linux: support for monitoring syscall

Signed-off-by: John Sanpe <sanpeqf@gmail.com>

Author: sanpeqf

linux/LinuxProcess.c

@@ -112,6 +112,7 @@ const ProcessFieldData Process_fields[LAST_PROCESSFIELD] = {
 #endif
    [GPU_TIME] = { .name = "GPU_TIME", .title = "GPU_TIME ", .description = "Total GPU time", .flags = PROCESS_FLAG_LINUX_GPU, .defaultSortDesc = true, },
    [GPU_PERCENT] = { .name = "GPU_PERCENT", .title = " GPU% ", .description = "Percentage of the GPU time the process used in the last sampling", .flags = PROCESS_FLAG_LINUX_GPU, .defaultSortDesc = true, },
+   [SYSCALL] = { .name = "SYSCALL", .title = "SYSCALL", .description = "Current syscall of the process", .flags = PROCESS_FLAG_LINUX_SYSCALL, .autoWidth = true, },
 };
 
 Process* LinuxProcess_new(const Machine* host) {
@@ -362,6 +363,17 @@ static void LinuxProcess_rowWriteField(const Row* super, RichString* str, Proces
          xSnprintf(buffer, n, "N/A  ");
       }
       break;
+   case SYSCALL: {
+      const char* syscall;
+      if (lp->syscall) {
+         syscall = lp->syscall;
+      } else {
+         attr = CRT_colors[PROCESS_SHADOW];
+         syscall = "N/A";
+      }
+      Row_printLeftAlignedField(str, attr, syscall, 8);
+      return;
+   }
    default:
       Process_writeField(this, str, field);
       return;
@@ -466,6 +478,8 @@ static int LinuxProcess_compareByKey(const Process* v1, const Process* v2, Proce
       return SPACESHIP_NUMBER(p1->gpu_time, p2->gpu_time);
    case ISCONTAINER:
       return SPACESHIP_NUMBER(v1->isRunningInContainer, v2->isRunningInContainer);
+   case SYSCALL:
+      return SPACESHIP_NULLSTR(p1->syscall, p2->syscall);
    default:
       return Process_compareByKey_Base(v1, v2, key);
    }

linux/LinuxProcess.h

@@ -31,6 +31,7 @@ in the source distribution for its full text.
 #define PROCESS_FLAG_LINUX_AUTOGROUP 0x00080000
 #define PROCESS_FLAG_LINUX_GPU       0x00100000
 #define PROCESS_FLAG_LINUX_CONTAINER 0x00200000
+#define PROCESS_FLAG_LINUX_SYSCALL   0x00400000
 
 typedef struct LinuxProcess_ {
    Process super;
@@ -118,6 +119,8 @@ typedef struct LinuxProcess_ {
    /* Autogroup scheduling (CFS) information */
    long int autogroup_id;
    int autogroup_nice;
+
+   char *syscall;
 } LinuxProcess;
 
 extern int pageSize;

linux/LinuxProcessTable.c

@@ -1098,6 +1098,33 @@ static void LinuxProcessTable_readCwd(LinuxProcess* process, openat_arg_t procFd
    free_and_xStrdup(&process->super.procCwd, pathBuffer);
 }
 
+/*
+ * Read /proc/<pid>/syscall (process-shared data)
+ */
+static void LinuxProcessTable_readSyscall(LinuxProcess* process, openat_arg_t procFd) {
+   char buffer[PATH_MAX];
+   ssize_t r;
+
+   r = xReadfileat(procFd, "syscall", buffer, sizeof(buffer));
+   if (r <= 0) {
+      free(process->syscall);
+      process->syscall = NULL;
+      return;
+   }
+
+   buffer[r - 1] = '\0';
+
+   char* arg = strchr(buffer, ' ');
+   if (arg) {
+      *arg = '\0';
+   }
+
+   if (process->syscall && String_eq(buffer, process->syscall))
+      return;
+
+   free_and_xStrdup(&process->syscall, buffer);
+}
+
 /*
  * Read /proc/<pid>/exe (process-shared data)
  */
@@ -1694,6 +1721,10 @@ static bool LinuxProcessTable_recurseProcTree(LinuxProcessTable* this, openat_ar
          LinuxProcessTable_readCwd(lp, procFd, mainTask);
       }
 
+      if (ss->flags & PROCESS_FLAG_LINUX_SYSCALL) {
+         LinuxProcessTable_readSyscall(lp, procFd);
+      }
+
       if ((ss->flags & PROCESS_FLAG_LINUX_AUTOGROUP) && this->haveAutogroup) {
          LinuxProcessTable_readAutogroup(lp, procFd, mainTask);
       }

linux/ProcessField.h

@@ -51,6 +51,7 @@ in the source distribution for its full text.
    GPU_TIME = 132,               \
    GPU_PERCENT = 133,            \
    ISCONTAINER = 134,            \
+   SYSCALL = 135,                \
    // End of list