From a52ceb05e49d6d5b5adeaa733037d558187848f7 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 7 Aug 2022 17:45:11 +0200
Subject: user/shell: make `>>` work for executables
---
src/user/app/shell/shell.c | 41 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 38 insertions(+), 3 deletions(-)
(limited to 'src/user')
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++) {
--
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