1 /* strerror.c --- POSIX compatible system error routine 2 3 Copyright (C) 2007-2012 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 #include <config.h> 19 20 /* Specification. */ 21 #include <string.h> 22 23 #include <errno.h> 24 #include <stdio.h> 25 #include <stdlib.h> 26 #include <string.h> 27 28 #include "intprops.h" 29 #include "strerror-override.h" 30 #include "verify.h" 31 32 /* Use the system functions, not the gnulib overrides in this file. */ 33 #undef sprintf 34 35 char * 36 strerror (int n) 37 #undef strerror 38 { 39 static char buf[STACKBUF_LEN]; 40 size_t len; 41 42 /* Cast away const, due to the historical signature of strerror; 43 callers should not be modifying the string. */ 44 const char *msg = strerror_override (n); 45 if (msg) 46 return (char *) msg; 47 48 msg = strerror (n); 49 50 /* Our strerror_r implementation might use the system's strerror 51 buffer, so all other clients of strerror have to see the error 52 copied into a buffer that we manage. This is not thread-safe, 53 even if the system strerror is, but portable programs shouldn't 54 be using strerror if they care about thread-safety. */ 55 if (!msg || !*msg) 56 { 57 static char const fmt[] = "Unknown error %d"; 58 verify (sizeof buf >= sizeof (fmt) + INT_STRLEN_BOUND (n)); 59 sprintf (buf, fmt, n); 60 errno = EINVAL; 61 return buf; 62 } 63 64 /* Fix STACKBUF_LEN if this ever aborts. */ 65 len = strlen (msg); 66 if (sizeof buf <= len) 67 abort (); 68 69 return memcpy (buf, msg, len + 1); 70 } 71
