Provide Musl derived fallbacks for getopt/getopt_long/getsubopt

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

7 files changed, 239 insertions, 33 deletions

diff --git a/COPYING.md b/COPYING.md
index 107fabd..19f8c5d 100644
--- a/COPYING.md
+++ b/COPYING.md
@@ -22,8 +22,14 @@ The rest of squashfs-tools-ng is released under the terms and conditions of
 the **GNU General Public License version 3 or later**, with the following
 exceptions:
 
- - `lib/compat/fnmatch.c` has been copied from Musl libc, which is subject to
-   an MIT style license. See `liceneses/musl.txt` for details.
+ - `lib/compat/fnmatch.c` has been copied from Musl libc.
+ - `lib/compat/getopt.c` has been copied from Musl libc.
+ - `lib/compat/getopt_long.c` has been copied from Musl libc.
+ - `lib/compat/getsubopt.c` has been copied from Musl libc.
+
+The components copied from Musl libc are subejct to an MIT style license.
+See `liceneses/musl.txt` for details and only compiled into executable programs
+if the target system does not provide an implementation.
 
 Copies of the LGPLv3 and GPLv3 are included in `licenses/LGPLv3.txt` and
 `licenses/GPLv3.txt` respectively.
diff --git a/configure.ac b/configure.ac
index 593734b..ddef2c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -269,7 +269,7 @@ AC_CHECK_HEADERS([sys/xattr.h], [], [])
 AC_CHECK_HEADERS([sys/sysinfo.h], [], [])
 AC_CHECK_HEADERS([alloca.h], [], [])
 
-AC_CHECK_FUNCS([strndup getsubopt fnmatch])
+AC_CHECK_FUNCS([strndup getopt getopt_long getsubopt fnmatch])
 
 ##### generate output #####
 
diff --git a/include/compat.h b/include/compat.h
index e5785d3..8a2522e 100644
--- a/include/compat.h
+++ b/include/compat.h
@@ -181,6 +181,31 @@ void w32_perror(const char *str);
 char *strndup(const char *str, size_t max_len);
 #endif
 
+#ifndef HAVE_GETOPT
+extern char *optarg;
+extern int optind, opterr, optopt, optpos, optreset;
+
+void __getopt_msg(const char *a, const char *b, const char *c, size_t l);
+
+int getopt(int argc, char * const argv[], const char *optstring);
+#endif
+
+#ifndef HAVE_GETOPT_LONG
+struct option {
+	const char *name;
+	int has_arg;
+	int *flag;
+	int val;
+};
+
+#define no_argument        0
+#define required_argument  1
+#define optional_argument  2
+
+int getopt_long(int, char *const *, const char *,
+		const struct option *, int *);
+#endif
+
 #ifndef HAVE_GETSUBOPT
 int getsubopt(char **opt, char *const *keys, char **val);
 #endif
diff --git a/lib/compat/Makemodule.am b/lib/compat/Makemodule.am
index 6c3c2b4..6ea0750 100644
--- a/lib/compat/Makemodule.am
+++ b/lib/compat/Makemodule.am
@@ -4,5 +4,7 @@ libcompat_a_SOURCES += lib/compat/chdir.c include/compat.h
 libcompat_a_SOURCES += lib/compat/path_to_windows.c
 libcompat_a_SOURCES += lib/compat/w32_perror.c
 libcompat_a_SOURCES += lib/compat/fnmatch.c
+libcompat_a_SOURCES += lib/compat/getopt.c
+libcompat_a_SOURCES += lib/compat/getopt_long.c
 
 noinst_LIBRARIES += libcompat.a
diff --git a/lib/compat/getopt.c b/lib/compat/getopt.c
new file mode 100644
index 0000000..9876a87
--- /dev/null
+++ b/lib/compat/getopt.c
@@ -0,0 +1,96 @@
+#include "compat.h"
+
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#ifndef HAVE_GETOPT
+char *optarg;
+int optind=1, opterr=1, optopt, optpos, optreset=0;
+
+void __getopt_msg(const char *a, const char *b, const char *c, size_t l)
+{
+	fputs(a, stderr);
+	fwrite(b, strlen(b), 1, stderr);
+	fwrite(c, 1, l, stderr);
+	putc('\n', stderr);
+}
+
+int getopt(int argc, char * const argv[], const char *optstring)
+{
+	int i;
+	wchar_t c, d;
+	int k, l;
+	char *optchar;
+
+	if (!optind || __optreset) {
+		optreset = 0;
+		optpos = 0;
+		optind = 1;
+	}
+
+	if (optind >= argc || !argv[optind])
+		return -1;
+
+	if (argv[optind][0] != '-') {
+		if (optstring[0] == '-') {
+			optarg = argv[optind++];
+			return 1;
+		}
+		return -1;
+	}
+
+	if (!argv[optind][1])
+		return -1;
+
+	if (argv[optind][1] == '-' && !argv[optind][2])
+		return optind++, -1;
+
+	if (!optpos) optpos++;
+	if ((k = mbtowc(&c, argv[optind]+optpos, MB_LEN_MAX)) < 0) {
+		k = 1;
+		c = 0xfffd; /* replacement char */
+	}
+	optchar = argv[optind]+optpos;
+	optpos += k;
+
+	if (!argv[optind][optpos]) {
+		optind++;
+		optpos = 0;
+	}
+
+	if (optstring[0] == '-' || optstring[0] == '+')
+		optstring++;
+
+	i = 0;
+	d = 0;
+	do {
+		l = mbtowc(&d, optstring+i, MB_LEN_MAX);
+		if (l>0) i+=l; else i++;
+	} while (l && d != c);
+
+	if (d != c || c == ':') {
+		optopt = c;
+		if (optstring[0] != ':' && opterr)
+			__getopt_msg(argv[0], ": unrecognized option: ", optchar, k);
+		return '?';
+	}
+	if (optstring[i] == ':') {
+		optarg = 0;
+		if (optstring[i+1] != ':' || optpos) {
+			optarg = argv[optind++] + optpos;
+			optpos = 0;
+		}
+		if (optind > argc) {
+			optopt = c;
+			if (optstring[0] == ':') return ':';
+			if (opterr) __getopt_msg(argv[0],
+				": option requires an argument: ",
+				optchar, k);
+			return '?';
+		}
+	}
+	return c;
+}
+#endif
diff --git a/lib/compat/getopt_long.c b/lib/compat/getopt_long.c
new file mode 100644
index 0000000..58354c3
--- /dev/null
+++ b/lib/compat/getopt_long.c
@@ -0,0 +1,95 @@
+#include "compat.h"
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifndef HAVE_GETOPT_LONG
+static void permute(char *const *argv, int dest, int src)
+{
+	char **av = (char **)argv;
+	char *tmp = av[src];
+	int i;
+	for (i=src; i>dest; i--)
+		av[i] = av[i-1];
+	av[dest] = tmp;
+}
+
+int getopt_long(int argc, char *const *argv, const char *optstring, const struct option *longopts, int *idx)
+{
+	optarg = 0;
+	if (longopts && argv[optind][0] == '-' &&
+	    (argv[optind][1] == '-' && argv[optind][2]))
+	{
+		int colon = optstring[optstring[0]=='+'||optstring[0]=='-']==':';
+		int i, cnt, match;
+		char *arg, *opt, *start = argv[optind]+1;
+		for (cnt=i=0; longopts[i].name; i++) {
+			const char *name = longopts[i].name;
+			opt = start;
+			if (*opt == '-') opt++;
+			while (*opt && *opt != '=' && *opt == *name)
+				name++, opt++;
+			if (*opt && *opt != '=') continue;
+			arg = opt;
+			match = i;
+			if (!*name) {
+				cnt = 1;
+				break;
+			}
+			cnt++;
+		}
+		if (cnt==1) {
+			i = match;
+			opt = arg;
+			optind++;
+			if (*opt == '=') {
+				if (!longopts[i].has_arg) {
+					optopt = longopts[i].val;
+					if (colon || !opterr)
+						return '?';
+					__getopt_msg(argv[0],
+						": option does not take an argument: ",
+						longopts[i].name,
+						strlen(longopts[i].name));
+					return '?';
+				}
+				optarg = opt+1;
+			} else if (longopts[i].has_arg == required_argument) {
+				if (!(optarg = argv[optind])) {
+					optopt = longopts[i].val;
+					if (colon) return ':';
+					if (!opterr) return '?';
+					__getopt_msg(argv[0],
+						": option requires an argument: ",
+						longopts[i].name,
+						strlen(longopts[i].name));
+					return '?';
+				}
+				optind++;
+			}
+			if (idx) *idx = i;
+			if (longopts[i].flag) {
+				*longopts[i].flag = longopts[i].val;
+				return 0;
+			}
+			return longopts[i].val;
+		}
+		if (argv[optind][1] == '-') {
+			optopt = 0;
+			if (!colon && opterr)
+				__getopt_msg(argv[0], cnt ?
+					": option is ambiguous: " :
+					": unrecognized option: ",
+					argv[optind]+2,
+					strlen(argv[optind]+2));
+			optind++;
+			return '?';
+		}
+	}
+	return getopt(argc, argv, optstring);
+}
+#endif
diff --git a/lib/compat/getsubopt.c b/lib/compat/getsubopt.c
index d53a37d..e6fea1a 100644
--- a/lib/compat/getsubopt.c
+++ b/lib/compat/getsubopt.c
@@ -1,10 +1,3 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * getsubopt.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "config.h"
 #include "compat.h"
 
 #include <stdlib.h>
@@ -13,33 +6,22 @@
 #ifndef HAVE_GETSUBOPT
 int getsubopt(char **opt, char *const *keys, char **val)
 {
-	char *str = *opt;
-	size_t i, len;
+	char *s = *opt;
+	int i;
 
 	*val = NULL;
-	*opt = strchr(str, ',');
-
-	if (*opt == NULL) {
-		*opt = str + strlen(str);
-	} else {
-		*(*opt)++ = '\0';
-	}
-
-	for (i = 0; keys[i]; ++i) {
-		len = strlen(keys[i]);
-
-		if (strncmp(keys[i], str, len) != 0)
-			continue;
-
-		if (str[len] != '=' && str[len] != '\0')
-			continue;
-
-		if (str[len] == '=')
-			*val = str + len + 1;
-
+	*opt = strchr(s, ',');
+	if (*opt) *(*opt)++ = 0;
+	else *opt = s + strlen(s);
+
+	for (i=0; keys[i]; i++) {
+		size_t l = strlen(keys[i]);
+		if (strncmp(keys[i], s, l)) continue;
+		if (s[l] == '=')
+			*val = s + l + 1;
+		else if (s[l]) continue;
 		return i;
 	}
-
 	return -1;
 }
 #endif