select

commit 33db3341a40340d0b9e0f0872131380cbb84cfcb
Author: Antoine Amarilli <a3nm@a3nm.net>
Date:   Sat, 15 Dec 2012 19:34:13 +0100

initial commit

Diffstat:
select.c
 | 
121
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 121 insertions(+), 0 deletions(-)
diff --git a/select.c b/select.c
@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <argp.h> // TODO
+#include <string.h>
+
+// TODO
+#define MAXFDS 242
+#define BUFSIZE 1024
+
+#define E_SELECT 2
+#define E_READ 4
+
+int fds[MAXFDS];
+fd_set rfds;
+int nfds;
+
+int initfds() {
+  int i, max = -1;
+  for (i = 0; i < nfds; i++) {
+    if (fds[i] < 0)
+      continue;
+    FD_SET(fds[i], &rfds);
+    if (fds[i] > max)
+      max = fds[i];
+  }
+  return max;
+}
+
+int main(int argc, char **argv) {
+  int i, j, ret, max = 0;
+  int ready;
+  char buf[1024];
+  char separator[] = "\t";
+
+  setvbuf(stdout, NULL, _IONBF, 0);
+
+  nfds = argc;
+  fds[0] = -1;
+  // TODO
+  //if (argc == 1)
+    //FD_SET(0, &fds);
+  for (i = 1; i < argc; i++) {
+    if (!strcmp(argv[i], "-")) {
+      fds[i] = 0;
+      continue;
+    }
+    fds[i] = open(argv[i], O_RDONLY | O_NONBLOCK);
+    //printf("opened %s pos %d to %d\n", argv[i], i, fds[i]);
+    if (fds[i] < 0) {
+      perror(argv[i]); // TODO better
+      // TODO exit?
+      continue;
+    }
+  }
+
+  max = initfds();
+
+  // TODO timeout?
+  // TODO signals?
+  while (max >= 0) {
+    //printf("\n\nabout to select max %d nfds %d\n", max+1, nfds);
+    ret = select(max+1, &rfds, NULL, NULL, NULL);
+    //printf("done selecting\n");
+    // ignore signals?
+    // if (r == -1 && errno == EINTR
+    //   continue;
+    if (ret < 0) {
+      perror("select");
+      exit(E_SELECT);
+    }
+    for (i = 1; i < argc; i++) {
+      if (fds[i] < 0) continue;
+      if (!FD_ISSET(fds[i], &rfds)) continue;
+      ready = 1;
+      while (ready) {
+        ret = read(fds[i], buf, BUFSIZE);
+        //printf("%s%s/read %d", argv[i], separator, ret); // TODO
+        if (ret < 0) {
+          if (errno == EAGAIN || errno == EWOULDBLOCK) {
+            //printf("\n%s%s/wouldblock", argv[i], separator); // TODO
+            break;
+          }
+          // TODO signals?
+          // TODO accept errors here?
+          perror(argv[i]); // TODO better reporting?
+          exit(E_READ);
+        }
+        if (!ret) {
+          //printf("%s%s/closed", argv[i], separator); // TODO
+          FD_CLR(fds[i], &rfds);
+          close(fds[i]);
+          // TODO try to reopen?
+          fds[i] = -1;
+          break;
+        }
+        printf("%s%s", argv[i], separator);
+        // TODO is this really safe or might lines get cut?
+        for (j = 0; j < ret; j++) {
+          putchar(buf[j]);
+          if (buf[j] == '\n' && j != ret-1) {
+            printf("%s%s", argv[i], separator);
+          }
+        }
+        if (buf[ret-1] != '\n')
+          putchar('\n');
+      }
+      //printf("\n%s%s/doneread nfds%d", argv[i], separator, nfds); // TODO
+      max = initfds();
+    }
+  }
+  for (i = 1; i < argc; i++)
+    if (fds[i] > 0)
+      close(fds[i]);
+  return 0;
+}
+