[PATCH] eal: handle sysconf() negative return value

[PATCH] eal: handle sysconf() negative return value

[Morten Brørup]

Coverity reports some defects, where the root cause seems to be negative
return value from sysconf() not being handled.

rte_mem_page_size() has been updated to handle negative return value from
sysconf(_SC_PAGESIZE).

All other functions calling sysconf(_SC_PAGESIZE) directly have been
updated to call rte_mem_page_size() instead.

At this time, no other calls to sysconf() have been found in DPDK.

Also, an unrelated drive-by minor fix in eal_mem_set_dump():
When madvise() failed, an incorrect reason was logged.

Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
---
 lib/eal/freebsd/eal.c          |  3 ++-
 lib/eal/freebsd/eal_memory.c   |  7 +++----
 lib/eal/linux/eal.c            |  3 ++-
 lib/eal/unix/eal_unix_memory.c | 16 ++++++++++++++--
 lib/vhost/vduse.c              |  3 ++-
 5 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/lib/eal/freebsd/eal.c b/lib/eal/freebsd/eal.c
index d6fffa2170..ce7f5c3d65 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -26,6 +26,7 @@
 #include <rte_launch.h>
 #include <rte_eal.h>
 #include <rte_eal_memconfig.h>
+#include <rte_eal_paging.h>
 #include <rte_errno.h>
 #include <rte_per_lcore.h>
 #include <rte_lcore.h>
@@ -98,7 +99,7 @@ rte_eal_config_create(void)
 	struct rte_config *config = rte_eal_get_configuration();
 	const struct internal_config *internal_conf =
 		eal_get_internal_configuration();
-	size_t page_sz = sysconf(_SC_PAGE_SIZE);
+	size_t page_sz = rte_mem_page_size();
 	size_t cfg_len = sizeof(struct rte_mem_config);
 	size_t cfg_len_aligned = RTE_ALIGN(cfg_len, page_sz);
 	void *rte_mem_cfg_addr, *mapped_mem_cfg_addr;
diff --git a/lib/eal/freebsd/eal_memory.c b/lib/eal/freebsd/eal_memory.c
index 3b72e13506..6d3d46a390 100644
--- a/lib/eal/freebsd/eal_memory.c
+++ b/lib/eal/freebsd/eal_memory.c
@@ -11,6 +11,7 @@
 #include <fcntl.h>
 
 #include <rte_eal.h>
+#include <rte_eal_paging.h>
 #include <rte_errno.h>
 #include <rte_log.h>
 #include <rte_string_fns.h>
@@ -22,8 +23,6 @@
 #include "eal_memcfg.h"
 #include "eal_options.h"
 
-#define EAL_PAGE_SIZE (sysconf(_SC_PAGESIZE))
-
 uint64_t eal_get_baseaddr(void)
 {
 	/*
@@ -191,7 +190,7 @@ rte_eal_hugepage_init(void)
 			addr = mmap(addr, page_sz, PROT_READ|PROT_WRITE,
 					MAP_SHARED | MAP_FIXED,
 					hpi->lock_descriptor,
-					j * EAL_PAGE_SIZE);
+					j * rte_mem_page_size());
 			if (addr == MAP_FAILED) {
 				EAL_LOG(ERR, "Failed to mmap buffer %u from %s",
 						j, hpi->hugedir);
@@ -243,7 +242,7 @@ attach_segment(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 
 	addr = mmap(ms->addr, ms->len, PROT_READ | PROT_WRITE,
 			MAP_SHARED | MAP_FIXED, wa->fd_hugepage,
-			wa->seg_idx * EAL_PAGE_SIZE);
+			wa->seg_idx * rte_mem_page_size());
 	if (addr == MAP_FAILED || addr != ms->addr)
 		return -1;
 	wa->seg_idx++;
diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index 20f777b8b0..ad6de9b7ee 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -31,6 +31,7 @@
 #include <rte_launch.h>
 #include <rte_eal.h>
 #include <rte_eal_memconfig.h>
+#include <rte_eal_paging.h>
 #include <rte_errno.h>
 #include <rte_lcore.h>
 #include <rte_service_component.h>
@@ -179,7 +180,7 @@ static int
 rte_eal_config_create(void)
 {
 	struct rte_config *config = rte_eal_get_configuration();
-	size_t page_sz = sysconf(_SC_PAGE_SIZE);
+	size_t page_sz = rte_mem_page_size();
 	size_t cfg_len = sizeof(*config->mem_config);
 	size_t cfg_len_aligned = RTE_ALIGN(cfg_len, page_sz);
 	void *rte_mem_cfg_addr, *mapped_mem_cfg_addr;
diff --git a/lib/eal/unix/eal_unix_memory.c b/lib/eal/unix/eal_unix_memory.c
index c540f1e838..51de6780f2 100644
--- a/lib/eal/unix/eal_unix_memory.c
+++ b/lib/eal/unix/eal_unix_memory.c
@@ -85,7 +85,7 @@ eal_mem_set_dump(void *virt, size_t size, bool dump)
 	int ret = madvise(virt, size, flags);
 	if (ret) {
 		EAL_LOG(DEBUG, "madvise(%p, %#zx, %d) failed: %s",
-				virt, size, flags, strerror(rte_errno));
+				virt, size, flags, strerror(errno));
 		rte_errno = errno;
 	}
 	return ret;
@@ -141,8 +141,20 @@ rte_mem_page_size(void)
 {
 	static size_t page_size;
 
-	if (!page_size)
+	if (page_size == 0) {
+		/*
+		 * When the sysconf value cannot be determined, sysconf()
+		 * returns -1 without setting errno.
+		 * To distinguish an indeterminate value from an error,
+		 * clear errno before calling sysconf(), and check whether
+		 * errno has been set if sysconf() returns -1.
+		 */
+		errno = 0;
 		page_size = sysconf(_SC_PAGESIZE);
+		if ((ssize_t)page_size < 0)
+			rte_panic("sysconf(_SC_PAGESIZE) failed: %s",
+					errno == 0 ? "Indeterminate" : strerror(errno));
+	}
 
 	return page_size;
 }
diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
index a2a7d73388..9de7f04a4f 100644
--- a/lib/vhost/vduse.c
+++ b/lib/vhost/vduse.c
@@ -16,6 +16,7 @@
 #include <sys/stat.h>
 
 #include <rte_common.h>
+#include <rte_eal_paging.h>
 #include <rte_thread.h>
 
 #include "fd_man.h"
@@ -690,7 +691,7 @@ vduse_device_create(const char *path, bool compliant_ol_flags)
 		dev_config->vendor_id = 0;
 		dev_config->features = features;
 		dev_config->vq_num = total_queues;
-		dev_config->vq_align = sysconf(_SC_PAGE_SIZE);
+		dev_config->vq_align = rte_mem_page_size();
 		dev_config->config_size = sizeof(struct virtio_net_config);
 		memcpy(dev_config->config, &vnet_config, sizeof(vnet_config));
 
-- 
2.43.0