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Posted to common-issues@hadoop.apache.org by "cnauroth (via GitHub)" <gi...@apache.org> on 2026/02/28 07:33:43 UTC
Re: [PR] YARN-11919 segfault with get_user_info [hadoop]
cnauroth commented on code in PR #8177:
URL: https://github.com/apache/hadoop/pull/8177#discussion_r2867182367
##########
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/native/container-executor/impl/container-executor.c:
##########
@@ -915,26 +934,47 @@ static int create_container_directories(const char* user, const char *app_id,
/**
* Load the user information for a given user name.
+ * See <a href="https://linux.die.net/man/3/getpwnam_r">getpwname_r</a>
+ * Note: for user not found and some error conditions NULL is returned
*/
-static struct passwd* get_user_info(const char* user) {
- size_t string_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+static struct serialized_passwd* get_user_info(const char* user) {
+ struct passwd pwd;
struct passwd *result = NULL;
- if(string_size < 1024) {
- string_size = 1024;
- }
- struct passwd* buffer = malloc(sizeof(struct passwd) + string_size);
- if (NULL == buffer) {
- fprintf(LOGFILE, "Failed malloc in get_user_info\n");
- return NULL;
- }
- if (getpwnam_r(user, buffer, ((char*)buffer) + sizeof(struct passwd),
- string_size, &result) != 0) {
- free(buffer);
- fprintf(LOGFILE, "Can't get user information %s - %s\n", user,
- strerror(errno));
+ struct serialized_passwd *serialized_result;
+ char *buf;
+ size_t bufsize;
+ int s;
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1){
+ bufsize = 1024;
+ }
+ buf = malloc(bufsize);
+ if (buf == NULL) {
+ exit(EXIT_FAILURE);
+ }
+ while ((s = getpwnam_r(user, &pwd, buf, bufsize, &result)) == ERANGE){
+ bufsize = 2 * bufsize;
+ char *newbuffer = realloc(buf, bufsize);
+ if (newbuffer == NULL){
Review Comment:
Nitpick: space before curly brace please.
##########
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/native/container-executor/impl/container-executor.c:
##########
@@ -915,26 +934,47 @@ static int create_container_directories(const char* user, const char *app_id,
/**
* Load the user information for a given user name.
+ * See <a href="https://linux.die.net/man/3/getpwnam_r">getpwname_r</a>
+ * Note: for user not found and some error conditions NULL is returned
*/
-static struct passwd* get_user_info(const char* user) {
- size_t string_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+static struct serialized_passwd* get_user_info(const char* user) {
+ struct passwd pwd;
struct passwd *result = NULL;
- if(string_size < 1024) {
- string_size = 1024;
- }
- struct passwd* buffer = malloc(sizeof(struct passwd) + string_size);
- if (NULL == buffer) {
- fprintf(LOGFILE, "Failed malloc in get_user_info\n");
- return NULL;
- }
- if (getpwnam_r(user, buffer, ((char*)buffer) + sizeof(struct passwd),
- string_size, &result) != 0) {
- free(buffer);
- fprintf(LOGFILE, "Can't get user information %s - %s\n", user,
- strerror(errno));
+ struct serialized_passwd *serialized_result;
+ char *buf;
+ size_t bufsize;
+ int s;
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1){
+ bufsize = 1024;
+ }
+ buf = malloc(bufsize);
+ if (buf == NULL) {
+ exit(EXIT_FAILURE);
+ }
+ while ((s = getpwnam_r(user, &pwd, buf, bufsize, &result)) == ERANGE){
+ bufsize = 2 * bufsize;
+ char *newbuffer = realloc(buf, bufsize);
+ if (newbuffer == NULL){
+ exit(EXIT_FAILURE);
+ }
+ buf = newbuffer;
+ }
+ if (result == NULL) {
+ if (s == 0){
Review Comment:
Nitpick: space before curly brace please.
##########
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/native/container-executor/impl/container-executor.c:
##########
@@ -915,26 +934,47 @@ static int create_container_directories(const char* user, const char *app_id,
/**
* Load the user information for a given user name.
+ * See <a href="https://linux.die.net/man/3/getpwnam_r">getpwname_r</a>
+ * Note: for user not found and some error conditions NULL is returned
*/
-static struct passwd* get_user_info(const char* user) {
- size_t string_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+static struct serialized_passwd* get_user_info(const char* user) {
+ struct passwd pwd;
struct passwd *result = NULL;
- if(string_size < 1024) {
- string_size = 1024;
- }
- struct passwd* buffer = malloc(sizeof(struct passwd) + string_size);
- if (NULL == buffer) {
- fprintf(LOGFILE, "Failed malloc in get_user_info\n");
- return NULL;
- }
- if (getpwnam_r(user, buffer, ((char*)buffer) + sizeof(struct passwd),
- string_size, &result) != 0) {
- free(buffer);
- fprintf(LOGFILE, "Can't get user information %s - %s\n", user,
- strerror(errno));
+ struct serialized_passwd *serialized_result;
+ char *buf;
+ size_t bufsize;
+ int s;
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1){
+ bufsize = 1024;
+ }
+ buf = malloc(bufsize);
+ if (buf == NULL) {
+ exit(EXIT_FAILURE);
+ }
+ while ((s = getpwnam_r(user, &pwd, buf, bufsize, &result)) == ERANGE){
+ bufsize = 2 * bufsize;
+ char *newbuffer = realloc(buf, bufsize);
Review Comment:
If a [`realloc`](https://linux.die.net/man/3/realloc) fails, it returns `NULL`. If there is a failure, the original buffer remains in place. This implies we need to `free` the original if the `realloc` fails.
##########
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/native/container-executor/impl/container-executor.c:
##########
@@ -915,26 +934,47 @@ static int create_container_directories(const char* user, const char *app_id,
/**
* Load the user information for a given user name.
+ * See <a href="https://linux.die.net/man/3/getpwnam_r">getpwname_r</a>
+ * Note: for user not found and some error conditions NULL is returned
*/
-static struct passwd* get_user_info(const char* user) {
- size_t string_size = sysconf(_SC_GETPW_R_SIZE_MAX);
+static struct serialized_passwd* get_user_info(const char* user) {
+ struct passwd pwd;
struct passwd *result = NULL;
- if(string_size < 1024) {
- string_size = 1024;
- }
- struct passwd* buffer = malloc(sizeof(struct passwd) + string_size);
- if (NULL == buffer) {
- fprintf(LOGFILE, "Failed malloc in get_user_info\n");
- return NULL;
- }
- if (getpwnam_r(user, buffer, ((char*)buffer) + sizeof(struct passwd),
- string_size, &result) != 0) {
- free(buffer);
- fprintf(LOGFILE, "Can't get user information %s - %s\n", user,
- strerror(errno));
+ struct serialized_passwd *serialized_result;
+ char *buf;
+ size_t bufsize;
+ int s;
+ bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (bufsize == -1){
+ bufsize = 1024;
+ }
+ buf = malloc(bufsize);
+ if (buf == NULL) {
+ exit(EXIT_FAILURE);
+ }
+ while ((s = getpwnam_r(user, &pwd, buf, bufsize, &result)) == ERANGE){
+ bufsize = 2 * bufsize;
+ char *newbuffer = realloc(buf, bufsize);
+ if (newbuffer == NULL){
Review Comment:
Nitpick: space before the curly brace please.
##########
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/native/container-executor/impl/container-executor.c:
##########
@@ -120,6 +120,25 @@ void set_nm_uid(uid_t user, gid_t group) {
nm_gid = group;
}
+//function to make a deep clone of passwd to serialized_passwd
+void deep_copy_passwd(const struct passwd *src, struct serialized_passwd *dest){
+ dest->pw_name = strdup(src->pw_name);
Review Comment:
[`strdup`](https://man7.org/linux/man-pages/man3/strdup.3.html) can return `NULL` if there is insufficient memory. (There are pre-existing calls to `strdup` that don't have the error checking. No expectation that you need to do a mass update of all error handling in scope of this patch.)
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