[musl] [PATCH] getusershell: Only return absolute paths

[Samanta Navarro <ferivoz@riseup.net>]

Also strip comments to be compatible with other getusershell
implementations (glibc, *BSD).

Running `chsh -l` of util-linux built with musl is effectively
a `cat /etc/shells`.

Signed-off-by: Samanta Navarro <ferivoz@riseup.net>
---
 src/legacy/getusershell.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/legacy/getusershell.c b/src/legacy/getusershell.c
index 5fecdec2..81e872df 100644
--- a/src/legacy/getusershell.c
+++ b/src/legacy/getusershell.c
@@ -1,5 +1,6 @@
 #define _GNU_SOURCE
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 
 static const char defshells[] = "/bin/sh\n/bin/csh\n";
@@ -22,11 +23,12 @@ void setusershell(void)
 
 char *getusershell(void)
 {
-	ssize_t l;
 	if (!f) setusershell();
 	if (!f) return 0;
-	l = getline(&line, &linesize, f);
-	if (l <= 0) return 0;
-	if (line[l-1]=='\n') line[l-1]=0;
+	do {
+		ssize_t l = getline(&line, &linesize, f);
+		if (l <= 0) return 0;
+	} while (line[0] != '/');
+	line[strcspn(line, "#\n")] = 0;
 	return line;
 }
-- 
2.40.1