[PATCH v3 05/17] linux-user: Replace alloca() by g_try_new() in ppoll() syscall

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

The ALLOCA(3) man-page mentions its "use is discouraged".

Use autofree heap allocation instead (returning ENOMEM on failure).

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 linux-user/syscall.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 2fa6b89b3de..0bf4273fc7a 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1605,11 +1605,10 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3,
 {
     struct target_pollfd *target_pfd;
     unsigned int nfds = arg2;
-    struct pollfd *pfd;
+    g_autofree struct pollfd *pfd = NULL;
     unsigned int i;
     abi_long ret;
 
-    pfd = NULL;
     target_pfd = NULL;
     if (nfds) {
         if (nfds > (INT_MAX / sizeof(struct target_pollfd))) {
@@ -1621,7 +1620,10 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3,
             return -TARGET_EFAULT;
         }
 
-        pfd = alloca(sizeof(struct pollfd) * nfds);
+        pfd = g_try_new(struct pollfd, nfds);
+        if (!pfd) {
+            return -TARGET_ENOMEM;
+        }
         for (i = 0; i < nfds; i++) {
             pfd[i].fd = tswap32(target_pfd[i].fd);
             pfd[i].events = tswap16(target_pfd[i].events);
-- 
2.26.3