From 6e7c006e4047c319e9330106c16f29a9b81e22e6 Mon Sep 17 00:00:00 2001 From: Zhao Zhili Date: Thu, 15 Dec 2022 01:10:10 +0800 Subject: [PATCH] avformat/file: add fd protocol Unlike the pipe protocol, fd protocol has seek support if it corresponding to a regular file. Signed-off-by: Zhao Zhili --- doc/protocols.texi | 27 +++++++++++++ libavformat/Makefile | 1 + libavformat/file.c | 87 +++++++++++++++++++++++++++++++++-------- libavformat/protocols.c | 1 + libavformat/version.h | 4 +- 5 files changed, 101 insertions(+), 19 deletions(-) diff --git a/doc/protocols.texi b/doc/protocols.texi index a686a7f0ac..21ae6181a0 100644 --- a/doc/protocols.texi +++ b/doc/protocols.texi @@ -275,6 +275,33 @@ For example, to convert a GIF file given inline with @command{ffmpeg}: ffmpeg -i "data:image/gif;base64,R0lGODdhCAAIAMIEAAAAAAAA//8AAP//AP///////////////ywAAAAACAAIAAADF0gEDLojDgdGiJdJqUX02iB4E8Q9jUMkADs=" smiley.png @end example +@section fd + +File descriptor access protocol. + +The accepted syntax is: +@example +fd: -fd @var{file_descriptor} +@end example + +If @option{fd} is not specified, by default the stdout file descriptor will be +used for writing, stdin for reading. Unlike the pipe protocol, fd protocol has +seek support if it corresponding to a regular file. fd protocol doesn't support +pass file descriptor via URL for security. + +This protocol accepts the following options: + +@table @option +@item blocksize +Set I/O operation maximum block size, in bytes. Default value is +@code{INT_MAX}, which results in not limiting the requested block size. +Setting this value reasonably low improves user termination request reaction +time, which is valuable if data transmission is slow. + +@item fd +Set file descriptor. +@end table + @section file File access protocol. diff --git a/libavformat/Makefile b/libavformat/Makefile index 2699409e43..fa71ec12f7 100644 --- a/libavformat/Makefile +++ b/libavformat/Makefile @@ -647,6 +647,7 @@ OBJS-$(CONFIG_DATA_PROTOCOL) += data_uri.o OBJS-$(CONFIG_FFRTMPCRYPT_PROTOCOL) += rtmpcrypt.o rtmpdigest.o rtmpdh.o OBJS-$(CONFIG_FFRTMPHTTP_PROTOCOL) += rtmphttp.o OBJS-$(CONFIG_FILE_PROTOCOL) += file.o +OBJS-$(CONFIG_FD_PROTOCOL) += file.o OBJS-$(CONFIG_FTP_PROTOCOL) += ftp.o urldecode.o OBJS-$(CONFIG_GOPHER_PROTOCOL) += gopher.o OBJS-$(CONFIG_GOPHERS_PROTOCOL) += gopher.o diff --git a/libavformat/file.c b/libavformat/file.c index 878983a336..d20208e31f 100644 --- a/libavformat/file.c +++ b/libavformat/file.c @@ -110,6 +110,13 @@ static const AVClass pipe_class = { .version = LIBAVUTIL_VERSION_INT, }; +static const AVClass fd_class = { + .class_name = "fd", + .item_name = av_default_item_name, + .option = pipe_options, + .version = LIBAVUTIL_VERSION_INT, +}; + static int file_read(URLContext *h, unsigned char *buf, int size) { FileContext *c = h->priv_data; @@ -197,6 +204,23 @@ static int file_close(URLContext *h) return (ret == -1) ? AVERROR(errno) : 0; } +/* XXX: use llseek */ +static int64_t file_seek(URLContext *h, int64_t pos, int whence) +{ + FileContext *c = h->priv_data; + int64_t ret; + + if (whence == AVSEEK_SIZE) { + struct stat st; + ret = fstat(c->fd, &st); + return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size); + } + + ret = lseek(c->fd, pos, whence); + + return ret < 0 ? AVERROR(errno) : ret; +} + #if CONFIG_FILE_PROTOCOL static int file_delete(URLContext *h) @@ -276,23 +300,6 @@ static int file_open(URLContext *h, const char *filename, int flags) return 0; } -/* XXX: use llseek */ -static int64_t file_seek(URLContext *h, int64_t pos, int whence) -{ - FileContext *c = h->priv_data; - int64_t ret; - - if (whence == AVSEEK_SIZE) { - struct stat st; - ret = fstat(c->fd, &st); - return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size); - } - - ret = lseek(c->fd, pos, whence); - - return ret < 0 ? AVERROR(errno) : ret; -} - static int file_open_dir(URLContext *h) { #if HAVE_LSTAT @@ -441,3 +448,49 @@ const URLProtocol ff_pipe_protocol = { }; #endif /* CONFIG_PIPE_PROTOCOL */ + +#if CONFIG_FD_PROTOCOL + +static int fd_open(URLContext *h, const char *filename, int flags) +{ + FileContext *c = h->priv_data; + struct stat st; + + if (strcmp(filename, "fd:") != 0) { + av_log(h, AV_LOG_ERROR, "Doesn't support pass file descriptor via URL," + " please set it via -fd {num}\n"); + return AVERROR(EINVAL); + } + + if (c->fd < 0) { + if (flags & AVIO_FLAG_WRITE) { + c->fd = 1; + } else { + c->fd = 0; + } + } + if (fstat(c->fd, &st) < 0) + return AVERROR(errno); + h->is_streamed = !(S_ISREG(st.st_mode) || S_ISBLK(st.st_mode)); + c->fd = fd_dup(h, c->fd); + if (c->fd == -1) + return AVERROR(errno); + + return 0; +} + +const URLProtocol ff_fd_protocol = { + .name = "fd", + .url_open = fd_open, + .url_read = file_read, + .url_write = file_write, + .url_seek = file_seek, + .url_close = file_close, + .url_get_file_handle = file_get_handle, + .url_check = file_check, + .priv_data_size = sizeof(FileContext), + .priv_data_class = &fd_class, + .default_whitelist = "crypto,data" +}; + +#endif /* CONFIG_FD_PROTOCOL */ diff --git a/libavformat/protocols.c b/libavformat/protocols.c index d3a7d4310b..9491dc7d00 100644 --- a/libavformat/protocols.c +++ b/libavformat/protocols.c @@ -29,6 +29,7 @@ extern const URLProtocol ff_concat_protocol; extern const URLProtocol ff_concatf_protocol; extern const URLProtocol ff_crypto_protocol; extern const URLProtocol ff_data_protocol; +extern const URLProtocol ff_fd_protocol; extern const URLProtocol ff_ffrtmpcrypt_protocol; extern const URLProtocol ff_ffrtmphttp_protocol; extern const URLProtocol ff_file_protocol; diff --git a/libavformat/version.h b/libavformat/version.h index 63e753a3aa..f5a7f579b3 100644 --- a/libavformat/version.h +++ b/libavformat/version.h @@ -31,8 +31,8 @@ #include "version_major.h" -#define LIBAVFORMAT_VERSION_MINOR 34 -#define LIBAVFORMAT_VERSION_MICRO 103 +#define LIBAVFORMAT_VERSION_MINOR 35 +#define LIBAVFORMAT_VERSION_MICRO 100 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \ LIBAVFORMAT_VERSION_MINOR, \