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/*
* Copyright (c) 2012, Chris Andrews. All rights reserved.
*/
#include "usdt_internal.h"
#ifdef __APPLE__
uint32_t
usdt_probe_offset(usdt_probe_t *probe, char *dof, uint8_t argc)
{
uint32_t offset;
#ifdef __x86_64__
offset = ((uint64_t) probe->probe_addr - (uint64_t) dof + 2);
#elif __i386__
offset = ((uint32_t) probe->probe_addr - (uint32_t) dof + 2);
#else
#error "only x86_64 and i386 supported"
#endif
return (offset);
}
uint32_t
usdt_is_enabled_offset(usdt_probe_t *probe, char *dof)
{
uint32_t offset;
#ifdef __x86_64__
offset = ((uint64_t) probe->isenabled_addr - (uint64_t) dof + 6);
#elif __i386__
offset = ((uint32_t) probe->isenabled_addr - (uint32_t) dof + 6);
#else
#error "only x86_64 and i386 supported"
#endif
return (offset);
}
#elif defined __linux__
uint32_t
usdt_probe_offset(usdt_probe_t *probe, char *dof, uint8_t argc)
{
return (16);
}
uint32_t
usdt_is_enabled_offset(usdt_probe_t *probe, char *dof)
{
return (10);
}
#else /* solaris and freebsd */
uint32_t
usdt_probe_offset(usdt_probe_t *probe, char *dof, uint8_t argc)
{
return (16);
}
uint32_t
usdt_is_enabled_offset(usdt_probe_t *probe, char *dof)
{
return (8);
}
#endif
int
usdt_create_tracepoints(usdt_probe_t *probe)
{
/* Prepare the tracepoints - for each probe, a separate chunk
* of memory with the tracepoint code copied into it, to give
* us unique addresses for each tracepoint.
*
* On Oracle Linux, this must be an mmapped file because USDT
* probes there are implemented as uprobes, which are
* addressed by inode and offset. The file used is a small
* mkstemp'd file we immediately unlink.
*
* Elsewhere, we can use the heap directly because USDT will
* instrument any memory mapped by the process.
*/
size_t size;
#ifdef __linux__
int fd;
char tmp[20] = "/tmp/libusdtXXXXXX";
if ((fd = mkstemp(tmp)) < 0)
return (-1);
if (unlink(tmp) < 0)
return (-1);
if (write(fd, "\0", FUNC_SIZE) < FUNC_SIZE)
return (-1);
probe->isenabled_addr = (int (*)())mmap(NULL, FUNC_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE, fd, 0);
#else
probe->isenabled_addr = (int (*)())valloc(FUNC_SIZE);
#endif
if (probe->isenabled_addr == NULL)
return (-1);
/* ensure that the tracepoints will fit the heap we're allocating */
size = ((char *)usdt_tracepoint_end - (char *)usdt_tracepoint_isenabled);
assert(size < FUNC_SIZE);
size = ((char *)usdt_tracepoint_probe - (char *)usdt_tracepoint_isenabled);
probe->probe_addr = (char *)probe->isenabled_addr + size;
memcpy((void *)probe->isenabled_addr,
(const void *)usdt_tracepoint_isenabled, FUNC_SIZE);
#ifdef __linux__
mprotect((void *)probe->isenabled_addr, FUNC_SIZE,
PROT_READ | PROT_EXEC);
#else
mprotect((void *)probe->isenabled_addr, FUNC_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC);
#endif
return (0);
}
void
usdt_free_tracepoints(usdt_probe_t *probe)
{
#ifdef __linux__
(void) munmap(probe->isenabled_addr, FUNC_SIZE);
#else
free(probe->isenabled_addr);
#endif
}
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