Refactor existing realloc code to use grow_array

The new grow_array function handles realloc failure properly without
leaking the previous array pointer or changing the capacity.

Author: jiegec

lib/lsof.c

@@ -772,8 +772,6 @@ enum lsof_error lsof_select_process_regex(struct lsof_context *ctx, char *x) {
     MALLOC_S xl;
     char *xp = (char *)NULL;
     enum lsof_error ret = LSOF_SUCCESS;
-    lsof_rx_t *new_rx;
-    int new_cmdrx_cap;
 
     if (!ctx || ctx->frozen) {
         return LSOF_ERROR_INVALID_ARGUMENT;
@@ -897,13 +895,7 @@ enum lsof_error lsof_select_process_regex(struct lsof_context *ctx, char *x) {
         /*
          * More CmdRx[] space must be assigned.
          */
-        new_cmdrx_cap = NCmdRxA + 32;
-        xl = (MALLOC_S)(new_cmdrx_cap * sizeof(lsof_rx_t));
-        if (CmdRx)
-            new_rx = (lsof_rx_t *)realloc((MALLOC_P *)CmdRx, xl);
-        else
-            new_rx = (lsof_rx_t *)malloc(xl);
-        if (!new_rx) {
+        if (grow_array((void **)&CmdRx, &NCmdRxA, sizeof(lsof_rx_t), 32)) {
             if (ctx->err) {
                 (void)fprintf(ctx->err, "%s: no space for regexp: ", Pn);
                 safestrprt(x, ctx->err, 1);
@@ -912,8 +904,6 @@ enum lsof_error lsof_select_process_regex(struct lsof_context *ctx, char *x) {
             ret = LSOF_ERROR_NO_MEMORY;
             goto cleanup;
         }
-        CmdRx = new_rx;
-        NCmdRxA = new_cmdrx_cap;
     }
     i = NCmdRxU;
     /*
@@ -977,15 +967,7 @@ enum lsof_error lsof_select_pid_pgid(struct lsof_context *ctx, int32_t id,
      * Allocate table table space.
      */
     if (*size >= *cap) {
-        *cap += 10;
-        if (!(*sel))
-            *sel = (struct int_lst *)malloc(
-                (MALLOC_S)(sizeof(struct int_lst) * (*cap)));
-        else
-            *sel = (struct int_lst *)realloc(
-                (MALLOC_P *)(*sel),
-                (MALLOC_S)(sizeof(struct int_lst) * (*cap)));
-        if (!(*sel)) {
+        if (grow_array((void **)sel, cap, sizeof(struct int_lst), 10)) {
             if (ctx->err) {
                 (void)fprintf(ctx->err, "%s: no space for %d process%s IDs", Pn,
                               *cap, is_pid ? "" : " group");
@@ -1061,13 +1043,7 @@ enum lsof_error lsof_select_uid_login(struct lsof_context *ctx, uint32_t uid,
      * Allocate space for User IDentifier.
      */
     if (Nuid >= Mxuid) {
-        Mxuid += 10;
-        len = (MALLOC_S)(Mxuid * sizeof(struct seluid));
-        if (!Suid)
-            Suid = (struct seluid *)malloc(len);
-        else
-            Suid = (struct seluid *)realloc((MALLOC_P *)Suid, len);
-        if (!Suid) {
+        if (grow_array((void **)&Suid, &Mxuid, sizeof(struct seluid), 10)) {
             if (ctx->err) {
                 (void)fprintf(ctx->err, "%s: no space for UIDs", Pn);
             }

lib/misc.c

@@ -56,7 +56,8 @@ static void closePipes(void);
 static int dolstat(char *path, char *buf, int len);
 static int dostat(char *path, char *buf, int len);
 static int doreadlink(char *path, char *buf, int len);
-static int doinchild(struct lsof_context *ctx, int (*fn)(char *path, char *buf, int len), char *fp,
+static int doinchild(struct lsof_context *ctx,
+                     int (*fn)(char *path, char *buf, int len), char *fp,
                      char *rbuf, int rbln);
 
 #if defined(HASINTSIGNAL)
@@ -259,10 +260,11 @@ void closefrom_shim(struct lsof_context *ctx, int low) {
  */
 
 static int doinchild(struct lsof_context *ctx,
-                     int (*fn)(char *path, char *buf, int len), /* function to perform */
-                     char *fp,    /* function parameter */
-                     char *rbuf,  /* response buffer */
-                     int rbln)    /* response buffer length */
+                     int (*fn)(char *path, char *buf,
+                               int len), /* function to perform */
+                     char *fp,           /* function parameter */
+                     char *rbuf,         /* response buffer */
+                     int rbln)           /* response buffer length */
 {
     int en, rv;
 
@@ -1625,3 +1627,37 @@ char *x2dev(char *s,  /* ASCII string */
     *d = r;
     return (s);
 }
+
+/*
+ * grow_array(): handle dynamic array growth
+ */
+int grow_array(void **array_ptr, int *cap, size_t elem_size, int growth_count) {
+    void *new_array;
+
+    /* Calculate new capacity */
+    int new_capacity = *cap + growth_count;
+    if (new_capacity < 0) {
+        return -1;
+    }
+    size_t new_size = (size_t)new_capacity * elem_size;
+
+    /* Check for overflow */
+    if (new_capacity < 0 || new_size / elem_size != (size_t)new_capacity) {
+        return -1;
+    }
+
+    if (*array_ptr) {
+        new_array = realloc((MALLOC_P *)*array_ptr, (MALLOC_S)new_size);
+    } else {
+        new_array = malloc((MALLOC_S)new_size);
+    }
+
+    if (!new_array) {
+        /* Allocation failed */
+        return -1;
+    }
+
+    *array_ptr = new_array;
+    *cap = new_capacity;
+    return 0;
+}

lib/proto.h

@@ -214,6 +214,8 @@ extern void usage(struct lsof_context *ctx, int err, int fh, int version);
 extern int util_strftime(char *fmtr, int fmtl, char *fmt);
 extern int vfy_dev(struct lsof_context *ctx, struct l_dev *dp);
 extern char *x2dev(char *s, dev_t *d);
+extern int grow_array(void **array_ptr, int *cap, size_t elem_size,
+                      int growth_count);
 
 #    if defined(HASBLKDEV)
 extern void find_bl_ino(struct lsof_context *ctx);