Hi Greg,
On Sun, Aug 25, 2024 at 02:29:13PM +0300, Greg Minshall wrote:
> Alex,
>
> > Would you mind sending the extracted files? That way I can comment on
> > those directly.
>
> here you go.
>
> cheers, Greg
>
>
> ----
>
> #define _GNU_SOURCE
> #include <assert.h>
> #include <err.h>
> #include <netdb.h>
> #include <signal.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
>
> #define CALLOC(n, type) ((type *) calloc(n, sizeof(type)))
>
> #define REALLOCF(ptr, n, type) \
> ({ \
> static_assert(__builtin_types_compatible_p(typeof(ptr), type *)); \
> \
> (type *) reallocarrayf(ptr, n, sizeof(type)); \
> })
>
> static struct gaicb **reqs = NULL;
> static size_t nreqs = 0;
> /* default is "no notification" ('n') */
> static char notification = 'n';
Would it be better to use an enum instead of comments?
enum {
NOTIFICATION_NONE = 'n',
NOTIFICATION_SIGNAL = 's',
NOTIFICATION_CALLBACK = 'c'
};
>
> /* forward declaration for callback routines */
> static void list_requests(void);
>
>
> static inline void *
> reallocarrayf(void *p, size_t nmemb, size_t size)
> {
> void *q;
>
> q = reallocarray(p, nmemb, size);
> if (q == NULL && nmemb != 0 && size != 0)
> free(p);
> return q;
> }
>
> static char *
> getcmd(void)
> {
> static char buf[256];
>
> fputs("> ", stdout); fflush(stdout);
> if (fgets(buf, sizeof(buf), stdin) == NULL)
> return NULL;
>
> if (buf[strlen(buf) - 1] == '\n')
> buf[strlen(buf) - 1] = 0;
If the string does not contain a newline, it probably means something is
wrong. Returning as if all were good is probably not a good idea.
I suggest
static inline char *
stpsep(char *s, const char *delim)
{
strsep(&s, delim);
return s;
}
and then:
if (stpsep(buf, "\n") == NULL)
return NULL;
>
> return buf;
> }
>
> /* Set notification type: none (default), signal, callback */
> static void
> notification_type(void)
> {
> char *type = strtok(NULL, " ");
>
> switch (type[0]) {
> case 'c':
> case 'n':
> case 's':
> notification = type[0];
> break;
> default:
> fprintf(stderr, "Bad type: '%c' (expecting 'c', 's', or 'n')\n", type[0]);
> break;
> }
> }
>
> /* callback routine for signal notifications */
>
> static void
> signal_handler(int signo) {
> fprintf(stdout, "notified by signal\n");
> list_requests();
> fprintf(stdout, "> ");
> fflush(stdout);
> }
>
> /* callback routine for thread/callback notifications */
>
> static void
> callback_handler(union sigval sev_value) {
> fprintf(stdout, "notified by callback\n");
> list_requests();
> fprintf(stdout, "> ");
> fflush(stdout);
> }
>
> /* Add requests for specified hostnames. */
> static void
> add_requests(void)
> {
> static struct sigevent senull; /* static, so initialized to zero */
> static struct sigaction sanull; /* static, so intitialized to zero */
These comments are redundant. Please remove them. Maybe add a blank
line between static variables and automatic ones to make it more
evident.
> struct sigevent se = senull;
> struct sigaction sa = sanull;
> size_t nreqs_base = nreqs;
> char *host;
> int ret;
>
> while ((host = strtok(NULL, " "))) {
> nreqs++;
> reqs = REALLOCF(reqs, nreqs, struct gaicb *);
> if (reqs == NULL)
> err(EXIT_FAILURE, "reallocf");
>
> reqs[nreqs - 1] = CALLOC(1, struct gaicb);
> if (reqs[nreqs - 1] == NULL)
> err(EXIT_FAILURE, "calloc");
>
> reqs[nreqs - 1]->ar_name = strdup(host);
> }
>
> switch (notification) {
> case 'c':
> /* notify via a callback */
> se.sigev_notify = SIGEV_THREAD;
> se.sigev_notify_function = callback_handler;
> break;
> case 'n':
> /* nothing to do */
> break;
> case 's':
> se.sigev_notify = SIGEV_SIGNAL;
> se.sigev_signo = SIGUSR1;
> sa.sa_handler = signal_handler;
> /* set SA_RESTART so read(2) in main doesn't get an EINTR */
> sa.sa_flags = SA_RESTART;
> ret = sigaction(SIGUSR1, &sa, NULL);
> if (ret) {
> err(EXIT_FAILURE, "sigaction");
> }
> break;
> default:
> fprintf(stderr, "program error: `notification` not one of [cns]: %c\n",
> notification);
> exit(4);
> }
>
> /* Queue nreqs_base..nreqs requests. */
>
> ret = getaddrinfo_a(GAI_NOWAIT, &reqs[nreqs_base],
> nreqs - nreqs_base, notification == 'n' ? NULL : &se);
> if (ret) {
> fprintf(stderr, "getaddrinfo_a() failed: %s\n",
> gai_strerror(ret));
> exit(EXIT_FAILURE);
> }
> }
>
> /* Wait until at least one of specified requests completes. */
> static void
> wait_requests(void)
> {
> char *id;
> int ret;
> size_t n;
> struct gaicb const **wait_reqs;
>
> wait_reqs = CALLOC(nreqs, const struct gaicb *);
> if (wait_reqs == NULL)
> err(EXIT_FAILURE, "calloc");
>
> /* NULL elements are ignored by gai_suspend(). */
>
> while ((id = strtok(NULL, " ")) != NULL) {
> n = atoi(id);
>
> if (n >= nreqs) {
> printf("Bad request number: %s\n", id);
> return;
> }
>
> wait_reqs[n] = reqs[n];
> }
>
> ret = gai_suspend(wait_reqs, nreqs, NULL);
> if (ret) {
> printf("gai_suspend(): %s\n", gai_strerror(ret));
> return;
> }
>
> for (size_t i = 0; i < nreqs; i++) {
> if (wait_reqs[i] == NULL)
> continue;
>
> ret = gai_error(reqs[i]);
> if (ret == EAI_INPROGRESS)
> continue;
>
> printf("[%02zu] %s: %s\n", i, reqs[i]->ar_name,
> ret == 0 ? "Finished" : gai_strerror(ret));
> }
> }
>
> /* Cancel specified requests. */
> static void
> cancel_requests(void)
> {
> char *id;
> int ret;
> size_t n;
>
> while ((id = strtok(NULL, " ")) != NULL) {
> n = atoi(id);
>
> if (n >= nreqs) {
> printf("Bad request number: %s\n", id);
> return;
> }
>
> ret = gai_cancel(reqs[n]);
> printf("[%s] %s: %s\n", id, reqs[atoi(id)]->ar_name,
> gai_strerror(ret));
> }
> }
>
> /* List all requests. */
> static void
> list_requests(void)
> {
> int ret;
> char host[NI_MAXHOST];
> struct addrinfo *res;
>
> for (size_t i = 0; i < nreqs; i++) {
> printf("[%02zu] %s: ", i, reqs[i]->ar_name);
> ret = gai_error(reqs[i]);
>
> if (!ret) {
> res = reqs[i]->ar_result;
>
> ret = getnameinfo(res->ai_addr, res->ai_addrlen,
> host, sizeof(host),
> NULL, 0, NI_NUMERICHOST);
> if (ret) {
> fprintf(stderr, "getnameinfo() failed: %s\n",
> gai_strerror(ret));
> exit(EXIT_FAILURE);
> }
> puts(host);
> } else {
> puts(gai_strerror(ret));
If you invert the conditional, you can add a continue after this, and
unindent the non-error code.
Thanks for the emanple program!
Have a lovely day!
Alex
> }
> }
> }
>
> int
> main(void)
> {
> char *cmdline;
> char *cmd;
>
> while ((cmdline = getcmd()) != NULL) {
> cmd = strtok(cmdline, " ");
>
> if (cmd == NULL) {
> list_requests();
> } else {
> switch (cmd[0]) {
> case 'a':
> add_requests();
> break;
> case 'w':
> wait_requests();
> break;
> case 'c':
> cancel_requests();
> break;
> case 'l':
> list_requests();
> break;
> case 'n':
> notification_type();
> break;
> default:
> fprintf(stderr, "Bad command: %c\n", cmd[0]);
> break;
> }
> }
> }
> exit(EXIT_SUCCESS);
> }
>
--
<https://www.alejandro-colomar.es/>
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