Hi GNU Team, I found that program called by timeout cannot interact with tty stdin when timeout is called by exec().
A simplest example is `timeout 10 timeout 5 cat`. cat cannot read input
from tty stdin.
I also tried to run `timeout 5 cat` in other programs by exec(), and
all of them cannot read tty stdin. For example,
import subprocess
subprocess.run(f"timeout 5 cat", shell=True)
with Python 3.
I guessed it is a problem with exec(), but trying with the simple C
program
/* system.c */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
int main(const int argc, const char* argv[]){
size_t cmd_length = argc;
for(int i=1; i<argc; i++){
cmd_length += strlen(argv[i]);
}
char* cmd_alloc = calloc(cmd_length, sizeof(char));
char* cmd = cmd_alloc;
for(int i=1; i<argc; i++){
strncpy(cmd_alloc, argv[i], strlen(argv[i]));
cmd_alloc += strlen(argv[i]);
cmd_alloc[0] = ' ';
cmd_alloc++;
}
cmd_alloc[ cmd_alloc != cmd ? -1 : 0 ] = '\0';
//printf("%s\n", cmd);
system(cmd);
free(cmd);
return 0;
}
with `./system ./system cat` it works as expected, while running
`./system timeout 5 cat` the bug occurs.
This bug (or is it a feature?) appears in coreutils 8.32 and 9.0, as I
have tested.
--
Zhaofeng Yang <yangzhaof...@arcas-da.com>
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