mailsplit: move NULL check before first use of file handle
The `split_mbox()` function calls fileno(f) to check whether the input is a terminal, but the NULL check for f (from `fopen()`) does not happen until later. When the file cannot be opened, f is NULL, and `fileno(NULL)` is undefined behavior, typically crashing with a segmentation fault. Move the NULL check above the `isatty()`/`fileno()` call so the error path is taken before any use of the potentially-NULL handle. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Johannes Schindelin committed
Jul 10, 2026 at 11:39 UTC
775f1f2b19e1c3d133356170373fedeb363988a3
1 file changed
+3
-3
builtin/mailsplit.c
+3
-3
@@ -225,14 +225,14 @@ static int split_mbox(const char *file, const char *dir, int allow_bare,
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FILE *f = !strcmp(file, "-") ? stdin : fopen(file, "r");
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int file_done = 0;
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- if (isatty(fileno(f)))
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- warning(_("reading patches from stdin/tty..."));
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-
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if (!f) {
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error_errno("cannot open mbox %s", file);
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goto out;
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}
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+ if (isatty(fileno(f)))
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+ warning(_("reading patches from stdin/tty..."));
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+
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do {
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peek = fgetc(f);
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if (peek == EOF) {