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unistd/getcwd: enhance getcwd when buf is NULL

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Change-Id: I595e1874349f089691dc5291f31fb376cf0e2e2c
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
This commit is contained in:
Jiuzhu Dong 2021-01-25 12:40:27 +08:00 • committed by David Sidrane
parent 1105cf0669
commit 6cac6c50d1
1 changed files with 24 additions and 5 deletions
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29
libs/libc/unistd/lib_getcwd.c
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@ -63,6 +63,12 @@
* symbolic links. The 'size' argument is the size in bytes of the
* character array pointed to by the 'buf' argument.
*
* As an extension to the POSIX.1-2001 standard, getcwd() allocates
* the buffer dynamically using lib_malloc if buf is NULL. In this case,
* the allocated buffer has the length size unless size is zero, when buf
* is allocated as big as necessary. The caller should free the
* returned buffer.
*
* Input Parameters:
* buf - a pointer to the location in which the current working directory
* pathname is returned.
@ -74,7 +80,7 @@
* the error:
*
* EINVAL
* The 'size' argument is 0 or the 'buf' argument is NULL.
* The 'size' argument is 0 and the 'buf' argument is not NULL.
* ERANGE
* The size argument is greater than 0, but is smaller than the length
* of the current working directory pathname +1.
@ -91,18 +97,21 @@ FAR char *getcwd(FAR char *buf, size_t size)
/* Verify input parameters */
#ifdef CONFIG_DEBUG_FEATURES
if (!buf || !size)
if (buf && size == 0)
{
set_errno(EINVAL);
return NULL;
}
#endif
if (size == 0)
{
size = PATH_MAX + 1;
}
/* If no working directory is defined, then default to the home directory */
pwd = getenv("PWD");
if (!pwd)
if (pwd == NULL)
{
pwd = CONFIG_LIB_HOMEDIR;
}
@ -115,6 +124,16 @@ FAR char *getcwd(FAR char *buf, size_t size)
return NULL;
}
if (buf == NULL)
{
buf = lib_malloc(size);
if (!buf)
{
set_errno(ENOMEM);
return NULL;
}
}
/* Copy the cwd to the user buffer */
strcpy(buf, pwd);