Re: Error in interpreting posix timezone TZ environment variable by musl-libc

[Rich Felker <dalias@libc.org>]

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On Wed, Oct 08, 2014 at 04:59:18PM -0400, Rich Felker wrote:
> On Thu, Oct 09, 2014 at 01:14:29AM +0530, vlse wrote:
> > musl-libc stable 1.0.3 has wrong implementation of posix timezone TZ environmental variable.
> > For e.g. if I set TZ="IST-5:30" and use busybox date command
> > compiled with musl-libc it's show One hour early than actual. Same
> > with c code using asctime from musl-libc.
> > 
> > Any known fix.
> 
> Can you show the expected and actual output of the date command, both
> with TZ=IST-5:30 and TZ=GMT?

Never mind -- I found the bug. I have a patch attached for current git
master, and I think it will apply cleanly to 1.0.3 too, but I haven't
checked yet. I'll be making a new release (1.1.5) from the mainline
branch soon but an updated 1.0.x release might take longer since
there's nontrivial backporting work to be done for other bugs too. If
you have trouble applying the patch let me know.

Rich

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diff --git a/src/time/__tz.c b/src/time/__tz.c
index 92c43a5..4ce2025 100644
--- a/src/time/__tz.c
+++ b/src/time/__tz.c
@@ -36,19 +36,16 @@ static int getint(const char **p)
 	return x;
 }
 
-static int getsigned(const char **p)
+static int getoff(const char **p)
 {
+	int neg = 0;
 	if (**p == '-') {
 		++*p;
-		return -getint(p);
+		neg = 1;
+	} else if (**p == '+') {
+		++*p;
 	}
-	if (**p == '+') ++*p;
-	return getint(p);
-}
-
-static int getoff(const char **p)
-{
-	int off = 3600*getsigned(p);
+	int off = 3600*getint(p);
 	if (**p == ':') {
 		++*p;
 		off += 60*getint(p);
@@ -57,7 +54,7 @@ static int getoff(const char **p)
 			off += getint(p);
 		}
 	}
-	return off;
+	return neg ? -off : off;
 }
 
 static void getrule(const char **p, int rule[5])