[lxc-devel] [PATCH 18/24] Add local implementation of mntent.h
Stéphane Graber
stgraber at ubuntu.com
Tue Jan 8 17:03:08 UTC 2013
Bionic (at least) is missing some of the usual mntent functions.
This adds code defining those that we need when they're missing from the C
library.
Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
---
configure.ac | 2 +-
src/include/mntent.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++++
src/include/mntent.h | 32 ++++++++++
src/lxc/Makefile.am | 6 +-
src/lxc/cgroup.c | 7 ++-
src/lxc/conf.c | 7 ++-
6 files changed, 222 insertions(+), 5 deletions(-)
create mode 100644 src/include/mntent.c
create mode 100644 src/include/mntent.h
diff --git a/configure.ac b/configure.ac
index 0d50bec..3770e8b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -227,7 +227,7 @@ AC_CHECK_HEADERS([sys/signalfd.h pty.h sys/capability.h sys/personality.h utmpx.
AC_CHECK_FUNCS([setns pivot_root sethostname unshare])
# Check for some functions
-AC_CHECK_FUNCS([getline fgetln openpty])
+AC_CHECK_FUNCS([getline fgetln openpty hasmntopt setmntent endmntent])
# Check for some standard binaries
AC_PROG_GCC_TRADITIONAL
diff --git a/src/include/mntent.c b/src/include/mntent.c
new file mode 100644
index 0000000..a96cd81
--- /dev/null
+++ b/src/include/mntent.c
@@ -0,0 +1,173 @@
+#include <mntent.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Since the values in a line are separated by spaces, a name cannot
+ contain a space. Therefore some programs encode spaces in names
+ by the strings "\040". We undo the encoding when reading an entry.
+ The decoding happens in place. */
+static char *
+decode_name (char *buf)
+{
+ char *rp = buf;
+ char *wp = buf;
+
+ do
+ if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '4' && rp[3] == '0')
+ {
+ /* \040 is a SPACE. */
+ *wp++ = ' ';
+ rp += 3;
+ }
+ else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '1')
+ {
+ /* \011 is a TAB. */
+ *wp++ = '\t';
+ rp += 3;
+ }
+ else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '2')
+ {
+ /* \012 is a NEWLINE. */
+ *wp++ = '\n';
+ rp += 3;
+ }
+ else if (rp[0] == '\\' && rp[1] == '\\')
+ {
+ /* We have to escape \\ to be able to represent all characters. */
+ *wp++ = '\\';
+ rp += 1;
+ }
+ else if (rp[0] == '\\' && rp[1] == '1' && rp[2] == '3' && rp[3] == '4')
+ {
+ /* \134 is also \\. */
+ *wp++ = '\\';
+ rp += 3;
+ }
+ else
+ *wp++ = *rp;
+ while (*rp++ != '\0');
+
+ return buf;
+}
+
+/* Read one mount table entry from STREAM. Returns a pointer to storage
+ reused on the next call, or null for EOF or error (use feof/ferror to
+ check). */
+struct mntent *getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
+{
+ char *cp;
+ char *head;
+
+ do
+ {
+ char *end_ptr;
+
+ if (fgets (buffer, bufsiz, stream) == NULL)
+ {
+ return NULL;
+ }
+
+ end_ptr = strchr (buffer, '\n');
+ if (end_ptr != NULL) /* chop newline */
+ *end_ptr = '\0';
+ else
+ {
+ /* Not the whole line was read. Do it now but forget it. */
+ char tmp[1024];
+ while (fgets (tmp, sizeof tmp, stream) != NULL)
+ if (strchr (tmp, '\n') != NULL)
+ break;
+ }
+
+ head = buffer + strspn (buffer, " \t");
+ /* skip empty lines and comment lines: */
+ }
+ while (head[0] == '\0' || head[0] == '#');
+
+ cp = strsep (&head, " \t");
+ mp->mnt_fsname = cp != NULL ? decode_name (cp) : (char *) "";
+ if (head)
+ head += strspn (head, " \t");
+ cp = strsep (&head, " \t");
+ mp->mnt_dir = cp != NULL ? decode_name (cp) : (char *) "";
+ if (head)
+ head += strspn (head, " \t");
+ cp = strsep (&head, " \t");
+ mp->mnt_type = cp != NULL ? decode_name (cp) : (char *) "";
+ if (head)
+ head += strspn (head, " \t");
+ cp = strsep (&head, " \t");
+ mp->mnt_opts = cp != NULL ? decode_name (cp) : (char *) "";
+ switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
+ {
+ case 0:
+ mp->mnt_freq = 0;
+ case 1:
+ mp->mnt_passno = 0;
+ case 2:
+ break;
+ }
+
+ return mp;
+}
+
+struct mntent *getmntent (FILE *stream)
+{
+ static struct mntent m;
+ static char *getmntent_buffer;
+
+ #define BUFFER_SIZE 4096
+ if (getmntent_buffer == NULL) {
+ getmntent_buffer = (char *) malloc (BUFFER_SIZE);
+ }
+
+ return getmntent_r (stream, &m, getmntent_buffer, BUFFER_SIZE);
+ #undef BUFFER_SIZE
+}
+
+
+/* Prepare to begin reading and/or writing mount table entries from the
+ beginning of FILE. MODE is as for `fopen'. */
+FILE *setmntent (const char *file, const char *mode)
+{
+ /* Extend the mode parameter with "c" to disable cancellation in the
+ I/O functions and "e" to set FD_CLOEXEC. */
+ size_t modelen = strlen (mode);
+ char newmode[modelen + 3];
+ memcpy (newmode, mode, modelen);
+ memcpy (newmode + modelen, "ce", 3);
+ FILE *result = fopen (file, newmode);
+
+ return result;
+}
+
+
+/* Close a stream opened with `setmntent'. */
+int endmntent (FILE *stream)
+{
+ if (stream) /* SunOS 4.x allows for NULL stream */
+ fclose (stream);
+ return 1; /* SunOS 4.x says to always return 1 */
+}
+
+/* Search MNT->mnt_opts for an option matching OPT.
+ Returns the address of the substring, or null if none found. */
+char *hasmntopt (const struct mntent *mnt, const char *opt)
+{
+ const size_t optlen = strlen (opt);
+ char *rest = mnt->mnt_opts, *p;
+
+ while ((p = strstr (rest, opt)) != NULL)
+ {
+ if ((p == rest || p[-1] == ',')
+ && (p[optlen] == '\0' || p[optlen] == '=' || p[optlen] == ','))
+ return p;
+
+ rest = strchr (p, ',');
+ if (rest == NULL)
+ break;
+ ++rest;
+ }
+
+ return NULL;
+}
diff --git a/src/include/mntent.h b/src/include/mntent.h
new file mode 100644
index 0000000..3f1d16f
--- /dev/null
+++ b/src/include/mntent.h
@@ -0,0 +1,32 @@
+#ifndef _mntent_h
+#define _mntent_h
+
+#include <../config.h>
+
+#if IS_BIONIC
+struct mntent
+{
+ char* mnt_fsname;
+ char* mnt_dir;
+ char* mnt_type;
+ char* mnt_opts;
+ int mnt_freq;
+ int mnt_passno;
+};
+
+extern struct mntent *getmntent (FILE *stream);
+#endif
+
+#ifndef HAVE_SETMNTENT
+FILE *setmntent (const char *file, const char *mode);
+#endif
+
+#ifndef HAVE_ENDMNTENT
+int endmntent (FILE *stream);
+#endif
+
+#ifndef HAVE_HASMNTOPT
+extern char *hasmntopt (const struct mntent *mnt, const char *opt);
+#endif
+
+#endif
diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am
index 3d800d5..8bc7b4b 100644
--- a/src/lxc/Makefile.am
+++ b/src/lxc/Makefile.am
@@ -20,7 +20,8 @@ pkginclude_HEADERS = \
if IS_BIONIC
pkginclude_HEADERS += \
../include/getline.h \
- ../include/openpty.h
+ ../include/openpty.h \
+ ../include/mntent.h
endif
sodir=$(libdir)
@@ -70,7 +71,8 @@ liblxc_so_SOURCES = \
if IS_BIONIC
liblxc_so_SOURCES += \
../include/getline.c ../include/getline.h \
- ../include/openpty.c ../include/openpty.h
+ ../include/openpty.c ../include/openpty.h \
+ ../include/mntent.c ../include/mntent.h
endif
AM_CFLAGS=-I$(top_srcdir)/src \
diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
index f6243b8..0f2057f 100644
--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -25,7 +25,6 @@
#undef _GNU_SOURCE
#include <stdlib.h>
#include <errno.h>
-#include <mntent.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
@@ -44,6 +43,12 @@
#include <lxc/cgroup.h>
#include <lxc/start.h>
+#if IS_BIONIC
+#include <../include/mntent.h>
+#else
+#include <mntent.h>
+#endif
+
lxc_log_define(lxc_cgroup, lxc);
#define MTAB "/proc/mounts"
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 4a2fd22..e6efcf0 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -28,7 +28,6 @@
#include <errno.h>
#include <string.h>
#include <dirent.h>
-#include <mntent.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/syscall.h>
@@ -78,6 +77,12 @@
#include <sys/personality.h>
#endif
+#if IS_BIONIC
+#include <../include/mntent.h>
+#else
+#include <mntent.h>
+#endif
+
#include "lxcseccomp.h"
lxc_log_define(lxc_conf, lxc);
--
1.8.0
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