From 91e5e8db334b9a87c54f03982dfa0c88e3c9d7a1 Mon Sep 17 00:00:00 2001 From: Kamil Rytarowski Date: Wed, 7 Oct 2020 05:57:52 +0200 Subject: Add common write_memory and read_memory NetBSD routines Instead of sharing the native-only code with all BSDs with slightly different semantics of the kernels, share the NetBSD-only behavior beteen the NetBSD native and gdbserver setup. NetBSD does not differentiate the address space I and D in the operations (contrary to OpenBSD). NetBSD handles EACCES that integrates with NetBSD specific PaX MPROTECT error handling. Add a verbose message in the native client that an operation could be cancelled due to PaX MPROTECT setup. gdb/ChangeLog: * nat/netbsd-nat.c (write_memory, read_memory): Add. * nat/netbsd-nat.h (write_memory, read_memory): Likewise. * nbsd-nat.c (nbsd_nat_target::xfer_partial): Update. gdbserver/ChangeLog: * netbsd-low.cc (netbsd_process_target::read_memory) (netbsd_process_target::write_memory): Update. --- gdb/ChangeLog | 6 ++++ gdb/nat/netbsd-nat.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++ gdb/nat/netbsd-nat.h | 22 +++++++++++++++ gdb/nbsd-nat.c | 23 +++++++++++++++ 4 files changed, 131 insertions(+) (limited to 'gdb') diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 6a69e63..4dc729c 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2020-10-07 Kamil Rytarowski + + * nat/netbsd-nat.c (write_memory, read_memory): Add. + * nat/netbsd-nat.h (write_memory, read_memory): Likewise. + * nbsd-nat.c (nbsd_nat_target::xfer_partial): Update. + 2020-10-07 Simon Marchi * break-catch-sig.c (signal_catch_counts): Make a static arrray. diff --git a/gdb/nat/netbsd-nat.c b/gdb/nat/netbsd-nat.c index 41b67cb..cae9cc2 100644 --- a/gdb/nat/netbsd-nat.c +++ b/gdb/nat/netbsd-nat.c @@ -210,4 +210,84 @@ qxfer_siginfo (pid_t pid, const char *annex, unsigned char *readbuf, return len; } +/* See netbsd-nat.h. */ + +int +write_memory (pid_t pid, unsigned const char *writebuf, CORE_ADDR offset, + size_t len, size_t *xfered_len) +{ + struct ptrace_io_desc io; + io.piod_op = PIOD_WRITE_D; + io.piod_len = len; + + size_t bytes_written = 0; + + /* Zero length write always succeeds. */ + if (len > 0) + { + do + { + io.piod_addr = (void *)(writebuf + bytes_written); + io.piod_offs = (void *)(offset + bytes_written); + + errno = 0; + int rv = ptrace (PT_IO, pid, &io, 0); + if (rv == -1) + { + gdb_assert (errno != 0); + return errno; + } + if (io.piod_len == 0) + return 0; + + bytes_written += io.piod_len; + io.piod_len = len - bytes_written; + } + while (bytes_written < len); + } + + if (xfered_len != nullptr) + *xfered_len = bytes_written; + + return 0; +} + +/* See netbsd-nat.h. */ + +int +read_memory (pid_t pid, unsigned char *readbuf, CORE_ADDR offset, + size_t len, size_t *xfered_len) +{ + struct ptrace_io_desc io; + io.piod_op = PIOD_READ_D; + io.piod_len = len; + + size_t bytes_read = 0; + + /* Zero length read always succeeds. */ + if (len > 0) + { + do + { + io.piod_offs = (void *)(offset + bytes_read); + io.piod_addr = readbuf + bytes_read; + + int rv = ptrace (PT_IO, pid, &io, 0); + if (rv == -1) + return errno; + if (io.piod_len == 0) + return 0; + + bytes_read += io.piod_len; + io.piod_len = len - bytes_read; + } + while (bytes_read < len); + } + + if (xfered_len != nullptr) + *xfered_len = bytes_read; + + return 0; +} + } diff --git a/gdb/nat/netbsd-nat.h b/gdb/nat/netbsd-nat.h index d77119b..594dec1 100644 --- a/gdb/nat/netbsd-nat.h +++ b/gdb/nat/netbsd-nat.h @@ -67,6 +67,28 @@ extern void enable_proc_events (pid_t pid); extern int qxfer_siginfo (pid_t pid, const char *annex, unsigned char *readbuf, unsigned const char *writebuf, CORE_ADDR offset, int len); + +/* Write gdb's LEN bytes from WRITEBUF and copy it to OFFSET in inferior + process' address space. The inferior is specified by PID. + Returns 0 on success or errno on failure and the number of bytes + on a successful transfer in XFERED_LEN. + + This function assumes internally that the queried process is stopped and + traced. */ + +extern int write_memory (pid_t pid, unsigned const char *writebuf, + CORE_ADDR offset, size_t len, size_t *xfered_len); + +/* Read inferior process's LEN bytes from OFFSET and copy it to WRITEBUF in + gdb's address space. + Returns 0 on success or errno on failure and the number of bytes + on a successful transfer in XFERED_LEN. + + This function assumes internally that the queried process is stopped and + traced. */ + +extern int read_memory (pid_t pid, unsigned char *readbuf, CORE_ADDR offset, + size_t len, size_t *xfered_len); } #endif diff --git a/gdb/nbsd-nat.c b/gdb/nbsd-nat.c index 7a07fbf..46dcfac 100644 --- a/gdb/nbsd-nat.c +++ b/gdb/nbsd-nat.c @@ -764,6 +764,29 @@ nbsd_nat_target::xfer_partial (enum target_object object, *xfered_len = len; return TARGET_XFER_OK; } + case TARGET_OBJECT_MEMORY: + { + size_t xfered; + int res; + if (writebuf != nullptr) + res = netbsd_nat::write_memory (pid, writebuf, offset, len, &xfered); + else + res = netbsd_nat::read_memory (pid, readbuf, offset, len, &xfered); + if (res != 0) + { + if (res == EACCES) + fprintf_unfiltered (gdb_stderr, "Cannot %s process at %s (%s). " + "Is PaX MPROTECT active? See security(7), " + "sysctl(7), paxctl(8)\n", + (writebuf ? "write to" : "read from"), + pulongest (offset), safe_strerror (errno)); + return TARGET_XFER_E_IO; + } + if (xfered == 0) + return TARGET_XFER_EOF; + *xfered_len = (ULONGEST) xfered; + return TARGET_XFER_OK; + } default: return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf, offset, -- cgit v1.1