heh

err.c

@@ -0,0 +1,55 @@
+#define _POSIX_C_SOURCE 200809l
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include "err.h"
+
+void die(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+
+     	vfprintf(stderr, fmt, ap);
+
+	if (fmt[0] && fmt[strlen(fmt) - 1] == ':')
+		fprintf(stderr, " %s", strerror(errno));
+	else
+		fputc('\n', stderr);
+
+	va_end(ap);
+	exit(errno ? errno : EXIT_FAILURE);
+}
+
+void *emalloc(size_t s)
+{
+	if (!s || s == (size_t)-1)
+		die("bad malloc: invalid size");
+	void *p = malloc(s);
+	if (!p)
+		die("bad malloc:");
+	return p;
+}
+
+void *erealloc(void *p, size_t s)
+{
+	if (!s || s == (size_t)-1)
+		die("bad realloc: invalid size");
+	void *r = realloc(p, s);
+	if (!r)
+		die("bad realloc:");
+	return r;
+}
+
+char *estrdup(const char *s)
+{
+	if (!s)
+		die("bad strdup: cannot duplicate NULL pointer");
+	char *r = strdup(s);
+	if (!r)
+		die("bad strdup:");
+	return r;
+}

err.h

@@ -0,0 +1,16 @@
+#ifndef _ACRON_ERR_H
+#define _ACRON_ERR_H
+
+/* Helper error/error-ing functions, like die() and dying versions of memory
+ * allocating functions */
+
+#include <stdlib.h>
+
+void die(const char *, ...);
+
+/* Erroring functions */
+void *emalloc(size_t);
+void *erealloc(void *, size_t);
+char *estrdup(const char *);
+
+#endif

fstr.c

@@ -3,11 +3,12 @@
 #include <stdlib.h>
 
 #include "fstr.h"
+#include "err.h"
 #include "config.h"
 
 void fstr_add_space(fstr_t *fs)
 {
-	erealloc(fs->s, fs->len + fs->space + DEF_CHUNKSIZE + 1);
+	fs->s = erealloc(fs->s, fs->len + fs->space + DEF_CHUNKSIZE + 1);
 	fs->space += DEF_CHUNKSIZE;
 }
 
@@ -17,7 +18,15 @@ void fstr_append_char(fstr_t *fs, char c)
 		return;
 	if (fs->space < 1)
 		fstr_add_space(fs);
-	fs->s[fs->len++] = c;
-	fs->s[fs->len] = '\0';
+	// I don't know if this is faster
+	if (fs->s[fs->len] != c)
+		fs->s[fs->len] = c;
+	fs->s[++fs->len] = '\0';
 	fs->space--;
 }
+
+void fstr_clear(fstr_t *fs)
+{
+	fs->space += fs->len;
+	fs->len = 0;
+}

fstr.h

@@ -10,5 +10,6 @@ typedef struct _fstr {
 } fstr_t;
 
 void fstr_append_char(fstr_t *, char);
+void fstr_clear(fstr_t *);
 
 #endif

makefile

@@ -1,8 +1,8 @@
 .POSIX:
 
-CFLAGS = -Wall -Werror -pedantic -Wextra -std=c11
+CFLAGS = -Wall -Werror -pedantic -Wextra -std=c11 -O0 -g
 
-msh: msh.c fstr.c
+msh: msh.c fstr.c err.c
 
 clean:
 	rm -f msh *.o

msh.c

@@ -2,13 +2,15 @@
 
 #include <sys/types.h>
 
-#include <stdio.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <unistd.h>
 #include <pwd.h>
+#include <termios.h>
 
 #include "config.h"
 #include "fstr.h"
+#include "err.h"
 
 fstr_t PS1 = {0};
 unsigned int histsize = DEF_HISTSIZE;
@@ -26,6 +28,12 @@ struct {
 	char tag;
 } shinfo;
 
+struct {
+	struct termios tio;
+	struct termios tio_before;
+} terminfo;
+
+void sh_setup_terminal(void);
 void sh_update_uinfo(void);
 void sh_update_shinfo(void);
 void sh_update_ps1(void);
@@ -35,19 +43,40 @@ int main(int argc, char **argv)
 {
 	(void)argc;
 	(void)argv;
+	char i;
 
+	sh_setup_terminal();
 	for (;;) {
 		sh_update_uinfo();
 		sh_update_shinfo();
 		sh_update_ps1();
 		sh_print_ps1();
-		for(;;);
+		fflush(stdout);
+		while (1) {
+			read(STDIN_FILENO, &i, 1); // This blocks
+			fputc(i, stdout);
+			fflush(stdout);
+			if (i == '\n')
+				break;
+		}
 	}
 
 	return EXIT_SUCCESS;
 }
 
-void sh_fill_uinfo(void)
+void sh_setup_terminal(void)
+{
+	if (tcgetattr(STDOUT_FILENO, &terminfo.tio_before) == -1)
+		die("tcgetattr:");
+	terminfo.tio = terminfo.tio_before;
+	/* Do not echo and input is available immediately */
+	terminfo.tio.c_lflag &= ~ECHO;
+	terminfo.tio.c_lflag &= ~ICANON;
+	if (tcsetattr(STDOUT_FILENO, TCSANOW, &terminfo.tio) == -1)
+		die("tcsetattr:");
+}
+
+void sh_update_uinfo(void)
 {
 	struct passwd *pw;
 	uid_t nuid;
@@ -58,7 +87,7 @@ void sh_fill_uinfo(void)
 	pw = getpwuid(uinfo.uid);
 	// User not found
 	if (!pw)
-		exit(EXIT_FAILURE);
+		die("getpwuid:");
 	uinfo.gid = pw->pw_gid;
 	uinfo.name = estrdup(pw->pw_name);
 	uinfo.home = estrdup(pw->pw_dir);
@@ -69,13 +98,14 @@ void sh_update_shinfo(void)
 	shinfo.tag = uinfo.uid ? '$' : '#';
 }
 
-inline void sh_print_ps1(void)
+void sh_print_ps1(void)
 {
-	puts(PS1.s);
+	fputs(PS1.s, stdout);
 }
 
 void sh_update_ps1(void)
 {
+	fstr_clear(&PS1);
 	fstr_append_char(&PS1, shinfo.tag);
 	fstr_append_char(&PS1, ' ');
 }