Re: [RFC v3 04/10] linux-user: Implement envlist_appendenv

[Alex Bennée]

Yeqi Fu <fufuyqqqqqq@gmail.com> writes:

> Signed-off-by: Yeqi Fu <fufuyqqqqqq@gmail.com>
> ---
>  include/qemu/envlist.h |  1 +
>  util/envlist.c         | 61 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 62 insertions(+)
>
> diff --git a/include/qemu/envlist.h b/include/qemu/envlist.h
> index 6006dfae44..865eb18e17 100644
> --- a/include/qemu/envlist.h
> +++ b/include/qemu/envlist.h
> @@ -7,6 +7,7 @@ envlist_t *envlist_create(void);
>  void envlist_free(envlist_t *);
>  int envlist_setenv(envlist_t *, const char *);
>  int envlist_unsetenv(envlist_t *, const char *);
> +int envlist_appendenv(envlist_t *, const char *, const char *);
>  int envlist_parse_set(envlist_t *, const char *);
>  int envlist_parse_unset(envlist_t *, const char *);
>  char **envlist_to_environ(const envlist_t *, size_t *);
> diff --git a/util/envlist.c b/util/envlist.c
> index db937c0427..635c9c4fab 100644
> --- a/util/envlist.c
> +++ b/util/envlist.c
> @@ -201,6 +201,67 @@ envlist_unsetenv(envlist_t *envlist, const char *env)
>      return (0);
>  }
>  
> +/*
> + * Appends environment value to envlist. If the environment
> + * variable already exists, the new value is appended to the
> + * existing one.
> + *
> + * Returns 0 in success, errno otherwise.
> + */
> +int
> +envlist_appendenv(envlist_t *envlist, const char *env, const char *separator)
> +{
> +    struct envlist_entry *entry = NULL;
> +    const char *eq_sign;
> +    size_t envname_len;
> +
> +    if ((envlist == NULL) || (env == NULL) || (separator == NULL)) {
> +        return (EINVAL);

No () around the EINVAL needed here.

> +    }
> +
> +    /* find out first equals sign in given env */
> +    eq_sign = strchr(env, '=');
> +    if (eq_sign == NULL) {
> +        return (EINVAL);
> +    }
> +
> +    if (strchr(eq_sign + 1, '=') != NULL) {
> +        return (EINVAL);
> +    }
> +
> +    envname_len = eq_sign - env + 1;
> +
> +    /*
> +     * If there already exists variable with given name,
> +     * we append the new value to the existing one.
> +     */
> +    for (entry = envlist->el_entries.lh_first; entry != NULL;
> +        entry = entry->ev_link.le_next) {
> +        if (strncmp(entry->ev_var, env, envname_len) == 0) {
> +            break;
> +        }
> +    }
> +
> +    if (entry != NULL) {
> +        char *new_env_value = NULL;
> +        size_t new_env_len = strlen(entry->ev_var) + strlen(eq_sign)
> +            + strlen(separator) + 1;
> +        new_env_value = g_malloc(new_env_len);
> +        strcpy(new_env_value, entry->ev_var);
> +        strcat(new_env_value, separator);
> +        strcat(new_env_value, eq_sign + 1);
> +        g_free((char *)entry->ev_var);
> +        entry->ev_var = new_env_value;
> +    } else {
> +        envlist->el_count++;
> +        entry = g_malloc(sizeof(*entry));
> +        entry->ev_var = g_strdup(env);
> +        QLIST_INSERT_HEAD(&envlist->el_entries, entry, ev_link);
> +    }
> +
> +    return (0);
> +}
> +

We really should add something to tests/unit/test-env to check the
various operations work as expected.


>  /*
>   * Returns given envlist as array of strings (in same form that
>   * global variable environ is).  Caller must free returned memory


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro