#include <err.h>
#include <fcntl.h>
-#include <signal.h>
+#include <limits.h>
+#include <signal.h> // TODO: Use sigaction for portability?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
-struct termios canonical;
-
-void ashexit(void) {
- if (tcsetattr(STDIN_FILENO, TCSANOW, &canonical) == -1)
- warn("Unable to return to initial terminal settings");
-}
+struct termios canonical, raw;
void *allocate(size_t s) {
void *r;
#define PROMPT "% "
#define HISTNAME ".ashhistory"
+// TODO: This could be its own struct and use macros like the stopped process table
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;
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);
if (fclose(histfile) == EOF) warn("Unable to close history stream");
}
+void ashexit(void) {
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &canonical) == -1)
+ warn("Unable to return to initial terminal settings");
+}
+
enum {
CTRLC = '\003',
CTRLD,
break;
}
}
+ fpurge(stdout);
+ if (result == end) return NULL;
strcpy(*ht, result);
ht = history + (ht - history + 1) % HISTLEN;
hc = ht;
if (ht == hb) hb = history + (hb - history + 1) % HISTLEN;
-
- return end > result ? result : NULL;
+ return result;
}
int delimiter(char c) {
return c == ' ' || c == '&' || c == '|' || c == ';' || c == '`' || c == '\0';
}
-char **tokenize(char *p) {
- size_t i;
- static char *result[BUFLEN];
-
- while (*p == ' ') ++p;
- for (i = 0; *p; ++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';
+enum terminator {
+ BG,
+ AND,
+ PIPE,
+ OR,
+ SEMI,
+};
+
+enum terminator strp2term(char **strp) {
+ enum terminator result;
+ char *p;
+
+ switch (*(p = (*strp)++)) {
+ case '&':
+ result = **strp == '&' ? (++*strp, AND) : BG;
+ break;
+ case '|':
+ result = **strp == '|' ? (++*strp, OR) : PIPE;
+ break;
+ default:
+ result = SEMI;
+ }
+ *p = '\0';
+
+ return result;
+}
+
+struct cmd {
+ char **args;
+ enum terminator type;
+};
+
+struct cmd *getcmds(char *b) {
+ size_t i, j;
+ char **t;
+ struct cmd *c;
+ enum terminator term;
+ static char *tokens[BUFLEN + 1];
+ static struct cmd result[BUFLEN / 2 + 1];
+
+ *tokens = NULL;
+ t = tokens + 1;
+ c = result;
+ while (*b == ' ') ++b;
+ c->args = t;
+ while (*b) switch (*b) {
+ default:
+ *t++ = b;
+ while (!delimiter(*b)) ++b;
+ break;
+ case ' ':
+ *b++ = '\0';
+ while (*b == ' ') ++b;
+ break;
+ case ';':
+ case '&':
+ case '|':
+ if (!*(t - 1)) {
+ strp2term(&b);
break;
- default:
- result[i] = p++;
- while (!delimiter(*p)) ++p;
}
+ *t++ = NULL;
+ c++->type = strp2term(&b);
+ c->args = t;
+ break;
+ case '`':
+ *t++ = ++b;
+ while (*b != '\'') ++b;
+ *b = '\0';
+ break;
}
- result[i] = NULL;
+ if (*(t - 1)) {
+ *t = NULL;
+ c++->type = SEMI;
+ }
+ c->args = NULL;
+
return result;
}
-#define BGMAX 128
-struct {
- pid_t pgids[BGMAX];
- size_t bp, sp;
-} bgps; // TODO: These are stopped jobs, not background jobs
+struct pg {
+ pid_t id;
+ struct termios config;
+};
+
+#define MAXPG 128
+#define INITPGS(pgs) {MAXPG, (pgs).data, (pgs).data, (pgs).data}
+struct pgs {
+ size_t len;
+ struct pg *b, *c, *t, data[MAXPG];
+} sus = INITPGS(sus), bg = INITPGS(bg);
+
+struct pgs *recent = &sus;
-void pushbgps(pid_t pgid) {
- if ((bgps.sp + 1) % BGMAX == bgps.bp) killpg(bgps.pgids[bgps.bp++], SIGKILL);
- bgps.pgids[++bgps.sp] = pgid;
-// printf("PUSHED pgid %d to stack: bp = %zu, sp = %zu\n", pgid, bgps.bp, bgps.sp);
+#define PLUSONE(s, m) ((s).data + ((s).m - (s).data + 1) % (s).len)
+#define INC(s, m) ((s).m = PLUSONE(s, m))
+#define MINUSONE(s, m) ((s).data + ((s).m - (s).data + (s).len - 1) % (s).len)
+#define DEC(s, m) ((s).m = MINUSONE(s, m))
+
+void push(struct pgs *pgs, struct pg pg) {
+ if (PLUSONE(*pgs, t) == pgs->b) {
+ killpg(pgs->b->id, SIGKILL);
+ INC(*pgs, b);
+ }
+ *pgs->t = pg;
+ INC(*pgs, t);
}
-pid_t popbgps(void) {
- return bgps.sp != bgps.bp ? bgps.pgids[bgps.sp--] : -1;
+struct pg peek(struct pgs *pgs) {
+ if (pgs->t == pgs->b) return (struct pg){0};
+ return *MINUSONE(*pgs, t);
+}
+
+struct pg pull(struct pgs *pgs) {
+ struct pg result;
+
+ if ((result = peek(pgs)).id) DEC(*pgs, t);
+ return result;
+}
+
+struct pg *find(struct pgs *pgs, pid_t pgid) {
+ if (pgid == 0 || pgs->t == pgs->b) return NULL;
+ for (pgs->c = MINUSONE(*pgs, t); pgs->c->id != pgid; DEC(*pgs, c))
+ if (pgs->c == pgs->b) return NULL;
+ return pgs->c;
+}
+
+void delete(struct pgs *pgs) {
+ if (pgs->c >= pgs->b) {
+ memmove(pgs->b + 1, pgs->b, sizeof(struct pg) * (pgs->c - pgs->b));
+ ++pgs->b;
+ INC(*pgs, c);
+ } else {
+ memmove(pgs->c, pgs->c + 1, sizeof(struct pg) * (pgs->t - pgs->c - 1));
+ --pgs->t;
+ }
}
pid_t self;
-void await(pid_t cpgid) {
- int status;
+int waitfg(pid_t cpgid) {
+ int status, result;
+ struct pg pg;
if (waitpid(cpgid, &status, WUNTRACED) != -1 && !WIFSTOPPED(status)) {
while (waitpid(-cpgid, NULL, 0) != -1);
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');
- if (WIFSTOPPED(status)) pushbgps(cpgid);
+ if (WIFSIGNALED(status)) {
+ putchar('\n');
+ result = WTERMSIG(status);
+ } else if (WIFSTOPPED(status)) {
+ pg = (struct pg){
+ .id = cpgid,
+ .config = canonical,
+ };
+ if (tcgetattr(STDIN_FILENO, &pg.config) == -1)
+ warn("Unable to save termios state for stopped process group %d", cpgid);
+ push(&sus, pg);
+ recent = &sus;
+ result = WSTOPSIG(status);
+ } else result = WEXITSTATUS(status);
+
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
+ warn("Unable to set termios state back to raw");
+
+ return result;
}
int builtin(char **tokens) {
- pid_t fgpgid;
+ long id;
+ struct pg pg;
+ int fg;
if (strcmp(tokens[0], "cd") == 0) {
if (chdir(tokens[1]) == -1)
warn("Unable to change directory to `%s'", tokens[1]);
- } else if (strcmp(tokens[0], "fg") == 0) { // TODO: Take an argument
- if ((fgpgid = popbgps()) == -1) {
- warnx("No background processes");
+ } else if (strcmp(tokens[0], "fg") == 0) {
+ if (tokens[1]) {
+ errno = 0;
+ if ((id = strtol(tokens[1], NULL, 10)) == LONG_MAX && errno || id <= 0) {
+ warn("Invalid process group id");
+ return 1;
+ }
+ if (find(&sus, (pid_t)id)) pg = *sus.c;
+ else if (find(&bg, (pid_t)id)) pg = *bg.c;
+ else {
+ warn("Unable to find process group %ld", id);
+ return 1;
+ }
+ } else if (!(pg = peek(recent)).id) {
+ warnx("No processes to bring into the foreground");
return 1;
}
- if (tcsetpgrp(STDIN_FILENO, fgpgid) == -1) {
- warn("Unable to bring process group %d to foreground", fgpgid);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &pg.config) == -1) {
+ warn("Unable to reload termios state for process group %d", pg.id);
return 1;
}
- if (killpg(fgpgid, SIGCONT) == -1) {
+ if (tcsetpgrp(STDIN_FILENO, pg.id) == -1) {
+ warn("Unable to bring process group %d to foreground", pg.id);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
+ warn("Unable to set termios state back to raw mode");
+ return 1;
+ }
+ if (killpg(pg.id, SIGCONT) == -1) {
if (tcsetpgrp(STDIN_FILENO, self) == -1) _Exit(EXIT_FAILURE);
- warn("Unable to wake up process group %d", fgpgid);
+ warn("Unable to wake up suspended process group %d", pg.id);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
+ warn("Unable to set termios state back to raw mode");
+ return 1;
+ }
+ if (tokens[1]) delete(recent); else pull(recent);
+ waitfg(pg.id);
+ } else if (strcmp(tokens[0], "bg") == 0) {
+ if (tokens[1]) {
+ errno = 0;
+ if ((id = strtol(tokens[1], NULL, 10)) == LONG_MAX && errno || id <= 0) {
+ warn("Invalid process group id");
+ return 1;
+ }
+ if (!find(&sus, (pid_t)id)) {
+ warn("Unable to find process group %ld", id);
+ return 1;
+ }
+ pg = *sus.c;
+ } else if (!(pg = peek(&sus)).id) {
+ warnx("No suspended processes to run in the background");
+ return 1;
+ }
+ if (killpg(pg.id, SIGCONT) == -1) {
+ warn("Unable to wake up suspended process group %d", pg.id);
return 1;
}
- await(fgpgid);
- } else return 0;
+ if (tokens[1]) delete(&sus); else pull(&sus);
+ push(&bg, pg);
+ recent = &bg;
+ } else {
+ return 0;
+ }
return 1;
}
+void waitbg(int sig) {
+ int status;
+ pid_t pid, pgid;
+
+ (void)sig;
+ for (bg.c = bg.b; bg.c != bg.t; INC(bg, c))
+ do switch ((pid = waitpid(-bg.c->id, &status, WNOHANG | WUNTRACED))) {
+ case -1:
+ if (errno != ECHILD) warn("Unable to wait on some child processes");
+ case 0:
+ break;
+ default:
+ if (WIFSTOPPED(status)) {
+ push(&sus, *bg.c);
+ delete(&bg);
+ recent = &sus;
+ pid = 0;
+ }
+ } while (pid > 0);
+}
+
int main(void) {
- char *input, **tokens;
- pid_t cpgid;
- struct termios raw;
+ char *input;
+ struct cmd *cmds;
+ pid_t cpid;
+ int status;
readhist();
if (atexit(writehist) == -1)
err(EXIT_FAILURE, "Unable to add `ashexit()' to `atexit()'");
if ((self = getpgid(0)) == -1) err(EXIT_FAILURE, "Unable to get pgid of self");
- for (;;) {
+ for (;; waitbg(0)) {
+ signal(SIGCHLD, waitbg);
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) {
- warn("Unable to run command `%s'", tokens[0]);
- _Exit(EXIT_FAILURE);
- }
- if (setpgid(cpgid, cpgid) == -1) {
- warn("Unable to set process group of process %d", cpgid);
- if (kill(cpgid, SIGKILL) == -1)
- warn("Unable to kill process %d; manual termination required", cpgid);
- continue;
- }
- if (tcsetpgrp(STDIN_FILENO, cpgid) == -1) {
- warn("Unable to bring process group %d to foreground", cpgid);
- if (killpg(cpgid, SIGKILL) == -1)
- warn("Unable to kill process group %d; manual termination required", cpgid);
- continue;
- }
- if (killpg(cpgid, SIGCONT) == -1) {
- 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);
- else warn("Successfully terminated process group %d", cpgid);
- continue;
+ signal(SIGCHLD, SIG_DFL);
+ for (cmds = getcmds(input); (*cmds).args; ++cmds) {
+ switch ((*cmds).type) {
+ case PIPE:
+ break;
+ case OR:
+ case BG:
+ case AND:
+ case SEMI:
+ if (!builtin((*cmds).args)) {
+ if ((cpid = fork()) == -1) {
+ warn("Unable to fork command `%s'", *(*cmds).args);
+ goto end;
+ } else if (cpid == 0) {
+ if (execvp(*(*cmds).args, (*cmds).args) == -1) {
+ warn("Unable to run command `%s'", *(*cmds).args);
+ _Exit(EXIT_FAILURE);
+ }
+ }
+ if (setpgid(cpid, cpid) == -1) {
+ warn("Unable to set process group of process %d", cpid);
+ if (kill(cpid, SIGKILL) == -1)
+ warn("Unable to kill process %d; manual termination required", cpid);
+ goto end;
+ }
+ if ((*cmds).type == BG) {
+ push(&bg, (struct pg){
+ .id = cpid,
+ .config = canonical,
+ });
+ recent = &bg;
+ } else {
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &canonical) == -1)
+ warn("Unable to set termios structure");
+ if (tcsetpgrp(STDIN_FILENO, cpid) == -1) {
+ warn("Unable to bring process group %d to foreground", cpid);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
+ warn("Unable to set termios state back to raw");
+ if (killpg(cpid, SIGKILL) == -1)
+ warn("Unable to kill process group %d; manual termination required", cpid);
+ goto end;
+ }
+ if (killpg(cpid, SIGCONT) == -1) {
+ if (tcsetpgrp(STDIN_FILENO, self) == -1) _Exit(EXIT_FAILURE);
+ warn("Process group %d may be blocked; killing it", cpid);
+ if (killpg(cpid, SIGKILL) == -1)
+ warn("Unable to kill process group %d; manual termination required", cpid);
+ else warn("Successfully terminated process group %d", cpid);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == -1)
+ warn("Unable to set termios state back to raw");
+ goto end;
+ }
+ status = waitfg(cpid);
+ if ((*cmds).type == AND && status != 0) goto end;
+ if ((*cmds).type == OR && status == 0) goto end;
+ }
+ }
+ }
}
- await(cpgid);
+ end:;
}
return 0;
code / thus.git / commitdiff