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authorTobias Klauser <tklauser@distanz.ch>2007-09-18 13:28:59 +0200
committerTobias Klauser <tklauser@xenon.tklauser.home>2007-09-18 13:28:59 +0200
commit8787c5e9f422ae6a9d3e3f5445301f753c3fe02d (patch)
tree50fca56db6cc694df2522ba17e4024521c218b74
parent21fc4aa4615803896f28bfc8e0009504effdd690 (diff)
inotail.c: Implement tail_pipe_bytes()
For now more or less a copy from coreutils
-rw-r--r--inotail.c79
-rw-r--r--inotail.h7
2 files changed, 77 insertions, 9 deletions
diff --git a/inotail.c b/inotail.c
index 02cf462..cd96ec1 100644
--- a/inotail.c
+++ b/inotail.c
@@ -345,23 +345,84 @@ out:
return rc;
}
-/* TODO: Implement me :) */
static ssize_t tail_pipe_bytes(struct file_struct *f, unsigned long n_bytes)
{
+ struct char_buf *first, *last, *tmp;
ssize_t rc;
- char buf[BUFSIZ];
+ unsigned long total_bytes = 0;
+ unsigned long i = 0; /* Index into buffer */
- /* We will just tail everything here */
- while ((rc = read(f->fd, buf, f->blksize)) > 0) {
- if (write(STDOUT_FILENO, buf, (size_t) rc) <= 0) {
- /* e.g. when writing to a pipe which gets closed */
+ if (n_bytes == 0)
+ return 0;
+
+ first = last = emalloc(sizeof(struct char_buf));
+ first->n_bytes = 0;
+ first->next = NULL;
+ tmp = emalloc(sizeof(struct char_buf));
+
+ while(1) {
+ if ((rc = read(f->fd, tmp->buf, BUFSIZ)) <= 0) {
+ if (rc < 0 && (errno == EINTR || errno == EAGAIN))
+ continue;
+ else
+ break;
+ }
+ total_bytes += rc;
+ tmp->n_bytes = rc;
+ tmp->next = NULL;
+
+ /* Try to append to the previous buffer if there's enough free
+ * space
+ */
+ if (tmp->n_bytes + last->n_bytes < BUFSIZ) {
+ memcpy(&last->buf[last->n_bytes], tmp->buf, tmp->n_bytes);
+ last->n_bytes += tmp->n_bytes;
+ } else {
+ last = last->next = tmp;
+ if (total_bytes - first->n_bytes > n_bytes) {
+ tmp = first;
+ total_bytes -= first->n_bytes;
+ first = first->next;
+ } else
+ tmp = emalloc(sizeof(struct char_buf));
+ }
+ }
+
+ free(tmp);
+
+ if (rc < 0) {
+ fprintf(stderr, "Error: Could not read from %s\n", pretty_name(f->name));
+ goto out;
+ }
+
+ /* Skip unneeded buffers */
+ for (tmp = first; total_bytes - tmp->n_bytes > n_bytes; tmp = tmp->next)
+ total_bytes -= tmp->n_bytes;
+
+ if (total_bytes > n_bytes)
+ i = total_bytes - n_bytes;
+
+ if ((rc = write(STDOUT_FILENO, &tmp->buf[i], tmp->n_bytes - i)) <= 0) {
+ /* e.g. when writing to a pipe which gets closed */
+ fprintf(stderr, "Error: Could not write to stdout (%s)\n", strerror(errno));
+ goto out;
+ }
+
+ for (tmp = tmp->next; tmp; tmp = tmp->next)
+ if ((rc = write(STDOUT_FILENO, tmp->buf, tmp->n_bytes)) <= 0) {
fprintf(stderr, "Error: Could not write to stdout (%s)\n", strerror(errno));
- rc = -1;
- break;
+ goto out;
}
+
+
+ rc = 0;
+out:
+ while (first) {
+ tmp = first->next;
+ free(first);
+ first = tmp;
}
- free(buf);
return rc;
}
diff --git a/inotail.h b/inotail.h
index f9eabba..5029540 100644
--- a/inotail.h
+++ b/inotail.h
@@ -32,6 +32,13 @@ struct line_buf {
struct line_buf *next;
};
+/* struct for linked list of byte buffers in tail_pipe_bytes */
+struct char_buf {
+ char buf[BUFSIZ];
+ size_t n_bytes;
+ struct char_buf *next;
+};
+
#define IS_PIPELIKE(mode) \
(S_ISFIFO(mode) || S_ISSOCK(mode))