Remove -e flag, remove long options, start rewriting in C, add support for changing shell

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 245 insertions, 0 deletions

diff --git a/gpp.c b/gpp.c
new file mode 100644
index 0000000..569ae76
--- /dev/null
+++ b/gpp.c
@@ -0,0 +1,245 @@
+/* See LICENSE file for copyright and license details. */
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "arg.h"
+
+
+char *argv0;
+
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s [-D name[=value]] [-f file | [-i input-file] [-o output-file]] "
+	                "[-n count] [-s symbol] [-u [-u]] [shell [argument] ...]\n", argv0);
+	exit(1);
+}
+
+
+static int
+get_fd(const char *path)
+{
+	const char *p;
+	char *s;
+	long int tmp;
+
+	if (!strcmp(path, "/dev/stdin"))
+		return STDIN_FILENO;
+	if (!strcmp(path, "/dev/stdout"))
+		return STDOUT_FILENO;
+	if (!strcmp(path, "/dev/stderr"))
+		return STDERR_FILENO;
+
+	if (!strncmp(path, "/dev/fd/", sizeof("/dev/fd/") - 1))
+		p = &path[sizeof("/dev/fd/") - 1];
+	else if (!strncmp(path, "/proc/self/fd/", sizeof("/proc/self/fd/") - 1))
+		p = &path[sizeof("/proc/self/fd/") - 1];
+	else
+		return -1;
+
+	if (!isdigit(*p))
+		return -1;
+	errno = 0;
+	tmp = strtol(p, &s, 10);
+	if (errno || tmp > INT_MAX || *s)
+		return -1;
+	return (int)tmp;
+}
+
+
+static int
+xopen(const char *path, int *do_close)
+{
+	int fd = get_fd(path);
+	if (fd >= 0) {
+		*do_close = 0;
+		return fd;
+	}
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "%s: open %s O_RDONLY: %s\n", argv0, path, strerror(errno));
+		exit(1);
+	}
+	*do_close = 1;
+	return fd;
+}
+
+
+static int
+xcreate(const char *path)
+{
+	int fd = get_fd(path);
+	if (fd >= 0)
+		return fd;
+	fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0) {
+		fprintf(stderr, "%s: open %s O_WRONLY|O_CREAT|O_TRUNC 0666: %s\n", argv0, path, strerror(errno));
+		exit(1);
+	}
+	return fd;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	const char *shell_[] = {"bash", NULL}, **shell = shell_;
+	const char *input_file = NULL;
+	const char *output_file = NULL;
+	const char *symbol = NULL;
+	int iterations = -1;
+	int unshebang = 0;
+	long int tmp;
+	char *arg, *p, *q;
+	char *in_data = NULL, *out_data = NULL;
+	size_t in_size = 0, in_len = 0, in_off = 0;
+	size_t out_size = 0, out_len = 0, out_off = 0;
+	int in_fd, out_fd, do_close;
+	ssize_t r;
+
+	ARGBEGIN {
+	case 'D':
+		arg = EARGF(usage());
+		if (!*arg || *arg == '=')
+			usage();
+		p = strchr(arg, '=');
+		if (p)
+			*p++ = '\0';
+		if (setenv(arg, p ? p : "1", 1)) {
+			fprintf(stderr, "%s: setenv %s %s 1: %s\n", argv0, arg, p ? p : "1", strerror(errno));
+			return 1;
+		}
+		break;
+	case 'f':
+		if (input_file || output_file)
+			usage();
+		input_file = output_file = EARGF(usage());
+		if (!*input_file)
+			usage();
+		break;
+	case 'i':
+		if (input_file)
+			usage();
+		input_file = EARGF(usage());
+		if (!*input_file)
+			usage();
+		break;
+	case 'n':
+		if (iterations >= 0)
+			usage();
+		arg = EARGF(usage());
+		if (!isdigit(*arg))
+			usage();
+		errno = 0;
+		tmp = strtol(arg, &arg, 10);
+		if (errno || tmp > INT_MAX || *arg)
+			usage();
+		iterations = (int)tmp;
+		break;
+	case 'o':
+		if (output_file)
+			usage();
+		output_file = EARGF(usage());
+		if (!*output_file)
+			usage();
+		break;
+	case 's':
+		if (symbol)
+			usage();
+		symbol = EARGF(usage());
+		break;
+	case 'u':
+		if (unshebang == 2)
+			usage();
+		unshebang += 1;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc)
+		shell = (void *)argv;
+
+	if (setenv("_GPP", argv0, 1))
+		fprintf(stderr, "%s: setenv _GPP %s 1: %s\n", argv0, argv0, strerror(errno));
+
+	if (iterations < 0)
+		iterations = 1;
+	if (!symbol)
+		symbol = "@";
+	if (!input_file || (input_file[0] == '-' && !input_file[1]))
+		input_file = "/dev/stdin";
+	if (!output_file || (output_file[0] == '-' && !output_file[1]))
+		output_file = "/dev/stdout";
+
+	in_fd = xopen(input_file, &do_close);
+	for (;;) {
+		if (in_len == in_size) {
+			in_data = realloc(in_data, in_size += 8096);
+			if (!in_data) {
+				fprintf(stderr, "%s: realloc: %s\n", argv0, strerror(errno));
+				return 1;
+			}
+		}
+		r = read(in_fd, &in_data[in_len], in_size - in_len);
+		if (r <= 0) {
+			if (!r)
+				break;
+			fprintf(stderr, "%s: read %s: %s\n", argv0, input_file, strerror(errno));
+		}
+		in_len += (size_t)r;
+	}
+	if (do_close)
+		close(in_fd);
+
+	if (unshebang && in_len >= 2 && in_data[0] == '#' && in_data[1] == '!') {
+		p = memchr(in_data, '\n', in_len);
+		if (!p)
+			goto after_unshebang;
+		in_off = (size_t)(++p - in_data);
+		if (in_off == in_len)
+			goto after_unshebang;
+		if (unshebang >= 2) {
+			q = memchr(p--, '\n', in_len - in_off);
+			if (!q)
+				goto after_unshebang;
+			memmove(p, &p[1], (size_t)(q - in_data) - in_off--);
+			*--q = '\n';
+		}
+	}
+after_unshebang:
+
+	while (iterations--) {
+		/* TODO parse: in -> out */
+
+		in_len = 0;
+		in_off = 0;
+
+		/* TODO shell: out -> in */
+
+		out_len = 0;
+		out_off = 0;
+	}
+
+	free(out_data);
+	out_fd = xcreate(output_file);
+	while (in_off < in_len) {
+		r = write(out_fd, &in_data[in_off], in_len - in_off);
+		if (r <= 0) {
+			fprintf(stderr, "%s: write %s: %s\n", argv0, output_file, strerror(errno));
+			return 1;
+		}
+		in_off += (size_t)r;
+	}
+	if (close(out_fd))
+		fprintf(stderr, "%s: write %s: %s\n", argv0, output_file, strerror(errno));
+	free(in_data);
+	return 0;
+}