diff options
Diffstat (limited to 'multipart-replace.c')
| -rw-r--r-- | multipart-replace.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/multipart-replace.c b/multipart-replace.c new file mode 100644 index 0000000..30ae7bb --- /dev/null +++ b/multipart-replace.c @@ -0,0 +1,145 @@ +/* Copyright 2016 Luke Shumaker */ + +#include <errno.h> +#include <error.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "multipart-replace.h" +#include "util.h" + +static +char *boundary_line(const char *old) { + size_t len = strlen(old); + char *new = xrealloc(NULL, len+5); + new[0] = '-'; + new[1] = '-'; + strcpy(&new[2], old); + new[2+len+0] = '\r'; + new[2+len+1] = '\n'; + new[2+len+2] = '\0'; + return new; +} + +static +ssize_t safe_atoi(char *str) { + while (*str == ' ') + str++; + size_t len = 0; + while ('0' <= str[len] && str[len] <= '9') + len++; + size_t i = len; + while (str[i] == ' ') + i++; + if (len < 1 || strcmp(&str[i], "\r\n") != 0) + return -1; + return atoi(str); +} + +#define rgetline() do { if ((line_len = getline(&line_buf, &line_cap, stream)) < 0) { error(0, 0, "source hung up"); return; } } while(0) +void multipart_replace_reader(struct multipart_replace_stream *s, int fd, const char *boundary) { + FILE *stream = fdopen(fd, "r"); + boundary = boundary_line(boundary); + + char *line_buf = NULL; + size_t line_cap = 0; + ssize_t line_len = 0; + ssize_t content_length = -1; + + while (1) { + content_length = -1; + /* scan for the first non-empty line */ + do { + rgetline(); + } while (strcmp(line_buf, "\r\n") == 0); + /* make sure it matches the boundary separator */ + if (strcmp(line_buf, boundary) != 0) { + error(0, 0, "line does not match boundary: \"%s\"", line_buf); + return; + } + /* read the frame header (MIME headers) */ + do { + rgetline(); + /* append the line to the frame contents */ + if ((ssize_t)s->back->cap < s->back->len + line_len) + s->back->buf = xrealloc(s->back->buf, s->back->cap = s->back->len + line_len); + memcpy(&s->back->buf[s->back->len], line_buf, line_len); + s->back->len += line_len; + /* parse the Content-length (if applicable) */ + if (strncasecmp(line_buf, "Content-length:", strlen("Content-length:")) == 0) { + content_length = safe_atoi(&line_buf[strlen("Content-length:")]); + } + } while (strcmp(line_buf, "\r\n") != 0); + /* make sure that it included a Content-length header */ + if (content_length < 0) { + error(0, 0, "did not get frame length"); + return; + } + /* read the frame contents */ + if ((ssize_t)s->back->cap < s->back->len + content_length) + s->back->buf = xrealloc(s->back->buf, s->back->cap = s->back->len + content_length); + if (fread(s->back->buf, s->back->len, 1, stream) != 1) { + error(0, ferror(stream), "fread(%zd)", s->back->len); + return; + } + s->back->len += content_length; + + /* swap the frames */ + pthread_rwlock_wrlock(&s->frontlock); + struct frame *tmp = s->front; + s->front = s->back; + s->back = tmp; + s->framecount++; + pthread_rwlock_unlock(&s->frontlock); + } +} + +void multipart_replace_writer(struct multipart_replace_stream *s, int fd, const char *boundary) { + struct frame myframe = { 0 }; + long lastframe = 0; + boundary = boundary_line(boundary); + size_t boundary_len = strlen(boundary); + + while(1) { + /* poll until there's a new frame */ + pthread_rwlock_rdlock(&s->frontlock); + while (s->framecount == lastframe) { + pthread_rwlock_unlock(&s->frontlock); + usleep(30000); /* a bit over 30 FPS */ + pthread_rwlock_rdlock(&s->frontlock); + } + + /* get the most recent frame (copy `s->front` to `myframe`) */ + if (myframe.cap < (size_t)s->front->len) + myframe.buf = xrealloc(myframe.buf, myframe.cap = s->front->len); + memcpy(myframe.buf, s->front->buf, myframe.len = s->front->len); + lastframe = s->framecount; + + pthread_rwlock_unlock(&s->frontlock); + + /* send the frame to the client */ + if (write(fd, boundary, boundary_len) < (ssize_t)boundary_len) { + error(0, errno, "write"); + return; + } + if (write(fd, myframe.buf, myframe.len) < myframe.len) { + error(0, errno, "write"); + return; + } + /* send a blank line for pleasantness */ + if (write(fd, "\r\n", 2) < 2) { + error(0, errno, "write"); + return; + } + } +} + +void init_multipart_replace_stream(struct multipart_replace_stream *s) { + ZERO(s->a); + ZERO(s->b); + s->front = &s->a; + s->back = &s->b; + pthread_rwlock_init(&s->frontlock, NULL); +} |