First commit

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

1 files changed, 197 insertions, 0 deletions

diff --git a/makelint.c b/makelint.c
new file mode 100644
index 0000000..45f599a
--- /dev/null
+++ b/makelint.c
@@ -0,0 +1,197 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+NUSAGE(EXIT_ERROR, "[-f makefile]");
+
+
+
+int exit_status = 0;
+
+static const char *default_makefiles[] = {
+	"makefile",
+	"Makefile"
+};
+
+
+static int
+open_default_makefile(const char **pathp)
+{
+	int fd;
+	size_t i;
+
+	/* The specification says that the alternatives “shall be
+	 * tried”, but it uses the phrase “if neither … are found”,
+	 * implying that make(1) shall fail if a file cannot be
+	 * opened and only try the next alternative if it failed
+	 * becomes the file does not exist.
+	 */
+
+	for (i = 0; i < ELEMSOF(default_makefiles); i++) {
+		*pathp = default_makefiles[i];
+		fd = open(*pathp, O_RDONLY);
+		if (fd >= 0) {
+			printinfof(WC_MAKEFILE, "found standard makefile to use: %s", *pathp);
+			goto find_existing_fallbacks;
+		} else if (errno != ENOENT) {
+			eprintf("found standard makefile to use, but failed to open: %s:", *pathp);
+		}
+	}
+
+	printerrorf("couldn't find any makefile to use, portable "
+	            "alternatives are ./makefile and ./Makefile");
+
+find_existing_fallbacks:
+	for (; i < ELEMSOF(default_makefiles); i++)
+		if (!access(default_makefiles[i], F_OK))
+			warnf_warning(WC_EXTRA_MAKEFILE, "found additional standard makefile: %s", *pathp);
+
+	return fd;
+}
+
+
+static void
+cmdline_opt_f(const char *arg, const char **makefile_pathp)
+{
+	static int warning_emitted = 0;
+
+	if (*makefile_pathp && !warning_emitted) {
+		warning_emitted = 1;
+		warnf_unspecified(WC_CMDLINE, "the -f option has been specified multiple times, "
+		                              "they are processed in order, but the behaviour is "
+	                                      "otherwise unspecified");
+		printinfof(WC_CMDLINE, "this implementation will use the last "
+		                       "option and discard earlier options");
+	}
+
+	*makefile_pathp = arg;
+}
+
+
+static struct line *
+load_file(int fd, const char *fname, size_t *nlinesp)
+{
+	struct line *lines;
+	char *buf = NULL, *p;
+	size_t size = 0;
+	size_t len = 0;
+	size_t i;
+	ssize_t r;
+
+	/* getline(3) may seem like the best way to read line by line,
+	 * however, it may terminate before the end of the line is
+	 * reached, which we would have to deal with, additionally,
+	 * we want to check for null bytes. Therefore we will keep
+	 * this simple and use read(3) and scan manually; and as a
+	 * bonus we can leave the file descriptor open, and let the
+	 * caller than created it close it.
+	 */
+
+	i = 0;
+	*nlinesp = 0;
+	for (;;) {
+		if (len == size)
+			buf = erealloc(buf, size += 2048);
+		r = read(fd, &buf[len], size - len);
+		if (r > 0)
+			len += (size_t)r;
+		else if (!r)
+			break;
+		else if (errno == EINTR)
+			continue;
+		else
+			eprintf("read %s:", fname);
+
+		for (; i < len; i++) {
+			if (buf[i] == '\n') {
+				*nlinesp += 1;
+				buf[i] = '\0';
+			} else if (buf[i] == '\0') {
+				/* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_403 */
+				warnf_undefined(WC_TEXT, "%s:%zu: file contains a NUL byte, this is disallowed, because "
+				                         "input files are text files, and causes undefined behaviour",
+				                fname, *nlinesp + 1);
+				/* make(1) should probably just abort */
+				printinfof(WC_TEXT, "this implementation will replace it with a <space>");
+				buf[i] = ' ';
+			}
+		}
+	}
+
+	if (len && buf[len - 1] != '\0') { /* LF has been converted to NUL above */
+		/* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_403 */
+		warnf_undefined(WC_TEXT, "%s:%zu: is non-empty but does not end with a <newline>, which is "
+		                         "required because input files are text files, and omission of it "
+		                         "causes undefined behaviour",
+		                fname, *nlinesp + 1);
+		/* make(1) should probably just abort */
+		printinfof(WC_TEXT, "this implementation will add the missing <newline>");
+		buf = erealloc(buf, len + 1);
+		buf[len++] = '\0';
+		*nlinesp += 1;
+	}
+
+	lines = *nlinesp ? ecalloc(*nlinesp, sizeof(*lines)) : NULL;
+	for (p = buf, i = 0; i < *nlinesp; i++) {
+		lines[i].lineno = i + 1;
+		lines[i].path = fname;
+		lines[i].len = strlen(p);
+		lines[i].data = ememdup(p, lines[i].len + 1);
+		if (lines[i].len + 1 > 2048) {
+			/* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_403 */
+			warnf_undefined(WC_TEXT, "%s:%zu: line is, including the <newline> character, longer than "
+			                         "2048 bytes which causes undefined behaviour as input files are "
+			                         "text files and POSIX only guarantees support for lines up to 2048 "
+			                         "including the <newline> character in text files",
+			                fname, *nlinesp + 1);
+		}
+		p += lines[i].len + 1;
+	}
+
+	free(buf);
+	return lines;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	const char *path = NULL;
+	int fd;
+	struct line *lines;
+	size_t nlines;
+
+	libsimple_default_failure_exit = EXIT_ERROR;
+
+	/* make(1) shall support mixing of options and operands (uptil --) */
+	ARGBEGIN {
+	case 'f':
+		cmdline_opt_f(ARG(), &path);
+		break;
+
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc)
+		usage();
+
+	if (!path) {
+		fd = open_default_makefile(&path);
+	} else if (!strcmp(path, "-")) {
+		/* “A pathname of '-' shall denote the standard input” */
+		fd = dup(STDIN_FILENO);
+		if (fd < 0)
+			eprintf("dup <stdin>:");
+		path = "<stdin>";
+	} else {
+		fd = open(path, O_RDONLY);
+		if (fd < 0)
+			eprintf("open %s O_RDONLY:", path);
+	}
+
+	lines = load_file(fd, path, &nlines);
+	close(fd);
+
+	free(lines);
+	return exit_status;
+}