From e8aedb0ef4f73961a98a1505527dc9ec8780a0d5 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Wed, 27 Jul 2022 21:09:31 +0200
Subject: user/shell: basic shell script support

---
 src/user/app/shell/parser.c | 12 +++++++++++-
 src/user/app/shell/shell.c  | 24 +++++++++++++++++-------
 2 files changed, 28 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/user/app/shell/parser.c b/src/user/app/shell/parser.c
index bd70350..878202d 100644
--- a/src/user/app/shell/parser.c
+++ b/src/user/app/shell/parser.c
@@ -13,11 +13,16 @@ static char skipspace(char **sp) {
 	return *s;
 }
 
+static bool isspecial(char c) {
+	return c == '>' || c == '#';
+}
+
 static char *parg(char **sp) {
 	char *s = *sp;
 	char *res = NULL;
 
 	if (skipspace(&s)) {
+		// TODO incorrectly handles strings like a"b"
 		switch (*s) {
 			case '"':
 				s++;
@@ -27,8 +32,13 @@ static char *parg(char **sp) {
 				break;
 			default:
 				res = s;
-				while (*s && !isspace(*s) && *s != '>')
+				while (*s && !isspace(*s) && !isspecial(*s))
 					s++;
+				if (*s == '#') {
+					*s = '\0'; /* end parsing early */
+					if (res == s) /* don't output an empty arg */
+						res = NULL;
+				}
 				break;
 		}
 		if (*s) *s++ = '\0';
diff --git a/src/user/app/shell/shell.c b/src/user/app/shell/shell.c
index e1514d9..995ce53 100644
--- a/src/user/app/shell/shell.c
+++ b/src/user/app/shell/shell.c
@@ -10,11 +10,10 @@
 
 int main();
 
-// TODO fgets
-static int readline(char *buf, size_t max) {
+static int readline(char *buf, size_t max, FILE *f) {
 	char c = '\0';
 	size_t pos = 0;
-	while (pos < (max-1) && c != '\n' && fread(&c, 1, 1, stdin))
+	while (pos < (max-1) && c != '\n' && fread(&c, 1, 1, f))
 		buf[pos++] = c;
 	buf[pos++] = '\0';
 	return pos;
@@ -111,12 +110,23 @@ static void run(char *cmd) {
 }
 
 
-int main(void) {
+int main(int argc, char **argv) {
 	static char buf[256];
+	FILE *f = stdin;
+
+	if (argc > 1) {
+		f = fopen(argv[1], "r");
+		if (!f) {
+			printf("sh: couldn't open %s\n", argv[1]);
+			return 1;
+		}
+	}
+
 	for (;;) {
-		printf("$ ");
-		readline(buf, 256);
-		if (feof(stdin)) return 0;
+		if (f == stdin)
+			printf("$ ");
+		readline(buf, 256, f);
+		if (feof(f)) return 0;
 		run(buf);
 	}
 }
-- 
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