diff options
| -rw-r--r-- | client/mysqltest.cc | 11 | ||||
| -rw-r--r-- | include/my_stacktrace.h | 2 | ||||
| -rw-r--r-- | mysys/stacktrace.c | 103 | ||||
| -rw-r--r-- | sql/mysqld.cc | 14 |
4 files changed, 112 insertions, 18 deletions
diff --git a/client/mysqltest.cc b/client/mysqltest.cc index fc111bf7645..9613bc2e929 100644 --- a/client/mysqltest.cc +++ b/client/mysqltest.cc @@ -8074,13 +8074,16 @@ static void dump_backtrace(void) { struct st_connection *conn= cur_con; - my_safe_print_str("read_command_buf", read_command_buf, - sizeof(read_command_buf)); + fprintf(stderr, "read_command_buf (%p): ", read_command_buf); + my_safe_print_str(read_command_buf, sizeof(read_command_buf)); + if (conn) { - my_safe_print_str("conn->name", conn->name, conn->name_len); + fprintf(stderr, "conn->name (%p): ", conn->name); + my_safe_print_str(conn->name, conn->name_len); #ifdef EMBEDDED_LIBRARY - my_safe_print_str("conn->cur_query", conn->cur_query, conn->cur_query_len); + fprintf(stderr, "conn->cur_query (%p): ", conn->cur_query); + my_safe_print_str(conn->cur_query, conn->cur_query_len); #endif } fputs("Attempting backtrace...\n", stderr); diff --git a/include/my_stacktrace.h b/include/my_stacktrace.h index 78e3dbca577..8c2c97c68e5 100644 --- a/include/my_stacktrace.h +++ b/include/my_stacktrace.h @@ -45,7 +45,7 @@ C_MODE_START #if defined(HAVE_STACKTRACE) || defined(HAVE_BACKTRACE) void my_init_stacktrace(); void my_print_stacktrace(uchar* stack_bottom, ulong thread_stack); -void my_safe_print_str(const char* name, const char* val, int max_len); +void my_safe_print_str(const char* val, int max_len); void my_write_core(int sig); #if BACKTRACE_DEMANGLE char *my_demangle(const char *mangled_name, int *status); diff --git a/mysys/stacktrace.c b/mysys/stacktrace.c index 451a2c7d06a..ed3a15ae27e 100644 --- a/mysys/stacktrace.c +++ b/mysys/stacktrace.c @@ -24,6 +24,11 @@ #include <unistd.h> #include <strings.h> +#ifdef __linux__ +#include <ctype.h> /* isprint */ +#include <sys/syscall.h> /* SYS_gettid */ +#endif + #if HAVE_EXECINFO_H #include <execinfo.h> #endif @@ -43,10 +48,96 @@ void my_init_stacktrace() #endif } -void my_safe_print_str(const char* name, const char* val, int max_len) +#ifdef __linux__ + +static void print_buffer(char *buffer, size_t count) +{ + for (; count && *buffer; --count) + { + int c= (int) *buffer++; + fputc(isprint(c) ? c : ' ', stderr); + } +} + +/** + Access the pages of this process through /proc/self/task/<tid>/mem + in order to safely print the contents of a memory address range. + + @param addr The address at the start of the memory region. + @param max_len The length of the memory region. + + @return Zero on success. +*/ +static int safe_print_str(const char *addr, int max_len) +{ + int fd; + pid_t tid; + off_t offset; + ssize_t nbytes= 0; + size_t total, count; + char buf[256]; + + tid= (pid_t) syscall(SYS_gettid); + + sprintf(buf, "/proc/self/task/%d/mem", tid); + + if ((fd= open(buf, O_RDONLY)) < 0) + return -1; + + total= max_len; + offset= (off_t) addr; + + /* Read up to the maximum number of bytes. */ + while (total) + { + count= min(sizeof(buf), total); + + if ((nbytes= pread(fd, buf, count, offset)) < 0) + { + /* Just in case... */ + if (errno == EINTR) + continue; + else + break; + } + + /* Advance offset into memory. */ + total-= nbytes; + offset+= nbytes; + addr+= nbytes; + + /* Output the printable characters. */ + print_buffer(buf, nbytes); + + /* Break if less than requested... */ + if ((count - nbytes)) + break; + } + + /* Output a new line if something was printed. */ + if (total != (size_t) max_len) + fputc('\n', stderr); + + if (nbytes == -1) + fprintf(stderr, "Can't read from address %p: %m.\n", addr); + + close(fd); + + return 0; +} + +#endif + +void my_safe_print_str(const char* val, int max_len) { - char *heap_end= (char*) sbrk(0); - fprintf(stderr, "%s at %p ", name, val); + char *heap_end; + +#ifdef __linux__ + if (!safe_print_str(val, max_len)) + return; +#endif + + heap_end= (char*) sbrk(0); if (!PTR_SANE(val)) { @@ -54,7 +145,6 @@ void my_safe_print_str(const char* name, const char* val, int max_len) return; } - fprintf(stderr, "= "); for (; max_len && PTR_SANE(val) && *val; --max_len) fputc(*val++, stderr); fputc('\n', stderr); @@ -607,10 +697,9 @@ void my_write_core(int unused) } -void my_safe_print_str(const char *name, const char *val, int len) +void my_safe_print_str(const char *val, int len) { - fprintf(stderr,"%s at %p", name, val); - __try + __try { fprintf(stderr,"=%.*s\n", len, val); } diff --git a/sql/mysqld.cc b/sql/mysqld.cc index 7fec30520d0..cf8fd7f7d2e 100644 --- a/sql/mysqld.cc +++ b/sql/mysqld.cc @@ -2427,7 +2427,7 @@ the thread stack. Please read http://dev.mysql.com/doc/mysql/en/linux.html\n\n", if (!(test_flags & TEST_NO_STACKTRACE)) { - fprintf(stderr, "thd: 0x%lx\n",(long) thd); + fprintf(stderr, "Thread pointer: 0x%lx\n", (long) thd); fprintf(stderr, "Attempting backtrace. You can use the following " "information to find out\nwhere mysqld died. If " "you see no messages after this, something went\n" @@ -2455,11 +2455,13 @@ the thread stack. Please read http://dev.mysql.com/doc/mysql/en/linux.html\n\n", kreason= "KILLED_NO_VALUE"; break; } - fprintf(stderr, "Trying to get some variables.\n\ -Some pointers may be invalid and cause the dump to abort...\n"); - my_safe_print_str("thd->query", thd->query(), 1024); - fprintf(stderr, "thd->thread_id=%lu\n", (ulong) thd->thread_id); - fprintf(stderr, "thd->killed=%s\n", kreason); + fprintf(stderr, "\nTrying to get some variables.\n" + "Some pointers may be invalid and cause the dump to abort.\n"); + fprintf(stderr, "Query (%p): ", thd->query()); + my_safe_print_str(thd->query(), min(1024, thd->query_length())); + fprintf(stderr, "Connection ID (thread ID): %lu\n", (ulong) thd->thread_id); + fprintf(stderr, "Status: %s\n", kreason); + fputc('\n', stderr); } fprintf(stderr, "\ The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains\n\ |