2020-04-29 19:22:58 (UTC-03:00)

Marcel Rodrigues <marcelgmr@gmail.com>

first commit: list status once and wait for q keypress

diff --git a/isv.c b/isv.c
new file mode 100644
index 0000000..c95986e
--- /dev/null
+++ b/isv.c
@@ -0,0 +1,187 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <dirent.h>
+
+#define DEFAULT_BASE_DIR    "/service"
+#define MAX_NAME            32
+#define MAX_SERV            64
+
+static struct service {
+    bool active;            /* false when a "down" file is present */
+    pid_t pid, log_pid;
+    unsigned long uptime;   /* in seconds */
+    char name[MAX_NAME];
+} services[MAX_SERV];
+
+static char path[4096];
+static int name_col_width;
+
+int32_t
+read_lei32(unsigned char *buf)
+{
+    int32_t  n  = buf[3];
+    n <<= 8; n += buf[2];
+    n <<= 8; n += buf[1];
+    n <<= 8; n += buf[0];
+    return n;
+}
+
+uint64_t
+read_beu64(unsigned char *buf)
+{
+    uint64_t n  = buf[0];
+    n <<= 8; n += buf[1];
+    n <<= 8; n += buf[2];
+    n <<= 8; n += buf[3];
+    n <<= 8; n += buf[4];
+    n <<= 8; n += buf[5];
+    n <<= 8; n += buf[6];
+    n <<= 8; n += buf[7];
+    return n;
+}
+
+int
+sprint_uptime(char buf[9], unsigned long seconds)
+{
+    char suffix = 's';
+    unsigned long value = seconds;
+
+    if (value >= 60) {
+        value /= 60;
+        suffix = 'm';
+    }
+    if (value >= 60) {
+        value /= 60;
+        suffix = 'h';
+    }
+    if (value >= 24) {
+        value /= 24;
+        suffix = 'd';
+    }
+    return snprintf(buf, 9, "%5lu %c", value, suffix);
+}
+
+void
+load_services(const char *base_dir, int nservices)
+{
+    int i, fd;
+    unsigned char stt[18];
+    uint64_t when;
+    struct stat st;
+
+    for (i = 0; i < nservices; i++) {
+        strcpy(path, base_dir);
+        strcat(path, "/");
+        strcat(path, services[i].name);
+        strcat(path, "/supervise/status");
+        fd = open(path, O_RDONLY);
+        read(fd, stt, sizeof stt);
+        close(fd);
+        services[i].pid = read_lei32(&stt[12]);
+        when = read_beu64(&stt[0]);
+        services[i].uptime = time(NULL) + 4611686018427387914ULL - when;
+        strcpy(path, base_dir);
+        strcat(path, "/");
+        strcat(path, services[i].name);
+        strcat(path, "/log/supervise/status");
+        fd = open(path, O_RDONLY);
+        read(fd, stt, sizeof stt);
+        close(fd);
+        services[i].log_pid = read_lei32(&stt[12]);
+        strcpy(path, base_dir);
+        strcat(path, "down");
+        services[i].active = !!stat(path, &st);
+    }
+}
+
+void
+show_services(int nservices)
+{
+    int i;
+    char uptime_str[8];
+
+    printf("%*s active   run   log  uptime\n", name_col_width, "name");
+    for (i = 0; i < nservices; i++) {
+        sprint_uptime(uptime_str, services[i].uptime);
+        printf("%*s %6s %5d %5d %s\n",
+               name_col_width, services[i].name,
+               services[i].active ? "yes" : "no",
+               services[i].pid, services[i].log_pid,
+               uptime_str);
+    }
+}
+
+int
+main(int argc, char *argv[])
+{
+    DIR *dir;
+    const char *base_dir = NULL;
+    struct dirent *entry;
+    int nservices;
+    int name_size;
+    struct winsize term_size;
+    struct termios term_prev, term_raw;
+    char byte;
+
+    if (!isatty(0))
+        return 1;   /* quit if stdin is not a terminal */
+    if (argc == 2)
+        base_dir = argv[1];
+    else
+        base_dir = getenv("SVDIR");
+    if (base_dir == NULL)
+        base_dir = DEFAULT_BASE_DIR;
+    if ((dir = opendir(base_dir)) == NULL) {
+        fprintf(stderr, "could not read directory '%s'\n", base_dir);
+        return 1;
+    }
+    nservices = 0;
+    name_col_width = 4;
+    while ((entry = readdir(dir)) != NULL) {
+        if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
+            continue;
+        strncpy(services[nservices].name, entry->d_name, MAX_NAME-1);
+        name_size = strlen(entry->d_name);
+        if (name_size > name_col_width && name_col_width < MAX_NAME)
+            name_col_width = name_size;
+        nservices++;
+        if (nservices == MAX_SERV)
+            break;
+    }
+    closedir(dir);
+    if (nservices == 0) {
+        fprintf(stderr, "no services in '%s'\n", base_dir);
+        return 1;
+    }
+    ioctl(0, TIOCGWINSZ, &term_size);
+    if (term_size.ws_col < (name_col_width + 29) || term_size.ws_row < (nservices + 3)) {
+        fprintf(stderr, "sorry, terminal too small\n");
+        return 1;
+    }
+    tcgetattr(0, &term_prev);
+    term_raw = term_prev;
+    term_raw.c_lflag &= ~(ECHO | ICANON);
+    term_raw.c_cc[VMIN] = 0x00;
+    term_raw.c_cc[VTIME] = 0x01; /* in deciseconds */
+    tcsetattr(0, TCSAFLUSH, &term_raw);
+    load_services(base_dir, nservices);
+    show_services(nservices);
+    while (1) {
+        if (read(0, &byte, 1) == 1) {
+            if (byte == 'q')
+                break;
+        }
+    }
+    tcsetattr(0, TCSAFLUSH, &term_prev);
+    return 0;
+}