From 4364b9ebb3acef566a2c1955423426584147226e Mon Sep 17 00:00:00 2001 From: Luca Boccassi Date: Mon, 20 Mar 2023 01:40:20 +0000 Subject: Support /proc in _dbus_file_get_content procfs has special semantics: most files are 0 size, only one read can be done on a file, and they are not larger than 4MB. Enhance _dbus_file_get_content() so that we can read files from /proc with it. Signed-off-by: Luca Boccassi --- cmake/ConfigureChecks.cmake | 3 +++ cmake/config.h.cmake | 3 +++ configure.ac | 3 +++ dbus/dbus-file-unix.c | 50 +++++++++++++++++++++++++++++++++++++++++---- meson.build | 9 ++++++++ 5 files changed, 64 insertions(+), 4 deletions(-) diff --git a/cmake/ConfigureChecks.cmake b/cmake/ConfigureChecks.cmake index 172db213..dfa21a55 100644 --- a/cmake/ConfigureChecks.cmake +++ b/cmake/ConfigureChecks.cmake @@ -15,6 +15,7 @@ check_include_file(errno.h HAVE_ERRNO_H) # dbus-sysdeps.c check_include_file(inttypes.h HAVE_INTTYPES_H) # dbus-pipe.h check_include_file(io.h HAVE_IO_H) # internal check_include_file(linux/close_range.h HAVE_LINUX_CLOSE_RANGE_H) +check_include_file(linux/magic.h HAVE_LINUX_MAGIC_H) check_include_file(locale.h HAVE_LOCALE_H) check_include_file(signal.h HAVE_SIGNAL_H) check_include_file(stdio.h HAVE_STDIO_H) # dbus-sysdeps.h @@ -26,6 +27,7 @@ check_include_file(sys/resource.h HAVE_SYS_RESOURCE_H) check_include_file(sys/syscall.h HAVE_SYS_SYSCALL_H) check_include_file(sys/prctl.h HAVE_SYS_PRCTL_H) check_include_file(sys/time.h HAVE_SYS_TIME_H)# dbus-sysdeps-win.c +check_include_file(sys/vfs.h HAVE_SYS_VFS_H) check_include_file(ws2tcpip.h HAVE_WS2TCPIP_H)# dbus-sysdeps-win.c check_include_file(unistd.h HAVE_UNISTD_H) # dbus-sysdeps-util-win.c check_include_file(sys/inotify.h DBUS_BUS_ENABLE_INOTIFY) @@ -64,6 +66,7 @@ check_symbol_exists(environ "unistd.h" HAVE_DECL_ENVIRON) check_symbol_exists(LOG_PERROR "syslog.h" HAVE_DECL_LOG_PERROR) check_symbol_exists(setresuid "unistd.h" HAVE_SETRESUID) check_symbol_exists(getresuid "unistd.h" HAVE_GETRESUID) +check_symbol_exists(fstatfs "sys/vfs.h" HAVE_FSTATFS) check_struct_member(cmsgcred cmcred_pid "sys/types.h;sys/socket.h" HAVE_CMSGCRED) # dbus-sysdeps.c diff --git a/cmake/config.h.cmake b/cmake/config.h.cmake index 395a583d..43771b99 100644 --- a/cmake/config.h.cmake +++ b/cmake/config.h.cmake @@ -120,10 +120,12 @@ #cmakedefine HAVE_SYSLOG_H 1 #cmakedefine HAVE_SYS_EVENTS_H 1 #cmakedefine HAVE_SYS_INOTIFY_H 1 +#cmakedefine HAVE_LINUX_MAGIC_H 1 #cmakedefine HAVE_SYS_PRCTL_H 1 #cmakedefine HAVE_SYS_RANDOM_H 1 #cmakedefine HAVE_SYS_RESOURCE_H 1 #cmakedefine HAVE_SYS_SYSCALL_H 1 +#cmakedefine HAVE_SYS_VFS_H 1 /* Define to 1 if you have sys/time.h */ #cmakedefine HAVE_SYS_TIME_H 1 @@ -185,6 +187,7 @@ #cmakedefine HAVE_ACCEPT4 1 +#cmakedefine HAVE_FSTATFS 1 #cmakedefine HAVE_INOTIFY_INIT1 1 #cmakedefine HAVE_GETRANDOM 1 #cmakedefine HAVE_GETRLIMIT 1 diff --git a/configure.ac b/configure.ac index 92124838..2620f372 100644 --- a/configure.ac +++ b/configure.ac @@ -1023,6 +1023,9 @@ if test x$with_valgrind != xno; then AC_DEFINE([WITH_VALGRIND], [1], [Define to add Valgrind instrumentation]) fi +AC_CHECK_HEADERS(sys/vfs.h, [AC_CHECK_FUNCS(fstatfs)]) +AC_CHECK_HEADERS([linux/magic.h]) + #### Set up final flags LIBDBUS_LIBS="$THREAD_LIBS $NETWORK_libs $SYSTEMD_LIBS" AC_SUBST([LIBDBUS_LIBS]) diff --git a/dbus/dbus-file-unix.c b/dbus/dbus-file-unix.c index 6da44504..d5fa029e 100644 --- a/dbus/dbus-file-unix.c +++ b/dbus/dbus-file-unix.c @@ -33,7 +33,13 @@ #include "dbus-sysdeps.h" #include "dbus-sysdeps-unix.h" +#ifdef HAVE_LINUX_MAGIC_H +#include +#endif #include +#ifdef HAVE_SYS_VFS_H +#include +#endif #include #include #include @@ -60,9 +66,14 @@ _dbus_file_get_contents (DBusString *str, { int fd; struct stat sb; +#ifdef HAVE_FSTATFS + struct statfs sfs; +#endif int orig_len; int total; + int file_size; const char *filename_c; + dbus_bool_t is_procfs = FALSE; _DBUS_ASSERT_ERROR_IS_CLEAR (error); @@ -104,17 +115,47 @@ _dbus_file_get_contents (DBusString *str, _dbus_close (fd, NULL); return FALSE; } + + /* procfs has different semantics - most files are 0 size, + * we can do only one read, and at most we can read 4M. + */ +#ifdef HAVE_FSTATFS + if (sb.st_size == 0) + { + if (fstatfs(fd, &sfs) < 0) + { + dbus_set_error (error, _dbus_error_from_errno (errno), + "Failed to stat \"%s\": %s", + filename_c, + _dbus_strerror (errno)); + + _dbus_verbose ("fstatvfs() failed: %s", + _dbus_strerror (errno)); + + _dbus_close (fd, NULL); + + return FALSE; + } + if (sfs.f_type == PROC_SUPER_MAGIC) + is_procfs = TRUE; + } +#endif + + if (is_procfs) + file_size = _DBUS_ONE_MEGABYTE; + else + file_size = sb.st_size; total = 0; orig_len = _dbus_string_get_length (str); - if (sb.st_size > 0 && S_ISREG (sb.st_mode)) + if (file_size > 0 && S_ISREG (sb.st_mode)) { int bytes_read; - while (total < (int) sb.st_size) + do { bytes_read = _dbus_read (fd, str, - sb.st_size - total); + file_size - total); if (bytes_read <= 0) { dbus_set_error (error, _dbus_error_from_errno (errno), @@ -132,11 +173,12 @@ _dbus_file_get_contents (DBusString *str, else total += bytes_read; } + while (total < file_size && !is_procfs); _dbus_close (fd, NULL); return TRUE; } - else if (sb.st_size != 0) + else if (file_size != 0) { _dbus_verbose ("Can only open regular files at the moment.\n"); dbus_set_error (error, DBUS_ERROR_FAILED, diff --git a/meson.build b/meson.build index df302a7d..e2cbc368 100644 --- a/meson.build +++ b/meson.build @@ -670,6 +670,7 @@ check_headers = [ 'io.h', 'locale.h', 'linux/close_range.h', + 'linux/magic.h', 'locale.h', 'signal.h', 'syslog.h', @@ -678,6 +679,7 @@ check_headers = [ 'sys/resource.h', 'sys/syscall.h', 'sys/time.h', + 'sys/vfs.h', 'unistd.h', 'ws2tcpip.h', ] @@ -753,6 +755,13 @@ config.set('HAVE_UNPCBID', ) ) +config.set('HAVE_FSTATFS', + cc.has_function( + 'fstatfs', + prefix : '#include ', + args: compile_args_c, + ) +) ############################################################################### # Project options -- cgit v1.2.1