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Fix handling of r10 in Linux ptrace(2). This fixes decoding

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of the 'flags' argument to mmap(2) with Linux strace(1).

Reviewed by:	dchagin
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D20223
This commit is contained in:
Edward Tomasz Napierala 2019-05-14 20:59:44 +00:00
parent db226f0d8e
commit 060d0b57b8
1 changed files with 30 additions and 15 deletions
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45
sys/amd64/linux/linux_ptrace.c
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@ -338,17 +338,26 @@ linux_ptrace_getregs(struct thread *td, pid_t pid, void *data)
map_regs_to_linux(&b_reg, &l_reg); map_regs_to_linux(&b_reg, &l_reg);
/*
* The strace(1) utility depends on RAX being set to -ENOSYS
* on syscall entry.
*/
error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo)); error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo));
if (error != 0) { if (error != 0) {
printf("%s: PT_LWPINFO failed with error %d\n", __func__, error); printf("%s: PT_LWPINFO failed with error %d\n", __func__, error);
return (error); return (error);
} }
if (lwpinfo.pl_flags & PL_FLAG_SCE) if (lwpinfo.pl_flags & PL_FLAG_SCE) {
l_reg.rax = -38; // XXX: Don't hardcode? /*
* The strace(1) utility depends on RAX being set to -ENOSYS
* on syscall entry; otherwise it loops printing those:
*
* [ Process PID=928 runs in 64 bit mode. ]
* [ Process PID=928 runs in x32 mode. ]
*/
l_reg.rax = -38; /* -ENOSYS */
/*
* Undo the mangling done in exception.S:fast_syscall_common().
*/
l_reg.r10 = l_reg.rcx;
}
error = copyout(&l_reg, (void *)data, sizeof(l_reg)); error = copyout(&l_reg, (void *)data, sizeof(l_reg));
return (error); return (error);
@ -399,21 +408,27 @@ linux_ptrace_getregset_prstatus(struct thread *td, pid_t pid, l_ulong data)
map_regs_to_linux_regset(&b_reg, fsbase, gsbase, &l_regset); map_regs_to_linux_regset(&b_reg, fsbase, gsbase, &l_regset);
/*
* The strace(1) utility depends on RAX being set to -ENOSYS
* on syscall entry; otherwise it loops printing those:
*
* [ Process PID=928 runs in 64 bit mode. ]
* [ Process PID=928 runs in x32 mode. ]
*/
error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo)); error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo));
if (error != 0) { if (error != 0) {
printf("%s: PT_LWPINFO failed with error %d\n", printf("%s: PT_LWPINFO failed with error %d\n",
__func__, error); __func__, error);
return (error); return (error);
} }
if (lwpinfo.pl_flags & PL_FLAG_SCE) if (lwpinfo.pl_flags & PL_FLAG_SCE) {
l_regset.rax = -38; // XXX: Don't hardcode? /*
* The strace(1) utility depends on RAX being set to -ENOSYS
* on syscall entry; otherwise it loops printing those:
*
* [ Process PID=928 runs in 64 bit mode. ]
* [ Process PID=928 runs in x32 mode. ]
*/
l_regset.rax = -38; /* -ENOSYS */
/*
* Undo the mangling done in exception.S:fast_syscall_common().
*/
l_regset.r10 = l_regset.rcx;
}
len = MIN(iov.iov_len, sizeof(l_regset)); len = MIN(iov.iov_len, sizeof(l_regset));
error = copyout(&l_regset, (void *)iov.iov_base, len); error = copyout(&l_regset, (void *)iov.iov_base, len);