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modified post ce2 by Anonymous on Wed 6th Jul 2022 12:53
original post a1ab9a3 by Anonymous on Wed 6th Jul 2022 12:17
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--- /dev/null	2022-04-19 22:28:32.062891741 +0200

1	1		--- /dev/null 2022-04-19 22:28:32.062891741 +0200
2		-	+++ pthread_mutex_init_log.c 2022-07-06 13:16:29.462859109 +0200
	2	+	+++ pthread_interceptor.c 2022-07-06 13:47:43.337141261 +0200
3		-	@@ -0,0 +1,82 @@
	3	+	@@ -0,0 +1,86 @@
4	4		+/*
5		-	+ * phread_mutext_init_log.c
	5	+	+ * pthread_interceptor.c
6	6		+ *
7		-	+ * intercept \|pthread_mutex_init()\| via LD_PRELOAD
	7	+	+ * intercept pthread calls liek \|pthread_mutex_init()\| via LD_PRELOAD
8	8		+ *
9	9		+ * Written by Roland Mainz <roland.mainz@nrubsig.org>
10	10		+ */
11	11		+
12	12		+#define _GNU_SOURCE 1 /* needed for \|RTLD_NEXT\| */
13	13		+
14	14		+#include <pthread.h>
15	15		+#include <unistd.h>
16	16		+#include <errno.h>
17	17		+#include <stdio.h>
18	18		+#include <string.h>
19	19		+#include <stdbool.h>
20	20		+#include <dlfcn.h>
21	21		+
22	22		+/* config */
23		-	+#define PMICFG_PRINT_ONCE_MSG 1
	23	+	+#define PICFG_PRINT_ONCE_MSG 1
24		-	+#define PMICFG_ENFORCE_PRIO_INHERIT 1
	24	+	+#define PICFG_ENFORCE_PRIO_INHERIT 1
25	25		+
	26	+	+/* misc */
27	27		+#define STDERR_MSG(msg) \
28	28		+ (void)write(STDERR_FILENO, (msg), strlen(msg))
29	29		+
	30	+	+
30	34		+int pthread_mutex_init(pthread_mutex_t *restrict mutex,
31	35		+ const pthread_mutexattr_t *restrict attr) {
32	36		+ pthread_mutexattr_t xattr = (pthread_mutexattr_t )attr;
33	37		+ int pmi_res;
34	38		+ int pmi_errno;
35	39		+
36		-	+#if PMICFG_PRINT_ONCE_MSG
	40	+	+#if PICFG_PRINT_ONCE_MSG
37	41		+ static int once = 0;
38		-	+ const char *mymessage = "pthread_mutex_init_log.so: "
	42	+	+ const char *mymessage = "pthread_interceptor.so: "
39	43		+ "Once: In our own pthread_mutex_init()\n";
40	44		+ /* just print message ONCE */
41	45		+ if (once++ == 0)
42	46		+ STDERR_MSG(mymessage);
43		-	+#endif /* PMICFG_PRINT_ONCE_MSG */
	47	+	+#endif /* PICFG_PRINT_ONCE_MSG */
44	48		+
45	49		+ int (original_pthread_mutex_init)(pthread_mutex_t restrict mutex,
46	50		+ const pthread_mutexattr_t *restrict attr);
47	51		+ original_pthread_mutex_init = dlsym(RTLD_NEXT, "pthread_mutex_init");
48	52		+
49	53		+ pthread_mutexattr_t myattr;
50	54		+ bool myattr_used = false;
51	55		+
52	56		+ if (!xattr) {
53	57		+ (void)pthread_mutexattr_init(&myattr);
54	58		+ myattr_used = true;
55	59		+ xattr = &myattr;
56	60		+ }
57	61		+
58		-	+#if PMICFG_ENFORCE_PRIO_INHERIT
	62	+	+#if PICFG_ENFORCE_PRIO_INHERIT
59	63		+ int mutex_protocol = -666;
60	64		+ (void)pthread_mutexattr_getprotocol(xattr, &mutex_protocol);
61	65		+ if (mutex_protocol != PTHREAD_PRIO_INHERIT) {
62	66		+ char msgbuff[256]; /* fixed size, but no \|malloc()\| allowed here */
63	67		+
64	68		+ (void)pthread_mutexattr_setprotocol(xattr, PTHREAD_PRIO_INHERIT);
65	69		+ (void)snprintf(msgbuff,
66	70		+ sizeof(msgbuff),
67		-	+ "pthread_mutex_init_log.so: "
	71	+	+ "pthread_interceptor.so: "
68	72		+ "PTHREAD_PRIO_INHERIT enforced "
69		-	+ "for mutex=%lx, was protocol=%d\n",
	73	+	+ "for mutex=0x%lx, was protocol=%d\n",
70		-	+ (void *)mutex,
	74	+	+ (unsigned long)(void *)mutex,
71	75		+ mutex_protocol);
72	76		+ STDERR_MSG(msgbuff);
73	77		+ }
74		-	+#endif /* PMICFG_ENFORCE_PRIO_INHERIT */
	78	+	+#endif /* PICFG_ENFORCE_PRIO_INHERIT */
75	79		+
76	80		+ pmi_res = (*original_pthread_mutex_init)(mutex, xattr);
77	81		+ pmi_errno = errno;
78	82		+
79	83		+ if (myattr_used) {
80	84		+ (void)pthread_mutexattr_destroy(&myattr);
81	85		+ }
82	86		+
83	87		+ errno = pmi_errno;
84	88		+ return pmi_res;
85	89		+}
86	90		--- /dev/null 2022-04-19 22:28:32.062891741 +0200
87		-	+++ test1.c 2022-07-06 13:15:43.266402121 +0200
	91	+	+++ test1.c 2022-07-06 13:52:16.151772792 +0200
88		-	@@ -0,0 +1,20 @@
	92	+	@@ -0,0 +1,27 @@
	93	+	+/*
92	97		+
93		-	+int main(void) {
	98	+	+#include <stdlib.h>
	99	+	+#include <stdio.h>
95	102		+
	103	+	+int main(int ac, char *av[])
96	107		+ pthread_mutex_t mutex1;
97	108		+ pthread_mutex_t mutex2;
98	109		+
99		-	+ pthread_mutex_init(&mutex1, NULL);
	110	+	+ (void)pthread_mutex_init(&mutex1, NULL);
100	111		+ perror("pthread_mutex_init(1) result");
101	112		+
102		-	+ pthread_mutex_init(&mutex2, NULL);
	113	+	+ (void)pthread_mutex_init(&mutex2, NULL);
103	114		+ perror("pthread_mutex_init(2) result");
104	115		+
105	116		+ (void)puts("# end.");
106	117		+
107		-	+ return 0;
	118	+	+ return EXIT_SUCCESS;
108	119		+}
109	120		--- /dev/null 2022-04-19 22:28:32.062891741 +0200
110		-	+++ Makefile 2022-07-06 13:07:04.461318913 +0200
	121	+	+++ Makefile 2022-07-06 13:50:52.426969179 +0200
111		-	@@ -0,0 +1,22 @@
	122	+	@@ -0,0 +1,24 @@
113	123		+#
114		-	+# Makefile for pthread_mutex_init.so
	124	+	+# Makefile for LD_PRELOAD pthreadinterceptor
116	125		+#
117	126		+
118		-	+pthread_mutex_init_log.o: pthread_mutex_init_log.c
	127	+	+CSTDFLAGS=-std=c11
119		-	+ gcc -std=gnu11 -g pthread_mutex_init_log.c -fPIC -c -o pthread_mutex_init_log.o
	128	+	+CC=gcc # gcc or clang
122	129		+
	130	+	+pthread_interceptor.o: pthread_interceptor.c
123	135		+test1: test1.c
124		-	+ gcc -std=gnu11 -g test1.c -o test1
	136	+	+ $(CC) $(CSTDFLAGS) -Wall -g test1.c -o test1
125	137		+
126		-	+run_test: test1 pthread_mutex_init_log.so
	138	+	+run_test: test1 pthread_interceptor.so
127		-	+ ksh93 -c 'LD_PRELOAD=$$PWD/pthread_mutex_init_log.so ./test1'
	139	+	+ ksh93 -c 'LD_PRELOAD=$$PWD/pthread_interceptor.so ./test1'
128	140		+
129	141		+all: run_test
130	142		+
131	143		+clean:
132	144		+ rm -f .o .so test1
133	145		+
	146	+	+# EOF.
134	147