[PATCH] getopt_long: Support abbreviated option matching

[PATCH] getopt_long: Support abbreviated option matching

[Michael Forney]

From the getopt_long manpage:

    Long option names may be abbreviated if the abbreviation is unique
    or is an exact match for some defined option
---
This patch is fairly straightforward and provides more compatibility with
glibc's getopt_long.

I've run into at least one case where a script called getopt from util-linux
with the abbreviation --long instead of the full option name --longoptions.

 src/misc/getopt_long.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/misc/getopt_long.c b/src/misc/getopt_long.c
index 4ef5a5c..65bc14c 100644
--- a/src/misc/getopt_long.c
+++ b/src/misc/getopt_long.c
@@ -2,6 +2,7 @@
 #include <stddef.h>
 #include <getopt.h>
 #include <stdio.h>
+#include <string.h>
 
 extern int __optpos, __optreset;
 
@@ -16,14 +17,19 @@ static int __getopt_long(int argc, char *const *argv, const char *optstring, con
 	if ((longonly && argv[optind][1]) ||
 		(argv[optind][1] == '-' && argv[optind][2]))
 	{
-		int i;
+		int i, j;
 		for (i=0; longopts[i].name; i++) {
 			const char *name = longopts[i].name;
-			char *opt = argv[optind]+1;
+			char *opt = argv[optind]+1, *c;
 			if (*opt == '-') opt++;
-			for (; *name && *name == *opt; name++, opt++);
-			if (*name || (*opt && *opt != '=')) continue;
-			if (*opt == '=') {
+			for (c = opt; *name && *name == *c; name++, c++);
+			if (*c && *c != '=') continue;
+			if (*name) {
+				if (name == longopts[i].name) continue;
+				for (j=i+1; longopts[j].name && strncmp(opt, longopts[j].name, c - opt); j++);
+				if (longopts[j].name) continue;
+			}
+			if (*c == '=') {
 				if (!longopts[i].has_arg) continue;
 				optarg = opt+1;
 			} else {
-- 
1.8.4.2

[PATCH v2] getopt_long: Support abbreviated option matching

[Michael Forney]

From the getopt_long manpage:

    Long option names may be abbreviated if the abbreviation is unique
    or is an exact match for some defined option
---
The previous version missed changing "optarg = opt+1;" to "optarg = c+1;",
breaking long options with =.

 src/misc/getopt_long.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/misc/getopt_long.c b/src/misc/getopt_long.c
index 4ef5a5c..9bf8e87 100644
--- a/src/misc/getopt_long.c
+++ b/src/misc/getopt_long.c
@@ -2,6 +2,7 @@
 #include <stddef.h>
 #include <getopt.h>
 #include <stdio.h>
+#include <string.h>
 
 extern int __optpos, __optreset;
 
@@ -16,16 +17,21 @@ static int __getopt_long(int argc, char *const *argv, const char *optstring, con
 	if ((longonly && argv[optind][1]) ||
 		(argv[optind][1] == '-' && argv[optind][2]))
 	{
-		int i;
+		int i, j;
 		for (i=0; longopts[i].name; i++) {
 			const char *name = longopts[i].name;
-			char *opt = argv[optind]+1;
+			char *opt = argv[optind]+1, *c;
 			if (*opt == '-') opt++;
-			for (; *name && *name == *opt; name++, opt++);
-			if (*name || (*opt && *opt != '=')) continue;
-			if (*opt == '=') {
+			for (c = opt; *name && *name == *c; name++, c++);
+			if (*c && *c != '=') continue;
+			if (*name) {
+				if (name == longopts[i].name) continue;
+				for (j=i+1; longopts[j].name && strncmp(opt, longopts[j].name, c - opt); j++);
+				if (longopts[j].name) continue;
+			}
+			if (*c == '=') {
 				if (!longopts[i].has_arg) continue;
-				optarg = opt+1;
+				optarg = c+1;
 			} else {
 				if (longopts[i].has_arg == required_argument) {
 					if (!(optarg = argv[++optind]))
-- 
1.8.4.2