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

Yeqi Fu posted 10 patches 2 years, 7 months ago
There is a newer version of this series
[RFC v3 04/10] linux-user: Implement envlist_appendenv
Posted by Yeqi Fu 2 years, 7 months ago 
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);
+    }
+
+    /* 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);
+}
+
 /*
  * Returns given envlist as array of strings (in same form that
  * global variable environ is).  Caller must free returned memory
-- 
2.34.1
Re: [RFC v3 04/10] linux-user: Implement envlist_appendenv
Posted by Alex Bennée 2 years, 7 months ago 
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
Re: [RFC v3 04/10] linux-user: Implement envlist_appendenv
Posted by Warner Losh 2 years, 7 months ago 
On Mon, Jul 3, 2023, 10:40 AM Alex Bennée <alex.bennee@linaro.org> wrote:

>
> 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);
>

No parens here

>  }
> >
> > +/*
> > + * 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.
>

And elsewhere...

Warner

> +    }
> > +
> > +    /* 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
>
>

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