vatrog-vm-signaling/src/daemon/config.c

/* config.c — vmsigd config parser (see vmsigd.h). INI-ish: `key = value` globals + repeated
 * `[grant uid=N]` stanzas. Pure libc; no core/vmie dependency (unit-testable in any build). */
#define _GNU_SOURCE
#include "vmsigd.h"
#include "vmsig_control.h"        /* VMSIG_CAP_* */
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

void vmsigd_config_defaults(vmsigd_config* c) {
    memset(c, 0, sizeof *c);
    snprintf(c->socket,   sizeof c->socket,   "%s", "/run/vmsig/vmsigd.sock");
    snprintf(c->watch,    sizeof c->watch,    "%s", "/dev/shm/vmsig");
    snprintf(c->pve_conf, sizeof c->pve_conf, "%s", "/etc/pve/qemu-server");
    snprintf(c->qmp_dir,  sizeof c->qmp_dir,  "%s", "/var/run/qemu-server");
    snprintf(c->slots,    sizeof c->slots,    "%s", "/dev/shm/vmsig/.slots");
}

uint32_t vmsigd_caps_from_str(const char* s) {
    static const struct { const char* k; uint32_t bit; } map[] = {
        { "observe",   VMSIG_CAP_OBSERVE },
        { "input",     VMSIG_CAP_INPUT },
        { "lifecycle", VMSIG_CAP_LIFECYCLE },
        { "power",     VMSIG_CAP_POWER },
        { "vm",        VMSIG_CAP_VM },
        { "memctx",    VMSIG_CAP_MEMCTX },
        { "memwrite",  VMSIG_CAP_MEMWRITE },
        { "roster",    VMSIG_CAP_ROSTER },
    };
    uint32_t mask = 0;
    while (s && *s) {
        while (*s == ',' || *s == ' ' || *s == '\t') s++;
        const char* w = s;
        while (*s && *s != ',' && *s != ' ' && *s != '\t') s++;
        size_t len = (size_t)(s - w);
        for (size_t i = 0; i < sizeof map / sizeof map[0]; i++)
            if (len == strlen(map[i].k) && strncmp(w, map[i].k, len) == 0) { mask |= map[i].bit; break; }
    }
    return mask;
}

/* Trim leading/trailing whitespace in place; returns the trimmed start. */
static char* trim(char* s) {
    while (*s == ' ' || *s == '\t' || *s == '\r') s++;
    char* e = s + strlen(s);
    while (e > s && (e[-1] == ' ' || e[-1] == '\t' || e[-1] == '\r' || e[-1] == '\n')) *--e = 0;
    return s;
}

static void set_path(char* dst, size_t cap, const char* v) { snprintf(dst, cap, "%s", v); }

static void parse_vmids(vmsigd_grant_rule* g, const char* v) {
    g->all_vms = 0; g->nvmids = 0;
    if (strchr(v, '*')) { g->all_vms = 1; return; }
    while (*v) {
        while (*v == ',' || *v == ' ' || *v == '\t') v++;
        if (*v < '0' || *v > '9') { if (*v) v++; continue; }
        uint32_t id = (uint32_t)strtoul(v, NULL, 10);
        while (*v >= '0' && *v <= '9') v++;
        if (id && g->nvmids < VMSIGD_MAX_VMIDS) g->vmids[g->nvmids++] = id;
    }
}

int vmsigd_config_parse_buf(vmsigd_config* c, const char* buf) {
    if (!c || !buf) return -1;
    char* copy = strdup(buf);
    if (!copy) return -1;

    vmsigd_grant_rule* cur = NULL;   /* current [grant] stanza, or NULL for globals */
    char* save = NULL;
    for (char* line = strtok_r(copy, "\n", &save); line; line = strtok_r(NULL, "\n", &save)) {
        char* p = trim(line);
        if (!*p || *p == '#' || *p == ';') continue;

        if (*p == '[') {
            cur = NULL;
            /* [grant uid=N] */
            char* u = strstr(p, "uid=");
            if (u && c->ngrants < VMSIGD_MAX_GRANTS) {
                cur = &c->grants[c->ngrants++];
                memset(cur, 0, sizeof *cur);
                cur->uid = (uint32_t)strtoul(u + 4, NULL, 10);
            }
            continue;
        }

        char* eq = strchr(p, '=');
        if (!eq) continue;
        *eq = 0;
        char* key = trim(p);
        char* val = trim(eq + 1);

        if (cur) {
            if      (!strcmp(key, "vmids"))    parse_vmids(cur, val);
            else if (!strcmp(key, "caps"))     cur->cap_mask = vmsigd_caps_from_str(val);
            else if (!strcmp(key, "arb_prio")) cur->arb_prio = (uint32_t)strtoul(val, NULL, 10);
        } else {
            if      (!strcmp(key, "socket"))   set_path(c->socket,   sizeof c->socket,   val);
            else if (!strcmp(key, "watch"))    set_path(c->watch,    sizeof c->watch,    val);
            else if (!strcmp(key, "pve_conf")) set_path(c->pve_conf, sizeof c->pve_conf, val);
            else if (!strcmp(key, "qmp_dir"))  set_path(c->qmp_dir,  sizeof c->qmp_dir,  val);
            else if (!strcmp(key, "slots"))    set_path(c->slots,    sizeof c->slots,    val);
        }
    }
    free(copy);
    return 0;
}

int vmsigd_config_parse_file(vmsigd_config* c, const char* path) {
    int fd = open(path, O_RDONLY | O_CLOEXEC);
    if (fd < 0) return -1;
    char buf[16 * 1024];
    size_t got = 0;
    for (;;) {
        ssize_t n = read(fd, buf + got, sizeof buf - 1 - got);
        if (n < 0) { close(fd); return -1; }
        if (n == 0) break;
        got += (size_t)n;
        if (got >= sizeof buf - 1) break;
    }
    close(fd);
    buf[got] = 0;
    return vmsigd_config_parse_buf(c, buf);
}