MDEV-23491: __bss_start breaks compilation of various platforms
Remove __bss_start & Co, because systen call "write" check buffer address and return EFAULT if it is wrong.
This commit is contained in:
Oleksandr Byelkin
parent
5796021174
commit
ece0b0623c
@ -34,107 +34,16 @@
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#include <execinfo.h>
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#endif
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#ifdef __linux__
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#define PTR_SANE(p) ((p) && (char*)(p) >= heap_start && (char*)(p) <= heap_end)
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static char *heap_start;
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char *__bss_start;
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#else
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#define PTR_SANE(p) (p)
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#endif /* __linux */
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void my_init_stacktrace()
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{
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#ifdef __linux__
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heap_start = (char*) &__bss_start;
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#endif /* __linux__ */
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}
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#ifdef __linux__
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static void print_buffer(char *buffer, size_t count)
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{
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const char s[]= " ";
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for (; count && *buffer; --count)
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{
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my_write_stderr(isprint(*buffer) ? buffer : s, 1);
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++buffer;
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}
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}
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/**
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Access the pages of this process through /proc/self/task/<tid>/mem
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in order to safely print the contents of a memory address range.
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@param addr The address at the start of the memory region.
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@param max_len The length of the memory region.
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@return Zero on success.
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*/
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static int safe_print_str(const char *addr, int max_len)
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{
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int fd;
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pid_t tid;
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off_t offset;
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ssize_t nbytes= 0;
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size_t total, count;
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char buf[256];
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tid= (pid_t) syscall(SYS_gettid);
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sprintf(buf, "/proc/self/task/%d/mem", tid);
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if ((fd= open(buf, O_RDONLY)) < 0)
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return -1;
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/* Ensure that off_t can hold a pointer. */
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compile_time_assert(sizeof(off_t) >= sizeof(intptr));
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total= max_len;
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offset= (intptr) addr;
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/* Read up to the maximum number of bytes. */
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while (total)
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{
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count= MY_MIN(sizeof(buf), total);
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if ((nbytes= pread(fd, buf, count, offset)) < 0)
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{
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/* Just in case... */
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if (errno == EINTR)
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continue;
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else
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break;
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}
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/* Advance offset into memory. */
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total-= nbytes;
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offset+= nbytes;
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addr+= nbytes;
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/* Output the printable characters. */
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print_buffer(buf, nbytes);
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/* Break if less than requested... */
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if ((count - nbytes))
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break;
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}
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if (nbytes == -1)
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my_safe_printf_stderr("Can't read from address %p", addr);
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close(fd);
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return 0;
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}
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#endif
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/*
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Attempt to print a char * pointer as a string.
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SYNOPSIS
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Prints either until the end of string ('\0'), or max_len characters have
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been printed.
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Prints until max_len characters have been printed.
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RETURN VALUE
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0 Pointer was within the heap address space.
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@ -149,24 +58,25 @@ static int safe_print_str(const char *addr, int max_len)
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int my_safe_print_str(const char* val, int max_len)
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{
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#ifdef __linux__
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char *heap_end;
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// Try and make use of /proc filesystem to safely print memory contents.
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if (!safe_print_str(val, max_len))
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return 0;
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heap_end= (char*) sbrk(0);
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#endif
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if (!PTR_SANE(val))
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const char *orig_val= val;
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if (!val)
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{
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my_safe_printf_stderr("%s", "is an invalid pointer");
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my_safe_printf_stderr("%s", "(null)");
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return 1;
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}
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for (; max_len && PTR_SANE(val) && *val; --max_len)
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my_write_stderr((val++), 1);
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for (; max_len; --max_len)
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{
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if (my_write_stderr((val++), 1) != 1)
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{
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if ((errno == EFAULT) &&(val == orig_val + 1))
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{
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// We can not read the address from very beginning
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my_safe_printf_stderr("Can't access address %p", orig_val);
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}
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break;
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}
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}
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my_safe_printf_stderr("%s", "\n");
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return 0;
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@ -15,7 +15,7 @@
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MY_ADD_TESTS(bitmap base64 my_atomic my_rdtsc lf my_malloc my_getopt dynstring
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aes
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queues LINK_LIBRARIES mysys)
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queues stacktrace LINK_LIBRARIES mysys)
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MY_ADD_TESTS(my_vsnprintf LINK_LIBRARIES strings mysys)
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ADD_DEFINITIONS(${SSL_DEFINES})
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67
unittest/mysys/stacktrace-t.c
Normal file
67
unittest/mysys/stacktrace-t.c
Normal file
@ -0,0 +1,67 @@
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/* Copyright (c) 2020, MariaDB Corporation.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
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#include <my_global.h>
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#include <my_sys.h>
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#include <stdio.h>
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#include <my_stacktrace.h>
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#include <tap.h>
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char b_bss[10];
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void test_my_safe_print_str()
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{
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char b_stack[10];
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char *b_heap= strdup("LEGAL");
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memcpy(b_stack, "LEGAL", 6);
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memcpy(b_bss, "LEGAL", 6);
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#ifndef __SANITIZE_ADDRESS__
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fprintf(stderr, "\n===== stack =====\n");
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my_safe_print_str(b_stack, 65535);
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fprintf(stderr, "\n===== heap =====\n");
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my_safe_print_str(b_heap, 65535);
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fprintf(stderr, "\n===== BSS =====\n");
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my_safe_print_str(b_bss, 65535);
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fprintf(stderr, "\n===== data =====\n");
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my_safe_print_str("LEGAL", 65535);
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fprintf(stderr, "\n===== Above is a junk, but it is expected. =====\n");
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#endif /*__SANITIZE_ADDRESS__*/
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fprintf(stderr, "\n===== Nornal length test =====\n");
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my_safe_print_str("LEGAL", 5);
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fprintf(stderr, "\n===== NULL =====\n");
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my_safe_print_str(0, 5);
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#ifndef __SANITIZE_ADDRESS__
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fprintf(stderr, "\n===== (const char*) 1 =====\n");
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my_safe_print_str((const char*)1, 5);
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#endif /*__SANITIZE_ADDRESS__*/
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free(b_heap);
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ok(1, "test_my_safe_print_str");
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}
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int main(int argc __attribute__((unused)), char **argv)
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{
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MY_INIT(argv[0]);
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plan(1);
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test_my_safe_print_str();
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my_end(0);
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return exit_status();
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}
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