1 /* This is part of GDB, the GNU debugger. 2 3 Copyright 2011-2020 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #define _GNU_SOURCE 1 20 #include <dlfcn.h> 21 #include <unistd.h> 22 #include <fcntl.h> 23 #include <stdlib.h> 24 25 /* Wrap 'read', forcing it to return only one byte at a time, if 26 reading from the terminal. */ 27 28 ssize_t 29 read (int fd, void *buf, size_t count) 30 { 31 static ssize_t (*read2) (int fd, void *buf, size_t count) = NULL; 32 if (read2 == NULL) 33 { 34 /* Use setenv (v, "", 1) rather than unsetenv (v) to work around 35 https://core.tcl-lang.org/tcl/tktview?name=67fd4f973a "incorrect 36 results of 'info exists' when unset env var in one interp and check 37 for existence from another interp". */ 38 setenv ("LD_PRELOAD", "", 1); 39 read2 = dlsym (RTLD_NEXT, "read"); 40 } 41 if (count > 1 && isatty (fd) >= 1) 42 count = 1; 43 return read2 (fd, buf, count); 44 } 45