libreboot-utils: simplify lbgetprogname

make it more reliable; it can't segfault
now, under any circumstance. not even
once.

the problem arised when lbsetname was not
called in a program, before calling the
function: lbgetprogname. a segfault would
occur, due to it being NULL.

not every os/libc has getprogname, so i have
my own implementation.

Signed-off-by: Leah Rowe <leah@libreboot.org>

2 files changed, 17 insertions, 27 deletions

diff --git a/util/libreboot-utils/README.md b/util/libreboot-utils/README.md
index 6e94035b..dca1b92e 100644
--- a/util/libreboot-utils/README.md
+++ b/util/libreboot-utils/README.md
@@ -31,7 +31,7 @@ of something like e.g. unveil, but in userspace!
 
 Mkhtemp is designed to be the most secure implementation
 possible, of mktemp, offering a heavy amount of hardening
-over traditional mktemp. Written in C89, and the plan is
+over traditional mktemp. Written in C99, and the plan is
 very much to keep this code portable over time - patches
 very much welcome.
 
@@ -241,7 +241,7 @@ a drop-in replacement on Linux distros (and BSDs if they
 want it), while providing a more hardened version and
 recommending that where possible.
 
-~~Rewrite it in rust~~ (nothing against it though, I just like C89 for some reason)
+~~Rewrite it in rust~~ (nothing against it though, I just like C99 for some reason)
 
 Also, generally document the history of mktemp, and how
 mkhtemp works in comparison.
diff --git a/util/libreboot-utils/lib/string.c b/util/libreboot-utils/lib/string.c
index d5e2de85..6a372dcf 100644
--- a/util/libreboot-utils/lib/string.c
+++ b/util/libreboot-utils/lib/string.c
@@ -359,22 +359,16 @@ no_op(void)
 const char *
 lbgetprogname(void)
 {
-	static char *rval = NULL;
-	static char *p;	
-	static int setname = 0;
-
-	if (!setname) {
-		if ((rval = lbsetprogname(NULL)) == NULL)
-			return NULL;
-
-		p = strrchr(rval, '/');
-		if (p)
-			rval = p + 1;
-
-		setname = 1;
-	}
-
-	return rval;
+	char *name = lbsetprogname(NULL);
+	char *p = NULL;
+	if (name)
+		p = strrchr(name, '/');
+	if (p)
+		return p + 1;
+	else if (name)
+		return name;
+	else
+		return "libreboot-utils";
 }
 
 /* singleton. if string not null,
@@ -385,17 +379,13 @@ lbgetprogname(void)
 char *
 lbsetprogname(char *argv0)
 {
-	static int setname = 0;
 	static char *progname = NULL;
-	size_t len;
-
-	if (!setname) {
-		if (if_err(argv0 == NULL || *argv0 == '\0', EFAULT) ||
-		    slen(argv0, 4096, &len) < 0)
-			return NULL;
+	static int set = 0;
 
-		memcpy(smalloc(&progname, len + 1), argv0, len + 1);
-		setname = 1;
+	if (!set) {
+		if (argv0 == NULL || sdup(argv0, 4096, &progname) < 0)
+			return "libreboot-utils";
+		set = 1;
 	}
 
 	return progname;