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-rw-r--r--linux-user/main.c12
-rw-r--r--linux-user/signal-common.h2
-rw-r--r--linux-user/signal.c108
-rw-r--r--meson.build3
-rw-r--r--meson_options.txt2
-rw-r--r--scripts/meson-buildoptions.sh2
6 files changed, 106 insertions, 23 deletions
diff --git a/linux-user/main.c b/linux-user/main.c
index 8143a0d4b0..b09af8d436 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -412,6 +412,13 @@ static void handle_arg_reserved_va(const char *arg)
     reserved_va = val ? val - 1 : 0;
 }
 
+static const char *rtsig_map = CONFIG_QEMU_RTSIG_MAP;
+
+static void handle_arg_rtsig_map(const char *arg)
+{
+    rtsig_map = arg;
+}
+
 static void handle_arg_one_insn_per_tb(const char *arg)
 {
     opt_one_insn_per_tb = true;
@@ -494,6 +501,9 @@ static const struct qemu_argument arg_table[] = {
      "address",    "set guest_base address to 'address'"},
     {"R",          "QEMU_RESERVED_VA", true,  handle_arg_reserved_va,
      "size",       "reserve 'size' bytes for guest virtual address space"},
+    {"t",          "QEMU_RTSIG_MAP",   true,  handle_arg_rtsig_map,
+     "tsig hsig n[,...]",
+                   "map target rt signals [tsig,tsig+n) to [hsig,hsig+n]"},
     {"d",          "QEMU_LOG",         true,  handle_arg_log,
      "item[,...]", "enable logging of specified items "
      "(use '-d help' for a list of items)"},
@@ -1002,7 +1012,7 @@ int main(int argc, char **argv, char **envp)
 
     target_set_brk(info->brk);
     syscall_init();
-    signal_init();
+    signal_init(rtsig_map);
 
     /* Now that we've loaded the binary, GUEST_BASE is fixed.  Delay
        generating the prologue until now so that the prologue can take
diff --git a/linux-user/signal-common.h b/linux-user/signal-common.h
index f4cbe6185e..8584d9ecc2 100644
--- a/linux-user/signal-common.h
+++ b/linux-user/signal-common.h
@@ -56,7 +56,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_sigset_t *set, CPUArchState *env);
 
 void process_pending_signals(CPUArchState *cpu_env);
-void signal_init(void);
+void signal_init(const char *rtsig_map);
 void queue_signal(CPUArchState *env, int sig, int si_type,
                   target_siginfo_t *info);
 void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info);
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 63ac2df53b..9b6d772882 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -18,6 +18,7 @@
  */
 #include "qemu/osdep.h"
 #include "qemu/bitops.h"
+#include "qemu/cutils.h"
 #include "gdbstub/user.h"
 #include "exec/page-protection.h"
 #include "hw/core/tcg-cpu-ops.h"
@@ -513,20 +514,81 @@ static int core_dump_signal(int sig)
     }
 }
 
-static void signal_table_init(void)
+static void signal_table_init(const char *rtsig_map)
 {
     int hsig, tsig, count;
 
+    if (rtsig_map) {
+        /*
+         * Map host RT signals to target RT signals according to the
+         * user-provided specification.
+         */
+        const char *s = rtsig_map;
+
+        while (true) {
+            int i;
+
+            if (qemu_strtoi(s, &s, 10, &tsig) || *s++ != ' ') {
+                fprintf(stderr, "Malformed target signal in QEMU_RTSIG_MAP\n");
+                exit(EXIT_FAILURE);
+            }
+            if (qemu_strtoi(s, &s, 10, &hsig) || *s++ != ' ') {
+                fprintf(stderr, "Malformed host signal in QEMU_RTSIG_MAP\n");
+                exit(EXIT_FAILURE);
+            }
+            if (qemu_strtoi(s, &s, 10, &count) || (*s && *s != ',')) {
+                fprintf(stderr, "Malformed signal count in QEMU_RTSIG_MAP\n");
+                exit(EXIT_FAILURE);
+            }
+
+            for (i = 0; i < count; i++, tsig++, hsig++) {
+                if (tsig < TARGET_SIGRTMIN || tsig > TARGET_NSIG) {
+                    fprintf(stderr, "%d is not a target rt signal\n", tsig);
+                    exit(EXIT_FAILURE);
+                }
+                if (hsig < SIGRTMIN || hsig > SIGRTMAX) {
+                    fprintf(stderr, "%d is not a host rt signal\n", hsig);
+                    exit(EXIT_FAILURE);
+                }
+                if (host_to_target_signal_table[hsig]) {
+                    fprintf(stderr, "%d already maps %d\n",
+                            hsig, host_to_target_signal_table[hsig]);
+                    exit(EXIT_FAILURE);
+                }
+                host_to_target_signal_table[hsig] = tsig;
+            }
+
+            if (*s) {
+                s++;
+            } else {
+                break;
+            }
+        }
+    } else {
+        /*
+         * Default host-to-target RT signal mapping.
+         *
+         * Signals are supported starting from TARGET_SIGRTMIN and going up
+         * until we run out of host realtime signals.  Glibc uses the lower 2
+         * RT signals and (hopefully) nobody uses the upper ones.
+         * This is why SIGRTMIN (34) is generally greater than __SIGRTMIN (32).
+         * To fix this properly we would need to do manual signal delivery
+         * multiplexed over a single host signal.
+         * Attempts for configure "missing" signals via sigaction will be
+         * silently ignored.
+         *
+         * Reserve one signal for internal usage (see below).
+         */
+
+        hsig = SIGRTMIN + 1;
+        for (tsig = TARGET_SIGRTMIN;
+             hsig <= SIGRTMAX && tsig <= TARGET_NSIG;
+             hsig++, tsig++) {
+            host_to_target_signal_table[hsig] = tsig;
+        }
+    }
+
     /*
-     * Signals are supported starting from TARGET_SIGRTMIN and going up
-     * until we run out of host realtime signals.  Glibc uses the lower 2
-     * RT signals and (hopefully) nobody uses the upper ones.
-     * This is why SIGRTMIN (34) is generally greater than __SIGRTMIN (32).
-     * To fix this properly we would need to do manual signal delivery
-     * multiplexed over a single host signal.
-     * Attempts for configure "missing" signals via sigaction will be
-     * silently ignored.
-     *
      * Remap the target SIGABRT, so that we can distinguish host abort
      * from guest abort.  When the guest registers a signal handler or
      * calls raise(SIGABRT), the host will raise SIG_RTn.  If the guest
@@ -536,21 +598,27 @@ static void signal_table_init(void)
      * parent sees the correct mapping from wait status.
      */
 
-    hsig = SIGRTMIN;
     host_to_target_signal_table[SIGABRT] = 0;
-    host_to_target_signal_table[hsig++] = TARGET_SIGABRT;
-
-    for (tsig = TARGET_SIGRTMIN;
-         hsig <= SIGRTMAX && tsig <= TARGET_NSIG;
-         hsig++, tsig++) {
-        host_to_target_signal_table[hsig] = tsig;
+    for (hsig = SIGRTMIN; hsig <= SIGRTMAX; hsig++) {
+        if (!host_to_target_signal_table[hsig]) {
+            host_to_target_signal_table[hsig] = TARGET_SIGABRT;
+            break;
+        }
+    }
+    if (hsig > SIGRTMAX) {
+        fprintf(stderr, "No rt signals left for SIGABRT mapping\n");
+        exit(EXIT_FAILURE);
     }
 
     /* Invert the mapping that has already been assigned. */
     for (hsig = 1; hsig < _NSIG; hsig++) {
         tsig = host_to_target_signal_table[hsig];
         if (tsig) {
-            assert(target_to_host_signal_table[tsig] == 0);
+            if (target_to_host_signal_table[tsig]) {
+                fprintf(stderr, "%d is already mapped to %d\n",
+                        tsig, target_to_host_signal_table[tsig]);
+                exit(EXIT_FAILURE);
+            }
             target_to_host_signal_table[tsig] = hsig;
         }
     }
@@ -573,13 +641,13 @@ static void signal_table_init(void)
     trace_signal_table_init(count);
 }
 
-void signal_init(void)
+void signal_init(const char *rtsig_map)
 {
     TaskState *ts = get_task_state(thread_cpu);
     struct sigaction act, oact;
 
     /* initialize signal conversion tables */
-    signal_table_init();
+    signal_table_init(rtsig_map);
 
     /* Set the signal mask from the host mask. */
     sigprocmask(0, 0, &ts->signal_mask);
diff --git a/meson.build b/meson.build
index c386593c52..9fa9d059ff 100644
--- a/meson.build
+++ b/meson.build
@@ -3178,7 +3178,8 @@ foreach target : target_dirs
     config_target += {
       'CONFIG_USER_ONLY': 'y',
       'CONFIG_QEMU_INTERP_PREFIX':
-        get_option('interp_prefix').replace('%M', config_target['TARGET_NAME'])
+        get_option('interp_prefix').replace('%M', config_target['TARGET_NAME']),
+      'CONFIG_QEMU_RTSIG_MAP': get_option('rtsig_map'),
     }
   endif
 
diff --git a/meson_options.txt b/meson_options.txt
index 24bf009056..ac4887a622 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -27,6 +27,8 @@ option('block_drv_ro_whitelist', type : 'string', value : '',
        description: 'set block driver read-only whitelist (by default affects only QEMU, not tools like qemu-img)')
 option('interp_prefix', type : 'string', value : '/usr/gnemul/qemu-%M',
        description: 'where to find shared libraries etc., use %M for cpu name')
+option('rtsig_map', type : 'string', value : 'NULL',
+       description: 'default value of QEMU_RTSIG_MAP')
 option('fuzzing_engine', type : 'string', value : '',
        description: 'fuzzing engine library for OSS-Fuzz')
 option('trace_file', type: 'string', value: 'trace',
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 6f2bb08ecd..51ed46e46a 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -72,6 +72,7 @@ meson_options_help() {
   printf "%s\n" '                           "manufacturer" name for qemu-ga registry entries'
   printf "%s\n" '                           [QEMU]'
   printf "%s\n" '  --qemu-ga-version=VALUE  version number for qemu-ga installer'
+  printf "%s\n" '  --rtsig-map=VALUE        default value of QEMU_RTSIG_MAP [NULL]'
   printf "%s\n" '  --smbd=VALUE             Path to smbd for slirp networking'
   printf "%s\n" '  --sysconfdir=VALUE       Sysconf data directory [etc]'
   printf "%s\n" '  --tls-priority=VALUE     Default TLS protocol/cipher priority string'
@@ -460,6 +461,7 @@ _meson_option_parse() {
     --disable-replication) printf "%s" -Dreplication=disabled ;;
     --enable-rng-none) printf "%s" -Drng_none=true ;;
     --disable-rng-none) printf "%s" -Drng_none=false ;;
+    --rtsig-map=*) quote_sh "-Drtsig_map=$2" ;;
     --enable-rust) printf "%s" -Drust=enabled ;;
     --disable-rust) printf "%s" -Drust=disabled ;;
     --enable-rutabaga-gfx) printf "%s" -Drutabaga_gfx=enabled ;;