Add warn() and die()

Given slstatus is a tool that runs in the background, most likely run
from .xinitrc, it's important to prepend the name of the tool to error
messages so it becomes clear where the error is coming from.

To make this much more consistent, this commit adds warn() and die()
utility functions consistent with other suckless projects and adapts all
calls to fprintf(stderr, *) to the warn() and die() functions, greatly
increasing the readability of the code.

diff --git a/components/battery.c b/components/battery.c
index 49f43e6465e3c35d740c5848f542b30548e61e30..807a7e62ca18c993f6994e071b40872fcda1bde6 100644 (file)
--- a/components/battery.c
+++ b/components/battery.c
@@ -59,13 +59,12 @@
 
                fd = open("/dev/apm", O_RDONLY);
                if (fd < 0) {
-                       fprintf(stderr, "open '/dev/apm': %s\n", strerror(errno));
+                       warn("open '/dev/apm':");
                        return NULL;
                }
 
                if (ioctl(fd, APM_IOC_GETPOWER, &apm_info) < 0) {
-                       fprintf(stderr, "ioctl 'APM_IOC_GETPOWER': %s\n",
-                               strerror(errno));
+                       warn("ioctl 'APM_IOC_GETPOWER':");
                        close(fd);
                        return NULL;
                }
@@ -90,13 +89,12 @@
 
                fd = open("/dev/apm", O_RDONLY);
                if (fd < 0) {
-                       fprintf(stderr, "open '/dev/apm': %s\n", strerror(errno));
+                       warn("open '/dev/apm':");
                        return NULL;
                }
 
                if (ioctl(fd, APM_IOC_GETPOWER, &apm_info) < 0) {
-                       fprintf(stderr, "ioctl 'APM_IOC_GETPOWER': %s\n",
-                               strerror(errno));
+                       warn("ioctl 'APM_IOC_GETPOWER':");
                        close(fd);
                        return NULL;
                }

diff --git a/components/cpu.c b/components/cpu.c
index 02e7671a885031fe5896fcc7fa87e36019ea52e9..b9b3924859ec46c27e90657c72006fc2cd60144c 100644 (file)
--- a/components/cpu.c
+++ b/components/cpu.c
@@ -57,7 +57,7 @@
                size = sizeof(freq);
 
                if (sysctl(mib, 2, &freq, &size, NULL, 0) < 0) {
-                       fprintf(stderr, "sysctl 'HW_CPUSPEED': %s\n", strerror(errno));
+                       warn("sysctl 'HW_CPUSPEED':");
                        return NULL;
                }
 
@@ -80,7 +80,7 @@
 
                memcpy(b, a, sizeof(b));
                if (sysctl(mib, 2, &a, &size, NULL, 0) < 0) {
-                       fprintf(stderr, "sysctl 'KERN_CPTIME': %s\n", strerror(errno));
+                       warn("sysctl 'KERN_CPTIME':");
                        return NULL;
                }
                if (!valid) {

diff --git a/components/datetime.c b/components/datetime.c
index 12d77170527e9e07973b3c8bca164acb6cd53b9c..c3efae33ff37bd8b02abb08b05ca66f0e8a2b786 100644 (file)
--- a/components/datetime.c
+++ b/components/datetime.c
@@ -11,7 +11,7 @@ datetime(const char *fmt)
 
        t = time(NULL);
        if (!strftime(buf, sizeof(buf), fmt, localtime(&t))) {
-               fprintf(stderr, "strftime: Result string exceeds buffer size\n");
+               warn("strftime: Result string exceeds buffer size");
                return NULL;
        }
 

diff --git a/components/disk.c b/components/disk.c
index bf6987577673d705c9a77a11490cd6634d3ad668..f4031ea0e8912e244d1c76109987d0fa6f8859fa 100644 (file)
--- a/components/disk.c
+++ b/components/disk.c
@@ -12,7 +12,7 @@ disk_free(const char *mnt)
        struct statvfs fs;
 
        if (statvfs(mnt, &fs) < 0) {
-               fprintf(stderr, "statvfs '%s': %s\n", mnt, strerror(errno));
+               warn("statvfs '%s':", mnt);
                return NULL;
        }
 
@@ -26,7 +26,7 @@ disk_perc(const char *mnt)
        struct statvfs fs;
 
        if (statvfs(mnt, &fs) < 0) {
-               fprintf(stderr, "statvfs '%s': %s\n", mnt, strerror(errno));
+               warn("statvfs '%s':", mnt);
                return NULL;
        }
 
@@ -40,7 +40,7 @@ disk_total(const char *mnt)
        struct statvfs fs;
 
        if (statvfs(mnt, &fs) < 0) {
-               fprintf(stderr, "statvfs '%s': %s\n", mnt, strerror(errno));
+               warn("statvfs '%s':", mnt);
                return NULL;
        }
 
@@ -54,7 +54,7 @@ disk_used(const char *mnt)
        struct statvfs fs;
 
        if (statvfs(mnt, &fs) < 0) {
-               fprintf(stderr, "statvfs '%s': %s\n", mnt, strerror(errno));
+               warn("statvfs '%s':", mnt);
                return NULL;
        }
 

diff --git a/components/hostname.c b/components/hostname.c
index d41465fa3204798fa8b61eaaaadb89eeaf71ca2e..dc3bbf15a83e8f812440a1a65258f90e6ba7d52d 100644 (file)
--- a/components/hostname.c
+++ b/components/hostname.c
@@ -10,7 +10,7 @@ const char *
 hostname(void)
 {
        if (gethostname(buf, sizeof(buf)) < 0) {
-               fprintf(stderr, "gethostbyname: %s\n", strerror(errno));
+               warn("gethostbyname:");
                return NULL;
        }
 

diff --git a/components/ip.c b/components/ip.c
index 85ac15e706fe84b189b9bd1191a94fb9d05832c8..fce2b66b4a02dbd807803f36fd16ef65c9610568 100644 (file)
--- a/components/ip.c
+++ b/components/ip.c
@@ -19,7 +19,7 @@ ipv4(const char *iface)
        char host[NI_MAXHOST];
 
        if (getifaddrs(&ifaddr) < 0) {
-               fprintf(stderr, "getifaddrs: %s\n", strerror(errno));
+               warn("getifaddrs:");
                return NULL;
        }
 
@@ -32,7 +32,7 @@ ipv4(const char *iface)
                if (!strcmp(ifa->ifa_name, iface) &&
                    (ifa->ifa_addr->sa_family == AF_INET)) {
                        if (s != 0) {
-                               fprintf(stderr, "getnameinfo: %s\n", gai_strerror(s));
+                               warn("getnameinfo: %s", gai_strerror(s));
                                return NULL;
                        }
                        return bprintf("%s", host);
@@ -52,7 +52,7 @@ ipv6(const char *iface)
        char host[NI_MAXHOST];
 
        if (getifaddrs(&ifaddr) < 0) {
-               fprintf(stderr, "getifaddrs: %s\n", strerror(errno));
+               warn("getifaddrs:");
                return NULL;
        }
 
@@ -65,7 +65,7 @@ ipv6(const char *iface)
                if (!strcmp(ifa->ifa_name, iface) &&
                    (ifa->ifa_addr->sa_family == AF_INET6)) {
                        if (s != 0) {
-                               fprintf(stderr, "getnameinfo: %s\n", gai_strerror(s));
+                               warn("getnameinfo: %s", gai_strerror(s));
                                return NULL;
                        }
                        return bprintf("%s", host);

diff --git a/components/kernel_release.c b/components/kernel_release.c
index 4e67a28509a1ad0a00a4ded819e8f731fd581ba1..531014cda62331f11144a571f3f42e8c73d36453 100644 (file)
--- a/components/kernel_release.c
+++ b/components/kernel_release.c
@@ -12,7 +12,7 @@ kernel_release(void)
        struct utsname udata;
 
        if (uname(&udata) < 0) {
-               fprintf(stderr, "uname: %s\n", strerror(errno));
+               warn("uname:");
                return NULL;
        }
 

diff --git a/components/keyboard_indicators.c b/components/keyboard_indicators.c
index 2f831c84ba460b61e05afcd2e1e8f87880d53a6f..73ba32e0e4b556d459d382bd6ad7dabb20ad1f76 100644 (file)
--- a/components/keyboard_indicators.c
+++ b/components/keyboard_indicators.c
@@ -11,7 +11,7 @@ keyboard_indicators(void)
        XKeyboardState state;
 
        if (!(dpy = XOpenDisplay(NULL))) {
-               fprintf(stderr, "Cannot open display\n");
+               warn("XOpenDisplay: Failed to open display");
                return NULL;
        }
        XGetKeyboardControl(dpy, &state);

diff --git a/components/load_avg.c b/components/load_avg.c
index 526dc7137456b7d778f529b63e200b9c5126017a..ea7bc2cdcdb30df7dc1f7a53de14352abfed96ca 100644 (file)
--- a/components/load_avg.c
+++ b/components/load_avg.c
@@ -10,7 +10,7 @@ load_avg(const char *fmt)
        double avgs[3];
 
        if (getloadavg(avgs, 3) < 0) {
-               fprintf(stderr, "getloadavg: Could not obtain load average.\n");
+               warn("getloadavg: Failed to obtain load average");
                return NULL;
        }
 

diff --git a/components/num_files.c b/components/num_files.c
index 327a64d621307982638d9f56a0a33aeed704e144..917903737652a4ddc03c02e024e9ef692e998ffa 100644 (file)
--- a/components/num_files.c
+++ b/components/num_files.c
@@ -14,7 +14,7 @@ num_files(const char *dir)
        int num;
 
        if (!(fd = opendir(dir))) {
-               fprintf(stderr, "opendir '%s': %s\n", dir, strerror(errno));
+               warn("opendir '%s':", dir);
                return NULL;
        }
 

diff --git a/components/run_command.c b/components/run_command.c
index 1aaae201235ace505f17db2b18896a7860265a9c..b5eeff0a6749d5f45b8bb4b313465213e81b914e 100644 (file)
--- a/components/run_command.c
+++ b/components/run_command.c
@@ -12,7 +12,7 @@ run_command(const char *cmd)
        FILE *fp;
 
        if (!(fp = popen(cmd, "r"))) {
-               fprintf(stderr, "popen '%s': %s\n", cmd, strerror(errno));
+               warn("popen '%s':", cmd);
                return NULL;
        }
        p = fgets(buf, sizeof(buf) - 1, fp);

diff --git a/components/swap.c b/components/swap.c
index caa478857bf519d4e54e31f98f6f247a16e22522..234e7d1a6fe59ec005c01fb1cced6e69d361b83b 100644 (file)
--- a/components/swap.c
+++ b/components/swap.c
@@ -13,11 +13,11 @@
                size_t bytes_read;
 
                if (!(fp = fopen(path, "r"))) {
-                       fprintf(stderr, "fopen '%s': %s\n", path, strerror(errno));
+                       warn("fopen '%s':", path);
                        return 0;
                }
                if (!(bytes_read = fread(buf, sizeof(char), bufsiz, fp))) {
-                       fprintf(stderr, "fread '%s': %s\n", path, strerror(errno));
+                       warn("fread '%s':", path);
                        fclose(fp);
                        return 0;
                }
@@ -139,21 +139,21 @@
 
                nswap = swapctl(SWAP_NSWAP, 0, 0);
                if (nswap < 1) {
-                       fprintf(stderr, "swaptctl 'SWAP_NSWAP': %s\n", strerror(errno));
+                       warn("swaptctl 'SWAP_NSWAP':");
                }
 
                fsep = sep = calloc(nswap, sizeof(*sep));
                if (!sep) {
-                       fprintf(stderr, "calloc 'nswap': %s\n", strerror(errno));
+                       warn("calloc 'nswap':");
                }
 
                rnswap = swapctl(SWAP_STATS, (void *)sep, nswap);
                if (rnswap < 0) {
-                       fprintf(stderr, "swapctl 'SWAP_STATA': %s\n", strerror(errno));
+                       warn("swapctl 'SWAP_STATA':");
                }
 
                if (nswap != rnswap) {
-                       fprintf(stderr, "SWAP_STATS != SWAP_NSWAP\n");
+                       warn("getstats: SWAP_STATS != SWAP_NSWAP");
                }
 
                *total = 0;

diff --git a/components/temperature.c b/components/temperature.c
index 812ae77a952b7a650afdb744ca5e0166d0e97ce9..64199f5a0d4cb702e1fa20d503a165392fce1343 100644 (file)
--- a/components/temperature.c
+++ b/components/temperature.c
@@ -36,8 +36,7 @@
                size = sizeof(temp);
 
                if (sysctl(mib, 5, &temp, &size, NULL, 0) < 0) {
-                       fprintf(stderr, "sysctl 'SENSOR_TEMP': %s\n",
-                               strerror(errno));
+                       warn("sysctl 'SENSOR_TEMP':");
                        return NULL;
                }
 

diff --git a/components/uptime.c b/components/uptime.c
index 981f3cd338425fd88d287701abe13f8f4d0c0338..45e12db0ad4553b642e61d3616dd14cb6e2e9d2b 100644 (file)
--- a/components/uptime.c
+++ b/components/uptime.c
@@ -50,7 +50,7 @@ format(int uptime)
                size = sizeof(boottime);
 
                if (sysctl(mib, 2, &boottime, &size, NULL, 0) < 0) {
-                       fprintf(stderr, "sysctl 'KERN_BOOTTIME': %s\n", strerror(errno));
+                       warn("sysctl 'KERN_BOOTTIME':");
                        return NULL;
                }
 

diff --git a/components/user.c b/components/user.c
index 8ab6db9b9df0e8a3b9190ff5fd59f1f5c10dffb9..cd503f6eb517da73fc62958d8a7bd49ffa41ee0b 100644 (file)
--- a/components/user.c
+++ b/components/user.c
@@ -20,7 +20,7 @@ username(void)
        struct passwd *pw;
 
        if (!(pw = getpwuid(geteuid()))) {
-               fprintf(stderr, "getpwuid '%d': %s\n", geteuid(), strerror(errno));
+               warn("getpwuid '%d':", geteuid());
                return NULL;
        }
 

diff --git a/components/volume.c b/components/volume.c
index aa46446d2961ddd3421e5461ee3845facd775abe..8674211c420e513e039be6c1119343a450f0128f 100644 (file)
--- a/components/volume.c
+++ b/components/volume.c
@@ -21,21 +21,19 @@ vol_perc(const char *card)
        char *vnames[] = SOUND_DEVICE_NAMES;
 
        if ((afd = open(card, O_RDONLY | O_NONBLOCK)) < 0) {
-               fprintf(stderr, "open '%s': %s\n", card, strerror(errno));
+               warn("open '%s':", card);
                return NULL;
        }
 
        if (ioctl(afd, (int)SOUND_MIXER_READ_DEVMASK, &devmask) < 0) {
-               fprintf(stderr, "ioctl 'SOUND_MIXER_READ_DEVMASK': %s\n",
-                       strerror(errno));
+               warn("ioctl 'SOUND_MIXER_READ_DEVMASK':");
                close(afd);
                return NULL;
        }
        for (i = 0; i < LEN(vnames); i++) {
                if (devmask & (1 << i) && !strcmp("vol", vnames[i])) {
                        if (ioctl(afd, MIXER_READ(i), &v) < 0) {
-                               fprintf(stderr, "ioctl 'MIXER_READ(%ld)': %s\n", i,
-                                       strerror(errno));
+                               warn("ioctl 'MIXER_READ(%ld)':", i);
                                close(afd);
                                return NULL;
                        }

diff --git a/components/wifi.c b/components/wifi.c
index 414d5333fc116c45581bd849f0c27d2d78050db4..591f6ad9fed8b4cb7caadc4a6107640081a1bad7 100644 (file)
--- a/components/wifi.c
+++ b/components/wifi.c
@@ -26,8 +26,7 @@
                snprintf(path, sizeof(path), "%s%s%s", "/sys/class/net/", iface,
                         "/operstate");
                if (!(fp = fopen(path, "r"))) {
-                       fprintf(stderr, "fopen '%s': %s\n", path,
-                               strerror(errno));
+                       warn("fopen '%s':", path);
                        return NULL;
                }
                p = fgets(status, 5, fp);
@@ -37,8 +36,7 @@
                }
 
                if (!(fp = fopen("/proc/net/wireless", "r"))) {
-                       fprintf(stderr, "fopen '/proc/net/wireless': %s\n",
-                               strerror(errno));
+                       warn("fopen '/proc/net/wireless':");
                        return NULL;
                }
 
@@ -74,13 +72,12 @@
                snprintf(wreq.ifr_name, sizeof(wreq.ifr_name), "%s", iface);
 
                if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
-                       fprintf(stderr, "socket 'AF_INET': %s\n",
-                               strerror(errno));
+                       warn("socket 'AF_INET':");
                        return NULL;
                }
                wreq.u.essid.pointer = id;
                if (ioctl(sockfd,SIOCGIWESSID, &wreq) < 0) {
-                       fprintf(stderr, "ioctl 'SIOCGIWESSID': %s\n", strerror(errno));
+                       warn("ioctl 'SIOCGIWESSID':");
                        close(sockfd);
                        return NULL;
                }
@@ -111,22 +108,19 @@
                memset(&bssid, 0, sizeof(bssid));
                memset(nr, 0, sizeof(struct ieee80211_nodereq));
                if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
-                       fprintf(stderr, "socket 'AF_INET': %s\n",
-                               strerror(errno));
+                       warn("socket 'AF_INET':");
                        return 0;
                }
                strlcpy(bssid.i_name, iface, sizeof(bssid.i_name));
                if ((ioctl(sockfd, SIOCG80211BSSID, &bssid)) < 0) {
-                       fprintf(stderr, "ioctl 'SIOCG80211BSSID': %s\n",
-                               strerror(errno));
+                       warn("ioctl 'SIOCG80211BSSID':");
                        close(sockfd);
                        return 0;
                }
                strlcpy(nr->nr_ifname, iface, sizeof(nr->nr_ifname));
                memcpy(&nr->nr_macaddr, bssid.i_bssid, sizeof(nr->nr_macaddr));
                if ((ioctl(sockfd, SIOCG80211NODE, nr)) < 0 && nr->nr_rssi) {
-                       fprintf(stderr, "ioctl 'SIOCG80211NODE': %s\n",
-                               strerror(errno));
+                       warn("ioctl 'SIOCG80211NODE':");
                        close(sockfd);
                        return 0;
                }

diff --git a/slstatus.c b/slstatus.c
index 7ff323fc74053c397028efc81ff91eaaa18b88e0..0c4605fc9fe47dcb93746a027b57fed30e74cd44 100644 (file)
--- a/slstatus.c
+++ b/slstatus.c
@@ -17,7 +17,6 @@ struct arg {
        const char *args;
 };
 
-char *argv0;
 char buf[1024];
 static int done;
 static Display *dpy;
@@ -43,8 +42,7 @@ difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
 static void
 usage(void)
 {
-       fprintf(stderr, "usage: %s [-s]\n", argv0);
-       exit(1);
+       die("usage: %s [-s]", argv0);
 }
 
 int
@@ -80,14 +78,12 @@ main(int argc, char *argv[])
        }
 
        if (!sflag && !(dpy = XOpenDisplay(NULL))) {
-               fprintf(stderr, "XOpenDisplay: Failed to open display\n");
-               return 1;
+               die("XOpenDisplay: Failed to open display");
        }
 
        while (!done) {
                if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
-                       fprintf(stderr, "clock_gettime: %s\n", strerror(errno));
-                       return 1;
+                       die("clock_gettime:");
                }
 
                status[0] = '\0';
@@ -97,11 +93,10 @@ main(int argc, char *argv[])
                        }
                        if ((ret = snprintf(status + len, sizeof(status) - len,
                                            args[i].fmt, res)) < 0) {
-                               fprintf(stderr, "snprintf: %s\n",
-                                       strerror(errno));
+                               warn("snprintf:");
                                break;
                        } else if ((size_t)ret >= sizeof(status) - len) {
-                               fprintf(stderr, "snprintf: Output truncated\n");
+                               warn("snprintf: Output truncated");
                                break;
                        }
                        len += ret;
@@ -111,18 +106,14 @@ main(int argc, char *argv[])
                        printf("%s\n", status);
                } else {
                        if (XStoreName(dpy, DefaultRootWindow(dpy), status) < 0) {
-                               fprintf(stderr,
-                                       "XStoreName: Allocation failed\n");
-                               return 1;
+                               die("XStoreName: Allocation failed");
                        }
                        XFlush(dpy);
                }
 
                if (!done) {
                        if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
-                               fprintf(stderr, "clock_gettime: %s\n",
-                                       strerror(errno));
-                               return 1;
+                               die("clock_gettime:");
                        }
                        difftimespec(&diff, &current, &start);
 
@@ -133,9 +124,7 @@ main(int argc, char *argv[])
                        if (wait.tv_sec >= 0) {
                                if (nanosleep(&wait, NULL) < 0 &&
                                    errno != EINTR) {
-                                       fprintf(stderr, "nanosleep: %s\n",
-                                               strerror(errno));
-                                       return 1;
+                                       die("nanosleep:");
                                }
                        }
                }
@@ -144,9 +133,7 @@ main(int argc, char *argv[])
        if (!sflag) {
                XStoreName(dpy, DefaultRootWindow(dpy), NULL);
                if (XCloseDisplay(dpy) < 0) {
-                       fprintf(stderr,
-                               "XCloseDisplay: Failed to close display\n");
-                       return 1;
+                       die("XCloseDisplay: Failed to close display");
                }
        }
 

diff --git a/util.c b/util.c
index 6113049cdcae1f987e700ceaf8e826bb2549f7c9..08f14ffb9315ab5b4e7ec9acc6982dc6d46af67d 100644 (file)
--- a/util.c
+++ b/util.c
@@ -2,10 +2,52 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "util.h"
 
+char *argv0;
+
+static void
+verr(const char *fmt, va_list ap)
+{
+       if (argv0 && strncmp(fmt, "usage", sizeof("usage") - 1)) {
+               fprintf(stderr, "%s: ", argv0);
+       }
+
+       vfprintf(stderr, fmt, ap);
+
+       if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
+               fputc(' ', stderr);
+               perror(NULL);
+       } else {
+               fputc('\n', stderr);
+       }
+}
+
+void
+warn(const char *fmt, ...)
+{
+       va_list ap;
+
+       va_start(ap, fmt);
+       verr(fmt, ap);
+       va_end(ap);
+}
+
+void
+die(const char *fmt, ...)
+{
+       va_list ap;
+
+       va_start(ap, fmt);
+       verr(fmt, ap);
+       va_end(ap);
+
+       exit(1);
+}
+
 const char *
 bprintf(const char *fmt, ...)
 {
@@ -14,9 +56,9 @@ bprintf(const char *fmt, ...)
 
        va_start(ap, fmt);
        if ((ret = vsnprintf(buf, sizeof(buf), fmt, ap)) < 0) {
-               fprintf(stderr, "vsnprintf: %s\n", strerror(errno));
+               warn("vsnprintf:");
        } else if ((size_t)ret >= sizeof(buf)) {
-               fprintf(stderr, "vsnprintf: Output truncated\n");
+               warn("vsnprintf: Output truncated");
        }
        va_end(ap);
 
@@ -31,7 +73,7 @@ pscanf(const char *path, const char *fmt, ...)
        int n;
 
        if (!(fp = fopen(path, "r"))) {
-               fprintf(stderr, "fopen '%s': %s\n", path, strerror(errno));
+               warn("fopen '%s':", path);
                return -1;
        }
        va_start(ap, fmt);

diff --git a/util.h b/util.h
index e90c29d2b86a7d0cd30903dad4a2423891202a57..a73b103181eeff7eb1b99ae825fe5b3d3ac0655f 100644 (file)
--- a/util.h
+++ b/util.h
@@ -3,5 +3,10 @@ extern char buf[1024];
 
 #define LEN(x) (sizeof (x) / sizeof *(x))
 
+extern char *argv0;
+
+void warn(const char *, ...);
+void die(const char *, ...);
+
 const char *bprintf(const char *fmt, ...);
 int pscanf(const char *path, const char *fmt, ...);