Re: [Libguestfs] [PATCH] Recognise cd-rom devices in devsparts.c
Matthew Booth wrote:
Also:
* Un-duplicate device detection code by creating a common mapping function.
* Add some more comments.
---
daemon/devsparts.c | 168 ++++++++++++++++++++++++++++++----------------------
1 files changed, 96 insertions(+), 72 deletions(-)
diff --git a/daemon/devsparts.c b/daemon/devsparts.c
index 1970e7d..b89682c 100644
--- a/daemon/devsparts.c
+++ b/daemon/devsparts.c
@@ -29,14 +29,19 @@
#include "daemon.h"
#include "actions.h"
-char **
-do_list_devices (void)
+typedef int (*block_dev_func_t)(const char *dev,
+ char ***r, int *size, int *alloc);
+
+/* Execute a given function for each discovered block device */
+static char**
+foreach_block_device (block_dev_func_t func)
{
char **r = NULL;
int size = 0, alloc = 0;
+
DIR *dir;
struct dirent *d;
- char buf[256];
+ int err = 0;
dir = opendir ("/sys/block");
if (!dir) {
@@ -44,121 +49,140 @@ do_list_devices (void)
return NULL;
}
+ errno = 0;
while ((d = readdir (dir)) != NULL) {
...
}
- if (add_string (&r, &size, &alloc, NULL) == -1) {
- closedir (dir);
+ /* Check readdir didn't fail */
+ if(0 != errno) {
+ reply_with_perror ("readdir: /sys/block");
+ free_stringslen(r, size);
return NULL;
}
It's nice to detect a failing readdir.
However, that errno=0 assignment belongs inside the loop.
A minimal change would produce this ugliness:
while ((errno = 0, d = readdir (dir)) != NULL) {
...
}
This is more readable (also moving the decl of "d" into the loop):
while (true) {
errno = 0;
struct dirent *d = readdir (dir);
if (d != NULL)
break;
...
}