History/arrow keys, improved tokenizer

diff --git a/main.c b/main.c
index f833d413fc79ec95a7c733f3c684ea15e3c59363..66ff91e0d96cbd49a5d839cb29931209039c63f2 100644 (file)
--- a/main.c
+++ b/main.c
@@ -1,4 +1,5 @@
 #include <err.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -15,9 +16,81 @@ void ashexit(void) {
        warn("Unable to return to initial terminal settings");
 }
 
+void *allocate(size_t s) {
+   void *r;
+
+   if (!(r = malloc(s))) err(EXIT_FAILURE, "Memory allocation");
+
+   return memset(r, 0, s);
+}
+
 #define BUFLEN 1024
-#define HISTLEN 1000
+#define HISTLEN 100
 #define PROMPT "% "
+#define HISTNAME ".ashhistory"
+
+char history[HISTLEN][BUFLEN], (*hb)[BUFLEN], (*hc)[BUFLEN], (*ht)[BUFLEN];
+static char *histpath;
+
+static void freehistpath(void) {
+   free(histpath);
+}
+
+void readhist(void) {
+   char *homepath;
+   FILE *histfile;
+   int e;
+
+   if (!(homepath = getenv("HOME")))
+       errx(EXIT_FAILURE, "HOME environment variable does not exist");
+   histpath = allocate(strlen(homepath) + 1 + strlen(HISTNAME) + 1);
+   if (atexit(freehistpath) == -1)
+       err(EXIT_FAILURE, "Unable to add `freehistpath()' to `atexit()'");
+   strcpy(histpath, homepath);
+   strcat(histpath, "/");
+   strcat(histpath, HISTNAME);
+
+   ht = hc = hb = history;
+   if (!(histfile = fopen(histpath, "r"))) {
+       if (errno == ENOENT) return;
+       err(EXIT_FAILURE, "Unable to open history file for reading");
+   }
+   while (fgets(*ht, BUFLEN, histfile)) {
+       *(*ht + strlen(*ht) - 1) = '\0'; // Get rid of newline
+       ht = history + (ht - history + 1) % HISTLEN;
+       if (ht == hb) hb = NULL;
+   }
+
+   e = ferror(histfile) || !feof(histfile);
+   if (fclose(histfile) == EOF) err(EXIT_FAILURE, "Unable to close history file");
+   if (e) err(EXIT_FAILURE, "Unable to read from history file");
+
+   if (!hb) hb = history + (ht - history + 1) % HISTLEN;
+   hc = ht;
+}
+
+void writehist(void) {
+   FILE *histfile;
+
+   if (!(histfile = fopen(histpath, "w"))) {
+       warn("Unable to open history file for writing");
+       return;
+   }
+
+   while (hb != ht) {
+       if (fputs(*hb, histfile) == EOF) {
+           warn("Unable to write to history file");
+           break;
+       }
+       if (fputc('\n', histfile) == EOF) {
+           warn("Unable to write newline to history file");
+           break;
+       }
+       hb = history + (hb - history + 1) % HISTLEN;
+   }
+
+   if (fclose(histfile) == EOF) warn("Unable to close history stream");
+}
 
 enum {
    CTRLC = '\003',
@@ -31,9 +104,7 @@ enum {
 };
 
 char *getinput(void) {
-   static char history[HISTLEN][BUFLEN], result[BUFLEN],
-               (*hb)[BUFLEN] = history, (*hc)[BUFLEN] = history,
-               (*ht)[BUFLEN] = history;
+   static char result[BUFLEN];
    char *cursor, *end;
    int c, i;
 
@@ -112,19 +183,50 @@ char *getinput(void) {
    return end > result ? result : NULL;
 }
 
+int delimiter(char c) {
+   return c == ' ' || c == '&' || c == '|' || c == ';' || c == '`' || c == '\0';
+}
+
 char **tokenize(char *p) {
    size_t i;
-   static char *result[BUFLEN / 2];
+   static char *result[BUFLEN];
 
    while (*p == ' ') ++p;
    for (i = 0; *p; ++i) {
-       result[i] = p;
-       while (*p != ' ' && *p != '\0') ++p;
-       if (*p == '\0') {
-           ++i;
+       switch (*p) {
+       case ' ':
+           --i;
+           *p++ = '\0';
+           while (*p == ' ') ++p;
+           break;
+       case '&':
+           *p++ = '\0';
+           if (*p == '&') {
+               ++p;
+               result[i] = "&&";
+           } else result[i] = "&";
+           break;
+       case '|':
+           *p++ = '\0';
+           if (*p == '|') {
+               ++p;
+               result[i] = "||";
+           } else result[i] = "|";
            break;
+       case ';':
+           *p++ = '\0';
+           result[i] = ";";
+           break;
+       case '`':
+           *p++ = '\0';
+           result[i] = p;
+           while (*p != '\'') ++p;
+           *p++ = '\0';
+           break;
+       default:
+           result[i] = p++;
+           while (!delimiter(*p)) ++p;
        }
-       while (*p == ' ') ++p;
    }
    result[i] = NULL;
    return result;
@@ -153,10 +255,10 @@ void await(pid_t cpgid) {
 
    if (waitpid(cpgid, &status, WUNTRACED) != -1 && !WIFSTOPPED(status)) {
        while (waitpid(-cpgid, NULL, 0) != -1);
-       if (errno != ECHILD && killpg(cpgid, SIGKILL) == -1) exit(EXIT_FAILURE);
+       if (errno != ECHILD && killpg(cpgid, SIGKILL) == -1) _Exit(EXIT_FAILURE);
    }
-   if (signal(SIGTTOU, SIG_IGN) == SIG_ERR) exit(EXIT_FAILURE);
-   if (tcsetpgrp(STDIN_FILENO, self) == -1) exit(EXIT_FAILURE);
+   if (signal(SIGTTOU, SIG_IGN) == SIG_ERR) _Exit(EXIT_FAILURE);
+   if (tcsetpgrp(STDIN_FILENO, self) == -1) _Exit(EXIT_FAILURE);
    if (signal(SIGTTOU, SIG_DFL) == SIG_ERR) warn("Ignoring signal SIGTTOU");
 
    if (WIFSIGNALED(status)) putchar('\n');
@@ -179,7 +281,7 @@ int builtin(char **tokens) {
            return 1;
        }
        if (killpg(fgpgid, SIGCONT) == -1) {
-           if (tcsetpgrp(STDIN_FILENO, self) == -1) exit(EXIT_FAILURE);
+           if (tcsetpgrp(STDIN_FILENO, self) == -1) _Exit(EXIT_FAILURE);
            warn("Unable to wake up process group %d", fgpgid);
            return 1;
        }
@@ -194,6 +296,10 @@ int main(void) {
    pid_t cpgid;
    struct termios raw;
 
+   readhist();
+   if (atexit(writehist) == -1)
+       err(EXIT_FAILURE, "Unable to add `writehist()' to `atexit()'");
+
    if (tcgetattr(STDIN_FILENO, &canonical) == -1)
        err(EXIT_FAILURE, "Unable to get termios structure");
    raw = canonical;
@@ -202,13 +308,16 @@ int main(void) {
    if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
        err(EXIT_FAILURE, "Unable to set termios structure");
    if (atexit(ashexit) == -1)
-       err(EXIT_FAILURE, "Unable to set `atexit()'");
+       err(EXIT_FAILURE, "Unable to add `ashexit()' to `atexit()'");
 
    if ((self = getpgid(0)) == -1) err(EXIT_FAILURE, "Unable to get pgid of self");
    for (;;) {
        if (!(input = getinput())) continue;
        tokens = tokenize(input);
 
+// for (size_t i = 0; tokens[i]; ++i) printf("|%s|, ", tokens[i]);
+// putchar('\n');
+
        if (!*tokens || builtin(tokens)) continue;
 
        if ((cpgid = fork()) == 0 && execvp(tokens[0], tokens) == -1) {
@@ -228,7 +337,7 @@ int main(void) {
            continue;
        }
        if (killpg(cpgid, SIGCONT) == -1) {
-           if (tcsetpgrp(STDIN_FILENO, self) == -1) exit(EXIT_FAILURE);
+           if (tcsetpgrp(STDIN_FILENO, self) == -1) _Exit(EXIT_FAILURE);
            warn("Process group %d may be blocked; killing it", cpgid);
            if (killpg(cpgid, SIGKILL) == -1)
                warn("Unable to kill process group %d; manual termination required", cpgid);