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bionic/linker/linker_format.c
David 'Digit' Turner 5c734644ee Fix debug output in the dynamic linker. 
This provides a mini-printf implementation that reduces the
size of the dynamic linker by 25 KB, by preventing the drag of
formatting-related routines from the C library.

Also allow traces to be sent to the log, instead of stdout.

NOTE: You now need to modify Android.mk to enable/disable debug
      output.
2010-02-11 10:46:48 -08:00

704 lines
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/*
* Copyright (C) 2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdint.h>
#include <stddef.h>
#include "linker_format.h"
#include "linker_debug.h"
/* define UNIT_TESTS to build this file as a single executable that runs
* the formatter's unit tests
*/
#define xxUNIT_TESTS
/*** Generic output sink
***/
typedef struct {
void *opaque;
void (*send)(void *opaque, const char *data, int len);
} Out;
static void
out_send(Out *o, const void *data, size_t len)
{
o->send(o->opaque, data, (int)len);
}
static void
out_send_repeat(Out *o, char ch, int count)
{
char pad[8];
const int padSize = (int)sizeof(pad);
memset(pad, ch, sizeof(pad));
while (count > 0) {
int avail = count;
if (avail > padSize) {
avail = padSize;
}
o->send(o->opaque, pad, avail);
count -= avail;
}
}
/* forward declaration */
static void
out_vformat(Out *o, const char *format, va_list args);
/*** Bounded buffer output
***/
typedef struct {
Out out[1];
char *buffer;
char *pos;
char *end;
int total;
} BufOut;
static void
buf_out_send(void *opaque, const char *data, int len)
{
BufOut *bo = opaque;
if (len < 0)
len = strlen(data);
bo->total += len;
while (len > 0) {
int avail = bo->end - bo->pos;
if (avail == 0)
break;
if (avail > len)
avail = len;
memcpy(bo->pos, data, avail);
bo->pos += avail;
bo->pos[0] = '\0';
len -= avail;
}
}
static Out*
buf_out_init(BufOut *bo, char *buffer, size_t size)
{
if (size == 0)
return NULL;
bo->out->opaque = bo;
bo->out->send = buf_out_send;
bo->buffer = buffer;
bo->end = buffer + size - 1;
bo->pos = bo->buffer;
bo->pos[0] = '\0';
bo->total = 0;
return bo->out;
}
static int
buf_out_length(BufOut *bo)
{
return bo->total;
}
static int
vformat_buffer(char *buff, size_t buffsize, const char *format, va_list args)
{
BufOut bo;
Out *out;
out = buf_out_init(&bo, buff, buffsize);
if (out == NULL)
return 0;
out_vformat(out, format, args);
return buf_out_length(&bo);
}
int
format_buffer(char *buff, size_t buffsize, const char *format, ...)
{
va_list args;
int ret;
va_start(args, format);
ret = vformat_buffer(buff, buffsize, format, args);
va_end(args);
return ret;
}
/* The __stack_chk_fail() function calls __libc_android_log_print()
* which calls vsnprintf().
*
* We define our version of the function here to avoid dragging
* about 25 KB of C library routines related to formatting.
*/
int
vsnprintf(char *buff, size_t bufsize, const char *format, va_list args)
{
return format_buffer(buff, bufsize, format, args);
}
#if LINKER_DEBUG
#if !LINKER_DEBUG_TO_LOG
/*** File descriptor output
***/
typedef struct {
Out out[1];
int fd;
int total;
} FdOut;
static void
fd_out_send(void *opaque, const char *data, int len)
{
FdOut *fdo = opaque;
if (len < 0)
len = strlen(data);
while (len > 0) {
int ret = write(fdo->fd, data, len);
if (ret < 0) {
if (errno == EINTR)
continue;
break;
}
data += ret;
len -= ret;
fdo->total += ret;
}
}
static Out*
fd_out_init(FdOut *fdo, int fd)
{
fdo->out->opaque = fdo;
fdo->out->send = fd_out_send;
fdo->fd = fd;
fdo->total = 0;
return fdo->out;
}
static int
fd_out_length(FdOut *fdo)
{
return fdo->total;
}
int
format_fd(int fd, const char *format, ...)
{
FdOut fdo;
Out* out;
va_list args;
out = fd_out_init(&fdo, fd);
if (out == NULL)
return 0;
va_start(args, format);
out_vformat(out, format, args);
va_end(args);
return fd_out_length(&fdo);
}
#else /* LINKER_DEBUG_TO_LOG */
/*** Log output
***/
/* We need our own version of __libc_android_log_vprint, otherwise
* the log output is completely broken. Probably due to the fact
* that the C library is not initialized yet.
*
* You can test that by setting CUSTOM_LOG_VPRINT to 0
*/
#define CUSTOM_LOG_VPRINT 1
#if CUSTOM_LOG_VPRINT
#include <unistd.h>
#include <fcntl.h>
#include <sys/uio.h>
static int log_vprint(int prio, const char *tag, const char *fmt, va_list args)
{
char buf[1024];
int result;
static int log_fd = -1;
result = vformat_buffer(buf, sizeof buf, fmt, args);
if (log_fd < 0) {
log_fd = open("/dev/log/main", O_WRONLY);
if (log_fd < 0)
return result;
}
{
ssize_t ret;
struct iovec vec[3];
vec[0].iov_base = (unsigned char *) &prio;
vec[0].iov_len = 1;
vec[1].iov_base = (void *) tag;
vec[1].iov_len = strlen(tag) + 1;
vec[2].iov_base = (void *) buf;
vec[2].iov_len = strlen(buf) + 1;
do {
ret = writev(log_fd, vec, 3);
} while ((ret < 0) && (errno == EINTR));
}
return result;
}
#define __libc_android_log_vprint log_vprint
#else /* !CUSTOM_LOG_VPRINT */
extern int __libc_android_log_vprint(int prio, const char* tag, const char* format, va_list ap);
#endif /* !CUSTOM_LOG_VPRINT */
int
format_log(int prio, const char *tag, const char *format, ...)
{
int ret;
va_list args;
va_start(args, format);
ret = __libc_android_log_vprint(prio, tag, format, args);
va_end(args);
return ret;
}
#endif /* LINKER_DEBUG_TO_LOG */
#endif /* LINKER_DEBUG */
/*** formatted output implementation
***/
/* Parse a decimal string from 'format + *ppos',
* return the value, and writes the new position past
* the decimal string in '*ppos' on exit.
*
* NOTE: Does *not* handle a sign prefix.
*/
static unsigned
parse_decimal(const char *format, int *ppos)
{
const char* p = format + *ppos;
unsigned result = 0;
for (;;) {
int ch = *p;
unsigned d = (unsigned)(ch - '0');
if (d >= 10U)
break;
result = result*10 + d;
p++;
}
*ppos = p - format;
return result;
}
/* write an octal/decimal/number into a bounded buffer.
* assumes that bufsize > 0, and 'digits' is a string of
* digits of at least 'base' values.
*/
static void
format_number(char *buffer, size_t bufsize, uint64_t value, int base, const char *digits)
{
char *pos = buffer;
char *end = buffer + bufsize - 1;
/* generate digit string in reverse order */
while (value) {
unsigned d = value % base;
value /= base;
if (pos < end) {
*pos++ = digits[d];
}
}
/* special case for 0 */
if (pos == buffer) {
if (pos < end) {
*pos++ = '0';
}
}
pos[0] = '\0';
/* now reverse digit string in-place */
end = pos - 1;
pos = buffer;
while (pos < end) {
int ch = pos[0];
pos[0] = end[0];
end[0] = (char) ch;
pos++;
end--;
}
}
/* Write an integer (octal or decimal) into a buffer, assumes buffsize > 2 */
static void
format_integer(char *buffer, size_t buffsize, uint64_t value, int base, int isSigned)
{
if (isSigned && (int64_t)value < 0) {
buffer[0] = '-';
buffer += 1;
buffsize -= 1;
value = (uint64_t)(-(int64_t)value);
}
format_number(buffer, buffsize, value, base, "0123456789");
}
/* Write an octal into a buffer, assumes buffsize > 2 */
static void
format_octal(char *buffer, size_t buffsize, uint64_t value, int isSigned)
{
format_integer(buffer, buffsize, value, 8, isSigned);
}
/* Write a decimal into a buffer, assumes buffsize > 2 */
static void
format_decimal(char *buffer, size_t buffsize, uint64_t value, int isSigned)
{
format_integer(buffer, buffsize, value, 10, isSigned);
}
/* Write an hexadecimal into a buffer, isCap is true for capital alphas.
* Assumes bufsize > 2 */
static void
format_hex(char *buffer, size_t buffsize, uint64_t value, int isCap)
{
const char *digits = isCap ? "0123456789ABCDEF" : "0123456789abcdef";
format_number(buffer, buffsize, value, 16, digits);
}
/* Perform formatted output to an output target 'o' */
static void
out_vformat(Out *o, const char *format, va_list args)
{
int nn = 0, mm;
int padZero = 0;
int padLeft = 0;
char sign = '\0';
int width = -1;
int prec = -1;
size_t bytelen = sizeof(int);
const char* str;
int slen;
char buffer[32]; /* temporary buffer used to format numbers */
for (;;) {
char c;
/* first, find all characters that are not 0 or '%' */
/* then send them to the output directly */
mm = nn;
do {
c = format[mm];
if (c == '\0' || c == '%')
break;
mm++;
} while (1);
if (mm > nn) {
out_send(o, format+nn, mm-nn);
nn = mm;
}
/* is this it ? then exit */
if (c == '\0')
break;
/* nope, we are at a '%' modifier */
nn++; // skip it
/* parse flags */
for (;;) {
c = format[nn++];
if (c == '\0') { /* single trailing '%' ? */
c = '%';
out_send(o, &c, 1);
return;
}
else if (c == '0') {
padZero = 1;
continue;
}
else if (c == '-') {
padLeft = 1;
continue;
}
else if (c == ' ' || c == '+') {
sign = c;
continue;
}
break;
}
/* parse field width */
if ((c >= '0' && c <= '9')) {
nn --;
width = (int)parse_decimal(format, &nn);
c = format[nn++];
}
/* parse precision */
if (c == '.') {
prec = (int)parse_decimal(format, &nn);
c = format[nn++];
}
/* length modifier */
switch (c) {
case 'h':
bytelen = sizeof(short);
if (format[nn] == 'h') {
bytelen = sizeof(char);
nn += 1;
}
c = format[nn++];
break;
case 'l':
bytelen = sizeof(long);
if (format[nn] == 'l') {
bytelen = sizeof(long long);
nn += 1;
}
c = format[nn++];
break;
case 'z':
bytelen = sizeof(size_t);
c = format[nn++];
break;
case 't':
bytelen = sizeof(ptrdiff_t);
c = format[nn++];
break;
case 'p':
bytelen = sizeof(void*);
c = format[nn++];
default:
;
}
/* conversion specifier */
if (c == 's') {
/* string */
str = va_arg(args, const char*);
} else if (c == 'c') {
/* character */
/* NOTE: char is promoted to int when passed through the stack */
buffer[0] = (char) va_arg(args, int);
buffer[1] = '\0';
str = buffer;
} else if (c == 'p') {
uint64_t value = (uint64_t)(ptrdiff_t) va_arg(args, void*);
buffer[0] = '0';
buffer[1] = 'x';
format_hex(buffer + 2, sizeof buffer-2, value, 0);
str = buffer;
} else {
/* integers - first read value from stack */
uint64_t value;
int isSigned = (c == 'd' || c == 'i' || c == 'o');
/* NOTE: int8_t and int16_t are promoted to int when passed
* through the stack
*/
switch (bytelen) {
case 1: value = (uint8_t) va_arg(args, int); break;
case 2: value = (uint16_t) va_arg(args, int); break;
case 4: value = va_arg(args, uint32_t); break;
case 8: value = va_arg(args, uint64_t); break;
default: return; /* should not happen */
}
/* sign extension, if needed */
if (isSigned) {
int shift = 64 - 8*bytelen;
value = (uint64_t)(((int64_t)(value << shift)) >> shift);
}
/* format the number properly into our buffer */
switch (c) {
case 'i': case 'd':
format_integer(buffer, sizeof buffer, value, 10, isSigned);
break;
case 'o':
format_integer(buffer, sizeof buffer, value, 8, isSigned);
break;
case 'x': case 'X':
format_hex(buffer, sizeof buffer, value, (c == 'X'));
break;
default:
buffer[0] = '\0';
}
/* then point to it */
str = buffer;
}
/* if we are here, 'str' points to the content that must be
* outputted. handle padding and alignment now */
slen = strlen(str);
if (slen < width && !padLeft) {
char padChar = padZero ? '0' : ' ';
out_send_repeat(o, padChar, width - slen);
}
out_send(o, str, slen);
if (slen < width && padLeft) {
char padChar = padZero ? '0' : ' ';
out_send_repeat(o, padChar, width - slen);
}
}
}
#ifdef UNIT_TESTS
#include <stdio.h>
static int gFails = 0;
#define MARGIN 40
#define UTEST_CHECK(condition,message) \
printf("Checking %-*s: ", MARGIN, message); fflush(stdout); \
if (!(condition)) { \
printf("KO\n"); \
gFails += 1; \
} else { \
printf("ok\n"); \
}
static void
utest_BufOut(void)
{
char buffer[16];
BufOut bo[1];
Out* out;
int ret;
buffer[0] = '1';
out = buf_out_init(bo, buffer, sizeof buffer);
UTEST_CHECK(buffer[0] == '\0', "buf_out_init clears initial byte");
out_send(out, "abc", 3);
UTEST_CHECK(!memcmp(buffer, "abc", 4), "out_send() works with BufOut");
out_send_repeat(out, 'X', 4);
UTEST_CHECK(!memcmp(buffer, "abcXXXX", 8), "out_send_repeat() works with BufOut");
buffer[sizeof buffer-1] = 'x';
out_send_repeat(out, 'Y', 2*sizeof(buffer));
UTEST_CHECK(buffer[sizeof buffer-1] == '\0', "overflows always zero-terminates");
out = buf_out_init(bo, buffer, sizeof buffer);
out_send_repeat(out, 'X', 2*sizeof(buffer));
ret = buf_out_length(bo);
UTEST_CHECK(ret == 2*sizeof(buffer), "correct size returned on overflow");
}
static void
utest_expect(const char* result, const char* format, ...)
{
va_list args;
BufOut bo[1];
char buffer[256];
Out* out = buf_out_init(bo, buffer, sizeof buffer);
printf("Checking %-*s: ", MARGIN, format); fflush(stdout);
va_start(args, format);
out_vformat(out, format, args);
va_end(args);
if (strcmp(result, buffer)) {
printf("KO. got '%s' expecting '%s'\n", buffer, result);
gFails += 1;
} else {
printf("ok. got '%s'\n", result);
}
}
int main(void)
{
utest_BufOut();
utest_expect("", "");
utest_expect("a", "a");
utest_expect("01234", "01234", "");
utest_expect("01234", "%s", "01234");
utest_expect("aabbcc", "aa%scc", "bb");
utest_expect("a", "%c", 'a');
utest_expect("1234", "%d", 1234);
utest_expect("-8123", "%d", -8123);
utest_expect("16", "%hd", 0x7fff0010);
utest_expect("16", "%hhd", 0x7fffff10);
utest_expect("68719476736", "%lld", 0x1000000000);
utest_expect("70000", "%ld", 70000);
utest_expect("0xb0001234", "%p", (void*)0xb0001234);
utest_expect("12ab", "%x", 0x12ab);
utest_expect("12AB", "%X", 0x12ab);
utest_expect("00123456", "%08x", 0x123456);
utest_expect("01234", "0%d", 1234);
utest_expect(" 1234", "%5d", 1234);
utest_expect("01234", "%05d", 1234);
utest_expect(" 1234", "%8d", 1234);
utest_expect("1234 ", "%-8d", 1234);
utest_expect("abcdef ", "%-11s", "abcdef");
utest_expect("something:1234", "%s:%d", "something", 1234);
return gFails != 0;
}
#endif /* UNIT_TESTS */
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