[PATCH v3] eal: simplify argv[0] handling

[Stephen Hemminger <stephen@networkplumber.org>]

The rte_eal_init function looks at argv[0] to determine
the program name to pass to the log init function.
But in corner cases argv[0] maybe NULL leading to a SEGV.

The code here is just using argv[0] to generate logid which
does not have to be in a static string, openlog() will handle
a const char pointer.

Simple workaround for argv[0] being NULL is to pass NULL
to openlog() and let it handle it. Both glibc, and musl
handle this case.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
---

v3 - redo to make this limited to just the null argv[0] bug

 lib/eal/linux/eal.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index 9c8395ab14d0..c0ff325c4ce9 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -966,8 +966,7 @@ rte_eal_init(int argc, char **argv)
 	pthread_t thread_id;
 	static uint32_t run_once;
 	uint32_t has_run = 0;
-	const char *p;
-	static char logid[PATH_MAX];
+	const char *logid = NULL;
 	char cpuset[RTE_CPU_AFFINITY_STR_LEN];
 	char thread_name[RTE_MAX_THREAD_NAME_LEN];
 	bool phys_addrs;
@@ -989,8 +988,12 @@ rte_eal_init(int argc, char **argv)
 		return -1;
 	}
 
-	p = strrchr(argv[0], '/');
-	strlcpy(logid, p ? p + 1 : argv[0], sizeof(logid));
+	if (argv && argv[0]) {
+		const char *p = strrchr(argv[0], '/');
+
+		logid = p ? p + 1 : argv[0];
+	}
+
 	thread_id = pthread_self();
 
 	eal_reset_internal_config(internal_conf);
-- 
2.34.1