xref: /haiku/src/add-ons/kernel/file_systems/userlandfs/shared/Debug.cpp (revision cb837539f5d245cedff238f8894c0ae326c2eaf5)
1 /*
2  * Copyright 2003-2004, Ingo Weinhold, ingo_weinhold@gmx.de.
3  * All rights reserved. Distributed under the terms of the MIT license.
4  */
5 
6 #include <errno.h>
7 #include <fcntl.h>
8 #include <stdarg.h>
9 #include <stdio.h>
10 #include <string.h>
11 #include <unistd.h>
12 
13 #include <OS.h>
14 
15 #include "Debug.h"
16 
17 /*!
18 	\file Debug.cpp
19 	\brief Defines debug output function with printf() signature printing
20 		   into a file.
21 
22 	\note The initialization is not thread safe!
23 */
24 
25 // locking support
26 static int32 init_counter = 0;
27 static sem_id dbg_printf_sem = -1;
28 static thread_id dbg_printf_thread = -1;
29 static int dbg_printf_nesting = 0;
30 
31 #if DEBUG_PRINT
32 static int out = -1;
33 #endif
34 
35 // init_debugging
36 status_t
37 init_debugging()
38 {
39 	status_t error = B_OK;
40 	if (init_counter++ == 0) {
41 		// open the file
42 		#if DEBUG_PRINT
43 			out = open(DEBUG_PRINT_FILE, O_RDWR | O_CREAT | O_TRUNC);
44 			if (out < 0) {
45 				error = errno;
46 				init_counter--;
47 			}
48 		#endif	// DEBUG_PRINT
49 		// allocate the semaphore
50 		if (error == B_OK) {
51 			dbg_printf_sem = create_sem(1, "dbg_printf");
52 			if (dbg_printf_sem < 0)
53 				error = dbg_printf_sem;
54 		}
55 		if (error == B_OK) {
56 			#if DEBUG
57 				__out("##################################################\n");
58 			#endif
59 		} else
60 			exit_debugging();
61 	}
62 	return error;
63 }
64 
65 // exit_debugging
66 status_t
67 exit_debugging()
68 {
69 	status_t error = B_OK;
70 	if (--init_counter == 0) {
71 		#if DEBUG_PRINT
72 			close(out);
73 			out = -1;
74 		#endif	// DEBUG_PRINT
75 		delete_sem(dbg_printf_sem);
76 	} else
77 		error = B_NO_INIT;
78 	return error;
79 }
80 
81 // dbg_printf_lock
82 static inline
83 bool
84 dbg_printf_lock()
85 {
86 	thread_id thread = find_thread(NULL);
87 	if (thread != dbg_printf_thread) {
88 		if (acquire_sem(dbg_printf_sem) != B_OK)
89 			return false;
90 		dbg_printf_thread = thread;
91 	}
92 	dbg_printf_nesting++;
93 	return true;
94 }
95 
96 // dbg_printf_unlock
97 static inline
98 void
99 dbg_printf_unlock()
100 {
101 	thread_id thread = find_thread(NULL);
102 	if (thread != dbg_printf_thread)
103 		return;
104 	dbg_printf_nesting--;
105 	if (dbg_printf_nesting == 0) {
106 		dbg_printf_thread = -1;
107 		release_sem(dbg_printf_sem);
108 	}
109 }
110 
111 // dbg_printf_begin
112 void
113 dbg_printf_begin()
114 {
115 	dbg_printf_lock();
116 }
117 
118 // dbg_printf_end
119 void
120 dbg_printf_end()
121 {
122 	dbg_printf_unlock();
123 }
124 
125 #if DEBUG_PRINT
126 
127 // dbg_printf
128 void
129 dbg_printf(const char *format,...)
130 {
131 	if (!dbg_printf_lock())
132 		return;
133 	char buffer[1024];
134 	va_list args;
135 	va_start(args, format);
136 	// no vsnprintf() on PPC and in kernel
137 	#if defined(__i386__) && USER
138 		vsnprintf(buffer, sizeof(buffer) - 1, format, args);
139 	#else
140 		vsprintf(buffer, format, args);
141 	#endif
142 	va_end(args);
143 	buffer[sizeof(buffer) - 1] = '\0';
144 	write(out, buffer, strlen(buffer));
145 	dbg_printf_unlock();
146 }
147 
148 #endif	// DEBUG_PRINT
149