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comparison dyncallback/dyncall_alloc_wx_mmap.c @ 251:3f7c69fadfc3

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- regression fix for changing writable to executable memory for platforms where mmap has no MAP_ANON (usually older platforms, e.g. solaris 7)
author Tassilo Philipp
date Sun, 14 May 2017 02:26:21 +0200
parents 030fbb70aa1b
children 047d2829bdf6
comparison
equal deleted inserted replaced
250:7cb8a0aaf638 251:3f7c69fadfc3
43 43
44 DCerror dcAllocWX(size_t size, void** pp) 44 DCerror dcAllocWX(size_t size, void** pp)
45 { 45 {
46 void* p; 46 void* p;
47 #if !defined(MAP_ANON) && defined(DC_UNIX) 47 #if !defined(MAP_ANON) && defined(DC_UNIX)
48 // Hack around not having POSIX' MAP_ANON by going through /dev/zero; store 48 /* Hack around not having POSIX' MAP_ANON by going through /dev/zero; store
49 // file descriptor to close on dcFreeWX at beginning of memory, as tiny hack 49 file descr to close on dcFreeWX at beginning of memory, as tiny hack */
50 int fd = open("/dev/zero", O_RDWR); 50 int fd = open("/dev/zero", O_RDWR);
51 if(fd == -1) 51 if(fd == -1)
52 return -1; 52 return -1;
53 p = mmap(0, size+sizeof(int), PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 53 p = mmap(0, size+sizeof(int), PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
54 if(p == MAP_FAILED) { 54 if(p == MAP_FAILED) {
67 return 0; 67 return 0;
68 } 68 }
69 69
70 DCerror dcInitExecWX(void* p, size_t size) 70 DCerror dcInitExecWX(void* p, size_t size)
71 { 71 {
72 #if !defined(MAP_ANON) && defined(DC_UNIX)
73 /* Fixup pointer for no-MAP_ANON workaround (see above) */
74 p -= sizeof(int);
75 #endif
72 return mprotect(p, size, PROT_READ|PROT_EXEC); 76 return mprotect(p, size, PROT_READ|PROT_EXEC);
73 } 77 }
74 78
75 void dcFreeWX(void* p, size_t size) 79 void dcFreeWX(void* p, size_t size)
76 { 80 {
77 #if !defined(MAP_ANON) && defined(DC_UNIX) 81 #if !defined(MAP_ANON) && defined(DC_UNIX)
78 // Close file descriptor of no-MAP_ANON workaround (see above) 82 /* Close file descriptor for no-MAP_ANON workaround (see above) */
79 p -= sizeof(int); 83 p -= sizeof(int);
80 size += sizeof(int); 84 size += sizeof(int);
81 close(*(int*)p); 85 close(*(int*)p);
82 #endif 86 #endif
83 munmap(p, size); 87 munmap(p, size);