/* strerror.c --- POSIX compatible system error routine Copyright (C) 2007-2020 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>. */ #include <config.h> /* Specification. */ #include <string.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "intprops.h" #include "strerror-override.h" #include "verify.h" /* Use the system functions, not the gnulib overrides in this file. */ #undef sprintf char * strerror (int n) #undef strerror { static char buf[STACKBUF_LEN]; size_t len; /* Cast away const, due to the historical signature of strerror; callers should not be modifying the string. */ const char *msg = strerror_override (n); if (msg) return (char *) msg; msg = strerror (n); /* Our strerror_r implementation might use the system's strerror buffer, so all other clients of strerror have to see the error copied into a buffer that we manage. This is not thread-safe, even if the system strerror is, but portable programs shouldn't be using strerror if they care about thread-safety. */ if (!msg || !*msg) { static char const fmt[] = "Unknown error %d"; verify (sizeof buf >= sizeof (fmt) + INT_STRLEN_BOUND (n)); sprintf (buf, fmt, n); errno = EINVAL; return buf; } /* Fix STACKBUF_LEN if this ever aborts. */ len = strlen (msg); if (sizeof buf <= len) abort (); memcpy (buf, msg, len + 1); return buf; } |