Re: [PATCH 1/6] env: allow to copy value from default environment into a buffer

[Kever Yang]

On 2023/11/8 22:20, Quentin Schulz wrote:

From: Quentin Schulz <quentin.sch...@theobroma-systems.com>

env_get_default suffers from a particular issue int that it can only
return a value truncated to gd->env_buf (32) characters. This may be
enough for most variables but it isn't for others, so let's allow users
to provide a preallocated buffer to copy the value into instead,
allowing for more control, though it'll still be truncated if the value
size is bigger than the preallocated buffer.

Cc: Quentin Schulz <foss+ub...@0leil.net>
Signed-off-by: Quentin Schulz <quentin.sch...@theobroma-systems.com>

Reviewed-by: Kever Yang <kever.y...@rock-chips.com>

Thanks,
- Kever

---
  env/common.c  |  8 ++++++++
  include/env.h | 10 ++++++++++
  2 files changed, 18 insertions(+)

diff --git a/env/common.c b/env/common.c
index eb1a9137953..307003099dd 100644
--- a/env/common.c
+++ b/env/common.c
@@ -254,6 +254,14 @@ char *env_get_default(const char *name)
        return NULL;
  }

+/*

+ * Look up the variable from the default environment and store its value in buf
+ */
+int env_get_default_into(const char *name, char *buf, unsigned int len)
+{
+       return env_get_from_linear(default_environment, name, buf, len);
+}
+
  void env_set_default(const char *s, int flags)
  {
        if (s) {
diff --git a/include/env.h b/include/env.h
index 430c4fa94a4..9a406de3781 100644
--- a/include/env.h
+++ b/include/env.h
@@ -348,6 +348,16 @@ int env_import_redund(const char *buf1, int buf1_read_fail,
   */
  char *env_get_default(const char *name);

+/**

+ * env_get_default_into() - Look up a variable from the default environment and
+ * copy its value in buf.
+ *
+ * @name: Variable to look up
+ * Return: actual length of the variable value excluding the terminating
+ *     NULL-byte, or -1 if the variable is not found
+ */
+int env_get_default_into(const char *name, char *buf, unsigned int len);
+
  /* [re]set to the default environment */
  void env_set_default(const char *s, int flags);