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at 2025-11-10T07:02:47-08:00

Implement os_getpwuid per review comments

We implement os_getpwuid and use it as needed to get the user name
and/or user directory.  This requires updating os_get_username and
get_homedir_from_uid and their callers of course.

unix::unix-get-username needs updating too.

@@ -2543,15 +2543,26 @@
      (string-decode (cast result c-string) :default)))
  (defun unix-get-username (uid)
 -  (let (name)
 -    (unwind-protect
 -	 (progn
 -	   (setf name
 -		 (alien-funcall
 -		  (extern-alien "os_get_username"
 -				(function (* char) uid-t))
 -		  uid))
 -	   (unless (null-alien name)
 -	     (cast name c-call:c-string)))
 -      (unless (null-alien name)
 +  _N"Returns a string that is the user name corresponding to the given UID.
 +  If no such uid exists or if the user name does not exist, NIL is
 +  returned."
 +  (with-alien ((status c-call:int))
 +    (let (result)
 +      (unwind-protect
 +	   (progn
 +	     (setf result
 +		   (alien-funcall
 +		    (extern-alien "os_get_username"
 +				  (function (* c-call:c-string)
 +					    uid-t
 +					    (* c-call:int)))
 +		    uid
 +		    (addr status)))
 +	     (values
 +	      (if (and (zerop status)
 +		       (not (null-alien result)))
 +		  (cast result c-call:c-string)
 +		  nil)
 +	      status))
  	(free-alien name)))))
++

@@ -810,3 +810,10 @@ msgstr ""
  msgid "Returns a string that describes the error code Errno"
  msgstr ""
 +#: src/code/unix.lisp
 +msgid ""
 +"Returns a string that is the user name corresponding to the given UID.\n"
 +"  If no such uid exists or if the user name does not exist, NIL is\n"
 +"  returned."
 +msgstr ""
++

@@ -731,56 +731,37 @@ os_lstat(const char* path, uint64_t *dev, uint64_t *ino, unsigned int *mode, uin
+ }
  /*
 - * From the given UID, find the corresponding user name and home
 - * directory.
 - *
 - * NAME and DIR are set to the user name and home directory.  The
 - * caller must free these.  If no such uid exists, NAME and DIR are
 - * set to NULL.
 - *
 - * Returns the status of getpwuid.  Zero indicates success.  Otherwise
 - * the errno is returned.
 + * Basic interface to getpwuid, except we will automatically retry if
 + * the given buffer is too small.  To support this |buffer| is a
 + * pointer to a char buffer.  This will be updated with a new buffer
 + * if we needed to retry getpwuid with a larger buffer.  The remaining
 + * parameters are the same as for getpwuid.
   */
  int
 -os_get_user_info(uid_t uid, char **name, char **dir)
 +os_getpwuid(uid_t uid, struct passwd *pwd, char **buffer, size_t buflen, struct passwd **result)
+ {
 -    char initial[1024];
 -    char *buffer, *obuffer;
 -    size_t size;
 -    struct passwd pwd;
 -    struct passwd *ppwd;
      int status;
+-
 -    *name = NULL;
 -    *dir = NULL;
+-
 -    buffer = initial;
 -    obuffer = NULL;
 -    size = sizeof(initial) / sizeof(initial[0]);
 +    char *obuffer = NULL;
      /*
       * Keep trying with larger buffers until a maximum is reached.  We
       * assume (1 << 20) is large enough for any OS.
       */
  again:
 -    switch (status = getpwuid_r(uid, &pwd, buffer, size, &ppwd)) {
 +    switch (status = getpwuid_r(uid, pwd, *buffer, buflen, result)) {
        case 0:
  	  /* Success, though we might not have a matching entry */
 -	  if (ppwd) {
 -	      *name = strdup(pwd.pw_name);
 -	      *dir = strdup(pwd.pw_dir);
 -	  }
  	  break;
        case ERANGE:
  	  /* Buffer is too small, double its size and try again */
 -	  size *= 2;
 -	  if (size > (1 << 20)) {
 +	  buflen *= 2;
 +	  if (buflen > (1 << 20)) {
  	      break;
+ 	  }
 -	  if ((buffer = realloc(obuffer, size)) == NULL) {
 +	  if ((*buffer = realloc(obuffer, buflen)) == NULL) {
  	      break;
+ 	  }
 -	  obuffer = buffer;
 +	  obuffer = *buffer;
  	  goto again;
        default:
  	/* All other errors */
@@ -791,23 +772,38 @@ again:
      return status;
+ }
++
  /*
   * Given the UID, return the user name.  If the uid does not exist,
   * returns NULL.  The caller must call free on the string that is
   * returned.
   */
  char *
 -os_get_username(uid_t uid)
 +os_get_username(uid_t uid, int *status)
+ {
 -    int status;
 +    char *buf;
      char *name;
 -    char *dir;
 +    struct passwd pwd;
 +    struct passwd *result;
 +    char buffer[1024];
 -    status = os_get_user_info(uid, &name, &dir);
 +    buf = buffer;
 -    free(dir);
 +    *status = os_getpwuid(uid, &pwd, &buf, 1024, &result);
 -    return (status == 0) ? name : NULL;
 +    if (*status != 0 || result == NULL || result->pw_name == NULL) {
 +	name = NULL;
 +    } else {
 +	name = strdup(result->pw_name);
 +	if (name == NULL) {
 +	    *status = errno;
 +	}
 +	if (buf != buffer) {
 +	    free(buf);
 +	}
 +    }
++
 +    return name;
+ }
  /*
@@ -818,13 +814,14 @@ os_get_username(uid_t uid)
  char *
  os_file_author(const char *path)
+ {
 +    int status;
      struct stat sb;
      if (stat(path, &sb) != 0) {
          return NULL;
+     }
 -    return os_get_username(sb.st_uid);
 +    return os_get_username(sb.st_uid, &status);
+ }
  int
@@ -986,16 +983,29 @@ get_homedir_from_name(const char* name, int *status)
  static char *
  get_homedir_from_uid(uid_t uid, int *status)
+ {
 -    char *name;
 +    char buffer[1024];
 +    char *buf;
      char *dir;
+-
 -    *status = os_get_user_info(uid, &name, &dir);
 +    struct passwd pwd;
 +    struct passwd *result;
 -    free(name);
+-
 -    return (*status == 0) ? dir : NULL;
 -}
 +    buf = buffer;
 +    dir = NULL;
 +    *status = os_getpwuid(uid, &pwd, &buf, 1024, &result);
++
 +    if (*status == 0 && result != NULL && result->pw_dir != NULL) {
 +	dir = strdup(result->pw_dir);
 +	if (dir == NULL) {
 +	    *status = errno;
 +	}
 +	if (buf != buffer) {
 +	    free(buf);
 +	}
 +    }
++
 +    return dir;
 +}
  /*
   * Return the home directory of the user named NAME.  If NAME is the

Raymond Toy pushed to branch issue-408-get-user-name-and-homedir at cmucl / cmucl

Commits:

3 changed files:

Changes: