/Users/deen/code/yugabyte-db/build/debugcov-clang-dynamic-arm64-ninja/postgres_build/src/interfaces/ecpg/ecpglib/thread.c
Line | Count | Source (jump to first uncovered line) |
1 | | /*------------------------------------------------------------------------- |
2 | | * |
3 | | * thread.c |
4 | | * |
5 | | * Prototypes and macros around system calls, used to help make |
6 | | * threaded libraries reentrant and safe to use from threaded applications. |
7 | | * |
8 | | * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group |
9 | | * |
10 | | * src/port/thread.c |
11 | | * |
12 | | *------------------------------------------------------------------------- |
13 | | */ |
14 | | |
15 | | #include "c.h" |
16 | | |
17 | | #include <pwd.h> |
18 | | |
19 | | |
20 | | /* |
21 | | * Threading sometimes requires specially-named versions of functions |
22 | | * that return data in static buffers, like strerror_r() instead of |
23 | | * strerror(). Other operating systems use pthread_setspecific() |
24 | | * and pthread_getspecific() internally to allow standard library |
25 | | * functions to return static data to threaded applications. And some |
26 | | * operating systems have neither. |
27 | | * |
28 | | * Additional confusion exists because many operating systems that |
29 | | * use pthread_setspecific/pthread_getspecific() also have *_r versions |
30 | | * of standard library functions for compatibility with operating systems |
31 | | * that require them. However, internally, these *_r functions merely |
32 | | * call the thread-safe standard library functions. |
33 | | * |
34 | | * For example, BSD/OS 4.3 uses Bind 8.2.3 for getpwuid(). Internally, |
35 | | * getpwuid() calls pthread_setspecific/pthread_getspecific() to return |
36 | | * static data to the caller in a thread-safe manner. However, BSD/OS |
37 | | * also has getpwuid_r(), which merely calls getpwuid() and shifts |
38 | | * around the arguments to match the getpwuid_r() function declaration. |
39 | | * Therefore, while BSD/OS has getpwuid_r(), it isn't required. It also |
40 | | * doesn't have strerror_r(), so we can't fall back to only using *_r |
41 | | * functions for threaded programs. |
42 | | * |
43 | | * The current setup is to try threading in this order: |
44 | | * |
45 | | * use *_r function names if they exit |
46 | | * (*_THREADSAFE=yes) |
47 | | * use non-*_r functions if they are thread-safe |
48 | | * |
49 | | * One thread-safe solution for gethostbyname() might be to use getaddrinfo(). |
50 | | * |
51 | | * Run src/test/thread to test if your operating system has thread-safe |
52 | | * non-*_r functions. |
53 | | */ |
54 | | |
55 | | |
56 | | /* |
57 | | * Wrapper around strerror and strerror_r to use the former if it is |
58 | | * available and also return a more useful value (the error string). |
59 | | */ |
60 | | char * |
61 | | pqStrerror(int errnum, char *strerrbuf, size_t buflen) |
62 | 0 | { |
63 | 0 | #if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_STRERROR_R) |
64 | | /* reentrant strerror_r is available */ |
65 | 0 | #ifdef STRERROR_R_INT |
66 | | /* SUSv3 version */ |
67 | 0 | if (strerror_r(errnum, strerrbuf, buflen) == 0) |
68 | 0 | return strerrbuf; |
69 | 0 | else |
70 | 0 | return "Unknown error"; |
71 | | #else |
72 | | /* GNU libc */ |
73 | | return strerror_r(errnum, strerrbuf, buflen); |
74 | | #endif |
75 | | #else |
76 | | /* no strerror_r() available, just use strerror */ |
77 | | strlcpy(strerrbuf, strerror(errnum), buflen); |
78 | | |
79 | | return strerrbuf; |
80 | | #endif |
81 | 0 | } |
82 | | |
83 | | /* |
84 | | * Wrapper around getpwuid() or getpwuid_r() to mimic POSIX getpwuid_r() |
85 | | * behaviour, if that function is not available or required. |
86 | | * |
87 | | * Per POSIX, the possible cases are: |
88 | | * success: returns zero, *result is non-NULL |
89 | | * uid not found: returns zero, *result is NULL |
90 | | * error during lookup: returns an errno code, *result is NULL |
91 | | * (caller should *not* assume that the errno variable is set) |
92 | | */ |
93 | | #ifndef WIN32 |
94 | | int |
95 | | pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer, |
96 | | size_t buflen, struct passwd **result) |
97 | 79 | { |
98 | 79 | #if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETPWUID_R) |
99 | 79 | return getpwuid_r(uid, resultbuf, buffer, buflen, result); |
100 | | #else |
101 | | /* no getpwuid_r() available, just use getpwuid() */ |
102 | | errno = 0; |
103 | | *result = getpwuid(uid); |
104 | | /* paranoia: ensure we return zero on success */ |
105 | | return (*result == NULL) ? errno : 0; |
106 | | #endif |
107 | 79 | } |
108 | | #endif |
109 | | |
110 | | /* |
111 | | * Wrapper around gethostbyname() or gethostbyname_r() to mimic |
112 | | * POSIX gethostbyname_r() behaviour, if it is not available or required. |
113 | | * This function is called _only_ by our getaddinfo() portability function. |
114 | | */ |
115 | | #ifndef HAVE_GETADDRINFO |
116 | | int |
117 | | pqGethostbyname(const char *name, |
118 | | struct hostent *resultbuf, |
119 | | char *buffer, size_t buflen, |
120 | | struct hostent **result, |
121 | | int *herrno) |
122 | | { |
123 | | #if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETHOSTBYNAME_R) |
124 | | |
125 | | /* |
126 | | * broken (well early POSIX draft) gethostbyname_r() which returns 'struct |
127 | | * hostent *' |
128 | | */ |
129 | | *result = gethostbyname_r(name, resultbuf, buffer, buflen, herrno); |
130 | | return (*result == NULL) ? -1 : 0; |
131 | | #else |
132 | | |
133 | | /* no gethostbyname_r(), just use gethostbyname() */ |
134 | | *result = gethostbyname(name); |
135 | | |
136 | | if (*result != NULL) |
137 | | *herrno = h_errno; |
138 | | |
139 | | if (*result != NULL) |
140 | | return 0; |
141 | | else |
142 | | return -1; |
143 | | #endif |
144 | | } |
145 | | |
146 | | #endif |