Implement esnprintf() and make formatted calls more efficient

Within the components, snprintf() was unchecked and had inefficient
calls in some places.
We implement esnprintf() that does all the dirty laundry for us
and use it exclusively now.

diff --git a/components/battery.c b/components/battery.c
index 90e859070aaec4a51deeee647737939d6880fe88..bcd42cda413aac9b09aa1c2daff26559c68418d3 100644 (file)
--- a/components/battery.c
+++ b/components/battery.c
@@ -14,9 +14,16 @@
                int perc;
                char path[PATH_MAX];
 
-               snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/",
-                        bat, "/capacity");
-               return (pscanf(path, "%d", &perc) == 1) ? bprintf("%d", perc) : NULL;
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/power_supply/%s/capacity",
+                             bat) < 0) {
+                       return NULL;
+               }
+               if (pscanf(path, "%d", &perc) != 1) {
+                       return NULL;
+               }
+
+               return bprintf("%d", perc);
        }
 
        const char *
@@ -32,8 +39,11 @@
                size_t i;
                char path[PATH_MAX], state[12];
 
-               snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/",
-                        bat, "/status");
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/power_supply/%s/status",
+                             bat) < 0) {
+                       return NULL;
+               }
                if (pscanf(path, "%12s", state) != 1) {
                        return NULL;
                }
@@ -53,20 +63,29 @@
                float timeleft;
                char path[PATH_MAX], state[12];
 
-               snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/",
-                        bat, "/status");
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/power_supply/%s/status",
+                             bat) < 0) {
+                       return NULL;
+               }
                if (pscanf(path, "%12s", state) != 1) {
                        return NULL;
                }
 
                if (!strcmp(state, "Discharging")) {
-                       snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/",
-                                        bat, "/charge_now");
+                       if (esnprintf(path, sizeof(path),
+                                      "/sys/class/power_supply/%s/charge_now",
+                                     bat) < 0) {
+                               return NULL;
+                       }
                        if (pscanf(path, "%d", &charge_now) != 1) {
                                return NULL;
                        }
-                       snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/",
-                                        bat, "/current_now");
+                       if (esnprintf(path, sizeof(path),
+                                     "/sys/class/power_supply/%s/current_now",
+                                     bat) < 0) {
+                               return NULL;
+                       }
                        if (pscanf(path, "%d", &current_now) != 1) {
                                return NULL;
                        }

diff --git a/components/netspeeds.c b/components/netspeeds.c
index b4e6972133c9aae14fc70fd6f8c955c6ea2365cb..6adc3ea804fc5ed388bcb8bd38a776ffdc127d62 100644 (file)
--- a/components/netspeeds.c
+++ b/components/netspeeds.c
@@ -17,8 +17,11 @@
 
                oldrxbytes = rxbytes;
 
-               snprintf(path, sizeof(path),
-                        "/sys/class/net/%s/statistics/rx_bytes", interface);
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/net/%s/statistics/rx_bytes",
+                             interface) < 0) {
+                       return NULL;
+               }
                if (pscanf(path, "%llu", &rxbytes) != 1) {
                        return NULL;
                }
@@ -37,8 +40,11 @@
 
                oldtxbytes = txbytes;
 
-               snprintf(path, sizeof(path),
-                        "/sys/class/net/%s/statistics/tx_bytes", interface);
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/net/%s/statistics/tx_bytes",
+                             interface) < 0) {
+                       return NULL;
+               }
                if (pscanf(path, "%llu", &txbytes) != 1) {
                        return NULL;
                }

diff --git a/components/wifi.c b/components/wifi.c
index 591f6ad9fed8b4cb7caadc4a6107640081a1bad7..b3e1723bd9729e02672a95f05b2d8040ab84fe6a 100644 (file)
--- a/components/wifi.c
+++ b/components/wifi.c
@@ -23,8 +23,11 @@
                char status[5];
                FILE *fp;
 
-               snprintf(path, sizeof(path), "%s%s%s", "/sys/class/net/", iface,
-                        "/operstate");
+               if (esnprintf(path, sizeof(path),
+                             "/sys/class/net/%s/operstate",
+                             iface) < 0) {
+                       return NULL;
+               }
                if (!(fp = fopen(path, "r"))) {
                        warn("fopen '%s':", path);
                        return NULL;
@@ -69,7 +72,10 @@
 
                memset(&wreq, 0, sizeof(struct iwreq));
                wreq.u.essid.length = IW_ESSID_MAX_SIZE+1;
-               snprintf(wreq.ifr_name, sizeof(wreq.ifr_name), "%s", iface);
+               if (esnprintf(wreq.ifr_name, sizeof(wreq.ifr_name),
+                             "%s", iface) < 0) {
+                       return NULL;
+               }
 
                if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
                        warn("socket 'AF_INET':");

diff --git a/slstatus.c b/slstatus.c
index 0c4605fc9fe47dcb93746a027b57fed30e74cd44..3222b02375d06301e1347ccc7df992c4fac694bf 100644 (file)
--- a/slstatus.c
+++ b/slstatus.c
@@ -91,12 +91,8 @@ main(int argc, char *argv[])
                        if (!(res = args[i].func(args[i].args))) {
                                res = unknown_str;
                        }
-                       if ((ret = snprintf(status + len, sizeof(status) - len,
+                       if ((ret = esnprintf(status + len, sizeof(status) - len,
                                            args[i].fmt, res)) < 0) {
-                               warn("snprintf:");
-                               break;
-                       } else if ((size_t)ret >= sizeof(status) - len) {
-                               warn("snprintf: Output truncated");
                                break;
                        }
                        len += ret;

diff --git a/util.c b/util.c
index a7576b4702583d508b604e7551f30961b2e02bd8..923d4df3524070b4a77ef55016ac313bafbad5c9 100644 (file)
--- a/util.c
+++ b/util.c
@@ -48,6 +48,27 @@ die(const char *fmt, ...)
        exit(1);
 }
 
+int
+esnprintf(char *str, size_t size, const char *fmt, ...)
+{
+       va_list ap;
+       int ret;
+
+       va_start(ap, fmt);
+       ret = vsnprintf(str, size, fmt, ap);
+       va_end(ap);
+
+       if (ret < 0) {
+               warn("snprintf:");
+               return -1;
+       } else if ((size_t)ret >= size) {
+               warn("snprintf: Output truncated");
+               return -1;
+       }
+
+       return ret;
+}
+
 const char *
 bprintf(const char *fmt, ...)
 {

diff --git a/util.h b/util.h
index bd05574b18108611ab446381ac8e761517f9698f..5111b377310579acf123cb4d21281a8e41edfc35 100644 (file)
--- a/util.h
+++ b/util.h
@@ -8,6 +8,7 @@ extern char *argv0;
 void warn(const char *, ...);
 void die(const char *, ...);
 
+int esnprintf(char *str, size_t size, const char *fmt, ...);
 const char *bprintf(const char *fmt, ...);
 const char *fmt_scaled(size_t);
 int pscanf(const char *path, const char *fmt, ...);