Commit 084afa90 authored Jul 23, 2024 by Konrad Sztyber Committed by Tomasz Zawadzki Jul 23, 2024

util: copy errno before calling stdlib's functions



Functions are allowed to change the value of errno, even when they're
successful.  So, save it before calling other functions to ensure it's
not overwritten.

Additionally, scan-build complains that these errnos can still be zero,
even though the manual says that they're always set if an error is
encountered.  To keep it quiet, added a couple of assertions that check
it.

Fixes: #3453

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I76209bc1970f42cc8d52446fa651d5a9fee3d70f
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/24298


Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>
Community-CI: Mellanox Build Bot
Bypass-Merge-Requirements: Tomasz Zawadzki <tomasz.zawadzki@intel.com>

parent 2cf63d58

lib/util/file.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -67,6 +67,7 @@ read_sysfs_attribute(char *attribute_p, const char format, va_list args)
		char *path;
		size_t len = 0;
		ssize_t read;
		int errsv;

		path = spdk_vsprintf_alloc(format, args);
		if (path == NULL) {
		@@ -74,19 +75,23 @@ read_sysfs_attribute(char *attribute_p, const char format, va_list args)
		}

		file = fopen(path, "r");
		errsv = errno;
		free(path);
		if (file == NULL) {
		return -errno;
		assert(errsv != 0);
		return -errsv;
		}

		*attribute_p = NULL;
		read = getline(attribute_p, &len, file);
		errsv = errno;
		fclose(file);
		attribute = *attribute_p;
		if (read == -1) {
		/* getline man page says line should be freed even on failure. */
		free(attribute);
		return -errno;
		assert(errsv != 0);
		return -errsv;
		}

		/* len is the length of the allocated buffer, which may be more than