/*
* Look up the symbol at addr, returning a copy of the symbol and its name.
*/
static int
lookup_addr(Elf *e, Elf_Scn *scn, u_long stridx, uintptr_t off, uintptr_t addr,
const char **name, GElf_Sym *symcopy)
{
GElf_Sym sym;
Elf_Data *data;
const char *s;
uint64_t rsym;
int i;
if ((data = elf_getdata(scn, NULL)) == NULL) {
DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
return (1);
}
for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
rsym = off + sym.st_value;
if (addr >= rsym && addr < rsym + sym.st_size) {
s = elf_strptr(e, stridx, sym.st_name);
if (s != NULL) {
*name = s;
memcpy(symcopy, &sym, sizeof(*symcopy));
/*
* DTrace expects the st_value to contain
* only the address relative to the start of
* the function.
*/
symcopy->st_value = rsym;
return (0);
}
}
}
return (1);
}
int
proc_bkptset(struct proc_handle *phdl, uintptr_t address,
unsigned long *saved)
{
struct ptrace_io_desc piod;
unsigned long paddr, caddr;
int ret = 0;
*saved = 0;
if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
phdl->status == PS_IDLE) {
errno = ENOENT;
return (-1);
}
DPRINTFX("adding breakpoint at 0x%lx", address);
if (phdl->status != PS_STOP)
if (proc_stop(phdl) != 0)
return (-1);
/*
* Read the original instruction.
*/
caddr = address;
paddr = 0;
piod.piod_op = PIOD_READ_I;
piod.piod_offs = (void *)caddr;
piod.piod_addr = &paddr;
piod.piod_len = BREAKPOINT_INSTR_SZ;
if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
DPRINTF("ERROR: couldn't read instruction at address 0x%"
PRIuPTR, address);
ret = -1;
goto done;
}
*saved = paddr;
/*
* Write a breakpoint instruction to that address.
*/
caddr = address;
paddr = BREAKPOINT_INSTR;
piod.piod_op = PIOD_WRITE_I;
piod.piod_offs = (void *)caddr;
piod.piod_addr = &paddr;
piod.piod_len = BREAKPOINT_INSTR_SZ;
if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
DPRINTF("ERROR: couldn't write instruction at address 0x%"
PRIuPTR, address);
ret = -1;
goto done;
}
done:
if (phdl->status != PS_STOP)
/* Restart the process if we had to stop it. */
proc_cont(phdl);
return (ret);
}
int
proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
unsigned long saved)
{
struct ptrace_io_desc piod;
unsigned long paddr, caddr;
if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
phdl->status == PS_IDLE) {
errno = ENOENT;
return (-1);
}
DPRINTFX("removing breakpoint at 0x%lx\n", address);
/*
* Overwrite the breakpoint instruction that we setup previously.
*/
caddr = address;
paddr = saved;
piod.piod_op = PIOD_WRITE_I;
piod.piod_offs = (void *)caddr;
piod.piod_addr = &paddr;
piod.piod_len = BREAKPOINT_INSTR_SZ;
if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
DPRINTF("ERROR: couldn't write instruction at address 0x%"
PRIuPTR, address);
return (-1);
}
return (0);
}
int
proc_regset(struct proc_handle *phdl, proc_reg_t reg, unsigned long regvalue)
{
struct reg regs;
if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
phdl->status == PS_IDLE) {
errno = ENOENT;
return (-1);
}
if (ptrace(PT_GETREGS, proc_getpid(phdl), (caddr_t)®s, 0) < 0)
return (-1);
switch (reg) {
case REG_PC:
#if defined(__aarch64__)
regs.elr = regvalue;
#elif defined(__amd64__)
regs.r_rip = regvalue;
#elif defined(__arm__)
regs.r_pc = regvalue;
#elif defined(__i386__)
regs.r_eip = regvalue;
#elif defined(__mips__)
regs.r_regs[PC] = regvalue;
#elif defined(__powerpc__)
regs.pc = regvalue;
#elif defined(__riscv__)
regs.sepc = regvalue;
#endif
break;
case REG_SP:
#if defined(__aarch64__)
regs.sp = regvalue;
#elif defined(__amd64__)
regs.r_rsp = regvalue;
#elif defined(__arm__)
regs.r_sp = regvalue;
#elif defined(__i386__)
regs.r_esp = regvalue;
#elif defined(__mips__)
regs.r_regs[PC] = regvalue;
#elif defined(__powerpc__)
regs.fixreg[1] = regvalue;
#elif defined(__riscv__)
regs.sp = regvalue;
#endif
break;
default:
DPRINTFX("ERROR: no support for reg number %d", reg);
return (-1);
}
if (ptrace(PT_SETREGS, proc_getpid(phdl), (caddr_t)®s, 0) < 0)
return (-1);
return (0);
}
/*
* Step over the breakpoint.
*/
int
proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
{
unsigned long pc;
unsigned long samesaved;
int status;
if (proc_regget(phdl, REG_PC, &pc) < 0) {
DPRINTFX("ERROR: couldn't get PC register");
return (-1);
}
proc_bkptregadj(&pc);
if (proc_bkptdel(phdl, pc, saved) < 0) {
DPRINTFX("ERROR: couldn't delete breakpoint");
return (-1);
}
/*
* Go back in time and step over the new instruction just
* set up by proc_bkptdel().
*/
proc_regset(phdl, REG_PC, pc);
if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
DPRINTFX("ERROR: ptrace step failed");
return (-1);
}
proc_wstatus(phdl);
status = proc_getwstat(phdl);
if (!WIFSTOPPED(status)) {
DPRINTFX("ERROR: don't know why process stopped");
return (-1);
}
/*
* Restore the breakpoint. The saved instruction should be
* the same as the one that we were passed in.
*/
if (proc_bkptset(phdl, pc, &samesaved) < 0) {
DPRINTFX("ERROR: couldn't restore breakpoint");
return (-1);
}
assert(samesaved == saved);
return (0);
}
int
proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error = 0;
int status;
if (pid == 0 || pid == getpid())
return (EINVAL);
/*
* Allocate memory for the process handle, a structure containing
* all things related to the process.
*/
if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
return (ENOMEM);
memset(phdl, 0, sizeof(struct proc_handle));
phdl->pid = pid;
phdl->flags = flags;
phdl->status = PS_RUN;
elf_version(EV_CURRENT);
if (ptrace(PT_ATTACH, phdl->pid, 0, 0) != 0) {
error = errno;
DPRINTF("ERROR: cannot ptrace child process %d", pid);
goto out;
}
/* Wait for the child process to stop. */
if (waitpid(pid, &status, WUNTRACED) == -1) {
error = errno;
DPRINTF("ERROR: child process %d didn't stop as expected", pid);
goto out;
}
/* Check for an unexpected status. */
if (WIFSTOPPED(status) == 0)
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
else
phdl->status = PS_STOP;
out:
if (error)
proc_free(phdl);
else
*pphdl = phdl;
return (error);
}
int
proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
unsigned long saved)
{
struct ptrace_io_desc piod;
uintptr_t caddr;
int ret = 0, stopped;
instr_t instr;
if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
phdl->status == PS_IDLE) {
errno = ENOENT;
return (-1);
}
DPRINTFX("removing breakpoint at 0x%lx", address);
stopped = 0;
if (phdl->status != PS_STOP) {
if (proc_stop(phdl) != 0)
return (-1);
stopped = 1;
}
/*
* Overwrite the breakpoint instruction that we setup previously.
*/
caddr = address;
instr = saved;
piod.piod_op = PIOD_WRITE_I;
piod.piod_offs = (void *)caddr;
piod.piod_addr = &instr;
piod.piod_len = BREAKPOINT_INSTR_SZ;
if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
DPRINTF("ERROR: couldn't write instruction at address 0x%"
PRIuPTR, address);
ret = -1;
}
if (stopped)
/* Restart the process if we had to stop it. */
proc_continue(phdl);
return (ret);
}
static int
proc_stop(struct proc_handle *phdl)
{
int status;
if (kill(proc_getpid(phdl), SIGSTOP) == -1) {
DPRINTF("kill %d", proc_getpid(phdl));
return (-1);
} else if (waitpid(proc_getpid(phdl), &status, WSTOPPED) == -1) {
DPRINTF("waitpid %d", proc_getpid(phdl));
return (-1);
} else if (!WIFSTOPPED(status)) {
DPRINTFX("waitpid: unexpected status 0x%x", status);
return (-1);
}
return (0);
}
int
proc_regget(struct proc_handle *phdl, proc_reg_t reg, unsigned long *regvalue)
{
struct reg regs;
if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
phdl->status == PS_IDLE) {
errno = ENOENT;
return (-1);
}
memset(®s, 0, sizeof(regs));
if (ptrace(PT_GETREGS, proc_getpid(phdl), (caddr_t)®s, 0) < 0)
return (-1);
switch (reg) {
case REG_PC:
#if defined(__amd64__)
*regvalue = regs.r_rip;
#elif defined(__i386__)
*regvalue = regs.r_eip;
#elif defined(__mips__)
*regvalue = regs.r_regs[PC];
#elif defined(__powerpc__)
*regvalue = regs.pc;
#endif
break;
case REG_SP:
#if defined(__amd64__)
*regvalue = regs.r_rsp;
#elif defined(__i386__)
*regvalue = regs.r_esp;
#elif defined(__mips__)
*regvalue = regs.r_regs[SP];
#elif defined(__powerpc__)
*regvalue = regs.fixreg[1];
#endif
break;
default:
DPRINTFX("ERROR: no support for reg number %d", reg);
return (-1);
}
return (0);
}
/*
* Look up the symbol with the given name and return a copy of it.
*/
static int
lookup_name(Elf *e, Elf_Scn *scn, u_long stridx, const char *symbol,
GElf_Sym *symcopy, prsyminfo_t *si)
{
GElf_Sym sym;
Elf_Data *data;
char *s;
int i;
if ((data = elf_getdata(scn, NULL)) == NULL) {
DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
return (1);
}
for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
s = elf_strptr(e, stridx, sym.st_name);
if (s != NULL && strcmp(s, symbol) == 0) {
memcpy(symcopy, &sym, sizeof(*symcopy));
if (si != NULL)
si->prs_id = i;
return (0);
}
}
return (1);
}
int
proc_iter_symbyaddr(struct proc_handle *p, const char *object, int which,
int mask, proc_sym_f *func, void *cd)
{
Elf *e;
int i, fd;
prmap_t *map;
Elf_Scn *scn, *foundscn = NULL;
Elf_Data *data;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
GElf_Sym sym;
unsigned long stridx = -1;
char *s;
int error = -1;
if ((map = proc_name2map(p, object)) == NULL)
return (-1);
if ((fd = find_dbg_obj(map->pr_mapname)) < 0) {
DPRINTF("ERROR: open %s failed", map->pr_mapname);
goto err0;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
goto err1;
}
if (gelf_getehdr(e, &ehdr) == NULL) {
DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
goto err2;
}
/*
* Find the section we are looking for.
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
if (which == PR_SYMTAB &&
shdr.sh_type == SHT_SYMTAB) {
foundscn = scn;
break;
} else if (which == PR_DYNSYM &&
shdr.sh_type == SHT_DYNSYM) {
foundscn = scn;
break;
}
}
if (!foundscn)
return (-1);
stridx = shdr.sh_link;
if ((data = elf_getdata(foundscn, NULL)) == NULL) {
DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
goto err2;
}
for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) {
if (GELF_ST_BIND(sym.st_info) == STB_LOCAL &&
(mask & BIND_LOCAL) == 0)
continue;
if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL &&
(mask & BIND_GLOBAL) == 0)
continue;
if (GELF_ST_BIND(sym.st_info) == STB_WEAK &&
(mask & BIND_WEAK) == 0)
continue;
if (GELF_ST_TYPE(sym.st_info) == STT_NOTYPE &&
(mask & TYPE_NOTYPE) == 0)
continue;
if (GELF_ST_TYPE(sym.st_info) == STT_OBJECT &&
(mask & TYPE_OBJECT) == 0)
continue;
if (GELF_ST_TYPE(sym.st_info) == STT_FUNC &&
(mask & TYPE_FUNC) == 0)
continue;
if (GELF_ST_TYPE(sym.st_info) == STT_SECTION &&
(mask & TYPE_SECTION) == 0)
continue;
if (GELF_ST_TYPE(sym.st_info) == STT_FILE &&
(mask & TYPE_FILE) == 0)
continue;
s = elf_strptr(e, stridx, sym.st_name);
if (ehdr.e_type != ET_EXEC)
sym.st_value += map->pr_vaddr;
if ((error = (*func)(cd, &sym, s)) != 0)
goto err2;
}
error = 0;
err2:
elf_end(e);
err1:
close(fd);
err0:
free(map);
return (error);
}
int
proc_name2sym(struct proc_handle *p, const char *object, const char *symbol,
GElf_Sym *symcopy, prsyminfo_t *si)
{
Elf *e;
Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
GElf_Shdr shdr;
GElf_Ehdr ehdr;
prmap_t *map;
uintptr_t off;
u_long symtabstridx = 0, dynsymstridx = 0;
int fd, error = -1;
if ((map = proc_name2map(p, object)) == NULL) {
DPRINTFX("ERROR: couldn't find object %s", object);
goto err0;
}
if ((fd = find_dbg_obj(map->pr_mapname)) < 0) {
DPRINTF("ERROR: open %s failed", map->pr_mapname);
goto err0;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
goto err1;
}
if (gelf_getehdr(e, &ehdr) == NULL) {
DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
goto err2;
}
/*
* Find the index of the STRTAB and SYMTAB sections to locate
* symbol names.
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
switch (shdr.sh_type) {
case SHT_SYMTAB:
symtabscn = scn;
symtabstridx = shdr.sh_link;
break;
case SHT_DYNSYM:
dynsymscn = scn;
dynsymstridx = shdr.sh_link;
break;
}
}
/*
* First look up the symbol in the dynsymtab, and fall back to the
* symtab if the lookup fails.
*/
error = lookup_name(e, dynsymscn, dynsymstridx, symbol, symcopy, si);
if (error == 0)
goto out;
error = lookup_name(e, symtabscn, symtabstridx, symbol, symcopy, si);
if (error == 0)
goto out;
out:
off = ehdr.e_type == ET_EXEC ? 0 : map->pr_vaddr;
symcopy->st_value += off;
err2:
elf_end(e);
err1:
close(fd);
err0:
free(map);
return (error);
}
int
proc_addr2sym(struct proc_handle *p, uintptr_t addr, char *name,
size_t namesz, GElf_Sym *symcopy)
{
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf *e;
Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
prmap_t *map;
const char *s;
uintptr_t off;
u_long symtabstridx = 0, dynsymstridx = 0;
int fd, error = -1;
if ((map = proc_addr2map(p, addr)) == NULL)
return (-1);
if ((fd = find_dbg_obj(map->pr_mapname)) < 0) {
DPRINTF("ERROR: open %s failed", map->pr_mapname);
goto err0;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
goto err1;
}
if (gelf_getehdr(e, &ehdr) == NULL) {
DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
goto err2;
}
/*
* Find the index of the STRTAB and SYMTAB sections to locate
* symbol names.
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
switch (shdr.sh_type) {
case SHT_SYMTAB:
symtabscn = scn;
symtabstridx = shdr.sh_link;
break;
case SHT_DYNSYM:
dynsymscn = scn;
dynsymstridx = shdr.sh_link;
break;
}
}
off = ehdr.e_type == ET_EXEC ? 0 : map->pr_vaddr;
/*
* First look up the symbol in the dynsymtab, and fall back to the
* symtab if the lookup fails.
*/
error = lookup_addr(e, dynsymscn, dynsymstridx, off, addr, &s, symcopy);
if (error == 0)
goto out;
error = lookup_addr(e, symtabscn, symtabstridx, off, addr, &s, symcopy);
if (error != 0)
goto err2;
out:
demangle(s, name, namesz);
err2:
elf_end(e);
err1:
close(fd);
err0:
free(map);
return (error);
}
int
proc_name2sym(struct proc_handle *p, const char *object, const char *symbol,
GElf_Sym *symcopy)
{
Elf *e;
Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
Elf_Data *data;
GElf_Shdr shdr;
GElf_Sym sym;
GElf_Ehdr ehdr;
int fd, error = -1;
size_t i;
prmap_t *map;
char *s;
unsigned long symtabstridx = 0, dynsymstridx = 0;
if ((map = proc_name2map(p, object)) == NULL) {
DPRINTFX("ERROR: couldn't find object %s", object);
goto err0;
}
if ((fd = open(map->pr_mapname, O_RDONLY, 0)) < 0) {
DPRINTF("ERROR: open %s failed", map->pr_mapname);
goto err0;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
goto err1;
}
if (gelf_getehdr(e, &ehdr) == NULL) {
DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
goto err2;
}
/*
* Find the index of the STRTAB and SYMTAB sections to locate
* symbol names.
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
switch (shdr.sh_type) {
case SHT_SYMTAB:
symtabscn = scn;
symtabstridx = shdr.sh_link;
break;
case SHT_DYNSYM:
dynsymscn = scn;
dynsymstridx = shdr.sh_link;
break;
default:
break;
}
}
/*
* Iterate over the Dynamic Symbols table to find the symbol.
* Then look up the string name in STRTAB (.dynstr)
*/
if ((data = elf_getdata(dynsymscn, NULL))) {
i = 0;
while (gelf_getsym(data, i++, &sym) != NULL) {
s = elf_strptr(e, dynsymstridx, sym.st_name);
if (s && strcmp(s, symbol) == 0) {
memcpy(symcopy, &sym, sizeof(sym));
if (ehdr.e_type != ET_EXEC)
symcopy->st_value += map->pr_vaddr;
error = 0;
goto out;
}
}
}
/*
* Iterate over the Symbols Table to find the symbol.
* Then look up the string name in STRTAB (.dynstr)
*/
if ((data = elf_getdata(symtabscn, NULL))) {
i = 0;
while (gelf_getsym(data, i++, &sym) != NULL) {
s = elf_strptr(e, symtabstridx, sym.st_name);
if (s && strcmp(s, symbol) == 0) {
memcpy(symcopy, &sym, sizeof(sym));
if (ehdr.e_type != ET_EXEC)
symcopy->st_value += map->pr_vaddr;
error = 0;
goto out;
}
}
}
out:
DPRINTFX("found addr 0x%lx for %s", symcopy->st_value, symbol);
err2:
elf_end(e);
err1:
close(fd);
err0:
free(map);
return (error);
}
int
proc_addr2sym(struct proc_handle *p, uintptr_t addr, char *name,
size_t namesz, GElf_Sym *symcopy)
{
Elf *e;
Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
Elf_Data *data;
GElf_Shdr shdr;
GElf_Sym sym;
GElf_Ehdr ehdr;
int fd, error = -1;
size_t i;
uint64_t rsym;
prmap_t *map;
char *s;
unsigned long symtabstridx = 0, dynsymstridx = 0;
if ((map = proc_addr2map(p, addr)) == NULL)
return (-1);
if ((fd = open(map->pr_mapname, O_RDONLY, 0)) < 0) {
DPRINTF("ERROR: open %s failed", map->pr_mapname);
goto err0;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
goto err1;
}
if (gelf_getehdr(e, &ehdr) == NULL) {
DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
goto err2;
}
/*
* Find the index of the STRTAB and SYMTAB sections to locate
* symbol names.
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
switch (shdr.sh_type) {
case SHT_SYMTAB:
symtabscn = scn;
symtabstridx = shdr.sh_link;
break;
case SHT_DYNSYM:
dynsymscn = scn;
dynsymstridx = shdr.sh_link;
break;
default:
break;
}
}
/*
* Iterate over the Dynamic Symbols table to find the symbol.
* Then look up the string name in STRTAB (.dynstr)
*/
if ((data = elf_getdata(dynsymscn, NULL)) == NULL) {
DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
goto symtab;
}
i = 0;
while (gelf_getsym(data, i++, &sym) != NULL) {
/*
* Calculate the address mapped to the virtual memory
* by rtld.
*/
if (ehdr.e_type != ET_EXEC)
rsym = map->pr_vaddr + sym.st_value;
else
rsym = sym.st_value;
if (addr >= rsym && addr < rsym + sym.st_size) {
s = elf_strptr(e, dynsymstridx, sym.st_name);
if (s) {
if (s[0] == '_' && s[1] == 'Z' && s[2])
demangle(s, name, namesz);
else
strlcpy(name, s, namesz);
memcpy(symcopy, &sym, sizeof(sym));
/*
* DTrace expects the st_value to contain
* only the address relative to the start of
* the function.
*/
symcopy->st_value = rsym;
error = 0;
goto out;
}
}
}
symtab:
/*
* Iterate over the Symbols Table to find the symbol.
* Then look up the string name in STRTAB (.dynstr)
*/
if ((data = elf_getdata(symtabscn, NULL)) == NULL) {
DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
goto err2;
}
i = 0;
while (gelf_getsym(data, i++, &sym) != NULL) {
/*
* Calculate the address mapped to the virtual memory
* by rtld.
*/
if (ehdr.e_type != ET_EXEC)
rsym = map->pr_vaddr + sym.st_value;
else
rsym = sym.st_value;
if (addr >= rsym && addr < rsym + sym.st_size) {
s = elf_strptr(e, symtabstridx, sym.st_name);
if (s) {
if (s[0] == '_' && s[1] == 'Z' && s[2])
demangle(s, name, namesz);
else
strlcpy(name, s, namesz);
memcpy(symcopy, &sym, sizeof(sym));
/*
* DTrace expects the st_value to contain
* only the address relative to the start of
* the function.
*/
symcopy->st_value = rsym;
error = 0;
goto out;
}
}
}
out:
err2:
elf_end(e);
err1:
close(fd);
err0:
free(map);
return (error);
}
int
proc_create(const char *file, char * const *argv, proc_child_func *pcf,
void *child_arg, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error = 0;
int status;
pid_t pid;
/*
* Allocate memory for the process handle, a structure containing
* all things related to the process.
*/
if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
return (ENOMEM);
elf_version(EV_CURRENT);
/* Fork a new process. */
if ((pid = vfork()) == -1)
error = errno;
else if (pid == 0) {
/* The child expects to be traced. */
if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0)
_exit(1);
if (pcf != NULL)
(*pcf)(child_arg);
/* Execute the specified file: */
execvp(file, argv);
/* Couldn't execute the file. */
_exit(2);
} else {
/* The parent owns the process handle. */
memset(phdl, 0, sizeof(struct proc_handle));
phdl->pid = pid;
phdl->status = PS_IDLE;
/* Wait for the child process to stop. */
if (waitpid(pid, &status, WUNTRACED) == -1) {
error = errno;
DPRINTF("ERROR: child process %d didn't stop as expected", pid);
goto bad;
}
/* Check for an unexpected status. */
if (WIFSTOPPED(status) == 0) {
error = errno;
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
goto bad;
} else
phdl->status = PS_STOP;
}
bad:
if (error)
proc_free(phdl);
else
*pphdl = phdl;
return (error);
}
