[PATCH] miscutils: fix DIVISION_BY_ZERO.EX in beep.c

[Anton Moryakov]

Report of the static analyzer:
DIVISION_BY_ZERO.EX Variable xatou(...), 
whose possible value set allows a zero value at xatonum_template.c:118 by calling function 'xatou' at beep.c:90,
is used as a denominator at beep.c:90.

Corrections explained:
Fixed a potential division by zero issue in beep.c.  
The function xatou(optarg) could return0, leading to an  undefined behavior when used as a denominator.  
Changes:  
- Added a check to ensure the frequency value is nonzero before division.  - If an invalid frequency (0) is provided, the program exits with an error message.  
This fix prevents crashes and ensures safer execution.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov at gmail.com>

---
 miscutils/beep.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/miscutils/beep.c b/miscutils/beep.c
index 724a666c8..1667757ea 100644
--- a/miscutils/beep.c
+++ b/miscutils/beep.c
@@ -87,6 +87,9 @@ int beep_main(int argc, char **argv)
 		switch (c) {
 		case 'f':
 /* TODO: what "-f 0" should do? */
+			unsigned freq = xatou(optarg);
+			if (freq == 0) 
+    			bb_error_msg_and_die("frequency cannot be zero");
 			tickrate_div_freq = (unsigned)CLOCK_TICK_RATE / xatou(optarg);
 			continue;
 		case 'l':
-- 
2.30.2