On Monday, 2018-06-25 17:39:14 +0000, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
>
> Introduce a helper which gets the real sysfs path for the given pci
> device.
>
> In other words, instead opening the /sys/dev/char/*/device symlink, we
> opt for the actual /sys/devices/pci*/*/
>
> It folds three (nearly identical) snprintf's and paves the way of adding
> extra devices (see next patch) a piece of pie.
>
> Signed-off-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
> ---
> xf86drm.c | 62 ++++++++++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 50 insertions(+), 12 deletions(-)
>
> diff --git a/xf86drm.c b/xf86drm.c
> index d4810740..8ccd528f 100644
> --- a/xf86drm.c
> +++ b/xf86drm.c
> @@ -2992,16 +2992,37 @@ static int drmParseSubsystemType(int maj, int min)
> #endif
> }
>
> +static char *
> +get_real_pci_path(int maj, int min)
> +{
> + char path[PATH_MAX + 1];
> + char *real_path = malloc(PATH_MAX);
Why not allocate this on the stack and pass it in?
It would avoid the error handling you had to add in this patch :)
> +
> + if (!real_path)
> + return NULL;
> +
> + snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device", maj, min);
> + if (!realpath(path, real_path)) {
> + free(real_path);
> + return NULL;
> + }
> +
> + return real_path;
> +}
> +
> static int drmParsePciBusInfo(int maj, int min, drmPciBusInfoPtr info)
> {
> #ifdef __linux__
> unsigned int domain, bus, dev, func;
> - char path[PATH_MAX + 1], *value;
> + char *real_path, *value;
> int num;
>
> - snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device", maj, min);
> + real_path = get_real_pci_path(maj, min);
> + if (!real_path)
> + return -ENOENT;
>
> - value = sysfs_uevent_get(path, "PCI_SLOT_NAME");
> + value = sysfs_uevent_get(real_path, "PCI_SLOT_NAME");
> + free(real_path);
> if (!value)
> return -ENOENT;
>
> @@ -3114,24 +3135,32 @@ static int parse_separate_sysfs_files(int maj, int min,
> "subsystem_vendor",
> "subsystem_device",
> };
> - char path[PATH_MAX + 1];
> + char path[PATH_MAX + 1], *real_path;
> unsigned int data[ARRAY_SIZE(attrs)];
> FILE *fp;
> int ret;
>
> + real_path = get_real_pci_path(maj, min);
> + if (!real_path)
> + return -ENOENT;
> +
> for (unsigned i = ignore_revision ? 1 : 0; i < ARRAY_SIZE(attrs); i++) {
> - snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/%s", maj, min,
> - attrs[i]);
> + snprintf(path, PATH_MAX, "%s/%s", real_path, attrs[i]);
> fp = fopen(path, "r");
> - if (!fp)
> + if (!fp) {
> + free(real_path);
> return -errno;
> + }
>
> ret = fscanf(fp, "%x", &data[i]);
> fclose(fp);
> - if (ret != 1)
> + if (ret != 1) {
> + free(real_path);
> return -errno;
> + }
>
> }
> + free(real_path);
>
> device->revision_id = ignore_revision ? 0xff : data[0] & 0xff;
> device->vendor_id = data[1] & 0xffff;
> @@ -3145,19 +3174,28 @@ static int parse_separate_sysfs_files(int maj, int min,
> static int parse_config_sysfs_file(int maj, int min,
> drmPciDeviceInfoPtr device)
> {
> - char path[PATH_MAX + 1];
> + char path[PATH_MAX + 1], *real_path;
> unsigned char config[64];
> int fd, ret;
>
> - snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device/config", maj, min);
> + real_path = get_real_pci_path(maj, min);
> + if (!real_path)
> + return -ENOENT;
> +
> + snprintf(path, PATH_MAX, "%s/config", real_path);
> fd = open(path, O_RDONLY);
> - if (fd < 0)
> + if (fd < 0) {
> + free(real_path);
> return -errno;
> + }
>
> ret = read(fd, config, sizeof(config));
> close(fd);
> - if (ret < 0)
> + if (ret < 0) {
> + free(real_path);
> return -errno;
> + }
> + free(real_path);
>
> device->vendor_id = config[0] | (config[1] << 8);
> device->device_id = config[2] | (config[3] << 8);
> --
> 2.18.0
>
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