glibc/sysdeps/unix/sysv/linux/procutils.c

98 lines
2.4 KiB
C

/* Utilities functions to read/parse Linux procfs and sysfs.
Copyright (C) 2023-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <not-cancel.h>
#include <procutils.h>
#include <string.h>
static int
next_line (char **r, int fd, char *const buffer, char **cp, char **re,
char *const buffer_end)
{
char *res = *cp;
char *nl = memchr (*cp, '\n', *re - *cp);
if (nl == NULL)
{
if (*cp != buffer)
{
if (*re == buffer_end)
{
memmove (buffer, *cp, *re - *cp);
*re = buffer + (*re - *cp);
*cp = buffer;
ssize_t n = TEMP_FAILURE_RETRY (
__read_nocancel (fd, *re, buffer_end - *re));
if (n < 0)
return -1;
*re += n;
nl = memchr (*cp, '\n', *re - *cp);
if (nl == NULL)
/* Line too long. */
return 0;
}
else
nl = memchr (*cp, '\n', *re - *cp);
res = *cp;
}
if (nl == NULL)
nl = *re - 1;
}
*nl = '\0';
*cp = nl + 1;
assert (*cp <= *re);
if (res == *re)
return 0;
*r = res;
return 1;
}
bool
procutils_read_file (const char *filename, procutils_closure_t closure,
void *arg)
{
enum { buffer_size = PROCUTILS_MAX_LINE_LEN };
char buffer[buffer_size];
char *buffer_end = buffer + buffer_size;
char *cp = buffer_end;
char *re = buffer_end;
int fd = TEMP_FAILURE_RETRY (
__open64_nocancel (filename, O_RDONLY | O_CLOEXEC));
if (fd == -1)
return false;
char *l;
int r;
while ((r = next_line (&l, fd, buffer, &cp, &re, buffer_end)) > 0)
if (closure (l, arg) != 0)
break;
__close_nocancel_nostatus (fd);
return r == 1;
}