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/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <i915_drm.h>
#include "igt_sysfs.h"
static int readN(int fd, char *buf, int len)
{
int total = 0;
do {
int ret = read(fd, buf + total, len - total);
if (ret < 0 && (errno == EINTR || errno == EAGAIN))
continue;
if (ret <= 0)
return total ?: ret;
total += ret;
} while (1);
}
static int writeN(int fd, const char *buf, int len)
{
int total = 0;
do {
int ret = write(fd, buf + total, len - total);
if (ret < 0 && (errno == EINTR || errno == EAGAIN))
continue;
if (ret <= 0)
return total ?: ret;
total += ret;
} while (1);
}
/**
* igt_sysfs_open:
* @device: fd of the device (or -1 to default to Intel)
*
* This opens the sysfs directory corresponding to device for use
* with igt_sysfs_set() and igt_sysfs_get().
*
* Returns:
* The directory fd, or -1 on failure.
*/
int igt_sysfs_open(int fd, int *idx)
{
char path[80];
struct stat st;
if (fd != -1 && (fstat(fd, &st) || !S_ISCHR(st.st_mode)))
return -1;
for (int n = 0; n < 16; n++) {
int len = sprintf(path, "/sys/class/drm/card%d", n);
if (fd != -1) {
FILE *file;
int ret, maj, min;
sprintf(path + len, "/dev");
file = fopen(path, "r");
if (!file)
continue;
ret = fscanf(file, "%d:%d", &maj, &min);
fclose(file);
if (ret != 2 ||
major(st.st_rdev) != maj ||
minor(st.st_rdev) != min)
continue;
} else {
/* Bleh. Search for intel */
sprintf(path + len, "/error");
if (stat(path, &st))
continue;
}
path[len] = '\0';
if (idx)
*idx = n;
return open(path, O_RDONLY);
}
return -1;
}
/**
* igt_sysfs_set:
* @dir: directory for the device from igt_sysfs_open()
* @attr: name of the sysfs node to open
* @value: the string to write
*
* This writes the value to the sysfs file.
*
* Returns:
* True on success, false on failure.
*/
bool igt_sysfs_set(int dir, const char *attr, const char *value)
{
int fd, len, ret;
fd = openat(dir, attr, O_WRONLY);
if (fd < 0)
return false;
len = strlen(value);
ret = writeN(fd, value, len);
close(fd);
return len == ret;
}
/**
* igt_sysfs_get:
* @dir: directory for the device from igt_sysfs_open()
* @attr: name of the sysfs node to open
*
* This reads the value from the sysfs file.
*
* Returns:
* A nul-terminated string, must be freed by caller after use, or NULL
* on failure.
*/
char *igt_sysfs_get(int dir, const char *attr)
{
char *buf;
int len, offset, rem;
int ret, fd;
fd = openat(dir, attr, O_RDONLY);
if (fd < 0)
return NULL;
offset = 0;
len = 64;
rem = len - offset - 1;
buf = malloc(len);
if (!buf)
goto out;
while ((ret = readN(fd, buf + offset, rem)) == rem) {
char *newbuf;
newbuf = realloc(buf, 2*len);
if (!newbuf)
break;
buf = newbuf;
len *= 2;
offset += ret;
rem = len - offset - 1;
}
if (ret != -1)
offset += ret;
buf[offset] = '\0';
while (offset > 0 && buf[offset-1] == '\n')
buf[--offset] = '\0';
out:
close(fd);
return buf;
}
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