1 files changed, 95 insertions, 0 deletions
diff --git a/pm-genid.c b/pm-genid.c
new file mode 100644
index 0000000..5a481ce
--- /dev/null
+++ b/pm-genid.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2024 Mitchell Riedstra
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Since `tr` on MacOS cannot handle the binary stream.
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#if __linux__
+	#include "compat/strtonum.c"
+#endif
+
+#define BUF_SIZE 64
+#define MAX_OUT_CHARS 65534
+
+void
+help() {
+	puts("genid [-d <rand device>] [-n <numchars]");
+	exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+	const char *rdev = "/dev/urandom";
+	int chars = 8;
+	char **a = argv+1;
+	int fd, n;
+	char c;
+	int written = 0;
+
+	for (;*a;a++) {
+		if (strcmp(*a, "-d") == 0 && *(++a)) {
+			rdev = *a;
+		} else if (strcmp(*a, "-n") == 0 && *(++a)) {
+				const char *errstr;
+				chars = (int)strtonum(*a, 1, MAX_OUT_CHARS, &errstr);
+				if (errstr != NULL) {
+					printf("strtonum: %s\n", errstr);
+					help();
+				}
+		} else {
+			if (*a)
+				printf("Unknown option: '%s'\n", *a);
+
+			help();
+		}
+	}
+
+	fd = open(rdev, O_RDONLY);
+	if (fd == -1) {
+		perror("opening random device");
+		exit(1);
+	}
+
+	char buf[BUF_SIZE];
+	for (int i=0; written<chars && i<1000; i++) {
+		n = read(fd, &buf, BUF_SIZE-1);
+		if (n == -1) {
+			perror("read");
+			exit(1);
+		}
+
+		for (int j = 0; j<n && j<BUF_SIZE && written<chars; j++) {
+			c = buf[j];
+			if (
+					(c >= 'a' && c <= 'z') ||
+					(c >= 'A' && c <= 'Z') ||
+					(c >= '0' && c <= '9')
+				) {
+				written++;
+				putc(c, stdout);
+			}
+		}
+	}
+
+	puts("");
+	close(fd);
+}