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glibc/glibc-rh1810142-6.patch

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From: Florian Weimer <fweimer@redhat.com>
Date: Tue, 18 Feb 2020 12:44:48 +0000 (+0100)
Subject: Move implementation of <file_change_detection.h> into a C file
X-Git-Url: https://sourceware.org/git/?p=glibc.git;a=commitdiff_plain;h=631cf64bc1d8306e011ef39f60b8cb6de91bd271
Move implementation of <file_change_detection.h> into a C file
file_change_detection_for_stat partially initialize
struct file_change_detection in some cases, when the size member
alone determines the outcome of all comparisons. This results
in maybe-uninitialized compiler warnings in case of sufficiently
aggressive inlining.
Once the implementation is moved into a separate C file, this kind
of inlining is no longer possible, so the compiler warnings are gone.
---
diff --git a/include/file_change_detection.h b/include/file_change_detection.h
index aaed0a9b6d..767e578555 100644
--- a/include/file_change_detection.h
+++ b/include/file_change_detection.h
@@ -16,9 +16,10 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <errno.h>
+#ifndef _FILE_CHANGE_DETECTION_H
+#define _FILE_CHANGE_DETECTION_H
+
#include <stdbool.h>
-#include <stddef.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
@@ -38,103 +39,32 @@ struct file_change_detection
/* Returns true if *LEFT and *RIGHT describe the same version of the
same file. */
-static bool __attribute__ ((unused))
-file_is_unchanged (const struct file_change_detection *left,
- const struct file_change_detection *right)
-{
- if (left->size < 0 || right->size < 0)
- /* Negative sizes are used as markers and never match. */
- return false;
- else if (left->size == 0 && right->size == 0)
- /* Both files are empty or do not exist, so they have the same
- content, no matter what the other fields indicate. */
- return true;
- else
- return left->size == right->size
- && left->ino == right->ino
- && left->mtime.tv_sec == right->mtime.tv_sec
- && left->mtime.tv_nsec == right->mtime.tv_nsec
- && left->ctime.tv_sec == right->ctime.tv_sec
- && left->ctime.tv_nsec == right->ctime.tv_nsec;
-}
+bool __file_is_unchanged (const struct file_change_detection *left,
+ const struct file_change_detection *right);
/* Extract file change information to *FILE from the stat buffer
*ST. */
-static void __attribute__ ((unused))
-file_change_detection_for_stat (struct file_change_detection *file,
- const struct stat64 *st)
-{
- if (S_ISDIR (st->st_mode))
- /* Treat as empty file. */
- file->size = 0;
- else if (!S_ISREG (st->st_mode))
- /* Non-regular files cannot be cached. */
- file->size = -1;
- else
- {
- file->size = st->st_size;
- file->ino = st->st_ino;
- file->mtime = st->st_mtim;
- file->ctime = st->st_ctim;
- }
-}
+void __file_change_detection_for_stat (struct file_change_detection *file,
+ const struct stat64 *st);
/* Writes file change information for PATH to *FILE. Returns true on
success. For benign errors, *FILE is cleared, and true is
returned. For errors indicating resource outages and the like,
false is returned. */
-static bool __attribute__ ((unused))
-file_change_detection_for_path (struct file_change_detection *file,
- const char *path)
-{
- struct stat64 st;
- if (stat64 (path, &st) != 0)
- switch (errno)
- {
- case EACCES:
- case EISDIR:
- case ELOOP:
- case ENOENT:
- case ENOTDIR:
- case EPERM:
- /* Ignore errors due to file system contents. Instead, treat
- the file as empty. */
- file->size = 0;
- return true;
- default:
- /* Other errors are fatal. */
- return false;
- }
- else /* stat64 was successfull. */
- {
- file_change_detection_for_stat (file, &st);
- return true;
- }
-}
+bool __file_change_detection_for_path (struct file_change_detection *file,
+ const char *path);
/* Writes file change information for the stream FP to *FILE. Returns
ture on success, false on failure. If FP is NULL, treat the file
as non-existing. */
-static bool __attribute__ ((unused))
-file_change_detection_for_fp (struct file_change_detection *file,
- FILE *fp)
-{
- if (fp == NULL)
- {
- /* The file does not exist. */
- file->size = 0;
- return true;
- }
- else
- {
- struct stat64 st;
- if (fstat64 (__fileno (fp), &st) != 0)
- /* If we already have a file descriptor, all errors are fatal. */
- return false;
- else
- {
- file_change_detection_for_stat (file, &st);
- return true;
- }
- }
-}
+bool __file_change_detection_for_fp (struct file_change_detection *file,
+ FILE *fp);
+
+#ifndef _ISOMAC
+libc_hidden_proto (__file_is_unchanged)
+libc_hidden_proto (__file_change_detection_for_stat)
+libc_hidden_proto (__file_change_detection_for_path)
+libc_hidden_proto (__file_change_detection_for_fp)
+#endif
+
+#endif /* _FILE_CHANGE_DETECTION_H */
diff --git a/io/Makefile b/io/Makefile
index 04c4647dc0..cf380f3516 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -55,7 +55,7 @@ routines := \
posix_fadvise posix_fadvise64 \
posix_fallocate posix_fallocate64 \
sendfile sendfile64 copy_file_range \
- utimensat futimens
+ utimensat futimens file_change_detection
# These routines will be omitted from the libc shared object.
# Instead the static object files will be included in a special archive
diff --git a/io/Versions b/io/Versions
index f7e5dbe49e..ee468055ff 100644
--- a/io/Versions
+++ b/io/Versions
@@ -137,5 +137,9 @@ libc {
__fcntl_nocancel;
__open64_nocancel;
__write_nocancel;
+ __file_is_unchanged;
+ __file_change_detection_for_stat;
+ __file_change_detection_for_path;
+ __file_change_detection_for_fp;
}
}
diff --git a/io/file_change_detection.c b/io/file_change_detection.c
new file mode 100644
index 0000000000..c6d700ed05
--- /dev/null
+++ b/io/file_change_detection.c
@@ -0,0 +1,118 @@
+/* Detecting file changes using modification times.
+ Copyright (C) 2017-2020 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 <file_change_detection.h>
+
+#include <errno.h>
+#include <stddef.h>
+
+bool
+__file_is_unchanged (const struct file_change_detection *left,
+ const struct file_change_detection *right)
+{
+ if (left->size < 0 || right->size < 0)
+ /* Negative sizes are used as markers and never match. */
+ return false;
+ else if (left->size == 0 && right->size == 0)
+ /* Both files are empty or do not exist, so they have the same
+ content, no matter what the other fields indicate. */
+ return true;
+ else
+ return left->size == right->size
+ && left->ino == right->ino
+ && left->mtime.tv_sec == right->mtime.tv_sec
+ && left->mtime.tv_nsec == right->mtime.tv_nsec
+ && left->ctime.tv_sec == right->ctime.tv_sec
+ && left->ctime.tv_nsec == right->ctime.tv_nsec;
+}
+libc_hidden_def (__file_is_unchanged)
+
+void
+__file_change_detection_for_stat (struct file_change_detection *file,
+ const struct stat64 *st)
+{
+ if (S_ISDIR (st->st_mode))
+ /* Treat as empty file. */
+ file->size = 0;
+ else if (!S_ISREG (st->st_mode))
+ /* Non-regular files cannot be cached. */
+ file->size = -1;
+ else
+ {
+ file->size = st->st_size;
+ file->ino = st->st_ino;
+ file->mtime = st->st_mtim;
+ file->ctime = st->st_ctim;
+ }
+}
+libc_hidden_def (__file_change_detection_for_stat)
+
+bool
+__file_change_detection_for_path (struct file_change_detection *file,
+ const char *path)
+{
+ struct stat64 st;
+ if (stat64 (path, &st) != 0)
+ switch (errno)
+ {
+ case EACCES:
+ case EISDIR:
+ case ELOOP:
+ case ENOENT:
+ case ENOTDIR:
+ case EPERM:
+ /* Ignore errors due to file system contents. Instead, treat
+ the file as empty. */
+ file->size = 0;
+ return true;
+ default:
+ /* Other errors are fatal. */
+ return false;
+ }
+ else /* stat64 was successfull. */
+ {
+ __file_change_detection_for_stat (file, &st);
+ return true;
+ }
+}
+libc_hidden_def (__file_change_detection_for_path)
+
+bool
+__file_change_detection_for_fp (struct file_change_detection *file,
+ FILE *fp)
+{
+ if (fp == NULL)
+ {
+ /* The file does not exist. */
+ file->size = 0;
+ return true;
+ }
+ else
+ {
+ struct stat64 st;
+ if (fstat64 (__fileno (fp), &st) != 0)
+ /* If we already have a file descriptor, all errors are fatal. */
+ return false;
+ else
+ {
+ __file_change_detection_for_stat (file, &st);
+ return true;
+ }
+ }
+}
+libc_hidden_def (__file_change_detection_for_fp)
diff --git a/io/tst-file_change_detection.c b/io/tst-file_change_detection.c
index 035dd39c4d..6e00e787b1 100644
--- a/io/tst-file_change_detection.c
+++ b/io/tst-file_change_detection.c
@@ -16,10 +16,6 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-/* The header uses the internal __fileno symbol, which is not
- available outside of libc (even to internal tests). */
-#define __fileno(fp) fileno (fp)
-
#include <file_change_detection.h>
#include <array_length.h>
@@ -40,7 +36,7 @@ all_same (struct file_change_detection *array, size_t length)
{
if (test_verbose > 0)
printf ("info: comparing %zu and %zu\n", i, j);
- TEST_VERIFY (file_is_unchanged (array + i, array + j));
+ TEST_VERIFY (__file_is_unchanged (array + i, array + j));
}
}
@@ -54,7 +50,7 @@ all_different (struct file_change_detection *array, size_t length)
continue;
if (test_verbose > 0)
printf ("info: comparing %zu and %zu\n", i, j);
- TEST_VERIFY (!file_is_unchanged (array + i, array + j));
+ TEST_VERIFY (!__file_is_unchanged (array + i, array + j));
}
}
@@ -105,24 +101,24 @@ do_test (void)
struct file_change_detection fcd[10];
int i = 0;
/* Two empty files always have the same contents. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_empty1));
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_empty2));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_empty1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_empty2));
/* So does a missing file (which is treated as empty). */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++],
- path_does_not_exist));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++],
+ path_does_not_exist));
/* And a symbolic link loop. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_loop));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_loop));
/* And a dangling symbolic link. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_dangling));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_dangling));
/* And a directory. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], tempdir));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], tempdir));
/* And a symbolic link to an empty file. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_to_empty1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_to_empty1));
/* Likewise for access the file via a FILE *. */
- TEST_VERIFY (file_change_detection_for_fp (&fcd[i++], fp_empty1));
- TEST_VERIFY (file_change_detection_for_fp (&fcd[i++], fp_empty2));
+ TEST_VERIFY (__file_change_detection_for_fp (&fcd[i++], fp_empty1));
+ TEST_VERIFY (__file_change_detection_for_fp (&fcd[i++], fp_empty2));
/* And a NULL FILE * (missing file). */
- TEST_VERIFY (file_change_detection_for_fp (&fcd[i++], NULL));
+ TEST_VERIFY (__file_change_detection_for_fp (&fcd[i++], NULL));
TEST_COMPARE (i, array_length (fcd));
all_same (fcd, array_length (fcd));
@@ -132,9 +128,9 @@ do_test (void)
{
struct file_change_detection fcd[3];
int i = 0;
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_file1));
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_to_file1));
- TEST_VERIFY (file_change_detection_for_fp (&fcd[i++], fp_file1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_file1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_to_file1));
+ TEST_VERIFY (__file_change_detection_for_fp (&fcd[i++], fp_file1));
TEST_COMPARE (i, array_length (fcd));
all_same (fcd, array_length (fcd));
}
@@ -144,20 +140,20 @@ do_test (void)
struct file_change_detection fcd[5];
int i = 0;
/* The other files are not empty. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_empty1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_empty1));
/* These two files have the same contents, but have different file
identity. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_file1));
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_file2));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_file1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_file2));
/* FIFOs are always different, even with themselves. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_fifo));
- TEST_VERIFY (file_change_detection_for_path (&fcd[i++], path_fifo));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_fifo));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[i++], path_fifo));
TEST_COMPARE (i, array_length (fcd));
all_different (fcd, array_length (fcd));
/* Replacing the file with its symbolic link does not make a
difference. */
- TEST_VERIFY (file_change_detection_for_path (&fcd[1], path_to_file1));
+ TEST_VERIFY (__file_change_detection_for_path (&fcd[1], path_to_file1));
all_different (fcd, array_length (fcd));
}
@@ -166,16 +162,17 @@ do_test (void)
for (int use_stdio = 0; use_stdio < 2; ++use_stdio)
{
struct file_change_detection initial;
- TEST_VERIFY (file_change_detection_for_path (&initial, path_file1));
+ TEST_VERIFY (__file_change_detection_for_path (&initial, path_file1));
while (true)
{
support_write_file_string (path_file1, "line\n");
struct file_change_detection current;
if (use_stdio)
- TEST_VERIFY (file_change_detection_for_fp (&current, fp_file1));
+ TEST_VERIFY (__file_change_detection_for_fp (&current, fp_file1));
else
- TEST_VERIFY (file_change_detection_for_path (&current, path_file1));
- if (!file_is_unchanged (&initial, &current))
+ TEST_VERIFY (__file_change_detection_for_path
+ (&current, path_file1));
+ if (!__file_is_unchanged (&initial, &current))
break;
/* Wait for a bit to reduce system load. */
usleep (100 * 1000);
diff --git a/resolv/res_init.c b/resolv/res_init.c
index 98d84f264d..ee5dfdd391 100644
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -583,7 +583,7 @@ __resolv_conf_load (struct __res_state *preinit,
if (ok && change != NULL)
/* Update the file change information if the configuration was
loaded successfully. */
- ok = file_change_detection_for_fp (change, fp);
+ ok = __file_change_detection_for_fp (change, fp);
if (ok)
{
diff --git a/resolv/resolv_conf.c b/resolv/resolv_conf.c
index 29a1f4fb94..286149ffad 100644
--- a/resolv/resolv_conf.c
+++ b/resolv/resolv_conf.c
@@ -121,7 +121,7 @@ struct resolv_conf *
__resolv_conf_get_current (void)
{
struct file_change_detection initial;
- if (!file_change_detection_for_path (&initial, _PATH_RESCONF))
+ if (!__file_change_detection_for_path (&initial, _PATH_RESCONF))
return NULL;
struct resolv_conf_global *global_copy = get_locked_global ();
@@ -129,7 +129,7 @@ __resolv_conf_get_current (void)
return NULL;
struct resolv_conf *conf;
if (global_copy->conf_current != NULL
- && file_is_unchanged (&initial, &global_copy->file_resolve_conf))
+ && __file_is_unchanged (&initial, &global_copy->file_resolve_conf))
/* We can reuse the cached configuration object. */
conf = global_copy->conf_current;
else
@@ -149,7 +149,7 @@ __resolv_conf_get_current (void)
/etc/resolv.conf is temporarily replaced while the file
is read (after the initial measurement), and restored to
the initial version later. */
- if (file_is_unchanged (&initial, &after_load))
+ if (__file_is_unchanged (&initial, &after_load))
global_copy->file_resolve_conf = after_load;
else
/* If there is a discrepancy, trigger a reload during the
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