Support per-architecture syscall in/out parameter descriptions

The number of arguments of some syscalls varies from one architecture to
another. For instance, fanotify_mark, on most architectures has the
following signature:

fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, int dfd, const char *pathname)

However, on x86-32, the 64-bit mask parameter is split into two 32-bit parts:
fanotify_mark(int fanotify_fd, unsigned int flags, u32 mask_lo, u32 mask_hi, int dfd, const char *pathname)

Since the header generation scripts do not expect this, generating the
headers for x86-32 fails with:
  Error: argument number (6) is larger than number of syscall arguments (5)

The scripts are modified to search for an in/out description in a
per-architecture description list. For the moment only fanotify_mark()
has such an override.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7252f41f1d08100d099deab7328f7fc784e1c484

diff --git a/include/instrumentation/syscalls/lttng-get-syscall-inout.sh b/include/instrumentation/syscalls/lttng-get-syscall-inout.sh
index 8ddaad8d0e57c400f99b6a304d6b709bad879ac6..61bd86a42e2a68a1dc70258c1866fade2428185a 100755 (executable)
--- a/include/instrumentation/syscalls/lttng-get-syscall-inout.sh
+++ b/include/instrumentation/syscalls/lttng-get-syscall-inout.sh
@@ -4,16 +4,16 @@
 # example usage:
 # lttng-get-syscall-inout.sh table-syscall-inout.txt select 1
 
-FILENAME=$1
+ARCH_NAME=$1
 SYSCALL_NAME=$2
 ARG_NR=$3
 TMPFILE=$(mktemp)
+GENERIC_INOUT_DESCRIPTION_FILE="$(dirname "$0")/table-syscall-inout.txt"
 
 # Delete temp file on exit
 trap 'rm -f "$TMPFILE"' EXIT
 
-
-if [ x"${FILENAME}" = x"" ]; then
+if [ x"${GENERIC_INOUT_DESCRIPTION_FILE}" = x"" ]; then
        echo "Error: Please specify input file name as first argument" >&2
        exit 1
 fi
@@ -28,21 +28,48 @@ if [[ x"${ARG_NR}" = x"" || ${ARG_NR} == 0 ]]; then
        exit 1
 fi
 
+# Search for the in/out description of a syscall. This function attempts to find
+# a matching description in the per-architecture description override file (if it exists)
+# and falls back to the generic description file otherwise.
+#
+# Returns 0 if a description was found and written to the output file, 1 otherwise.
+function write_inout_description ()
+{
+       local arch_name=$1
+       local syscall_name=$2
+       local output_file=$3
+       local description_files=("$(dirname "$0")/table-syscall-inout-${arch_name}-override.txt" "$GENERIC_INOUT_DESCRIPTION_FILE")
+       local found=0
+
+       for file in ${description_files[@]}; do
+               if [ ! -f "$file" ]; then
+                       continue
+               fi
+
+               # Look for the syscall's in/out description
+               grep "syscall ${syscall_name} " "${file}" > "${output_file}" || true
+
+               # Error out if we got more than one syscall
+               local match_count=$(wc -l < "${output_file}")
+               if [ "${match_count}" -gt 1 ]; then
+                       # Fatal error; invalid description file
+                       echo "Error: more than one system call match" >&2
+                       exit 1
+               elif [ "${match_count}" -eq 1 ]; then
+                       # Description found
+                       return 0
+               fi
+       done
+
+       return 1
+}
+
 # Abort on error and undefined variable
 set -eu
 
-# Get the required syscall
-grep "syscall ${SYSCALL_NAME} " "${FILENAME}" > "${TMPFILE}" || true
-
-# Error out if we got more than one syscall
-NR_MATCH=$(wc -l < "${TMPFILE}")
-if [ "${NR_MATCH}" -gt 1 ]; then
-       echo "Error: more than one system call match" >&2
-       exit 1
-fi
 
 # Default to sc_inout for unknown syscalls
-if [ "${NR_MATCH}" -eq 0 ]; then
+if ! write_inout_description "$ARCH_NAME" "$SYSCALL_NAME" "$TMPFILE"; then
        echo "Warning: no match for syscall '${SYSCALL_NAME}', set to 'inout'" >&2
        # no match, default to inout
        echo "sc_inout"

diff --git a/include/instrumentation/syscalls/lttng-syscalls-generate-headers.sh b/include/instrumentation/syscalls/lttng-syscalls-generate-headers.sh
index df29abf71d7436c18ce38f441951349d7971c90e..b93bf7c7f9eed70528bc54510b0c357daa5cef84 100755 (executable)
--- a/include/instrumentation/syscalls/lttng-syscalls-generate-headers.sh
+++ b/include/instrumentation/syscalls/lttng-syscalls-generate-headers.sh
@@ -6,14 +6,15 @@
 #
 # example usage:
 #
-# lttng-syscalls-generate-headers.sh <type> <input_dir> <input_filename_in_dir> <bitness>
-# lttng-syscalls-generate-headers.sh integers 3.0.4 x86-64-syscalls 64
-# lttng-syscalls-generate-headers.sh pointers 3.0.4 x86-64-syscalls 64
+# lttng-syscalls-generate-headers.sh <type> <input_dir> <input_filename_in_dir> <arch_name> <bitness>
+# lttng-syscalls-generate-headers.sh integers 3.0.4 x86-64-syscalls x86-64 64
+# lttng-syscalls-generate-headers.sh pointers 3.0.4 x86-64-syscalls x86-64 64
 
 CLASS=$1
 VERSIONDIR=$2
 INPUTFILE=$3
-BITNESS=$4
+ARCH_NAME=$4
+BITNESS=$5
 INPUT=${VERSIONDIR}/${INPUTFILE}
 HEADER=headers/${INPUTFILE}_${CLASS}.h
 
@@ -32,6 +33,11 @@ if [ x"$BITNESS" != x"32" ] && [ x"$BITNESS" != x"64" ]; then
        exit 1
 fi
 
+if [ x"$ARCH_NAME" = x"" ]; then
+       echo "Error: Please specify the architecture name as fourth argument" >&2
+       exit 1
+fi
+
 # Abort on error and undefined variable
 set -eu
 
@@ -134,7 +140,7 @@ fi
 NRARGS=1
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
 
        echo Syscall: "${SC_NAME}" "${ARG1}"
 
@@ -157,8 +163,8 @@ done
 NRARGS=2
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
-       ARG2=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 2)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
+       ARG2=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 2)
 
        echo Syscall: "${SC_NAME}" "${ARG1}" "${ARG2}"
 
@@ -181,9 +187,9 @@ done
 NRARGS=3
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
-       ARG2=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 2)
-       ARG3=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 3)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
+       ARG2=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 2)
+       ARG3=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 3)
 
        echo Syscall: "${SC_NAME}" "${ARG1}" "${ARG2}" "${ARG3}"
 
@@ -207,10 +213,10 @@ done
 NRARGS=4
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
-       ARG2=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 2)
-       ARG3=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 3)
-       ARG4=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 4)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
+       ARG2=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 2)
+       ARG3=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 3)
+       ARG4=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 4)
 
        echo Syscall: "${SC_NAME}" "${ARG1}" "${ARG2}" "${ARG3}" "${ARG4}"
 
@@ -233,11 +239,11 @@ done
 NRARGS=5
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
-       ARG2=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 2)
-       ARG3=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 3)
-       ARG4=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 4)
-       ARG5=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 5)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
+       ARG2=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 2)
+       ARG3=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 3)
+       ARG4=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 4)
+       ARG5=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 5)
 
        echo Syscall: "${SC_NAME}" "${ARG1}" "${ARG2}" "${ARG3}" "${ARG4}" "${ARG5}"
 
@@ -261,12 +267,12 @@ done
 NRARGS=6
 grep "^syscall [^ ]* nr [^ ]* nbargs ${NRARGS} " "${SRCFILE}" | while read -r LINE; do
        SC_NAME=$(echo "${LINE}" | perl -p -e 's/^syscall ([^ ]*) .*/$1/g')
-       ARG1=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 1)
-       ARG2=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 2)
-       ARG3=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 3)
-       ARG4=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 4)
-       ARG5=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 5)
-       ARG6=$(./lttng-get-syscall-inout.sh table-syscall-inout.txt "${SC_NAME}" 6)
+       ARG1=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 1)
+       ARG2=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 2)
+       ARG3=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 3)
+       ARG4=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 4)
+       ARG5=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 5)
+       ARG6=$(./lttng-get-syscall-inout.sh "${ARCH_NAME}" "${SC_NAME}" 6)
 
        echo Syscall: "${SC_NAME}" "${ARG1}" "${ARG2}" "${ARG3}" "${ARG4}" "${ARG5}" "${ARG6}"
 

diff --git a/include/instrumentation/syscalls/table-syscall-inout-x86-32-override.txt b/include/instrumentation/syscalls/table-syscall-inout-x86-32-override.txt
new file mode 100644 (file)
index 0000000..4ddb597
--- /dev/null
+++ b/include/instrumentation/syscalls/table-syscall-inout-x86-32-override.txt
@@ -0,0 +1 @@
+syscall fanotify_mark nbargs 6 rw: (r, r, r, r, r, r)