Differential D30211 Diff 90968 usr.bin/truss/syscalls.c

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usr.bin/truss/syscalls.c

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#include <sys/capsicum.h> #include <sys/capsicum.h>

#include <sys/types.h> #include <sys/types.h>

#define _WANT_FREEBSD11_KEVENT #define _WANT_FREEBSD11_KEVENT

#include <sys/event.h> #include <sys/event.h>

#include <sys/ioccom.h> #include <sys/ioccom.h>

#include <sys/mman.h> #include <sys/mman.h>

#include <sys/mount.h> #include <sys/mount.h>

#include <sys/poll.h> #include <sys/poll.h>

#include <sys/procfs.h>

#include <sys/ptrace.h> #include <sys/ptrace.h>

#include <sys/resource.h> #include <sys/resource.h>

#include <sys/sched.h> #include <sys/sched.h>

#include <sys/socket.h> #include <sys/socket.h>

#define _WANT_FREEBSD11_STAT #define _WANT_FREEBSD11_STAT

#include <sys/stat.h> #include <sys/stat.h>

#include <sys/sysctl.h> #include <sys/sysctl.h>

#include <sys/time.h> #include <sys/time.h>

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static const char * static const char *

lookup(struct xlat *xlat, int val, int base) lookup(struct xlat *xlat, int val, int base)

{ {

static char tmp[16]; static char tmp[16];

for (; xlat->str != NULL; xlat++) for (; xlat->str != NULL; xlat++)

if (xlat->val == val) if (xlat->val == val)

return (xlat->str); return (xlat->str);

switch (base) { switch (base) {

case 8: case 8:

sprintf(tmp, "0%o", val); sprintf(tmp, "0%o", val);

break; break;

case 16: case 16:

sprintf(tmp, "0x%x", val); sprintf(tmp, "0x%x", val);

break; break;

case 10: case 10:

sprintf(tmp, "%u", val); sprintf(tmp, "%u", val);

break; break;

default: default:

errx(1,"Unknown lookup base"); errx(1, "Unknown lookup base");

jhbUnsubmitted

Done

default:

- errx(1,"Unknown lookup base");

+ errx(1, "Unknown lookup base");

}

return (tmp);

Maybe fix this while here?

jhb: Maybe fix this while here?

break;

} }

return (tmp); return (tmp);

} }

static const char * static const char *

xlookup(struct xlat *xlat, int val) xlookup(struct xlat *xlat, int val)

{ {

▲ Show 20 Lines • Show All 225 Lines • ▼ Show 20 Lines #endif

add_syscall(t->proc->abi, number, sc); add_syscall(t->proc->abi, number, sc);

return (sc); return (sc);

} }

/* /*

* Copy a fixed amount of bytes from the process. * Copy a fixed amount of bytes from the process.

*/ */

static int static int

get_struct(pid_t pid, uintptr_t offset, void *buf, int len) get_struct(pid_t pid, psaddr_t offset, void *buf, size_t len)

jhbUnsubmitted

Done

So kvaddr_t is in theory for kernel virtual addresses, not necessarily userland. However, there is a psaddr_t in <sys/procfs.h> that you could use as that is "process addresses" and is the type used in things like the libthread_db interface for user addresses. psaddr_t is uint64_t.

jhb: So `kvaddr_t` is in theory for kernel virtual addresses, not necessarily userland. However…

{ {

struct ptrace_io_desc iorequest; struct ptrace_io_desc iorequest;

iorequest.piod_op = PIOD_READ_D; iorequest.piod_op = PIOD_READ_D;

iorequest.piod_offs = (void *)offset; iorequest.piod_offs = (void *)(uintptr_t)offset;

iorequest.piod_addr = buf; iorequest.piod_addr = buf;

iorequest.piod_len = len; iorequest.piod_len = len;

if (ptrace(PT_IO, pid, (caddr_t)&iorequest, 0) < 0) if (ptrace(PT_IO, pid, (caddr_t)&iorequest, 0) < 0)

return (-1); return (-1);

return (0); return (0);

} }

#define MAXSIZE 4096 #define MAXSIZE 4096

/* /*

* Copy a string from the process. Note that it is * Copy a string from the process. Note that it is

* expected to be a C string, but if max is set, it will * expected to be a C string, but if max is set, it will

* only get that much. * only get that much.

*/ */

static char * static char *

get_string(pid_t pid, uintptr_t addr, int max) get_string(pid_t pid, psaddr_t addr, int max)

{ {

struct ptrace_io_desc iorequest; struct ptrace_io_desc iorequest;

char *buf, *nbuf; char *buf, *nbuf;

size_t offset, size, totalsize; size_t offset, size, totalsize;

offset = 0; offset = 0;

if (max) if (max)

size = max + 1; size = max + 1;

else { else {

/* Read up to the end of the current page. */ /* Read up to the end of the current page. */

size = PAGE_SIZE - ((uintptr_t)addr % PAGE_SIZE); size = PAGE_SIZE - (addr % PAGE_SIZE);

if (size > MAXSIZE) if (size > MAXSIZE)

size = MAXSIZE; size = MAXSIZE;

} }

totalsize = size; totalsize = size;

buf = malloc(totalsize); buf = malloc(totalsize);

if (buf == NULL) if (buf == NULL)

return (NULL); return (NULL);

for (;;) { for (;;) {

iorequest.piod_op = PIOD_READ_D; iorequest.piod_op = PIOD_READ_D;

iorequest.piod_offs = (void *)(addr + offset); iorequest.piod_offs = (void *)((uintptr_t)addr + offset);

iorequest.piod_addr = buf + offset; iorequest.piod_addr = buf + offset;

iorequest.piod_len = size; iorequest.piod_len = size;

if (ptrace(PT_IO, pid, (caddr_t)&iorequest, 0) < 0) { if (ptrace(PT_IO, pid, (caddr_t)&iorequest, 0) < 0) {

free(buf); free(buf);

return (NULL); return (NULL);

} }

if (memchr(buf + offset, '\0', size) != NULL) if (memchr(buf + offset, '\0', size) != NULL)

return (buf); return (buf);

▲ Show 20 Lines • Show All 544 Lines • ▼ Show 20 Lines print_sysctl(FILE *fp, int *oid, size_t len)

i = sizeof(name); i = sizeof(name);

if (sysctl(qoid, len + 2, name, &i, 0, 0) == -1) if (sysctl(qoid, len + 2, name, &i, 0, 0) == -1)

print_sysctl_oid(fp, oid, len); print_sysctl_oid(fp, oid, len);

else else

fprintf(fp, "%s", name); fprintf(fp, "%s", name);

} }

/* /*

* Convert a 32-bit user-space pointer to psaddr_t. Currently, this

jhbUnsubmitted

Not Done

I don't know what the right choice is for sign-extending vs not. I suspect it's actually wrong to sign-extend on just about every architecture. The question is what effective virtual address is used by the CPU when running in 32-bit mode? Perhaps for MIPS we have to sign extend, but it's probably wrong for every other platform. I would probably be tempted to invert this to sign extend only on MIPS and zero-extend everywhere else.

Hmm, indeed, truss is broken today for i386 due to the sign extending:

70294: vfork()                                   = 70295 (0x11297)
70295: <new process>
70295: freebsd32_execve("/sbin/echo",[ "echo", "I'm in the child
" ],[ "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(nu
ll)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(nu
ll)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(nu
ll)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)", "(null)" ]) ERR#2 'No such file or directory'

With sign extension disabled:

70371: <new process>
70370: vfork()                                   = 70371 (0x112e3)
70371: freebsd32_execve("/sbin/echo",[ "echo", "I'm in the child
" ],[ "ALTERNATE_EDITOR=vi", "BLOCKSIZE=K", "COLORFGBG=0;15", "COLORTERM=truecolor", "CSCOPE_EDITOR=emacsclient", "CVS_RSH=ssh", "DISPLAY=:0",
...

jhb: I don't know what the right choice is for sign-extending vs not. I suspect it's actually wrong…

arichardsonAuthorUnsubmitted

Done

Sounds good I'll change it to be MIPS only.

arichardson: Sounds good I'll change it to be MIPS only.

* sign-extends on MIPS and zero-extends on all other architectures.

static psaddr_t

user_ptr32_to_psaddr(int32_t user_pointer)

{

#if defined(__mips__)

return ((psaddr_t)(intptr_t)user_pointer);

#else

return ((psaddr_t)(uintptr_t)user_pointer);

jhbUnsubmitted

Not Done

#if defined(__i386__) || defined(__amd64__)

- return (psaddr_t)(uintptr_t)user_pointer;

+ return ((psaddr_t)(uintptr_t)user_pointer);

#else

- return (psaddr_t)(intptr_t)user_pointer;

+ return ((psaddr_t)(intptr_t)user_pointer);

#endif

jhb:

#endif

}

* Converts a syscall argument into a string. Said string is * Converts a syscall argument into a string. Said string is

* allocated via malloc(), so needs to be free()'d. sc is * allocated via malloc(), so needs to be free()'d. sc is

* a pointer to the syscall description (see above); args is * a pointer to the syscall description (see above); args is

* an array of all of the system call arguments. * an array of all of the system call arguments.

*/ */

char * char *

print_arg(struct syscall_arg *sc, unsigned long *args, register_t *retval, print_arg(struct syscall_arg *sc, unsigned long *args, register_t *retval,

struct trussinfo *trussinfo) struct trussinfo *trussinfo)

Show All 34 Lines print_arg(struct syscall_arg *sc, unsigned long *args, register_t *retval,

case Long: case Long:

fprintf(fp, "%ld", args[sc->offset]); fprintf(fp, "%ld", args[sc->offset]);

break; break;

case Sizet: case Sizet:

fprintf(fp, "%zu", (size_t)args[sc->offset]); fprintf(fp, "%zu", (size_t)args[sc->offset]);

break; break;

case ShmName: case ShmName:

/* Handle special SHM_ANON value. */ /* Handle special SHM_ANON value. */

if ((char *)args[sc->offset] == SHM_ANON) { if ((char *)(uintptr_t)args[sc->offset] == SHM_ANON) {

fprintf(fp, "SHM_ANON"); fprintf(fp, "SHM_ANON");

break; break;

} }

/* FALLTHROUGH */ /* FALLTHROUGH */

case Name: { case Name: {

/* NULL-terminated string. */ /* NULL-terminated string. */

char *tmp2; char *tmp2;

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} else { } else {

print_pointer(fp, args[sc->offset]); print_pointer(fp, args[sc->offset]);

} }

break; break;

} }

case ExecArgs: case ExecArgs:

case ExecEnv: case ExecEnv:

case StringArray: { case StringArray: {

uintptr_t addr; psaddr_t addr;

union { union {

int32_t strarray32[PAGE_SIZE / sizeof(int32_t)]; int32_t strarray32[PAGE_SIZE / sizeof(int32_t)];

int64_t strarray64[PAGE_SIZE / sizeof(int64_t)]; int64_t strarray64[PAGE_SIZE / sizeof(int64_t)];

char buf[PAGE_SIZE]; char buf[PAGE_SIZE];

} u; } u;

char *string; char *string;

size_t len; size_t len;

u_int first, i; u_int first, i;

Show All 13 Lines case StringArray: {

} }

/* /*

* Read a page of pointers at a time. Punt if the top-level * Read a page of pointers at a time. Punt if the top-level

* pointer is not aligned. Note that the first read is of * pointer is not aligned. Note that the first read is of

* a partial page. * a partial page.

*/ */

addr = args[sc->offset]; addr = args[sc->offset];

if (addr % pointer_size != 0) { if (!__is_aligned(addr, pointer_size)) {

print_pointer(fp, args[sc->offset]); print_pointer(fp, args[sc->offset]);

break; break;

} }

len = PAGE_SIZE - (addr & PAGE_MASK); len = PAGE_SIZE - (addr & PAGE_MASK);

if (get_struct(pid, addr, u.buf, len) == -1) { if (get_struct(pid, addr, u.buf, len) == -1) {

print_pointer(fp, args[sc->offset]); print_pointer(fp, args[sc->offset]);

break; break;

} }

assert(len > 0); assert(len > 0);

fputc('[', fp); fputc('[', fp);

first = 1; first = 1;

i = 0; i = 0;

for (;;) { for (;;) {

uintptr_t straddr; psaddr_t straddr;

if (pointer_size == 4) { if (pointer_size == 4) {

if (u.strarray32[i] == 0) straddr = user_ptr32_to_psaddr(u.strarray32[i]);

jhbUnsubmitted

Done

I kind of think intptr_t is better here than int64_t? For CheriBSD I'd guess this would need the signed variant of ptraddr_t (hah!, another reason for sptraddr_t).

Also, I'm not quite sure if sign-extending is always correct (it is for MIPS maybe, but not i386).

jhb: I kind of think intptr_t is better here than int64_t? For CheriBSD I'd guess this would need…

arichardsonAuthorUnsubmitted

Done

The latest version uses (u)intptr_t. I've changed it to zero-extend for i386 and sign-extend otherwise.

arichardson: The latest version uses (u)intptr_t. I've changed it to zero-extend for i386 and sign-extend…

break;

/* sign-extend 32-bit pointers */

straddr = (intptr_t)u.strarray32[i];

} else if (pointer_size == 8) { } else if (pointer_size == 8) {

if (u.strarray64[i] == 0) straddr = (psaddr_t)u.strarray64[i];

break;

straddr = (intptr_t)u.strarray64[i];

} else { } else {

errx(1, "Unsupported pointer size: %zu", errx(1, "Unsupported pointer size: %zu",

pointer_size); pointer_size);

} }

jhbUnsubmitted

Done

pointer_size);

}

/* Stop once we read the first NULL pointer. */

if (straddr == 0)

jhb:

/* Stop once we read the first NULL pointer. */

if (straddr == 0)

break;

string = get_string(pid, straddr, 0); string = get_string(pid, straddr, 0);

fprintf(fp, "%s \"%s\"", first ? "" : ",", string); fprintf(fp, "%s \"%s\"", first ? "" : ",", string);

free(string); free(string);

first = 0; first = 0;

i++; i++;

if (i == len / pointer_size) { if (i == len / pointer_size) {

addr += len; addr += len;

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