On many platforms /dev/fd/<n> is used to refer to open filedescriptor <n> of
the running process.
If we fail to open the provided filename and if the filename starts with
'/dev/fd/' then assume this is a platform which do not support these special
files.
In that case read out the descriptor value from the provided string and fdopen
it.
This allows to use /dev/fd/<n> syntax on all platforms, those that do provide
this indeface in /dev and an emulation of this for the platforms that do not
provide /dev/fd
Signed-off-by: Ronnie Sahlberg <ronniesahlb...@gmail.com>
---
qemu-config.c | 16 +++++++++++++++-
qemu-options.hx | 3 ++-
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/qemu-config.c b/qemu-config.c
index 7d9da78..96e7497 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -814,9 +814,23 @@ out:
int qemu_read_config_file(const char *filename)
{
- FILE *f = fopen(filename, "r");
+ FILE *f;
int ret;
+ f = fopen(filename, "r");
+
+ if (f == NULL && !strncmp(filename, "/dev/fd/", 8)) {
+ int fd;
+ char *ptr = NULL;
+
+ errno = 0;
+ fd = strtol(filename + 8, &ptr, 10);
+ if (errno != 0 || ptr == filename + 8 || *ptr != '\0') {
+ return -EINVAL;
+ }
+ f = fdopen(fd, "r");
+ }
+
if (f == NULL) {
return -errno;
}
diff --git a/qemu-options.hx b/qemu-options.hx
index b129996..c70c6e7 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2650,7 +2650,8 @@ DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
STEXI
@item -readconfig @var{file}
@findex -readconfig
-Read device configuration from @var{file}.
+Read device configuration from @var{file}. Use '/dev/fd/<n>' as filename
+to read from an existing, inherited, filedesriptor.
ETEXI
DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
"-writeconfig <file>\n"
--
1.7.3.1
