From b4f52f09ae712e1a813375712b6e58be49255cd0 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 19 Jul 2022 18:45:54 +0000 Subject: [PATCH] compat/win32: correct for incorrect compiler warning The 'win build' job of our CI build is failing with the following error: compat/win32/syslog.c: In function 'syslog': compat/win32/syslog.c:53:17: error: pointer 'pos' may be used after \ 'realloc' [-Werror=use-after-free] 53 | memmove(pos + 2, pos + 1, strlen(pos)); CC compat/poll/poll.o | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ compat/win32/syslog.c:47:23: note: call to 'realloc' here 47 | str = realloc(str, st_add(++str_len, 1)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ However, between this realloc() and the use we have a line that resets the value of 'pos'. Thus, this error is incorrect. It is likely due to a new version of the compiler on the CI machines. Instead of waiting for a new compiler, create a new variable to avoid this error. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- compat/win32/syslog.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/compat/win32/syslog.c b/compat/win32/syslog.c index 1f8d8934cc..0af18d8882 100644 --- a/compat/win32/syslog.c +++ b/compat/win32/syslog.c @@ -44,6 +44,7 @@ void syslog(int priority, const char *fmt, ...) while ((pos = strstr(str, "%1")) != NULL) { size_t offset = pos - str; + char *new_pos; char *oldstr = str; str = realloc(str, st_add(++str_len, 1)); if (!str) { @@ -51,9 +52,9 @@ void syslog(int priority, const char *fmt, ...) warning_errno("realloc failed"); return; } - pos = str + offset; - memmove(pos + 2, pos + 1, strlen(pos)); - pos[1] = ' '; + new_pos = str + offset; + memmove(new_pos + 2, new_pos + 1, strlen(new_pos)); + new_pos[1] = ' '; } switch (priority) {