1 /* $OpenBSD: strerror_r.c,v 1.6 2005/08/08 08:05:37 espie Exp $ */
2 /* Public Domain <marc@snafu.org> */
3 
4 // G++ automatically defines _GNU_SOURCE, which then means that <string.h>
5 // gives us the GNU variant.
6 #undef _GNU_SOURCE
7 
8 #include <string.h>
9 
10 #include <errno.h>
11 #include <limits.h>
12 #include <signal.h>
13 #include <stdio.h>
14 
15 #include "private/ErrnoRestorer.h"
16 #include "private/libc_logging.h"
17 
18 struct Pair {
19   int code;
20   const char* msg;
21 };
22 
__code_string_lookup(const Pair * strings,int code)23 static const char* __code_string_lookup(const Pair* strings, int code) {
24   for (size_t i = 0; strings[i].msg != NULL; ++i) {
25     if (strings[i].code == code) {
26       return strings[i].msg;
27     }
28   }
29   return NULL;
30 }
31 
32 static const Pair _sys_error_strings[] = {
33 #define  __BIONIC_ERRDEF(x,y,z)  { x, z },
34 #include <sys/_errdefs.h>
35   { 0, NULL }
36 };
37 
__strerror_lookup(int error_number)38 extern "C" __LIBC_HIDDEN__ const char* __strerror_lookup(int error_number) {
39   return __code_string_lookup(_sys_error_strings, error_number);
40 }
41 
42 static const Pair _sys_signal_strings[] = {
43 #define  __BIONIC_SIGDEF(signal_number, signal_description)  { signal_number, signal_description },
44 #include <sys/_sigdefs.h>
45   { 0, NULL }
46 };
47 
__strsignal_lookup(int signal_number)48 extern "C" __LIBC_HIDDEN__ const char* __strsignal_lookup(int signal_number) {
49   return __code_string_lookup(_sys_signal_strings, signal_number);
50 }
51 
strerror_r(int error_number,char * buf,size_t buf_len)52 int strerror_r(int error_number, char* buf, size_t buf_len) {
53   ErrnoRestorer errno_restorer;
54   size_t length;
55 
56   const char* error_name = __strerror_lookup(error_number);
57   if (error_name != NULL) {
58     length = strlcpy(buf, error_name, buf_len);
59   } else {
60     length = __libc_format_buffer(buf, buf_len, "Unknown error %d", error_number);
61   }
62   if (length >= buf_len) {
63     errno_restorer.override(ERANGE);
64     return -1;
65   }
66 
67   return 0;
68 }
69 
__gnu_strerror_r(int error_number,char * buf,size_t buf_len)70 extern "C" char* __gnu_strerror_r(int error_number, char* buf, size_t buf_len) {
71   ErrnoRestorer errno_restorer; // The glibc strerror_r doesn't set errno if it truncates...
72   strerror_r(error_number, buf, buf_len);
73   return buf; // ...and just returns whatever fit.
74 }
75 
__strsignal(int signal_number,char * buf,size_t buf_len)76 extern "C" __LIBC_HIDDEN__ const char* __strsignal(int signal_number, char* buf, size_t buf_len) {
77   const char* signal_name = __strsignal_lookup(signal_number);
78   if (signal_name != NULL) {
79     return signal_name;
80   }
81 
82   const char* prefix = "Unknown";
83   if (signal_number >= SIGRTMIN && signal_number <= SIGRTMAX) {
84     prefix = "Real-time";
85     signal_number -= SIGRTMIN;
86   }
87   size_t length = snprintf(buf, buf_len, "%s signal %d", prefix, signal_number);
88   if (length >= buf_len) {
89     return NULL;
90   }
91   return buf;
92 }
93