[PATCH v6 3/9] test: avoid overflowing huge directory path

Stephen Hemminger
2025-11-23T17:45:27Z

Modify the part of the test that is scanning for hugepages
mount point to use existing getmntent library calls.

As a result, the maximum mount path is smaller which is ok
since this is all handled by the standard library.
And the resulting huge path arguments don't overflow.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
app/test/test_eal_flags.c | 115 ++++++++++++++------------------------
1 file changed, 43 insertions(+), 72 deletions(-)

diff --git a/app/test/test_eal_flags.c b/app/test/test_eal_flags.c
index c2e6c00edb..0aebb5f611 100644
--- a/app/test/test_eal_flags.c
+++ b/app/test/test_eal_flags.c
@@ -107,6 +107,7 @@ test_misc_flags(void)
#include <sys/wait.h>
#include <limits.h>
#include <fcntl.h>
+#include <mntent.h>

#include <rte_lcore.h>
#include <rte_debug.h>
@@ -123,6 +124,8 @@ test_misc_flags(void)
#define vdev "--vdev"
#define file_prefix "--file-prefix"

+#define FS_HUGETLB "hugetlbfs"
+
#define memtest "memtest"
#define memtest1 "memtest1"
#define memtest2 "memtest2"
@@ -136,24 +139,6 @@ enum hugepage_action {
HUGEPAGE_INVALID
};

-/* if string contains a hugepage path */
-static int
-get_hugepage_path(char * src, int src_len, char * dst, int dst_len)
-{
-#define NUM_TOKENS 4
- char *tokens[NUM_TOKENS];
-
- /* if we couldn't properly split the string */
- if (rte_strsplit(src, src_len, tokens, NUM_TOKENS, ' ') < NUM_TOKENS)
- return 0;
-
- if (strncmp(tokens[2], "hugetlbfs", sizeof("hugetlbfs")) == 0) {
- strlcpy(dst, tokens[1], dst_len);
- return 1;
- }
- return 0;
-}
-
/*
* Cycles through hugepage directories and looks for hugepage
* files associated with a given prefix. Depending on value of
@@ -165,45 +150,39 @@ get_hugepage_path(char * src, int src_len, char * dst, int dst_len)
* Returns -1 if it encounters an error
*/
static int
-process_hugefiles(const char * prefix, enum hugepage_action action)
+process_hugefiles(const char *prefix, enum hugepage_action action)
{
- FILE * hugedir_handle = NULL;
- DIR * hugepage_dir = NULL;
- struct dirent *dirent = NULL;
-
- char hugefile_prefix[PATH_MAX] = {0};
- char hugedir[PATH_MAX] = {0};
- char line[PATH_MAX] = {0};
-
- int fd, lck_result, result = 0;
+ const struct mntent *entry;
+ char hugefile_prefix[PATH_MAX];
+ int result = 0;

- const int prefix_len = snprintf(hugefile_prefix,
- sizeof(hugefile_prefix), "%smap_", prefix);
- if (prefix_len <= 0 || prefix_len >= (int)sizeof(hugefile_prefix)
- || prefix_len >= (int)sizeof(dirent->d_name)) {
+ const int prefix_len = snprintf(hugefile_prefix, sizeof(hugefile_prefix), "%smap_", prefix);
+ if (prefix_len <= 0 || prefix_len >= NAME_MAX) {
printf("Error creating hugefile filename prefix\n");
return -1;
}

/* get hugetlbfs mountpoints from /proc/mounts */
- hugedir_handle = fopen("/proc/mounts", "r");
-
- if (hugedir_handle == NULL) {
+ FILE *mounts = setmntent("/proc/mounts", "r");
+ if (mounts == NULL) {
printf("Error parsing /proc/mounts!\n");
return -1;
}

- /* read and parse script output */
- while (fgets(line, sizeof(line), hugedir_handle) != NULL) {
+ /* foreach mountpoint */
+ while ((entry = getmntent(mounts)) != NULL) {
+ DIR *hugepage_dir;
+ struct dirent *dirent;

- /* check if we have a hugepage filesystem path */
- if (!get_hugepage_path(line, sizeof(line), hugedir, sizeof(hugedir)))
+ /* only want hugetlbfs filesystems */
+ if (strcmp(entry->mnt_type, FS_HUGETLB) != 0)
continue;

/* check if directory exists */
- if ((hugepage_dir = opendir(hugedir)) == NULL) {
- fclose(hugedir_handle);
- printf("Error reading %s: %s\n", hugedir, strerror(errno));
+ hugepage_dir = opendir(entry->mnt_dir);
+ if (hugepage_dir == NULL) {
+ endmntent(mounts);
+ printf("Error reading %s: %s\n", entry->mnt_dir, strerror(errno));
return -1;
}

@@ -222,10 +201,10 @@ process_hugefiles(const char * prefix, enum hugepage_action action)
break;
case HUGEPAGE_DELETE:
{
- char file_path[PATH_MAX] = {0};
+ char file_path[PATH_MAX];

snprintf(file_path, sizeof(file_path),
- "%s/%s", hugedir, dirent->d_name);
+ "%s/%s", entry->mnt_dir, dirent->d_name);

/* remove file */
if (remove(file_path) < 0) {
@@ -240,6 +219,8 @@ process_hugefiles(const char * prefix, enum hugepage_action action)
break;
case HUGEPAGE_CHECK_LOCKED:
{
+ int fd;
+
/* try and lock the file */
fd = openat(dirfd(hugepage_dir), dirent->d_name, O_RDONLY);

@@ -253,10 +234,7 @@ process_hugefiles(const char * prefix, enum hugepage_action action)
}

/* non-blocking lock */
- lck_result = flock(fd, LOCK_EX | LOCK_NB);
-
- /* if lock succeeds, there's something wrong */
- if (lck_result != -1) {
+ if (flock(fd, LOCK_EX | LOCK_NB) != -1) {
result = 0;

/* unlock the resulting lock */
@@ -278,7 +256,7 @@ process_hugefiles(const char * prefix, enum hugepage_action action)
closedir(hugepage_dir);
} /* read /proc/mounts */
end:
- fclose(hugedir_handle);
+ endmntent(mounts);
return result;
}

@@ -873,10 +851,10 @@ test_no_huge_flag(void)
static int
test_misc_flags(void)
{
- char hugepath[PATH_MAX] = {0};
- char hugepath_dir[PATH_MAX] = {0};
- char hugepath_dir2[PATH_MAX] = {0};
- char hugepath_dir3[PATH_MAX] = {0};
+ const char *hugepath = "";
+ char hugepath_dir[PATH_MAX];
+ char hugepath_dir2[PATH_MAX];
+ char hugepath_dir3[PATH_MAX];
#ifdef RTE_EXEC_ENV_FREEBSD
/* BSD target doesn't support prefixes at this point */
const char * prefix = "";
@@ -884,9 +862,7 @@ test_misc_flags(void)
#else
const char *prefix = get_file_prefix();
const char * nosh_prefix = "--file-prefix=noshconf";
- FILE * hugedir_handle = NULL;
- char line[PATH_MAX] = {0};
- unsigned i, isempty = 1;
+ struct mntent *entry;

if (prefix == NULL)
return -1;
@@ -896,29 +872,24 @@ test_misc_flags(void)
*/

/* get hugetlbfs mountpoints from /proc/mounts */
- hugedir_handle = fopen("/proc/mounts", "r");
-
- if (hugedir_handle == NULL) {
+ FILE *mounts = setmntent("/proc/mounts", "r");
+ if (mounts == NULL) {
printf("Error opening /proc/mounts!\n");
return -1;
}

- /* read /proc/mounts */
- while (fgets(line, sizeof(line), hugedir_handle) != NULL) {
-
- /* find first valid hugepath */
- if (get_hugepage_path(line, sizeof(line), hugepath, sizeof(hugepath)))
+ /* foreach mount point */
+ hugepath = NULL;
+ while ((entry = getmntent(mounts)) != NULL) {
+ /* only want hugetlbfs filesystems */
+ if (strcmp(entry->mnt_type, FS_HUGETLB) == 0) {
+ hugepath = strdupa(entry->mnt_dir);
break;
+ }
}
+ endmntent(mounts);

- fclose(hugedir_handle);
-
- /* check if path is not empty */
- for (i = 0; i < sizeof(hugepath); i++)
- if (hugepath[i] != '\0')
- isempty = 0;
-
- if (isempty) {
+ if (hugepath == NULL) {
printf("No mounted hugepage dir found!\n");
return -1;
}
--
2.51.0