diff options
Diffstat (limited to 'src/user/app/shell/shell.c')
| -rw-r--r-- | src/user/app/shell/shell.c | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/src/user/app/shell/shell.c b/src/user/app/shell/shell.c index 66725a1..505997a 100644 --- a/src/user/app/shell/shell.c +++ b/src/user/app/shell/shell.c @@ -62,9 +62,44 @@ static void run_args(int argc, char **argv, struct redir *redir) { return; } - if (redir->stdout && !freopen(redir->stdout, redir->append ? "a" : "w", stdout)) { - eprintf("couldn't open %s for redirection", redir->stdout); - exit(0); + if (redir->stdout) { + FILE *f = fopen(redir->stdout, redir->append ? "a" : "w"); + if (!f) { + eprintf("couldn't open %s for redirection", redir->stdout); + exit(1); + } + + /* a workaround for file offsets not being preserved across exec()s. + * TODO document that weird behaviour of exec() */ + + handle_t p[2]; + if (_syscall_pipe(p, 0) < 0) { + eprintf("couldn't create redirection pipe", redir->stdout); + exit(1); + } + if (!_syscall_fork(FORK_NOREAP, NULL)) { + /* the child forwards data from the pipe to the file */ + const size_t buflen = 512; + char *buf = malloc(buflen); + if (!buf) { + eprintf("when redirecting: malloc failure"); + exit(1); + } + close(p[1]); + for (;;) { + long len = _syscall_read(p[0], buf, buflen, 0); + if (len < 0) exit(0); + fwrite(buf, 1, len, f); + if (ferror(f)) exit(0); + } + } + + fclose(f); + close(p[0]); + if (_syscall_dup(p[1], 1, 0) < 0) { + eprintf("dup failure"); + exit(1); + } } for (struct builtin *iter = builtins; iter->name; iter++) { |