From 732d1963ed83abf4e5f1b06ec451a6943421d716 Mon Sep 17 00:00:00 2001
From: Guo Wenxue <guowenxue@gmail.com>
Date: Thu, 22 Sep 2022 00:36:11 +0800
Subject: [PATCH] update ds18b20.c to snprintf
---
apue/1.File_IO/ds18b20.c | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/apue/1.File_IO/ds18b20.c b/apue/1.File_IO/ds18b20.c
index 1ad5192..0ff2a34 100644
--- a/apue/1.File_IO/ds18b20.c
+++ b/apue/1.File_IO/ds18b20.c
@@ -45,14 +45,14 @@
int ds18b20_get_temperature(float *temp)
{
- char w1_path[50] = "/sys/bus/w1/devices/";
+ const char *w1_path = "/sys/bus/w1/devices/";
+ char ds_path[50];
char chip[20];
char buf[128];
DIR *dirp;
struct dirent *direntp;
int fd =-1;
char *ptr;
- float value;
int found = 0;
int rv = 0;
@@ -89,19 +89,18 @@
}
/* get DS18B20 sample file full path: /sys/bus/w1/devices/28-xxxx/w1_slave */
- strncat(w1_path, chip, sizeof(w1_path)-strlen(w1_path));
- strncat(w1_path, "/w1_slave", sizeof(w1_path)-strlen(w1_path));
+ snprintf(ds_path, sizeof(ds_path), "%s/%s/w1_slave", w1_path, chip);
/* open file /sys/bus/w1/devices/28-xxxx/w1_slave to get temperature */
- if( (fd=open(w1_path, O_RDONLY)) < 0 )
+ if( (fd=open(ds_path, O_RDONLY)) < 0 )
{
- printf("open %s error: %s\n", w1_path, strerror(errno));
+ printf("open %s error: %s\n", ds_path, strerror(errno));
return -4;
}
if(read(fd, buf, sizeof(buf)) < 0)
{
- printf("read %s error: %s\n", w1_path, strerror(errno));
+ printf("read %s error: %s\n", ds_path, strerror(errno));
rv = -5;
goto cleanup;
}
--
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