From 2c7d1ce088ba9b588652f58616eb2a8d7748ca88 Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Sat, 16 Oct 2021 06:15:05 +0200
Subject: [PATCH] passt: Static builds: don't redefine __vsyslog(), skip
 getpwnam() and initgroups()

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 Makefile |  2 +-
 conf.c   |  3 ++-
 passt.c  | 15 ++++++++++-----
 util.c   | 11 +++++++----
 util.h   |  2 +-
 5 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index 26b6840..0697b53 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ all: passt pasta passt4netns qrap
 avx2: CFLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
 avx2: clean all
 
-static: CFLAGS += -static
+static: CFLAGS += -static -DGLIBC_NO_STATIC_NSS
 static: clean all
 
 seccomp.h: *.c $(filter-out seccomp.h,$(wildcard *.h))
diff --git a/conf.c b/conf.c
index b91d09b..4287630 100644
--- a/conf.c
+++ b/conf.c
@@ -293,7 +293,8 @@ static void get_dns(struct ctx *c)
 	if ((fd = open("/etc/resolv.conf", O_RDONLY)) < 0)
 		goto out;
 
-	while (!(*buf = 0) && line_read(buf, BUFSIZ, fd)) {
+	*buf = 0;
+	while (line_read(buf, BUFSIZ, fd)) {
 		if (!dns_set && strstr(buf, "nameserver ") == buf) {
 			p = strrchr(buf, ' ');
 			if (!p)
diff --git a/passt.c b/passt.c
index 3e45095..6878668 100644
--- a/passt.c
+++ b/passt.c
@@ -212,17 +212,22 @@ static void check_root(void)
 	close(fd);
 
 	fprintf(stderr, "Don't run this as root. Changing to nobody...\n");
+#ifndef GLIBC_NO_STATIC_NSS
 	pw = getpwnam("nobody");
 	if (!pw) {
 		perror("getpwnam");
 		exit(EXIT_FAILURE);
 	}
 
-	if (initgroups(pw->pw_name, pw->pw_gid) ||
-	    setgid(pw->pw_gid) || setuid(pw->pw_uid)) {
-		fprintf(stderr, "Can't change to user/group nobody, exiting");
-		exit(EXIT_FAILURE);
-	}
+	if (!initgroups(pw->pw_name, pw->pw_gid) &&
+	    !setgid(pw->pw_gid) && !setuid(pw->pw_uid))
+		return;
+#else
+	(void)pw;
+#endif
+
+	fprintf(stderr, "Can't change to user/group nobody, exiting");
+	exit(EXIT_FAILURE);
 }
 
 /**
diff --git a/util.c b/util.c
index 016749c..56b256d 100644
--- a/util.c
+++ b/util.c
@@ -37,7 +37,7 @@
 #include "util.h"
 #include "passt.h"
 
-/* For __openlog() and __setlogmask() wrappers, and __vsyslog() (replacement) */
+/* For __openlog() and __setlogmask() wrappers, and passt_vsyslog() */
 static int	log_mask;
 static int	log_sock = -1;
 static char	log_ident[BUFSIZ];
@@ -56,7 +56,7 @@ void name(const char *format, ...) {					\
 			tp.tv_nsec / (100 * 1000));			\
 	} else {							\
 		va_start(args, format);					\
-		__vsyslog(level, format, args);				\
+		passt_vsyslog(level, format, args);			\
 		va_end(args);						\
 	}								\
 									\
@@ -121,12 +121,12 @@ void __setlogmask(int mask)
 }
 
 /**
- * __vsyslog() - vsyslog() implementation not using heap memory
+ * passt_vsyslog() - vsyslog() implementation not using heap memory
  * @pri:	Facility and level map, same as priority for vsyslog()
  * @format:	Same as vsyslog() format
  * @ap:		Same as vsyslog() ap
  */
-void __vsyslog(int pri, const char *format, va_list ap)
+void passt_vsyslog(int pri, const char *format, va_list ap)
 {
 	char buf[BUFSIZ];
 	int n;
@@ -389,6 +389,9 @@ char *line_read(char *buf, size_t len, int fd)
 
 		p = buf + strlen(buf) + 1;
 
+		while (*p == '\n' && strlen(p) && (size_t)(p - buf) < len)
+			p++;
+
 		if (!(nl = strchr(p, '\n')))
 			return NULL;
 		*nl = 0;
diff --git a/util.h b/util.h
index a2ed791..d5bff0c 100644
--- a/util.h
+++ b/util.h
@@ -147,7 +147,7 @@ enum bind_type {
 struct ctx;
 
 void __openlog(const char *ident, int option, int facility);
-void __vsyslog(int pri, const char *fmt, va_list ap);
+void passt_vsyslog(int pri, const char *fmt, va_list ap);
 void __setlogmask(int mask);
 char *ipv6_l4hdr(struct ipv6hdr *ip6h, uint8_t *proto);
 int sock_l4(struct ctx *c, int af, uint8_t proto, uint16_t port,