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libc/realpath: allocate link buffer of pseudofs to save stack

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The link buffer of pseudofs will occupy too much of stack, allocate from
the heap to save the stack usage.

Signed-off-by: chao an <anchao@xiaomi.com>
This commit is contained in:
chao an
2023-11-06 16:19:40 +08:00
committed by Xiang Xiao
parent 4d65d9908b
commit d410a6e1a6
1 changed files with 33 additions and 3 deletions
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36
libs/libc/stdlib/lib_realpath.c
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@@ -39,7 +39,10 @@
FAR char *realpath(FAR const char *path, FAR char *resolved) FAR char *realpath(FAR const char *path, FAR char *resolved)
{ {
#ifdef CONFIG_PSEUDOFS_SOFTLINKS #ifdef CONFIG_PSEUDOFS_SOFTLINKS
char wbuf[2][PATH_MAX]; FAR char *wbuf[2] =
{
};
int nlnk = 0; int nlnk = 0;
int idx = 0; int idx = 0;
ssize_t n; ssize_t n;
@@ -117,6 +120,14 @@ loop:
} }
*p = '\0'; *p = '\0';
#ifdef CONFIG_PSEUDOFS_SOFTLINKS
if (wbuf[0] != NULL)
{
lib_free(wbuf[0]);
}
#endif
return resolved; return resolved;
} }
@@ -186,7 +197,19 @@ loop:
goto out; goto out;
} }
n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1); if (wbuf[0] == NULL)
{
wbuf[0] = lib_calloc(2, PATH_MAX);
if (wbuf[0] == NULL)
{
set_errno(ENOMEM);
goto out;
}
wbuf[1] = wbuf[0] + PATH_MAX;
}
n = readlink(resolved, wbuf[idx], PATH_MAX - 1);
if (n <= 0) if (n <= 0)
{ {
if (n == 0) if (n == 0)
@@ -199,7 +222,7 @@ loop:
/* Append unresolved path to link target and switch to it. */ /* Append unresolved path to link target and switch to it. */
if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) if (n + (len = strlen(q)) + 1 > PATH_MAX)
{ {
set_errno(ENAMETOOLONG); set_errno(ENAMETOOLONG);
goto out; goto out;
@@ -234,5 +257,12 @@ loop:
out: out:
lib_free(fres); lib_free(fres);
#ifdef CONFIG_PSEUDOFS_SOFTLINKS
if (wbuf[0] != NULL)
{
lib_free(wbuf[0]);
}
#endif
return NULL; return NULL;
} }