Added support for user generated shell scripts:

	- create a director with shell scripts
	- call them within the chat with @<script-name>
	- four sample scripts

1 files changed, 164 insertions, 2 deletions

diff --git a/xmppcb.c b/xmppcb.c
index c934550..445345a 100644
--- a/xmppcb.c
+++ b/xmppcb.c
@@ -12,6 +12,7 @@
 #endif
 
 #include <ctype.h>
+#include <dirent.h>
 #include <errno.h>
 #include <netdb.h>
 #include <poll.h>
@@ -22,9 +23,11 @@
 #include <strings.h>
 #include <time.h>
 #include <unistd.h>
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 
 #include <openssl/err.h>
 #include <openssl/ssl.h>
@@ -46,6 +49,7 @@
 #define REQBUF       140000
 #define HTTPBUF      98304
 #define LLMOUT       8192
+#define CMDOUT       4096
 #define CTX_FILEBUF  131072
 #define CTX_MAXLINES 4000
 
@@ -822,13 +826,38 @@ static time_t parse_period(const char *tok) {
 }
 
 static const char *help_text(void) {
-	return
+	static char buf[2048];
+	int n = snprintf(buf, sizeof buf,
 		"Commands:\n"
 		"  " CMD_PREFIX " summarize [period]  - summarise the chat\n"
 		"  " CMD_PREFIX " tasks [period]      - extract action items\n"
 		"  " CMD_PREFIX " <question>          - ask anything\n"
 		"\n"
-		"  Period: 1h 1d 2d 1w 2w 1m   (default: last 50 messages)";
+		"  Period: 1h 1d 2d 1w 2w 1m   (default: last 50 messages)");
+
+	/* append the script commands found in CMD_DIR */
+	DIR *d = opendir(CMD_DIR);
+	if (d) {
+		struct dirent *e;
+		int first = 1;
+		while ((e = readdir(d)) != NULL && n > 0 && n < (int)sizeof buf - 80) {
+			if (e->d_name[0] == '.') continue;
+			char path[512];
+			struct stat stb;
+			snprintf(path, sizeof path, "%s/%s", CMD_DIR, e->d_name);
+			if (stat(path, &stb) != 0 || !S_ISREG(stb.st_mode)) continue;
+			if (access(path, X_OK) != 0) continue;
+			if (first) {
+				n += snprintf(buf + n, sizeof buf - (size_t)n,
+				              "\n\nScript commands:");
+				first = 0;
+			}
+			n += snprintf(buf + n, sizeof buf - (size_t)n,
+			              "\n  @%s", e->d_name);
+		}
+		closedir(d);
+	}
+	return buf;
 }
 
 static void muc_send(Conn *c, const char *room, const char *text) {
@@ -963,6 +992,138 @@ static void handle_command(Conn *c, const char *room, const char *body) {
 }
 
 /* ------------------------------------------------------------------ */
+/* @scriptname commands                                               */
+/* ------------------------------------------------------------------ */
+
+/* Run `path` with `args` passed as a single argv element - no shell is
+ * involved, so the user's text cannot be interpreted as a command.
+ * Captures combined stdout+stderr into out (NUL-terminated, capped at
+ * outsz). The child is SIGKILLed after CMD_TIMEOUT_SEC seconds.
+ * Returns 1 if the script exited 0, else 0. */
+static int run_script(const char *path, const char *args,
+                      char *out, size_t outsz) {
+	int pfd[2];
+	out[0] = '\0';
+	if (pipe(pfd) != 0) {
+		snprintf(out, outsz, "cmd: pipe failed");
+		return 0;
+	}
+	pid_t pid = fork();
+	if (pid < 0) {
+		close(pfd[0]);
+		close(pfd[1]);
+		snprintf(out, outsz, "cmd: fork failed");
+		return 0;
+	}
+	if (pid == 0) {                       /* child */
+		dup2(pfd[1], STDOUT_FILENO);
+		dup2(pfd[1], STDERR_FILENO);
+		close(pfd[0]);
+		close(pfd[1]);
+		if (args && *args)
+			execl(path, path, args, (char *)NULL);
+		else
+			execl(path, path, (char *)NULL);
+		_exit(127);                       /* exec failed */
+	}
+
+	close(pfd[1]);                        /* parent */
+	size_t len = 0;
+	time_t deadline = time(NULL) + CMD_TIMEOUT_SEC;
+	int killed = 0, truncated = 0;
+
+	/* read output until EOF, the buffer fills, or the deadline passes */
+	for (;;) {
+		fd_set rf;
+		FD_ZERO(&rf);
+		FD_SET(pfd[0], &rf);
+		struct timeval tv = { 1, 0 };
+		int s = select(pfd[0] + 1, &rf, NULL, NULL, &tv);
+		if (s < 0) {
+			if (errno == EINTR) continue;
+			break;
+		}
+		if (s > 0) {
+			ssize_t r = read(pfd[0], out + len, outsz - 1 - len);
+			if (r > 0) {
+				len += (size_t)r;
+				if (len >= outsz - 1) { truncated = 1; break; }
+			} else {
+				break;                    /* EOF or error */
+			}
+		}
+		if (time(NULL) >= deadline) { killed = 1; break; }
+	}
+	out[len] = '\0';
+	if (truncated && outsz > 32)
+		memcpy(out + outsz - 16, " ...[cut]", 10);
+
+	/* The child may still be running (timeout, or it outran the buffer).
+	 * Kill it, then reap with WNOHANG + a deadline so a child that closed
+	 * its output but kept running cannot hang the bot on waitpid(). */
+	if (killed || truncated)
+		kill(pid, SIGKILL);
+	close(pfd[0]);
+	int status = 0;
+	for (;;) {
+		pid_t w = waitpid(pid, &status, WNOHANG);
+		if (w != 0) break;                /* reaped, or error */
+		if (time(NULL) >= deadline) {
+			kill(pid, SIGKILL);
+			killed = 1;
+		}
+		struct timespec ts = { 0, 50000000 };  /* 50 ms */
+		nanosleep(&ts, NULL);
+	}
+	rtrim(out);
+
+	if (killed) {
+		snprintf(out, outsz, "cmd: timed out after %d s", CMD_TIMEOUT_SEC);
+		return 0;
+	}
+	if (!out[0])
+		snprintf(out, outsz, "(no output)");
+	return WIFEXITED(status) && WEXITSTATUS(status) == 0;
+}
+
+/* Parse a @scriptname message and run CMD_DIR/<scriptname>, posting its
+ * output back to the room. Unknown commands are ignored silently so the
+ * bot does not react to @-mentions of people. */
+static void handle_script_command(Conn *c, const char *room,
+                                  const char *body) {
+	while (*body == ' ' || *body == '\t') body++;
+	if (*body != '@') return;
+	if (strncasecmp(body, CMD_PREFIX, strlen(CMD_PREFIX)) == 0)
+		return;                            /* that is the @bot prefix */
+	body++;                                /* skip '@' */
+
+	/* command name: alphanumerics, '-' and '_' only (no path traversal) */
+	char name[64];
+	size_t n = 0;
+	while (body[n] && !isspace((unsigned char)body[n])) {
+		unsigned char ch = (unsigned char)body[n];
+		if (!isalnum(ch) && ch != '-' && ch != '_') return;
+		if (n >= sizeof name - 1) return;
+		name[n] = (char)ch;
+		n++;
+	}
+	if (n == 0) return;
+	name[n] = '\0';
+
+	const char *args = body + n;
+	while (*args == ' ' || *args == '\t') args++;
+
+	char path[256];
+	snprintf(path, sizeof path, "%s/%s", CMD_DIR, name);
+	if (access(path, X_OK) != 0) return;   /* not a command: stay silent */
+
+	fprintf(stderr, "xmppcb: running %s\n", path);
+	static char out[CMDOUT];
+	run_script(path, args, out, sizeof out);
+	muc_send(c, room, out);
+}
+
+/* ------------------------------------------------------------------ */
 /* stanza dispatch                                                    */
 /* ------------------------------------------------------------------ */
 
@@ -992,6 +1153,7 @@ static void dispatch(Conn *c, const char *st) {
 
 		history_append(room, nick, bdy);
 		handle_command(c, room, bdy);
+		handle_script_command(c, room, bdy);
 
 	} else if (strcmp(tag, "iq") == 0) {
 		if (strstr(st, "urn:xmpp:ping")) {         /* answer pings */