Linux: dynamically adjust the SECATTR column width

SELinux contexts can be quite long; adjust the column width dynamically
at each cycle to the longest value.

Also with the recent addition of multiple screens, over-long columns can
be moved into their own screen.

Process.c

@@ -1252,3 +1252,23 @@ void Process_updateExe(Process* this, const char* exe) {
    }
    this->mergedCommand.exeChanged = true;
 }
+
+uint8_t Process_fieldWidths[LAST_PROCESSFIELD] = { 0 };
+
+void Process_resetFieldWidths() {
+   for (size_t i = 0; i < LAST_PROCESSFIELD; i++) {
+      if (!Process_fields[i].autoWidth)
+         continue;
+
+      size_t len = strlen(Process_fields[i].title);
+      assert(len <= UINT8_MAX);
+      Process_fieldWidths[i] = (uint8_t)len;
+   }
+}
+
+void Process_updateFieldWidth(ProcessField key, size_t width) {
+   if (width > UINT8_MAX)
+      Process_fieldWidths[key] = UINT8_MAX;
+   else if (width > Process_fieldWidths[key])
+      Process_fieldWidths[key] = (uint8_t)width;
+}

Process.h

@@ -279,6 +279,9 @@ typedef struct ProcessFieldData_ {
 
    /* Whether the column should be sorted in descending order by default */
    bool defaultSortDesc;
+
+   /* Whether the column width is dynamically adjusted (the minimum width is determined by the title length) */
+   bool autoWidth;
 } ProcessFieldData;
 
 // Implemented in platform-specific code:
@@ -286,6 +289,7 @@ void Process_writeField(const Process* this, RichString* str, ProcessField field
 int Process_compare(const void* v1, const void* v2);
 void Process_delete(Object* cast);
 extern const ProcessFieldData Process_fields[LAST_PROCESSFIELD];
+extern uint8_t Process_fieldWidths[LAST_PROCESSFIELD];
 #define PROCESS_MIN_PID_DIGITS 5
 #define PROCESS_MAX_PID_DIGITS 19
 #define PROCESS_MIN_UID_DIGITS 5
@@ -406,4 +410,7 @@ void Process_makeCommandStr(Process* this);
 
 void Process_writeCommand(const Process* this, int attr, int baseAttr, RichString* str);
 
+void Process_resetFieldWidths(void);
+void Process_updateFieldWidth(ProcessField key, size_t width);
+
 #endif

ProcessList.c

@@ -114,6 +114,12 @@ static const char* alignedProcessFieldTitle(const ProcessList* this, ProcessFiel
       return titleBuffer;
    }
 
+   if (Process_fields[field].autoWidth) {
+      static char titleBuffer[UINT8_MAX + 1];
+      xSnprintf(titleBuffer, sizeof(titleBuffer), "%-*.*s ", Process_fieldWidths[field], Process_fieldWidths[field], title);
+      return titleBuffer;
+   }
+
    return title;
 }
 
@@ -453,6 +459,7 @@ void ProcessList_scan(ProcessList* this, bool pauseProcessUpdate) {
    this->kernelThreads = 0;
    this->runningTasks = 0;
 
+   Process_resetFieldWidths();
 
    // set scan timestamp
    static bool firstScanDone = false;

linux/LinuxProcess.c

@@ -94,7 +94,7 @@ const ProcessFieldData Process_fields[LAST_PROCESSFIELD] = {
    [M_SWAP] = { .name = "M_SWAP", .title = " SWAP ", .description = "Size of the process's swapped pages", .flags = PROCESS_FLAG_LINUX_SMAPS, .defaultSortDesc = true, },
    [M_PSSWP] = { .name = "M_PSSWP", .title = " PSSWP ", .description = "shows proportional swap share of this mapping, unlike \"Swap\", this does not take into account swapped out page of underlying shmem objects", .flags = PROCESS_FLAG_LINUX_SMAPS, .defaultSortDesc = true, },
    [CTXT] = { .name = "CTXT", .title = " CTXT ", .description = "Context switches (incremental sum of voluntary_ctxt_switches and nonvoluntary_ctxt_switches)", .flags = PROCESS_FLAG_LINUX_CTXT, .defaultSortDesc = true, },
-   [SECATTR] = { .name = "SECATTR", .title = "Security Attribute             ", .description = "Security attribute of the process (e.g. SELinux or AppArmor)", .flags = PROCESS_FLAG_LINUX_SECATTR, },
+   [SECATTR] = { .name = "SECATTR", .title = "Security Attribute", .description = "Security attribute of the process (e.g. SELinux or AppArmor)", .flags = PROCESS_FLAG_LINUX_SECATTR, .autoWidth = true, },
    [PROC_COMM] = { .name = "COMM", .title = "COMM            ", .description = "comm string of the process from /proc/[pid]/comm", .flags = 0, },
    [PROC_EXE] = { .name = "EXE", .title = "EXE             ", .description = "Basename of exe of the process from /proc/[pid]/exe", .flags = 0, },
    [CWD] = { .name = "CWD", .title = "CWD                       ", .description = "The current working directory of the process", .flags = PROCESS_FLAG_CWD, },
@@ -280,7 +280,7 @@ static void LinuxProcess_writeField(const Process* this, RichString* str, Proces
       }
       xSnprintf(buffer, n, "%5lu ", lp->ctxt_diff);
       break;
-   case SECATTR: snprintf(buffer, n, "%-30.30s ", lp->secattr ? lp->secattr : "?"); break;
+   case SECATTR: snprintf(buffer, n, "%-*.*s ", Process_fieldWidths[SECATTR], Process_fieldWidths[SECATTR], lp->secattr ? lp->secattr : "N/A"); break;
    case AUTOGROUP_ID:
       if (lp->autogroup_id != -1) {
          xSnprintf(buffer, n, "%4ld ", lp->autogroup_id);

linux/LinuxProcessList.c

@@ -1029,6 +1029,9 @@ static void LinuxProcessList_readSecattrData(LinuxProcess* process, openat_arg_t
    if (newline) {
       *newline = '\0';
    }
+
+   Process_updateFieldWidth(SECATTR, strlen(buffer));
+
    if (process->secattr && String_eq(process->secattr, buffer)) {
       return;
    }