr != 0)
        snprintf(buffer, buflen,
                 _("could not look up local user ID %d: %s"),
                 (int) user_id,
                 strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
    else
        snprintf(buffer, buflen,
                 _("local user with ID %d does not exist"),
                 (int) user_id);
    return false;
}
 
#endif                          /* !WIN32 */